Effect of 3D-Printed Hearts Used in Left Ventricular Outflow Tract Obstruction: A Multicenter Study

Effect of 3D-Printed Hearts Used in Left Ventricular Outflow Tract Obstruction: A Multicenter Study | 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 Effect of 3D-Printed Hearts Used in Left Ventricular Outflow Tract Obstruction: A Multicenter Study Xianzhi Wang, Jixiang Liang, Cunfu Mu, Wenlin Zhang, Chunzhu Xue, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1206928/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 8 You are reading this latest preprint version Abstract Objective: The purpose of this research was to explore the application value of a three-dimensional (3D)-printed heart in the operation for left ventricular outflow tract (LVOT) obstruction. Methods: From August 2019 to October 2021, 46 patients with LVOT obstruction underwent surgical treatment at Peking University International Hospital, Southwest Medical University Affiliated Hospital of Traditional Chinese Medicine and Guangyuan First People's Hospital. According to the treatment method, 22 cases were allocated to the experimental group and 24 cases to the control group . The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, postoperative ejection fraction (EF), left ventricular flow velocity (LVFV), LVOT pressure difference (LVP), postoperative interventricular septal thickness (IST), inner diameter of the left ventricular outflow tract (IDLV), systolic anterior motion (SAM), atrioventricular block rate, aortic regurgitation (AR) rate and surgical complication rate of the two groups were compared. Results: The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, LVP, postoperative IST, AR, SAM, and postoperative LVFV of the experimental group were significantly lower than those of the control group (P < 0.05). The IDLV was larger than that of the control group (P 0.05). Conclusion: A 3D-printed heart model for in vitro simulation surgery is conducive to formulating a more reasonable surgical plan and reducing surgical trauma and operation time, thereby promoting the recovery and maintenance of the heart. Cardiac & Cardiovascular Systems Three-dimensional printing Left ventricular outflow tract obstruction Cardiac surgery Cardiac imaging Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Introduction According to the hemodynamic characteristics of the left ventricular outflow tract (LVOT), hypertrophic cardiomyopathy (HCM) can be divided into hypertrophic obstructive cardiomyopathy (HOCM) and hypertrophic nonobstructive cardiomyopathy [ 1 ] . Nearly 50% of HCM patients have different degrees of LVOT obstruction due to the site and degree of myocardial hypertrophy [ 2 – 3 ] . The Morrow operation is an important method for the treatment of HCM. However, due to the complex anatomical relationship of HCM, the operation is relatively difficult. With the application of three-dimensional (3D) digital reconstruction technology in clinical disease treatment, it has been possible to provide a reference for the formulation of surgical plans by obtaining individual patient data [ 4 ] . This study explored the application value of a 3D-printed model of LVOT obstruction in Morrow operations. Materials And Methods Case sample selection From August 2019 to October 2021, 46 patients with HCM underwent surgery at Peking University International Hospital, Southwest Medical University Affiliated Hospital of Traditional Chinese Medicine and Guangyuan First People's Hospital. Inclusive criteria were as follows: LVOT pressure difference (rest or excitation)≥50 mmHg; interventricular septal thickness (IST) > 18 mm; a pressure difference in asymptomatic patients at rest of more than 75–100 mmHg; severe clinical symptoms, such as exertional dyspnea, that were not improved by medical treatment; and complete data regarding the operation and follow-up. Exclusion criteria were as follows: severe organic valvular (mitral or aortic) changes found before the operation; presence of atrioventricular block before the operation; severe cardiopulmonary dysfunction; and major diseases associated with other systems. According to the treatment methods, the subjects were divided into the experimental group (22 cases) and the control group (24 cases). There were no significant differences in the general data between the two groups (P > 0.05), which were comparable ( Table 1 ) . The study was approved by the hospital ethics committee, and all patients signed informed consent forms. Table 1 Comparison of basic data between the experimental group and the control group Variable Experimental group (n=22) Control group (n=24) t-value/χ2-value P-value Age (years, x±s) 49.2± 12.2 51.6± 11.1 -1.321 0.129 Male (n, %) 9 (40.9) 10 (41.6) -1.121 0.215 BMI 21.2± 2.1 20.8± 2.5 1.790 0.106 Preoperative EF (%) 61.0± 4.2 59.0± 4.1 1.308 0.115 LVP (mmHg) 71.5± 30.5 69.5± 42.5 2.864 0.095 IST (mm) 22.7± 5.3 21.9± 4.2 3.252 0.089 SAM (n, %) 7(31.8) 6(25.0) 1.581 0.125 IDLV (mm) 15.8± 4.7 16.5± 4.3 -3.693 0.082 LVFV (m/s) 2.4± 0.5 2.7± 0.6 -3.991 0.078 Note: BMI, body mass index. EF, ejection fraction. LVP, left ventricular outflow tract pressure difference. IST, interventricular septal thickness. SAM, systolic anterior motion. IDLV, inner diameter of the LVOT. LVFV, left ventricular flow velocity. Data collection The median follow-up time was 17.23 ± 10.58 months (range: from 6 to 26 months), and there were no deaths. The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, ejection fraction (EF), left ventricular flow velocity (LVFV), LVOT pressure difference (LVP), postoperative IST, inner diameter of the left ventricular outflow tract (IDLV), atrioventricular block rate, aortic regurgitation (AR) rate, SAM, and operation complication rate were compared between the two groups, and the operation complication rate was recorded. Treatment In the control group, the operation plan was made according to the conventional method, and the patients in the conventional group were treated with hypertrophic interventricular septal muscle resection and LVOT dredging through the thoracic median incision. According to the preoperative imaging examination, the location of the lesion was