Retrospective analysis of coronary angiograms showing myocardial bridging and its clinical manifestations in a specialized center in the Midwest of Brazil

Retrospective analysis of coronary angiograms showing myocardial bridging and its clinical manifestations in a specialized center in the Midwest of Brazil | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Retrospective analysis of coronary angiograms showing myocardial bridging and its clinical manifestations in a specialized center in the Midwest of Brazil Fabio Ridolfi Figueiredo, Alberto Najjar, José Alfredo Sejópoles, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7761739/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Myocardial bridging is a coronary anatomical variation in which a tunneled pathway of the coronary artery is covered by overlapping myocardial muscle fibers. The objective was to relate the angiographic findings of systolic constriction in myocardial bridging pathways with the various clinical presentations of angina in patients at this institution. Methods A retrospective review was performed on a database of diagnostic coronary angiography exams performed from May 2016 to May 2024, which included 15,108 exams. A total of 1,476 patients had myocardial bridging (9.77%), and 178 were selected for our sample. These patients had exclusively myocardial bridging and were free of coronary atherosclerotic obstructions. Results The sample groups were classified according to the degree of systolic compression as mild ( 75%). The sample had a mean age of 57.01 years, with 55.50% women, 61.23% hypertensive, 6.75% diabetic, and 14.60% smokers. Patients in the moderate and severe groups had significantly more episodes of angina pectoris than did those in the mild constriction group. A greater extent of the tunneled segment of the myocardial bridge was associated with anginal symptoms. Conclusion There was an association between anginal symptoms and the degree of systolic constriction and extension in the coronary segments affected by myocardial bridging in the coronary angiography exams analyzed in this study. angina pectoris dyspnea myocardial infarction heart Figures Figure 1 Figure 2 Figure 3 Introduction The myocardial bridge is a coronary anatomical variation defined as an intramyocardial course of an epicardial coronary vessel. It is a benign anomaly of cardiac vascular anatomy that does not normally cause anginal symptoms [ 1 ]. It was described by Reyman in 1737 in autopsy findings and later reported by Portman in 1960 in coronary angiography examinations [ 2 – 5 ]. Most patients diagnosed with myocardial bridging are asymptomatic. However, adrenergic stimuli during physical exertion in this group of patients may favor the occurrence of anginal symptoms [ 3 ]. Anginal chest pain in these patients can occur due to a possible reduction in coronary flow and impaired oxygen supply to the myocardium during contraction of the tunneled coronary artery wall [ 6 ]. A significant proportion of patients with chest pain symptoms are referred for invasive coronary angiography, which reveals varying degrees of systolic constriction in myocardial bridging coronary arteries without significant atheromatous disease [ 3 , 7 ]. Compression of the coronary vessel lumen in the myocardial bridge occurs in the systolic phase, and most of the blood flow in these arteries occurs in the diastolic phase. Thus, it is considered a benign condition and is characterized by a good long-term prognosis [ 8 ]. Myocardial bridges may be related to clinical conditions of myocardial ischemia, which may manifest as angina pectoris or dyspnea and lead to complications such as coronary spasm, arrhythmias, myocardial infarction, and even sudden death [ 9 , 10 ]. Given the complexity of the cardiovascular understanding of this cardiac anomaly, the objective was to relate the angiographic findings of systolic constriction in myocardial bridge pathways to the various clinical presentations of angina in patients. Methods Study design and population A retrospective review was performed on the database of specialized services of diagnostic coronary angiography exams performed between May 2016 and May 2024, among which we sought to identify those that presented myocardial bridging. The keywords “myocardial bridge” or “myocardial bridging” were used, associated with the analysis of dynamic images to filter the results obtained. After applying the inclusion and exclusion criteria, patients with myocardial bridging alone, without associated atherosclerotic obstructions, were selected. The final minimum number of 163 examinations was targeted after prior sample calculation (on the basis of the average frequency in the literature and with a 5% confidence limit). The inclusion criterion was the presence of myocardial bridging in the coronary artery. The exclusion criteria were the presence of associated atherosclerotic obstructions, dilated cardiomyopathy, valvular heart disease, and previous surgical or percutaneous coronary revascularization surgery. Coronary angiography All cardiac catheterization procedures were performed via GE Innova Cath Lab equipment (General Electric Healthcare - USA). The coronary angiography examinations followed the same standards for all patients, including protocols for asepsis, contrast volume, angulation, radiation dosage, and the use of intracoronary nitrates and heparin [11, 12]. Angiographic analysis was performed on the segment that presented the phenomenon of coronary systolic constriction with standardized measurements and gradations. For each angiographic analysis, the following criteria were evaluated: degree of systolic narrowing at the point of greatest lumen reduction, extension of the intramyocardial segment, coronary artery involvement, and location of the constriction. To characterize the location of the constriction within the involved coronary artery, the total arterial length was divided into three thirds: proximal, middle, and distal. To determine the degree of narrowing of the coronary lumen in the systolic phase visualized in the segment affected by the myocardial bridge, the grading system proposed by Noble et al. [13] was used: -Mild degree: 75% systolic narrowing of the coronary lumen Clinical data and medical record analysis The available medical records of all patients included in this study were retrospectively analyzed. Data such as age, sex, hypertension, dyslipidemia, smoking status, and diabetes mellitus status were cataloged. Patients who had undergone previous exercise stress tests were analyzed for positive changes. Cardiovascular symptoms were classified according to the angina pectoris grading recommended by the Canadian Cardiovascular Society (CCS) [14]: -Grade I: Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous, rapid or prolonged exertion at work or recreation. -Grade II: Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, or in cold, or in wind, or under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and under normal conditions. -Grade III: Marked limitation of ordinary physical activity. Walking one or two blocks on level ground and climbing one flight of ordinary stairs under normal conditions and at a normal pace. -Grade IV: Inability to carry out any physical activity without discomfort, and anginal syndrome may be present at rest. Statistical analysis Descriptive analyses were performed, and the results are presented as frequencies and percentages for categorical variables and means and medians for continuous variables. Comparisons between groups were performed via the Kruskal‒Wallis test, followed by Dunn's test with Bonferroni correction [15, 16]. Pearson's chi-square test was used to analyze the associations between categorical variables. Logistic regression analysis was also performed to verify the associations between independent variables. Values of p < 0.05 were considered statistically significant. The analyses were performed via R software version 4.5.1. Results Baseline characteristics Among the 15,108 cardiac catheterization exams in the database, 1,476 presented the phenomenon of myocardial bridging, with a prevalence in our sample of 9.77%. After applying the inclusion and exclusion criteria, 178 