determined, the ascending aorta and superior and inferior vena cava were intubated, cardiopulmonary bypass was established. After cardiac arrest, the right aortic coronary valve was pulled through the aortic root transverse incision approach, and the hypertrophic ventricular septum and anterior leaflet of the mitral valve were fully exposed and explored. The upper end was 5 mm below the aortic ring of the right coronary valve. The right side was 2–3 mm to the right of the midpoint of the right coronary sinus and to the left coronary sinus near the anterior mitral junction. The length of the longitudinal resection is usually 50–60 mm near the apex of the left ventricle. The abnormal chordae tendineae and papillary muscle involved in the anterior lobe of the mitral valve are removed at the same time. The abnormal connection between the body of the anterior papillary muscle and the lateral wall and interventricular septum of the left ventricle was removed to completely release the body of the anterior papillary muscle. The aortic incision was sutured and rewarmed, the ascending aorta was opened, the heartbeat was restored, and the blood was stopped. In the experimental group, CT scanning was performed before the operation, 3D reconstruction was performed with Mimics software attached to CT, and the data were input into a 3D printer to print the physical model of HOCM [ 5 ] . The virtual operation of myocardial resection was carried out by a computer, and the individualized operation scheme was designed according to the severity of obstruction. The operation was simulated on the physical model, and the best operation scheme was selected according to the resection effect ( Figure 1 ) . The patients’ resection site, depth, length and direction were recorded. After the LVOT was exposed during the operation, the site of severe stenosis was found according to the 3D-printed model, and the other operations were the same as those in the conventional group. Mitral valve replacement was performed in patients with mitral valve leaflet organic changes or severe calcification. Transesophageal or transthoracic echocardiography was used to evaluate the systolic anterior motion (SAM) sign, mitral and tricuspid valve function and surgical effects. For patients with coronary heart disease, coronary artery bypass grafting (CABG) was performed with the left internal mammary artery and/or great saphenous vein after the Morrow operation. Follow-up Patients were followed up with a mailed questionnaire or telephone call by contacting the referring cardiologist or general practitioner. Statistics SPSS 22.0 software (SPSS Inc., Chicago, Illinois) was used for statistical analysis. The mean ± standard deviation was determined by t-tests. Count data were expressed as percentages (%). The statistical analysis was performed by using the χ2 test, with P < 0.05 indicating a significant difference. Results Comparison of operation indexes and recovery between the two groups. The operation time, cardiopulmonary bypass time, intraoperative blood loss and hospitalization time of the experimental group were lower than those of the conventional group, and the difference was significant (P 0.05) ( Table 2 ) . Atrioventricular block includes three types, including not only cases requiring pacemaker insertion.At the same time, 2 patients underwent myocardial bridge lysis, 2 patients underwent mitral valve replacement, 2 patients underwent mitral valvuloplasty, 5 patients underwent tricuspid valvuloplasty, and 1 patient underwent a modified maze procedure. There were no intraoperative deaths or deaths within 30 days after the operation in either group. There was 1 case with 1 branch of CABG, 2 cases with 2 branches of CABG and 3 cases with 3 branches of CABG. Table 2 Comparison of the operation indexes between the two groups Operation index Experimental group (n=22) Control group (n=24) t-value/χ2-value P-value Operation time (min) 262.5± 59.6 281.7± 65.8 2.051 0.012 Cardiopulmonary bypass time (min) 79.5± 21.5 90.8± 26.2 3.894 <0.001 Intraoperative blood loss (ml) 472.5± 60.6 491.6± 73.8 4.981 0.001 Hospitalization time (d) 7.6± 1.8 8.1± 1.6 1.894 0.023 Postoperative EF (%) 61.8± 8.5 59.5± 7.9 -0.582 1.521 Atrioventricular block rate (%) 5.2± 1.8 5.5± 1.6 0.953 0.883 Note: EF, ejection fraction. Comparison of left ventricular morphology between the two groups. There was no significant difference in LVFV, LVP, IST, IDLV, AR rate or rate of a positive SAM sign between the two groups (P > 0.05). The measured values of LVFV, LVP, postoperative IST, AR rate and rate of a positive SAM sign in the experimental group were lower than those in the control group, and the IDLV was larger than that in the control group, with significant difference (P < 0.05), as shown in Table 3 . Table 3 Comparison of left ventricular morphological indexes Ultrasonic index Experimental group (n=22) Control group (n=24) t-value/χ2-value P-value LVFV (m/s) 1.6± 0.1 2.4± 0.2 6.942 <0.001 LVP (mmHg) 9.3± 0.3 12.3± 0.5 3.933 0.002 IST (mm) 8.8± 0.2 10.5± 0.3 3.912 0.001 SAM (n, %) 2 (9.09) 5 (20.83) 3.861 0.006 IDLV (mm) 30.7± 5.3 24.9± 4.2 3.257 <0.001 AR rate (%) 6.7± 0.5 9.5± 0.5 2.134 0.013 Note: LVFV, left ventricular flow velocity. LVP, left ventricular outflow tract pressure difference. IST, interventricular septal thickness. SAM, systolic anterior motion. IDLV, inner diameter of the left ventricular outflow tract. AR, aortic regurgitation. Comparison of the incidence of complications between the two groups. In the experimental group, deep venous thrombosis occurred in 1 case. In the control group, 1 case of incision infection and 2 cases of deep venous thrombosis occurred. There was no significant difference between the experimental group (6.25%) and the control group (11.36%) (χ2=0.579, P =0.447). Discussion The Morrow operation is the gold standard for the treatment of HCM. Although Lekaditi Dimitra and others believe that medical drug treatment can improve the outcome, the effect is not as clear as that of the operation [ 6 – 7 ] . Havndrup, O et al. believe that compared with other treatments, the Morrow operation is still the best in terms of postoperative effects [ 8 ] . In experienced hospitals, the mortality rate with experienced cardiac surgeons is less than 1%. After the operation, they can obtain immediate and permanent improvement of clinical symptoms, a decrease in the LVOT pressure difference and improvement of the exercise stress response. The life span of patients in the operation group was essentially the same as that of normal individuals, which was better than that yielded by any other treatment method for obstruction. Why 3D printing? The risk of Morrow surgery is increased due to the relatively poor visualization of the left ventricular cavity and the heterogeneity of the LVOT anatomy. The incidence of postoperative complications of the Morrow operation for doctors who have not yet acquired experience is relatively high; such complications include injury to the conduction tract, damage to the atrioventricular wall, coronary artery injury, valve injury and even the occurrence of new-onset postoperative atrial fibrillation(POAF) [ 9 ] . In recent years, 3D printing technology has been increasingly widely used in complex heart disease surgery. Lee, M et al. believed that a 3D-printed heart model can be used to reconstruct the coronary artery anatomy and improve the understanding of coronary artery abnormalities [ 10 ] . It has been proven that 3D printing technology can be widely used in congenital heart disease surgery. In the treatment of coronary heart disease and acquired valve disease, the curative effect is satisfactory [ 11 ] . Jivanji, SGM, et al. studied the repair of aneurysm neck occluders and right ventricular outflow tract Venus P valves using a 3D-printed heart model. The encouraging findings of the simulation enabled them to plan complex surgical procedures effectively and achieve successful results [ 12 ] . 3D printing can visually display the geometric relationship between the hypertrophic myocardium, papillary muscle, ventricular muscle band and mitral annulus with different colors and simulate myocardial resection in a 3D model to better grasp the scope of hypertrophic septum resection, define the position and length of the papillary muscle and abnormal ventricular muscle band, and formulate a better operation plan ( Figure 2 ) . The intraoperative effect of 3D printing. The results of this study showed that the operation time, cardiopulmonary bypass time, intraoperative blood loss and hospitalization time of the experimental group were significantly lower than those of the control group, suggesting that 3D printing of a heart model for extracorporeal simulation surgery for patients with LVOT obstruction is helpful to shorten the operation time and reduce surgical blood loss. The specific location, depth, direction and the best resection method for the stenosis can be determined before the operation, and the Morrow operation can be simulated on this basis. Surgeons can repeatedly test the resection on the model to determine the best resection range and depth.The simulation results can help to shorten the time of lesion resection in the actual operation and are also helpful for avoiding unnecessary exposure of the surgical field and the excessive anatomical bleeding caused by the formal operation, thus shortening the time necessary to search for the best resection site and depth in the operation ( Figure 3 ) . The postoperative effect of 3D printing. The results showed that the values of the LVFV, LVP, IST, AR rate and SAM-sign positive rate were lower in the experimental group than in the control group, and the IDLV was larger than that of the control group (P < 0.05). It is suggested that 3D printing of a cardiac model for in vitro simulated resection of a hypertrophic myocardium for the Morrow operation is helpful for patients with outflow tract obstruction to recover a better morphology and physiological anatomy and achieve an ideal long-term effect ( Figure 4 ) . The advantage of fat stem cell treatment in patients with coronary heart disease. It has been reported that the incidence rate of adult HOCM combined with CAD accounts for approximately 20% of HOCM. Huang, CH, et al. suggested that the risk of coronary heart disease with obstructive heart disease is higher whether interventional therapy or surgical treatment is applied [ 13 ] . The sudden death rate and total mortality of HOCM with severe CAD were significantly higher than those of HOCM alone. For patients with HOCM, CAD often aggravates the symptoms of angina pectoris and affects the prognosis of surgery. For patients with severe CAD, CABG should be performed at the same time. However, due to the hypertrophic myocardium, it is difficult to check the coronary artery and free blood vessels, so 3D printing technology can be used for preoperative evaluation ( Figure 5 ) . The treatment advantage of fat stem cells in valvular disease. For patients with HOCM complicated with valvular disease, hypertrophic ventricular muscle leads to valve changes. The common mitral valve problem is due to LVOT obstruction. The SAM of the mitral valve can contact the ventricular septum and produce dynamic subaortic occlusion. This problem can be solved by the Morrow operation. Lefebvre, XP and others studied the mechanism of mitral valve systolic forward motion in HCM under the condition of stable blood flow, which greatly facilitates completion of the Morrow operation [ 14 ] . However, valvular disease (such as valve calcification) requires surgical treatment to correct the valve, which cannot be simply removed as myocardial tissue can [ 15 ] . Therefore, preoperative 3D printing technology can simplify the repair of valvular disease by clarifying the scope and severity of the disease and simulating the operation ( Figure 6 ) . The treatment advantage of fat infarction patients with atrial fibrillation. We previously described a patient who had atrial fibrillation before surgery and needed modified maze surgery [ 16 ] . For the preoperative evaluation of patients with fat infarction, it is necessary not only to evaluate the extent of resection but also to understand the shape of the nerve tracts in patients with fat infarction. Because fat infarction patients are different from general heart patients, their