examinations were selected that presented exclusively myocardial bridging, without other anatomical changes (Fig. 1 ). The age of the sample ranged from 25–84 years, with a median of 57 years. Among the 178 patients, 55.50% were women, 61.23% were hypertensive, 6.75% were diabetic, and 14.60% were smokers. Sixty-five patients had available exercise stress tests, and 57 had electrocardiographic changes during exercise, as shown in Tables 1 and 2 below. Dyspnea, CCS I angina, CCS II angina, and myocardial infarction were the clinical presentations found. Among those with anginal symptoms, only CCS I and II classifications were specified, as no individual reported symptoms of the other Canadian Cardiovascular Society classes. Table 1 Demographic and clinical data of patients with myocardial bridging Variable Absolute frequency Relative frequency Gender Male 81 45.50% Female 97 55.50% Diabetes Yes 12 6.75% No 166 93.25% Smoking Yes 26 14.6% No 152 85.4% High blood pressure Yes 109 61.23% No 69 38.77% Exercise stress test + Yes 57 32.02% Symptoms Dyspnea 75 42.13% Angina CCS I 63 35.39% Angina CCS II 37 20.79% Myocardial Infarction 3 1.69% Source: Data analyzed from the sample Table 2 Descriptive statistics of the numerical variables Variable Median Minimum Maximum Age 57 25 84 Obstruction (%) 45.25% 18.1% 86.9% Extension (mm) 16.3 5.9 52.7 Source: Analyzed data from the sample Logistic regression revealed that the variables age, sex, smoking status, high blood pressure, and diabetes did not have significant p values. However, the variables length (mm), CCS I angina, and CCS II angina were statistically significant. As shown in Table 3 , the length of the myocardial bridge was significantly related to angina symptoms. According to the model, for every 1 mm of extension of the tunneled segment, there is a 5.9% increase in the chance of the individual being allocated to the moderate/severe group (> 50% obstruction). Individuals with CCS I angina were approximately 4.36 times more likely to be allocated to the moderate/severe group. Individuals with CCS II angina were 7.59 times more likely to be allocated to the moderate/severe group. The Myocardial Infarction variable was not statistically significant, as the confidence interval exceeded the lower limit. Table 3 Odds ratios of the model variables and their respective confidence intervals Variable Odds ratio 95% Confidence Interval Lower Upper Length (mm) 1.0598 1.0137 1.1113 Angina CCS I 4.3653 1.9538 10.2918 Angina CCS II 7.5974 3.0229 20.2269 Myocardial Infarction 10.7467 0.9202 248.3092 Source: Analyzed data from the sample Relationship between the presence of myocardial bridging and symptoms Patients with myocardial bridging were classified into three groups according to the degree of systolic compression of the coronary artery. There were 113 patients in the mild group (degree 75%). No statistically significant differences were found between the groups in terms of age, sex, hypertension, diabetes, smoking, or dyslipidemia. In terms of anatomical characteristics, 100% of the myocardial bridge pathways were restricted to the middle segment of the anterior descending artery. When the Kruskal‒Wallis test was used to verify whether there was any significant difference in the variables of obstruction (%) and age, there was a significant difference in the obstruction (%) variable between the mild, moderate, and severe groups, whereas there was no significant difference in the age variable between the groups (Table 4 ). Table 4 Descriptive statistics for the variables obstruction (%) and age grouped together Variable Classification Median Minimum Maximum Test statistic p value obstruction (%) Mild 39.2% 18.1% 49.0% 17,171 < 0.05* Moderate 58.4% 50.4% 73.8% Severe 78.2% 75.7% 86.9% Age Mild 59 25 84 Moderate 55 30 77 1.8258 0.4014 Serious 63 36 76 * Significant value for 𝝰 = 5% To verify which groups differed from each other in terms of the extension variable (mm), Dunn's test with Bonferroni correction was applied, as shown in Table 5 . A difference was observed in the comparisons: mild × moderate and mild × severe, with a p value < 0.05. However, in the comparison between the moderate and severe groups, there was no significant difference. These data revealed that there was a relationship between the severity of the obstruction and the extent of the myocardial bridge. Table 5 Group comparisons for the variable extent (mm) with Bonferroni correction Comparison Test statistic P value Adjusted p value Mild vs. Moderate 3.37 0.00075 0.00225* Mild vs. Severe 2.91 0.00364 0.01090* Moderate x Severe 1.27 0.20400 0.6120 * Significant value for 𝝰 =5% Figure 2 uses a box plot model that illustrates that the median extension (mm) of the moderate group is 49.98% greater than that of the mild group. In the severe group, it is approximately 99.49% greater than that of individuals classified as mild. To compare categorical data, Pearson's chi-square test was used to verify the existence of a significant association between two variables (the degree of obstruction (%) and angina classification (CCS)). A statistically significant value was found, as shown in Table 6 . Table 6 Descriptive statistics of symptoms grouped by degree of obstruction Symptoms Degree of obstruction Frequency (n) Frequency (%) Dyspnea Mild 64 56.64% Angina CCS I 34 30.09% Angina CCS II 14 12.39% Myocardial infarction 1 0.88% Dyspnea Moderate 11 19.65% Angina CCS I 28 50.00% Angina CCS II 16 28.57% Myocardial Infarction 1 01.78 Dyspnea Severe 0 0 Angina CCS I 1 11.11% Angina CCS II 7 77.77% Myocardial infarction 1 11.11% Test statistics: χ² = 46.636 P value: 0.00049 An analysis of these data revealed that as the degree of myocardial bridge obstruction increased, so did the likelihood of an individual having a higher angina classification (CCS). This data distribution can be visualized graphically in Fig. 3 . Discussion The intramyocardial course of a coronary artery is an anatomical variation that affects a significant proportion of individuals undergoing cardiological investigation to detect causal factors of probable coronary ischemia. Although the vast majority are asymptomatic, a significant number present cardiovascular symptoms such as dyspnea, angina, and arrhythmias [ 10 , 17 ]. This study encompasses a large series of patients with myocardial bridging at a specialized cardiology center in the Brazilian Midwest. A review of the medical literature revealed significant differences between studies with samples from autopsies (15% to 85%) and studies that evaluated coronary angiography (0.5 to 2.5%) [ 8 , 18 ]. The discrepancy in these estimates demonstrates the difficulty of accurately using various diagnostic methods, as well as the lack of clinical research on the subject. In similar comparative studies of this patient population, the frequency of myocardial bridging was 6% with coronary angiography and 30% with computed tomography angiography [ 19 ]. In this sample, the radial arterial access technique was used in 162 patients (91.0%) and was associated with intracoronary infusion of nitrates (nitroglycerin or isosorbide mononitrate) in 100% of the patients. Several published reports have shown an increase in the prevalence of myocardial bridging findings after the advent of universal radial arterial access for angiography [ 14 , 20 ]. In this study, myocardial bridging was found in 9.77% of the cardiac catheterization exams at the institution. These results are similar to the prevalence rates reported in the literature [ 3 , 21 ]. The anterior descending artery is the vessel most commonly affected by the intramyocardial course, with very little involvement of the other coronary arteries [ 7 , 22 ]. The middle segment of the anterior descending artery is the most frequently affected location, ranging from 1–10 mm in depth and 15–25 mm in length [ 7 ]. In this study, after the exclusion criteria were met, 100% involvement of the middle segment of the anterior descending artery was found. Notably, this study exclusively used coronary angiography, unlike other publications that used different associated diagnostic methods, such as computed tomography angiography and magnetic resonance imaging [ 3 , 17 , 23 ]. Myocardial bridges can cause significant systolic compression in some situations, leading to cardiovascular symptoms, usually starting in the fourth decade of life, such as exertional angina, myocardial ischemia, arrhythmias, and even cardiovascular death [ 2 , 3 , 7 ]. The dynamic constriction that occurs in the tunneled segment of the affected coronary artery can reduce not only systolic flow but also initial diastolic flow due to factors such as tachycardia, delayed ventricular relaxation, and arterial spasm phenomena that extend throughout diastole [ 8 ]. Another mechanism that could lead to coronary ischemia is "flow stealing" by the septal branches proximal to the intramyocardial segment, which can be explained by the decrease in perfusion pressure of the septal branches, according to previous studies using invasive diagnostic methods [ 24 , 25 ]. The altered laminar flow pattern observed in the proximal portion of the intramyocardial coronary segment appears to be responsible for the formation of atheromatous plaques [ 26 , 27 ]. In our sample, we did not include coronary arteries affected by atherosclerosis to avoid methodological bias. There is still controversy regarding the pathophysiological significance of the presence of myocardial coronary bridging. Several authors claim that myocardial bridging is benign and may even act as a protective factor for coronary atherosclerosis. However, several recent studies have shown that the presence of myocardial bridging may be associated with coronary ischemia, arrhythmias, and even sudden cardiac death [ 6 , 28 – 30 ]. As in this study, several other authors have demonstrated that the presence of myocardial bridging can cause angina episodes [ 2 , 31 ]. Another study with patients with myocardial bridging reported outcomes of myocardial infarction [ 32 , 33 ]. We found three cases of acute myocardial infarction in our sample, with no statistically significant relationship with the degree of myocardial bridging obstruction. Most myocardial bridge findings in our sample had a mild degree of obstruction (< 50%), but it should be noted that the severity of constriction is dynamic, depending on the hemodynamic factors and medications used. The clinical diagnosis of myocardial bridges should be considered in the cardiological investigation of patients with anginal symptoms. Although it is a coronary malformation, symptoms usually begin after the fourth decade of life [ 3 , 6 ]. In our study, the mean age at angiographic diagnosis was 57.01 years. The pathophysiology of ischemia in patients with myocardial bridging is multifactorial and extends beyond simple systolic compression. Even though compression is predominantly in the systole phase, studies have shown that there is a delay in the increase in luminal diameter during diastole, which could compromise coronary blood flow ([ 3 , 10 , 18 , 34 ]). Some factors may influence the clinical relevance and manifestation of various cardiological symptoms, such as the depth and length of the bridge, increased sympathetic tone, coronary vasospasm, and even proximal atherosclerosis [ 17 , 35 – 37 ]. In a recent study, myocardial bridging was associated with exercise-induced ischemia, even in the absence of atherosclerotic coronary artery disease [ 38 ]. Deeper and longer bridges are more strongly associated with ischemia and symptoms. Superficial bridges tend to be asymptomatic [ 3 , 7 , 10 , 39 ]. In our sample, there was wide variability in the length of the segment affected by the myocardial bridge (median 16.3 mm). Patients with extensive bridges were allocated to the groups with more anginal episodes, with statistical significance. Endothelial dysfunction and the mechanism of coronary vasospasm are related to reduced nitric oxide production. Chronic coronary systolic compression can lead to structural changes in endothelial cells due to changes in vascular hemodynamics in patients with significant myocardial bridging [ 25 , 35 ]. Although the tunneled segment of the coronary artery affected by myocardial bridging is generally free of atherosclerotic plaques, several studies cite high shear stress and changes in three-phase flow in the segment immediately proximal to the bridge as predisposing factors for the formation of atheromatous plaques in this location [ 3 , 7 , 10 ]. Situations such as physical exercise and emotional stress increase the heart rate and myocardial contraction force, increasing compression of the bridge and decreasing diastolic filling time, which can lead to cardiac ischemia [ 1 , 3 , 7 , 10 ]. Patients with significant myocardial bridges may experience angina episodes or dyspnea during strenuous physical exercise [40]. Owing to the single-center and retrospective design, there were methodological limitations in our research. The limited number of angiography exams and the studied population may constitute selection bias. Future multicenter and prospective clinical studies will be necessary to better understand and substantiate the relationship between myocardial bridging and cardiovascular symptoms. In conclusion, the presence of myocardial bridging, even if it angiographically promotes different degrees of coronary constriction, can lead to the appearance of clinical symptoms throughout life for multiple reasons and transient hemodynamic changes [ 10 , 34 , 41 ]. Conclusion There was an association between anginal symptoms and the degree of systolic constriction and extension in the coronary segments affected by myocardial bridging in the coronary angiography exams analyzed in this study. Declarations Conflict of interest The authors declare that they have no conflict of interest. Credit authorship contribution statement FRF collected the study data, wrote the final manuscript, and prepared the figures and tables. FFBL, AN, JAS, SMJr, and RCC reviewed the final manuscript. MNP and CPOB performed the statistical analysis and reviewed the final manuscript. All the authors have read and approved the final manuscript. Ethics approval: This project was submitted for review and approved by the Health Ethics Committee of the Federal University of Mato Grosso under No. 6,845,417, filed through the Plataforma Brazil. The study was conducted in accordance with the standards of the Declaration of Helsinki. Informed Consent: Given the retrospective design, the requirement for informed consent was waived. Data Availability The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request. Funding The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Author Contribution FRF collected the study data, wrote the final manuscript, and prepared the figures and tables. FFBL, AN, JAS, SMJr, and RCC reviewed the final manuscript. MNP and CPOB performed the statistical analysis and reviewed the final manuscript. All the authors have read and approved the final manuscript. Acknowledgments None. References Rogers IS, Tremmel JA, Schnittger I (2017) Myocardial bridges: Overview of diagnosis and management. Congenit Heart Dis 12(5):619–623. https://doi.org/10.1111/chd.12499 Matta A, Roncalli J, Carrié D (2024) Update review on myocardial bridging: New insights. Trends Cardiovasc Med 34(1):10–15. https://doi.org/10.1016/j.tcm.2022.06.002 Sternheim D, Power DA, Samtani R, Kini A, Fuster V, Sharma S (2021) Myocardial bridging: Diagnosis, functional assessment, and management: JACC state-of-the-art review. J Am Coll Cardiol 78(22):2196–2212. https://doi.org/10.1016/j.jacc.2021.09.859 Reyman HC Disertatio de vasis cordis propriis. 