nerve path is different because of the change in the heart state, such as the wrong ablation position, which may affect the surgical effect. Therefore, 3D printing before surgery poses certain advantages for understanding the overall shape of the heart and the patient's nerve path. Postoperative cardiac function. In the past, many experts have said that too much cardiac tissue resection may lead to postoperative cardiac dysfunction [ 17 ] . However, this study found that the LVOT diameter and wall thickness of the two groups were significantly improved compared with those of the control group (P 0.05). However, improvement of the LVOT can change the incidence of diseases related to the risk of an insufficient blood supply (e.g., stroke, myocardial insufficiency). Therefore, during the Morrow operation, with the aid of 3D printing technology, more cardiac tissue can be removed as much as possible without affecting the heart function of patients. The disadvantages of 3D printing. However, because the current 3D printing technology is caused by vascular perfusion imaging, the nerve conduction bundle cannot be displayed. Lau, IWW and other researchers found that even if 3D printing is perfect, it is still a serious defect to be unable to display the shape of the micro-nerve bundle [ 18 ] . When we try to remove hypertrophic myocardial tissue, it is difficult to detect the shape of the conduction beam and block conduction after the operation. This is a problem that 3D printing technology cannot solve. Therefore, in the experimental group and the control group, we found that there was no significant difference in the conduction block between the two groups (P > 0.05). Conclusion 3D printing of the heart model can enable the doctor to more instinctively understand the patient's heart condition and make the operation more intuitive. The optimal scheme simulation before the operation can help to reduce the damage to adjacent nerves, blood vessels and other tissues during the operation and can decrease the surgical risk. In conclusion, a 3D-printed heart model for in vitro simulation surgery is conducive to creating a more reasonable surgical plan, which can reduce surgical trauma and operation time and is conducive to the recovery and maintenance of the heart. Declarations Availability of data and materials : For data sharing, please contact the corresponding author of this article. Funding : The project was supported by the Beijing Municipal Science & Technology Commission (Z191100006619005), Peking University International Hospital Research Grant YN2019ZD01, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, and Nanjing Medical University Research Grant GSRCKY20210101. The funders had no role in the study design, data collection or analysis, decision to publish, or preparation of the manuscript. Ethical statement : This study has been approved by the Hospital Ethics Committee, with the approval No.: ks2585. Patients in this study have signed written informed consent and obtained relevant reports and attached pictures from patients. All methods were performed in accordance with the relevant guidelines and regulations. Acknowledgement : This work was supported by the Beijing Municipal Science & Technology Commission (Z191100006619005), Peking University International Hospital Research Grant (YN2019ZD01) and The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, and Nanjing Medical University Research Grant( GSRCKY20210101). Consent for publication : Not applicable. Declaration of conflict of interest: None. References Ten Cate, FJ. Prognosis of hypertrophic cardiomyopathy.J Insur Med.1996 ;28(1):42–5. Mirza, SJ, Radaideh, GA. Pattern of left ventricular hypertrophy seen on transthoracic echo in patients with hypertensive cardiomyopathy when compared with idiopathic hypertrophic cardiomyopathy. J Pak Med Assoc.2013 Jan;63(1):16–9. Eidem, BW, Lindor, NM, Driscoll, DJ. Resolution of neonatal hypertrophic cardiomyopathy in an infant with an affected mother. Pediatr Cardiol.1999;20(3):208–11. Lee, S; Squelch, A; Sun, Z. Quantitative Assessment of 3D Printed Model Accuracy in Delineating Congenital Heart Disease. Biomolecules.2021 02 12;11(2). Frank, DO, Zanation, AM, Dhandha, VH, McKinney, KA, Fleischman, GM, Ebert, CS, et al. Quantification of airflow into the maxillary sinuses before and after functional endoscopic sinus surgery. Int Forum Allergy Rhinol.2013 Oct;3(10):834–40. Saltman, AE; Lahey, SJ; Francalancia, NA; Tselentakis, EV. Origin of atrial fibrillation in a patient who had undergone septal myectomy. J Cardiovasc Electrophysiol.2003 Jul;14(7):786; author reply 786-7. Lekaditi, D; Sakellaropoulos, S. Myosin Modulators: The New Era of Medical Therapy for Systolic Heart Failure and Hypertrophic Cardiomyopathy. Cardiology ResearchVolume 12, Issue 3. 2021. PP 146–148. Havndrup, O, Bundgaard, H, Hansen, FV, Pietersen, AH, Kelbaek, HS. Treatment of hypertrophic cardiomyopathy. Ugeskr Laeger.1998 Sep 14;160(38):5495–500. Maaroos, M, Pohjantähti-Maaroos, H, Halonen, J, Vähämetsä, J, Turtiainen, J, Rantonen, J, et al. New onset postoperative atrial fibrillation and early anticoagulation after cardiac surgery. Scand Cardiovasc J.2017 Dec;51(6):323–326. Lee, M, Moharem-Elgamal, S, Beckingham, R, Hamilton, M, Manghat, N, Milano, EG, et al. Evaluating 3D-printed models of coronary anomalies: a survey among clinicians and researchers at a university hospital in the UK. BMJ Open.2019 03 08;9(3):e025227. Hachulla, AL, Noble, S, Guglielmi, G, Agulleiro, D, Müller, H, Vallée, JP. 3D-printed heart model to guide LAA closure: useful in clinical practice? Eur Radiol.2019 Jan;29(1):251–258. Jivanji, SGM, Qureshi, SA, Rosenthal, E. Novel use of a 3D printed heart model to guide simultaneous percutaneous repair of severe pulmonary regurgitation and right ventricular outflow tract aneurysm. Cardiol Young.2019 Apr;29(4):534–537. Huang, CH, Chen, IC, Chiou, HC. Coronary stent graft for hypertrophic obstructive cardiomyopathy combined with coronary artery disease. J Formos Med Assoc.2003 Aug;102(8):574–7. Lefebvre, XP, Yoganathan, AP, Levine, RA. Insights from in-vitro flow visualization into the mechanism of systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy under steady flow conditions. J Biomech Eng.1992 Aug;114(3):406–13. Ohkado, A, Kitamura, M, Hachida, M, Nishinaka, T, Hanayama, N, Sato, W. Hypertrophic obstructive cardiomyopathy with abnormalities of the mitral valve complex. J Heart Valve Dis.1997 Jan;6(1):60–2. Sayed, SA, Katewa, A, Srivastava, V, Jana, S, Patwardhan, AM. Modified radial v/s biatrial maze for atrial fibrillation in rheumatic valvular heart surgery. Indian Heart J.2014;66(5):510–6. Obase Kikuko; Maemura Koji; Matsumaru Ichiro; Eishi Kiyoyuki. Left ventricular outflow tract obstruction related to systolic anterior motion of anomalous secondary chords.Eur J Cardiothorac Surg. 2021 ;7(12):255. Lau, IWW, Liu, D, Xu, L, Fan, Z, Sun, Z. Clinical value of patient-specific three-dimensional printing of congenital heart disease: Quantitative and qualitative assessments. PLoS One.2018;13(3):e0194333. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revision 03 Feb, 2022 Reviews received at journal 19 Jan, 2022 Reviewers agreed at journal 06 Jan, 2022 Reviewers invited by journal 06 Jan, 2022 Editor assigned by journal 06 Jan, 2022 Editor invited by journal 06 Jan, 2022 Submission checks completed at journal 06 Jan, 2022 First submitted to journal 27 Dec, 2021 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-1206928","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":74627067,"identity":"32b572eb-3f61-4e7c-8a3e-224346cbfe22","order_by":0,"name":"Xianzhi Wang","email":"","orcid":"","institution":"The First People’s Hospital of Guangyuan","correspondingAuthor":false,"prefix":"","firstName":"Xianzhi","middleName":"","lastName":"Wang","suffix":""},{"id":74627068,"identity":"f59b5d9f-07e6-44d0-99a4-b0129f8bac55","order_by":1,"name":"Jixiang Liang","email":"","orcid":"","institution":"Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Jixiang","middleName":"","lastName":"Liang","suffix":""},{"id":74627069,"identity":"ab6194bd-af4b-456d-9629-8957ae021b93","order_by":2,"name":"Cunfu Mu","email":"","orcid":"","institution":"The First People’s Hospital of Guangyuan","correspondingAuthor":false,"prefix":"","firstName":"Cunfu","middleName":"","lastName":"Mu","suffix":""},{"id":74627070,"identity":"dc0a6f83-b6a1-40f1-8de1-88505ca68d3a","order_by":3,"name":"Wenlin Zhang","email":"","orcid":"","institution":"The First People’s Hospital of Guangyuan","correspondingAuthor":false,"prefix":"","firstName":"Wenlin","middleName":"","lastName":"Zhang","suffix":""},{"id":74627071,"identity":"ef55df90-0fb3-4a1d-b490-901a6700d224","order_by":4,"name":"Chunzhu Xue","email":"","orcid":"","institution":"The First People’s Hospital of Guangyuan","correspondingAuthor":false,"prefix":"","firstName":"Chunzhu","middleName":"","lastName":"Xue","suffix":""},{"id":74627072,"identity":"ffe3848c-e9d7-4f5a-b4f9-5f5a91286809","order_by":5,"name":"Yang He","email":"","orcid":"","institution":"The First People’s Hospital of Guangyuan","correspondingAuthor":false,"prefix":"","firstName":"Yang","middleName":"","lastName":"He","suffix":""},{"id":74627073,"identity":"361896fd-3af7-4db3-9db9-d98cadcd56f6","order_by":6,"name":"Gen Zhang","email":"","orcid":"","institution":"The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University","correspondingAuthor":false,"prefix":"","firstName":"Gen","middleName":"","lastName":"Zhang","suffix":""},{"id":74627074,"identity":"b1c93ff3-5a38-48bf-bd59-8f14d8109b46","order_by":7,"name":"Dianyuan Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYBACe2Yog4+Z+QADYwMRWgyboQw2ZrYE4rQYHIBpYeAxIFLLceZnj3nb7PLY2Hm+SfzcYSPHwH746Aa8Wg6zmRvztiUXszHzbpPsPZNmzMCTlnYDvxYGM2neNubENqAWCd62w4kNEjxmBLSwfwNqqQdq4Xkm+Zc4LTwgWw6DtLBJE2WLYTNPmeScc8eBWtiMrWXb0ozZCPnFnv/4Nok3ZdWJ/fyHH95822Yjx89++BheLSDAxAOhWSRAJBsh5SDA+ANCM38gRvUoGAWjYBSMPAAAJLVCulw3sVIAAAAASUVORK5CYII=","orcid":"","institution":"The Affiliated Suzhou Hospital of Nanjing Medical University, Nanjing Medical University","correspondingAuthor":true,"prefix":"","firstName":"Dianyuan","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2021-12-27 06:14:04","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1206928/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1206928/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":17116233,"identity":"5ac33c87-7f84-4326-a81f-909388683055","added_by":"auto","created_at":"2022-01-07 21:11:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1006581,"visible":true,"origin":"","legend":"\u003cp\u003eThe process of resection of hypertrophic myocardium by 3D-printed model. A. 3D-printed model of the hypertrophic myocardium before the operation. B. 3D-printed model of the resection site after the operation. C. Resected myocardial tissue model. D. Myocardial tissue excised according to 3D-printed model.\u003c/p\u003e","description":"","filename":"fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/7781858f2ddc08ef07468e57.png"},{"id":17116231,"identity":"550330a5-0580-4b9e-a477-2c5054d36a8c","added_by":"auto","created_at":"2022-01-07 21:11:44","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":170296,"visible":true,"origin":"","legend":"\u003cp\u003e3D rendering of LVOT obstruction before surgery. A. Different colors can be used to display the heart regions directly, which is helpful to distinguish the tissue components. B. The LVOT is extracted from the 3D reconstruction of the heart, which is convenient for understanding the shape of the LVOT, the location of stenosis and the relationship of the surrounding tissues.\u003c/p\u003e","description":"","filename":"fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/fbcaf65df4359037f13f2b26.png"},{"id":17116269,"identity":"3af067b9-abd8-48b8-a683-9d50d8d37136","added_by":"auto","created_at":"2022-01-07 21:14:44","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":408466,"visible":true,"origin":"","legend":"\u003cp\u003eComparison of the 3D printing thoracoscopic effect of patients with LVOT obstruction before and after the operation. A. 3D printing video-assisted thoracoscopy can show obstruction of the LVOT, which indicates severe stenosis and hypertrophy of the ventricular septum. B. After 3D printing, the LVOT obstruction was significantly improved, the diameter was significantly widened, and more hypertrophic tissue was removed. LVOC, left ventricular outflow channel, VS, ventricular septum.