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Korean J Radiol 11(5):514–521. https://doi.org/10.3348/kjr.2010.11.5.514 Zerbo S, Lanzarone A, Raimondi M, Martino LD, Malta G, Cappello F, Argo A (2020) Myocardial bridge pathology and preventable accidents during physical activity of healthy subjects: A case report and a literature review. Med Leg J 88(4):209–214. https://doi.org/10.1177/0025817220923638 Freiling TP, Dhawan R, Balkhy HH, Castillo J, Cotter EK, Chaney MA (2022) Myocardial bridge: Diagnosis, treatment, and challenges. J Cardiothorac Vasc Anesth 36(10):3955–3963. https://doi.org/10.1053/j.jvca.2022.06.024 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7761739","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":533912481,"identity":"dc800b4f-5fa7-4476-b8ef-8ba4dd467142","order_by":0,"name":"Fabio Ridolfi Figueiredo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8klEQVRIie3PsarCMBTG8RMydIl0jYOPIAhC8ULFB3GpS12sTyASEeokrvoWTuJwh1MO3ElxddTFSaSObqaKIBfS4uaQ/1j6y8cBsNm+MEcJQADJlMMOeFXZNzbCPCLwRTivJQsFUhNVSB4vZ4SXHgQgnzjbBK+/jcqMc0bNtT+sTkivDPy2kYh+kMxPsr4Yc6BoE0pv09HkL4yUgbSgVyOBsrMkFymKSXqoCVNkJMI9v4he+cnI7lhAZO+NsIzsi1bkRd+Cz1uSaRyWV3u9EuTcItyI0hSHlZkz5ukt9l1v1z0e0oFvJIaCz3632Ww227/uN5tl60jhICcAAAAASUVORK5CYII=","orcid":"","institution":"Federal University of Mato Grosso - MT","correspondingAuthor":true,"prefix":"","firstName":"Fabio","middleName":"Ridolfi","lastName":"Figueiredo","suffix":""},{"id":533912482,"identity":"21a15d15-74a7-4c30-9ab8-7a3f485f16e7","order_by":1,"name":"Alberto Najjar","email":"","orcid":"","institution":"LACIC – MT","correspondingAuthor":false,"prefix":"","firstName":"Alberto","middleName":"","lastName":"Najjar","suffix":""},{"id":533912483,"identity":"65edd8f1-1c9b-4919-a060-db495687960a","order_by":2,"name":"José Alfredo Sejópoles","email":"","orcid":"","institution":"LACIC – MT","correspondingAuthor":false,"prefix":"","firstName":"José","middleName":"Alfredo","lastName":"Sejópoles","suffix":""},{"id":533912484,"identity":"5fb9b91e-c4db-4663-9e90-7983471aae72","order_by":3,"name":"Sidney Munhoz Jr","email":"","orcid":"","institution":"LACIC – MT","correspondingAuthor":false,"prefix":"","firstName":"Sidney","middleName":"","lastName":"Munhoz","suffix":"Jr"},{"id":533912485,"identity":"ed942ac1-72a6-4666-a775-2bcf1e33ea12","order_by":4,"name":"Reynerr C. 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16:13:14","extension":"xml","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":116822,"visible":true,"origin":"","legend":"","description":"","filename":"a0653b1fcef74bf9948963d3ae3e230b1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/8dcdb8ab0d7a4b7aed6d72a4.xml"},{"id":94481543,"identity":"2071025b-633a-4ca8-9d68-38247a7f3a76","added_by":"auto","created_at":"2025-10-27 16:13:39","extension":"html","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":128146,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/2c22f6eb09f24bf05d66de78.html"},{"id":94481288,"identity":"303300a2-468b-428b-a83e-69e0b1520dbb","added_by":"auto","created_at":"2025-10-27 16:13:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":97521,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of the selection process\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/ced1dc741d8457a9f1f97029.png"},{"id":94481396,"identity":"fbfd1786-22fb-42e0-8f30-69f4c1e82f15","added_by":"auto","created_at":"2025-10-27 16:13:14","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":166854,"visible":true,"origin":"","legend":"\u003cp\u003eBox plot for the variables extension (mm) and age grouped by angina classification\u003c/p\u003e\n\u003cp\u003eSource: Analyzed data from the sample\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/1a3e498d54b9344b69167de0.jpeg"},{"id":94480939,"identity":"710538d2-8d0a-486b-b1a8-9d39505d2be1","added_by":"auto","created_at":"2025-10-27 16:12:16","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":35024,"visible":true,"origin":"","legend":"\u003cp\u003eBar chart for the angina classification variable, stacked by degree of obstruction\u003c/p\u003e\n\u003cp\u003eSource: Analyzed data from the sample\u003c/p\u003e","description":"","filename":"floatimage316.png","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/cf86177365b4cf1be2e4cf59.png"},{"id":100359607,"identity":"20566ed9-143f-4b8b-9fd0-df97f235bfcf","added_by":"auto","created_at":"2026-01-16 07:23:47","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1319253,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7761739/v1/d7f53402-d0f1-40ee-b648-2701e4c953f3.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Retrospective analysis of coronary angiograms showing myocardial bridging and its clinical manifestations in a specialized center in the Midwest of Brazil","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThe myocardial bridge is a coronary anatomical variation defined as an intramyocardial course of an epicardial coronary vessel. It is a benign anomaly of cardiac vascular anatomy that does not normally cause anginal symptoms [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It was described by Reyman in 1737 in autopsy findings and later reported by Portman in 1960 in coronary angiography examinations [\u003cspan additionalcitationids=\"CR3 CR4\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Most patients diagnosed with myocardial bridging are asymptomatic. However, adrenergic stimuli during physical exertion in this group of patients may favor the occurrence of anginal symptoms [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAnginal chest pain in these patients can occur due to a possible reduction in coronary flow and impaired oxygen supply to the myocardium during contraction of the tunneled coronary artery wall [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. A significant proportion of patients with chest pain symptoms are referred for invasive coronary angiography, which reveals varying degrees of systolic constriction in myocardial bridging coronary arteries without significant atheromatous disease [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eCompression of the coronary vessel lumen in the myocardial bridge occurs in the systolic phase, and most of the blood flow in these arteries occurs in the diastolic phase. Thus, it is considered a benign condition and is characterized by a good long-term prognosis [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Myocardial bridges may be related to clinical conditions of myocardial ischemia, which may manifest as angina pectoris or dyspnea and lead to complications such as coronary spasm, arrhythmias, myocardial infarction, and even sudden death [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eGiven the complexity of the cardiovascular understanding of this cardiac anomaly, the objective was to relate the angiographic findings of systolic constriction in myocardial bridge pathways to the various clinical presentations of angina in patients.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStudy design and population\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA retrospective review was performed on the database of specialized services of diagnostic coronary angiography exams performed between May 2016 and May 2024, among which we sought to identify those that presented myocardial bridging. The keywords \u0026ldquo;myocardial bridge\u0026rdquo; or \u0026ldquo;myocardial bridging\u0026rdquo; were used, associated with the analysis of dynamic images to filter the results obtained. After applying the inclusion and exclusion criteria, patients with myocardial bridging alone, without associated atherosclerotic obstructions, were selected. The final minimum number of 163 examinations was targeted after prior sample calculation (on the basis of the average frequency in the literature and with a 5% confidence limit). The inclusion criterion was the presence of myocardial bridging in the coronary artery. The exclusion criteria were the presence of associated atherosclerotic obstructions, dilated cardiomyopathy, valvular heart disease, and previous surgical or percutaneous coronary revascularization surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eCoronary angiography\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll cardiac catheterization procedures were performed via GE Innova Cath Lab equipment (General Electric Healthcare - USA). The coronary angiography examinations followed the same standards for all patients, including protocols for asepsis, contrast volume, angulation, radiation dosage, and the use of intracoronary nitrates and heparin [11, 12]. Angiographic analysis was performed on the segment that presented the phenomenon of coronary systolic constriction with standardized measurements and gradations.\u003c/p\u003e\n\u003cp\u003eFor each angiographic analysis, the following criteria were evaluated: degree of systolic narrowing at the point of greatest lumen reduction, extension of the intramyocardial segment, coronary artery involvement, and location of the constriction.