\u003c/p\u003e","description":"","filename":"fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/7609412cfb93c88be9684f95.png"},{"id":17116236,"identity":"8a196dbf-efff-4936-869f-f8775f9ca480","added_by":"auto","created_at":"2022-01-07 21:11:44","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":210004,"visible":true,"origin":"","legend":"\u003cp\u003e3D printing of preoperative and postoperative results in LVOT obstruction. A. 3D printing of coronary sections of patients with outflow tract obstruction showed severe stenosis of the outflow tract and hypertrophy of the ventricular septum. B. 3D printing of coronary cross sections of outflow tract obstruction showed that the outflow tract was significantly improved, the diameter was widened, and ventricular septal hypertrophy was reduced. C. 3D reconstruction of the LVOT in patients with outflow tract obstruction before 3D printing indicated severe stenosis. D. 3D reconstruction of the LVOT in patients with outflow tract obstruction after 3D printing indicated that the stenosis was significantly improved. LVOC, left ventricular outflow channel.\u003c/p\u003e","description":"","filename":"fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/95e39c152fbac58611942559.png"},{"id":17116271,"identity":"51a860f8-0ff2-49e0-8f58-77a7acbccc87","added_by":"auto","created_at":"2022-01-07 21:14:44","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":405009,"visible":true,"origin":"","legend":"\u003cp\u003e3D printing of the heart and coronary artery. A. According to the various parts, different colors were marked to display the 3D structure of the heart, and the RCA was clearly displayed. B. The left and right hearts were dissected as a whole to understand the shape of the coronary artery. PH, pulmonary heart, RCA, right coronary artery, CA, cor arteriosum.\u003c/p\u003e","description":"","filename":"fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/947f93fd5b8ec049219a7a1d.png"},{"id":17116270,"identity":"a26e543a-86dd-4460-9ca8-860886a75167","added_by":"auto","created_at":"2022-01-07 21:14:44","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":202655,"visible":true,"origin":"","legend":"\u003cp\u003eThe 3D-printed heart shows the calcified area of the valve. A. The coronary position can be used to determine the area covered by calcification, indicating that there are obvious calcifications in the aortic valve and mitral valve, and the range of involvement is wide. B. The relationship between the calcified valve and pulmonary artery and vein can be identified in the sagittal view, and the depth of calcification invasion, which is not easy to find in the operation field, can be determined. VCA, valve calcification area.\u003c/p\u003e","description":"","filename":"fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/bb098138e069f0f45fb01c51.png"},{"id":17116272,"identity":"8f9a3b03-373e-486e-af1f-ad81433d222b","added_by":"auto","created_at":"2022-01-07 21:14:51","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1091695,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1206928/v1/8ee22011-58da-4193-bcd3-7b616dabc53c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eEffect of 3D-Printed Hearts Used in Left Ventricular Outflow Tract Obstruction: A Multicenter Study\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eAccording to the hemodynamic characteristics of the left ventricular outflow tract (LVOT), hypertrophic cardiomyopathy (HCM) can be divided into hypertrophic obstructive cardiomyopathy (HOCM) and hypertrophic nonobstructive cardiomyopathy \u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]\u003c/sup\u003e. Nearly 50% of HCM patients have different degrees of LVOT obstruction due to the site and degree of myocardial hypertrophy \u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. The Morrow operation is an important method for the treatment of HCM. However, due to the complex anatomical relationship of HCM, the operation is relatively difficult. With the application of three-dimensional (3D) digital reconstruction technology in clinical disease treatment, it has been possible to provide a reference for the formulation of surgical plans by obtaining individual patient data \u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. This study explored the application value of a 3D-printed model of LVOT obstruction in Morrow operations.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv class=\"Section2\" id=\"Sec3\"\u003e\n \u003ch2\u003eCase sample selection\u003c/h2\u003e\n \u003cp\u003eFrom August 2019 to October 2021, 46 patients with HCM underwent surgery at Peking University International Hospital, Southwest Medical University Affiliated Hospital of Traditional Chinese Medicine and Guangyuan First People\u0026apos;s Hospital. Inclusive criteria were as follows: LVOT pressure difference (rest or excitation)\u0026ge;50 mmHg; interventricular septal thickness (IST) \u0026gt; 18 mm; a pressure difference in asymptomatic patients at rest of more than 75\u0026ndash;100 mmHg; severe clinical symptoms, such as exertional dyspnea, that were not improved by medical treatment; and complete data regarding the operation and follow-up. Exclusion criteria were as follows: severe organic valvular (mitral or aortic) changes found before the operation; presence of atrioventricular block before the operation; severe cardiopulmonary dysfunction; and major diseases associated with other systems. According to the treatment methods, the subjects were divided into the experimental group (22 cases) and the control group (24 cases). There were no significant differences in the general data between the two groups (P \u0026gt; 0.05), which were comparable \u003cstrong\u003e(\u003c/strong\u003eTable \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e. The study was approved by the hospital ethics committee, and all patients signed informed consent forms.