\u003c/p\u003e\n\u003cp\u003eTo characterize the location of the constriction within the involved coronary artery, the total arterial length was divided into three thirds: proximal, middle, and distal.\u003c/p\u003e\n\u003cp\u003eTo determine the degree of narrowing of the coronary lumen in the systolic phase visualized in the segment affected by the myocardial bridge, the grading system proposed by Noble et al.\u0026nbsp;[13] was used:\u003c/p\u003e\n\u003cp\u003e-Mild degree: \u0026lt;50% systolic narrowing of the coronary lumen\u003c/p\u003e\n\u003cp\u003e-Moderate degree: Systolic narrowing of the lumen between 50% and 75%\u003c/p\u003e\n\u003cp\u003e-Severe degree: \u0026gt;75% systolic narrowing of the coronary lumen\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eClinical data and medical record analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe available medical records of all patients included in this study were retrospectively analyzed.\u003c/p\u003e\n\u003cp\u003eData such as age, sex, hypertension, dyslipidemia, smoking status, and diabetes mellitus status were cataloged.\u003c/p\u003e\n\u003cp\u003ePatients who had undergone previous exercise stress tests were analyzed for positive changes.\u003c/p\u003e\n\u003cp\u003eCardiovascular symptoms were classified according to the angina pectoris grading recommended by the Canadian Cardiovascular Society (CCS) [14]:\u003c/p\u003e\n\u003cp\u003e-Grade I: Ordinary physical activity, such as walking and climbing stairs, does not cause angina. Angina with strenuous, rapid or prolonged exertion at work or recreation.\u003c/p\u003e\n\u003cp\u003e-Grade II: Slight limitation of ordinary activity. Walking or climbing stairs rapidly, walking uphill, walking or stair climbing after meals, or in cold, or in wind, or under emotional stress, or only during the few hours after awakening. Walking more than two blocks on the level and climbing more than one flight of ordinary stairs at a normal pace and under normal conditions.\u003c/p\u003e\n\u003cp\u003e-Grade III: Marked limitation of ordinary physical activity. Walking one or two blocks on level ground and climbing one flight of ordinary stairs under normal conditions and at a normal pace.\u003c/p\u003e\n\u003cp\u003e-Grade IV: Inability to carry out any physical activity without discomfort, and anginal syndrome may be present at rest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e\u003cem\u003eStatistical analysis\u003c/em\u003e\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDescriptive analyses were performed, and the results are presented as frequencies and percentages for categorical variables and means and medians for continuous variables. Comparisons between groups were performed via the Kruskal‒Wallis test, followed by Dunn\u0026apos;s test with Bonferroni correction [15, 16]. Pearson\u0026apos;s chi-square test was used to analyze the associations between categorical variables. Logistic regression analysis was also performed to verify the associations between independent variables. Values of p \u0026lt; 0.05 were considered statistically significant. The analyses were performed via R software version 4.5.1.\u003c/p\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eBaseline characteristics\u003c/h2\u003e\u003cp\u003eAmong the 15,108 cardiac catheterization exams in the database, 1,476 presented the phenomenon of myocardial bridging, with a prevalence in our sample of 9.77%.\u003c/p\u003e\u003cp\u003eAfter applying the inclusion and exclusion criteria, 178 examinations were selected that presented exclusively myocardial bridging, without other anatomical changes (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). The age of the sample ranged from 25\u0026ndash;84 years, with a median of 57 years. Among the 178 patients, 55.50% were women, 61.23% were hypertensive, 6.75% were diabetic, and 14.60% were smokers. Sixty-five patients had available exercise stress tests, and 57 had electrocardiographic changes during exercise, as shown in Tables\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and \u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e below. Dyspnea, CCS I angina, CCS II angina, and myocardial infarction were the clinical presentations found. Among those with anginal symptoms, only CCS I and II classifications were specified, as no individual reported symptoms of the other Canadian Cardiovascular Society classes.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDemographic and clinical data of patients with myocardial bridging\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAbsolute frequency\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eRelative frequency\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGender\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e45.50%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFemale\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e97\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e55.50%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDiabetes\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e6.75%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e166\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e93.25%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSmoking\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e14.6%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e152\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e85.4%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eHigh blood pressure\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e109\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e61.23%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eNo\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e69\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e38.77%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eExercise stress test +\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eYes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e32.02%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eSymptoms\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDyspnea\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e75\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e42.13%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAngina CCS I\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e35.39%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eAngina CCS II\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e20.79%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMyocardial Infarction\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.69%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eSource: Data analyzed from the sample\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDescriptive statistics of the numerical variables\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMedian\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMinimum\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMaximum\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e57\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e84\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eObstruction (%)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e45.25%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18.1%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e86.9%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eExtension (mm)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e16.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e52.7\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eSource: Analyzed data from the sample\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eLogistic regression revealed that the variables age, sex, smoking status, high blood pressure, and diabetes did not have significant p values. However, the variables length (mm), CCS I angina, and CCS II angina were statistically significant. As shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e, the length of the myocardial bridge was significantly related to angina symptoms. According to the model, for every 1 mm of extension of the tunneled segment, there is a 5.9% increase in the chance of the individual being allocated to the moderate/severe group (\u0026gt;\u0026thinsp;50% obstruction). Individuals with CCS I angina were approximately 4.36 times more likely to be allocated to the moderate/severe group. Individuals with CCS II angina were 7.59 times more likely to be allocated to the moderate/severe group. The Myocardial Infarction variable was not statistically significant, as the confidence interval exceeded the lower limit.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eOdds ratios of the model variables and their respective confidence intervals\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOdds ratio\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e\u003cp\u003e95% Confidence Interval\u003c/p\u003e\u003cp\u003eLower Upper\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eLength (mm)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.0598\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.0137\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e1.1113\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS I\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e4.3653\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1.9538\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e10.2918\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS II\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e7.5974\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e3.0229\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e20.2269\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMyocardial Infarction\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e10.7467\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.9202\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e248.3092\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eSource: Analyzed data from the sample\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eRelationship between the presence of myocardial bridging and symptoms\u003c/h3\u003e\n\u003cp\u003ePatients with myocardial bridging were classified into three groups according to the degree of systolic compression of the coronary artery. There were 113 patients in the mild group (degree\u0026thinsp;\u0026lt;\u0026thinsp;50%), 56 patients in the moderate group (degree between 50% and 75%), and 9 patients in the severe group (degree\u0026thinsp;\u0026gt;\u0026thinsp;75%). No statistically significant differences were found between the groups in terms of age, sex, hypertension, diabetes, smoking, or dyslipidemia.\u003c/p\u003e\u003cp\u003eIn terms of anatomical characteristics, 100% of the myocardial bridge pathways were restricted to the middle segment of the anterior descending artery.\u003c/p\u003e\u003cp\u003eWhen the Kruskal‒Wallis test was used to verify whether there was any significant difference in the variables of obstruction (%) and age, there was a significant difference in the obstruction (%) variable between the mild, moderate, and severe groups, whereas there was no significant difference in the age variable between the groups (Table\u0026nbsp;\u003cspan refid=\"Tab4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDescriptive statistics for the variables obstruction (%) and age grouped together\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"7\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eClassification\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMedian\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eMinimum\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eMaximum\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eTest statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003ep value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u003cb\u003eobstruction (%)\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e18.1%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e49.0%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e17,171\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u0026lt;\u0026thinsp;0.05*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e58.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e50.4%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e73.8%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSevere\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e78.2%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e75.7%\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e86.9%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003e\u003cb\u003eAge\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eMild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e59\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e25\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e30\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e77\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1.8258\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.4014\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSerious\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e63\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e76\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"7\"\u003e* Significant value for \u0026#120688; = 5%\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eTo verify which groups differed from each other in terms of the extension variable (mm), Dunn's test with Bonferroni correction was applied, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e5\u003c/span\u003e. A difference was observed in the comparisons: mild \u0026times; moderate and mild \u0026times; severe, with a p value\u0026thinsp;\u0026lt;\u0026thinsp;0.05. However, in the comparison between the moderate and severe groups, there was no significant difference. These data revealed that there was a relationship between the severity of the obstruction and the extent of the myocardial bridge.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 5\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eGroup comparisons for the variable extent (mm) with Bonferroni correction\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComparison\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eTest statistic\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eP value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eAdjusted p value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMild vs. Moderate\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e3.37\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.00075\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.00225*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMild vs. Severe\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e2.91\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.00364\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.01090*\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eModerate x Severe\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e1.27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0.20400\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.6120\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003e* Significant value for \u0026#120688; =5%\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e uses a box plot model that illustrates that the median extension (mm) of the moderate group is 49.98% greater than that of the mild group. In the severe group, it is approximately 99.49% greater than that of individuals classified as mild.