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eComparison of basic data between the experimental group and the control group\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eVariable\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExperimental group (n=22)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eControl group (n=24)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003et-value/\u0026chi;2-value\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAge (years, x\u0026plusmn;s)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e49.2\u0026plusmn; 12.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e51.6\u0026plusmn; 11.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-1.321\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.129\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eMale (n, %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9 (40.9)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10 (41.6)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-1.121\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.215\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eBMI\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21.2\u0026plusmn; 2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20.8\u0026plusmn; 2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.790\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.106\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePreoperative EF (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e61.0\u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e59.0\u0026plusmn; 4.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.308\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.115\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eLVP (mmHg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e71.5\u0026plusmn; 30.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.5\u0026plusmn; 42.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.864\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.095\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eIST (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e22.7\u0026plusmn; 5.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e21.9\u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.252\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.089\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSAM (n, %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7(31.8)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6(25.0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.581\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.125\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eIDLV (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15.8\u0026plusmn; 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16.5\u0026plusmn; 4.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-3.693\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.082\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eLVFV (m/s)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.4\u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.7\u0026plusmn; 0.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-3.991\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.078\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eNote: BMI, body mass index. EF, ejection fraction. LVP, left ventricular outflow tract pressure difference. IST, interventricular septal thickness. SAM, systolic anterior motion. IDLV, inner diameter of the LVOT. LVFV, left ventricular flow velocity.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cdiv class=\"Section3\" id=\"Sec4\"\u003e\n \u003ch2\u003eData collection\u003c/h2\u003e\n \u003cp\u003eThe median follow-up time was 17.23 \u0026plusmn; 10.58 months (range: from 6 to 26 months), and there were no deaths. The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, ejection fraction (EF), left ventricular flow velocity (LVFV), LVOT pressure difference (LVP), postoperative IST, inner diameter of the left ventricular outflow tract (IDLV), atrioventricular block rate, aortic regurgitation (AR) rate, SAM, and operation complication rate were compared between the two groups, and the operation complication rate was recorded.\u003c/p\u003e\n \u003c/div\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec5\"\u003e\n \u003ch2\u003eTreatment\u003c/h2\u003e\n \u003cp\u003eIn the control group, the operation plan was made according to the conventional method, and the patients in the conventional group were treated with hypertrophic interventricular septal muscle resection and LVOT dredging through the thoracic median incision. According to the preoperative imaging examination, the location of the lesion was determined, the ascending aorta and superior and inferior vena cava were intubated, cardiopulmonary bypass was established. After cardiac arrest, the right aortic coronary valve was pulled through the aortic root transverse incision approach, and the hypertrophic ventricular septum and anterior leaflet of the mitral valve were fully exposed and explored. The upper end was 5 mm below the aortic ring of the right coronary valve. The right side was 2\u0026ndash;3 mm to the right of the midpoint of the right coronary sinus and to the left coronary sinus near the anterior mitral junction. The length of the longitudinal resection is usually 50\u0026ndash;60 mm near the apex of the left ventricle. The abnormal chordae tendineae and papillary muscle involved in the anterior lobe of the mitral valve are removed at the same time. The abnormal connection between the body of the anterior papillary muscle and the lateral wall and interventricular septum of the left ventricle was removed to completely release the body of the anterior papillary muscle. The aortic incision was sutured and rewarmed, the ascending aorta was opened, the heartbeat was restored, and the blood was stopped. In the experimental group, CT scanning was performed before the operation, 3D reconstruction was performed with Mimics software attached to CT, and the data were input into a 3D printer to print the physical model of HOCM \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e. The virtual operation of myocardial resection was carried out by a computer, and the individualized operation scheme was