\u003c/p\u003e\u003cp\u003eTo compare categorical data, Pearson's chi-square test was used to verify the existence of a significant association between two variables (the degree of obstruction (%) and angina classification (CCS)). A statistically significant value was found, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab6\" class=\"InternalRef\"\u003e6\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab6\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 6\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eDescriptive statistics of symptoms grouped by degree of obstruction\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSymptoms\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eDegree of obstruction\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eFrequency (n)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eFrequency (%)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDyspnea\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eMild\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e64\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e56.64%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS I\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e34\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e30.09%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS II\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e12.39%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMyocardial infarction\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.88%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDyspnea\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eModerate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19.65%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS I\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e28\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e50.00%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS II\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e16\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e28.57%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMyocardial Infarction\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e01.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDyspnea\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"3\" rowspan=\"4\"\u003e\u003cp\u003eSevere\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS I\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11.11%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eAngina CCS II\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e77.77%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eMyocardial infarction\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e11.11%\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eTest statistics: χ\u0026sup2; = 46.636\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd colspan=\"4\"\u003eP value: 0.00049\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eAn analysis of these data revealed that as the degree of myocardial bridge obstruction increased, so did the likelihood of an individual having a higher angina classification (CCS). This data distribution can be visualized graphically in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe intramyocardial course of a coronary artery is an anatomical variation that affects a significant proportion of individuals undergoing cardiological investigation to detect causal factors of probable coronary ischemia. Although the vast majority are asymptomatic, a significant number present cardiovascular symptoms such as dyspnea, angina, and arrhythmias [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThis study encompasses a large series of patients with myocardial bridging at a specialized cardiology center in the Brazilian Midwest.\u003c/p\u003e\u003cp\u003eA review of the medical literature revealed significant differences between studies with samples from autopsies (15% to 85%) and studies that evaluated coronary angiography (0.5 to 2.5%) [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The discrepancy in these estimates demonstrates the difficulty of accurately using various diagnostic methods, as well as the lack of clinical research on the subject. In similar comparative studies of this patient population, the frequency of myocardial bridging was 6% with coronary angiography and 30% with computed tomography angiography [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn this sample, the radial arterial access technique was used in 162 patients (91.0%) and was associated with intracoronary infusion of nitrates (nitroglycerin or isosorbide mononitrate) in 100% of the patients. Several published reports have shown an increase in the prevalence of myocardial bridging findings after the advent of universal radial arterial access for angiography [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In this study, myocardial bridging was found in 9.77% of the cardiac catheterization exams at the institution. These results are similar to the prevalence rates reported in the literature [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe anterior descending artery is the vessel most commonly affected by the intramyocardial course, with very little involvement of the other coronary arteries [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The middle segment of the anterior descending artery is the most frequently affected location, ranging from 1\u0026ndash;10 mm in depth and 15\u0026ndash;25 mm in length [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. In this study, after the exclusion criteria were met, 100% involvement of the middle segment of the anterior descending artery was found. Notably, this study exclusively used coronary angiography, unlike other publications that used different associated diagnostic methods, such as computed tomography angiography and magnetic resonance imaging [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eMyocardial bridges can cause significant systolic compression in some situations, leading to cardiovascular symptoms, usually starting in the fourth decade of life, such as exertional angina, myocardial ischemia, arrhythmias, and even cardiovascular death [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe dynamic constriction that occurs in the tunneled segment of the affected coronary artery can reduce not only systolic flow but also initial diastolic flow due to factors such as tachycardia, delayed ventricular relaxation, and arterial spasm phenomena that extend throughout diastole [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAnother mechanism that could lead to coronary ischemia is \"flow stealing\" by the septal branches proximal to the intramyocardial segment, which can be explained by the decrease in perfusion pressure of the septal branches, according to previous studies using invasive diagnostic methods [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThe altered laminar flow pattern observed in the proximal portion of the intramyocardial coronary segment appears to be responsible for the formation of atheromatous plaques [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In our sample, we did not include coronary arteries affected by atherosclerosis to avoid methodological bias.\u003c/p\u003e\u003cp\u003eThere is still controversy regarding the pathophysiological significance of the presence of myocardial coronary bridging. Several authors claim that myocardial bridging is benign and may even act as a protective factor for coronary atherosclerosis. However, several recent studies have shown that the presence of myocardial bridging may be associated with coronary ischemia, arrhythmias, and even sudden cardiac death [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR29\" citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAs in this study, several other authors have demonstrated that the presence of myocardial bridging can cause angina episodes [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. Another study with patients with myocardial bridging reported outcomes of myocardial infarction [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. We found three cases of acute myocardial infarction in our sample, with no statistically significant relationship with the degree of myocardial bridging obstruction.\u003c/p\u003e\u003cp\u003eMost myocardial bridge findings in our sample had a mild degree of obstruction (\u0026lt;\u0026thinsp;50%), but it should be noted that the severity of constriction is dynamic, depending on the hemodynamic factors and medications used.\u003c/p\u003e\u003cp\u003eThe clinical diagnosis of myocardial bridges should be considered in the cardiological investigation of patients with anginal symptoms. Although it is a coronary malformation, symptoms usually begin after the fourth decade of life [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In our study, the mean age at angiographic diagnosis was 57.01 years.\u003c/p\u003e\u003cp\u003eThe pathophysiology of ischemia in patients with myocardial bridging is multifactorial and extends beyond simple systolic compression. Even though compression is predominantly in the systole phase, studies have shown that there is a delay in the increase in luminal diameter during diastole, which could compromise coronary blood flow ([\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]).\u003c/p\u003e\u003cp\u003eSome factors may influence the clinical relevance and manifestation of various cardiological symptoms, such as the depth and length of the bridge, increased sympathetic tone, coronary vasospasm, and even proximal atherosclerosis [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eIn a recent study, myocardial bridging was associated with exercise-induced ischemia, even in the absence of atherosclerotic coronary artery disease [\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. Deeper and longer bridges are more strongly associated with ischemia and symptoms. Superficial bridges tend to be asymptomatic [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e]. In our sample, there was wide variability in the length of the segment affected by the myocardial bridge (median 16.3 mm). Patients with extensive bridges were allocated to the groups with more anginal episodes, with statistical significance.\u003c/p\u003e\u003cp\u003eEndothelial dysfunction and the mechanism of coronary vasospasm are related to reduced nitric oxide production. Chronic coronary systolic compression can lead to structural changes in endothelial cells due to changes in vascular hemodynamics in patients with significant myocardial bridging [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eAlthough the tunneled segment of the coronary artery affected by myocardial bridging is generally free of atherosclerotic plaques, several studies cite high shear stress and changes in three-phase flow in the segment immediately proximal to the bridge as predisposing factors for the formation of atheromatous plaques in this location [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eSituations such as physical exercise and emotional stress increase the heart rate and myocardial contraction force, increasing compression of the bridge and decreasing diastolic filling time, which can lead to cardiac ischemia [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Patients with significant myocardial bridges may experience angina episodes or dyspnea during strenuous physical exercise [40].\u003c/p\u003e\u003cp\u003eOwing to the single-center and retrospective design, there were methodological limitations in our research. The limited number of angiography exams and the studied population may constitute selection bias. Future multicenter and prospective clinical studies will be necessary to better understand and substantiate the relationship between myocardial bridging and cardiovascular symptoms.\u003c/p\u003e\u003cp\u003eIn conclusion, the presence of myocardial bridging, even if it angiographically promotes different degrees of coronary constriction, can lead to the appearance of clinical symptoms throughout life for multiple reasons and transient hemodynamic changes [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e41\u003c/span\u003e].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThere was an association between anginal symptoms and the degree of systolic constriction and extension in the coronary segments affected by myocardial bridging in the coronary angiography exams analyzed in this study.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCredit authorship contribution statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFRF collected the study data, wrote the final manuscript, and prepared the figures and tables. FFBL, AN, JAS, SMJr, and RCC reviewed the final manuscript. MNP and CPOB performed the statistical analysis and reviewed the final manuscript. All the authors have read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis project was submitted for review and approved by the Health Ethics Committee of the Federal University of Mato Grosso under No. 6,845,417, filed through the Plataforma Brazil. The study was conducted in accordance with the standards of the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eGiven the retrospective design, the requirement for informed consent was waived.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003ch2\u003eFunding\u003c/h2\u003e\n\u003cp\u003eThe authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\n\u003cp\u003eFRF collected the study data, wrote the final manuscript, and prepared the figures and tables. FFBL, AN, JAS, SMJr, and RCC reviewed the final manuscript. MNP and CPOB performed the statistical analysis and reviewed the final manuscript. All the authors have read and approved the final manuscript.\u003c/p\u003e\n\u003ch2\u003eAcknowledgments\u003c/h2\u003e\n\u003cp\u003eNone.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRogers IS, Tremmel JA, Schnittger I (2017) Myocardial bridges: Overview of diagnosis and management. Congenit Heart Dis 12(5):619\u0026ndash;623. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1111/chd.12499\u003c/span\u003e\u003cspan address=\"10.1111/chd.12499\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMatta A, Roncalli J, Carri\u0026eacute; D (2024) Update review on myocardial bridging: New insights. 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J Cardiothorac Vasc Anesth 36(10):3955\u0026ndash;3963. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1053/j.jvca.2022.06.024\u003c/span\u003e\u003cspan address=\"10.1053/j.jvca.2022.06.024\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"angina pectoris, dyspnea, myocardial infarction, heart","lastPublishedDoi":"10.21203/rs.3.rs-7761739/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7761739/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e\u003cp\u003eMyocardial bridging is a coronary anatomical variation in which a tunneled pathway of the coronary artery is covered by overlapping myocardial muscle fibers. The objective was to relate the angiographic findings of systolic constriction in myocardial bridging pathways with the various clinical presentations of angina in patients at this institution.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eA retrospective review was performed on a database of diagnostic coronary angiography exams performed from May 2016 to May 2024, which included 15,108 exams. A total of 1,476 patients had myocardial bridging (9.77%), and 178 were selected for our sample. These patients had exclusively myocardial bridging and were free of coronary atherosclerotic obstructions.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eThe sample groups were classified according to the degree of systolic compression as mild (\u0026lt;\u0026thinsp;50%), moderate (50% to 75%), or severe (\u0026gt;\u0026thinsp;75%). The sample had a mean age of 57.01 years, with 55.50% women, 61.23% hypertensive, 6.75% diabetic, and 14.60% smokers. Patients in the moderate and severe groups had significantly more episodes of angina pectoris than did those in the mild constriction group. A greater extent of the tunneled segment of the myocardial bridge was associated with anginal symptoms.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e\u003cp\u003eThere was an association between anginal symptoms and the degree of systolic constriction and extension in the coronary segments affected by myocardial bridging in the coronary angiography exams analyzed in this study.\u003c/p\u003e","manuscriptTitle":"Retrospective analysis of coronary angiograms showing myocardial bridging and its clinical manifestations in a specialized center in the Midwest of Brazil","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-27 15:25:08","doi":"10.21203/rs.3.rs-7761739/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f28a8fca-03da-4992-8b03-3a46be533896","owner":[],"postedDate":"October 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-09T23:08:30+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-27 15:25:08","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7761739","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7761739","identity":"rs-7761739","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}