designed according to the severity of obstruction. The operation was simulated on the physical model, and the best operation scheme was selected according to the resection effect \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e. The patients\u0026rsquo; resection site, depth, length and direction were recorded. After the LVOT was exposed during the operation, the site of severe stenosis was found according to the 3D-printed model, and the other operations were the same as those in the conventional group. Mitral valve replacement was performed in patients with mitral valve leaflet organic changes or severe calcification. Transesophageal or transthoracic echocardiography was used to evaluate the systolic anterior motion (SAM) sign, mitral and tricuspid valve function and surgical effects. For patients with coronary heart disease, coronary artery bypass grafting (CABG) was performed with the left internal mammary artery and/or great saphenous vein after the Morrow operation.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec6\"\u003e\n \u003ch2\u003eFollow-up\u003c/h2\u003e\n \u003cp\u003ePatients were followed up with a mailed questionnaire or telephone call by contacting the referring cardiologist or general practitioner.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec7\"\u003e\n \u003ch2\u003eStatistics\u003c/h2\u003e\n \u003cp\u003eSPSS 22.0 software (SPSS Inc., Chicago, Illinois) was used for statistical analysis. The mean \u0026plusmn; standard deviation was determined by t-tests. Count data were expressed as percentages (%). The statistical analysis was performed by using the \u0026chi;2 test, with P \u0026lt; 0.05 indicating a significant difference.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cem\u003eComparison of operation indexes and recovery between the two groups.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe operation time, cardiopulmonary bypass time, intraoperative blood loss and hospitalization time of the experimental group were lower than those of the conventional group, and the difference was significant (P \u0026lt; 0.05). There was no significant difference in the postoperative EF or atrioventricular block rate between the experimental group and the control group (P \u0026gt; 0.05) \u003cstrong\u003e(\u003c/strong\u003eTable \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e. Atrioventricular block includes three types, including not only cases requiring pacemaker insertion.At the same time, 2 patients underwent myocardial bridge lysis, 2 patients underwent mitral valve replacement, 2 patients underwent mitral valvuloplasty, 5 patients underwent tricuspid valvuloplasty, and 1 patient underwent a modified maze procedure. There were no intraoperative deaths or deaths within 30 days after the operation in either group. There was 1 case with 1 branch of CABG, 2 cases with 2 branches of CABG and 3 cases with 3 branches of CABG.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eComparison of the operation indexes between the two groups\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eOperation index\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExperimental group (n=22)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eControl group (n=24)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003et-value/\u0026chi;2-value\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eOperation time (min)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e262.5\u0026plusmn; 59.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e281.7\u0026plusmn; 65.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.051\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.012\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eCardiopulmonary bypass time (min)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e79.5\u0026plusmn; 21.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e90.8\u0026plusmn; 26.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.894\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eIntraoperative blood loss (ml)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e472.5\u0026plusmn; 60.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e491.6\u0026plusmn; 73.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.981\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eHospitalization time (d)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e7.6\u0026plusmn; 1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.1\u0026plusmn; 1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.894\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.023\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003ePostoperative EF (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e61.8\u0026plusmn; 8.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e59.5\u0026plusmn; 7.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e-0.582\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.521\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAtrioventricular block rate (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.2\u0026plusmn; 1.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.5\u0026plusmn; 1.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.953\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.883\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eNote: EF, ejection fraction.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eComparison of left ventricular morphology between the two groups.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThere was no significant difference in LVFV, LVP, IST, IDLV, AR rate or rate of a positive SAM sign between the two groups (P \u0026gt; 0.05). The measured values of LVFV, LVP, postoperative IST, AR rate and rate of a positive SAM sign in the experimental group were lower than those in the control group, and the IDLV was larger than that in the control group, with significant difference (P \u0026lt; 0.05), as shown in Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u003ctable border=\"1\" id=\"Tab3\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eComparison of left ventricular morphological indexes\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eUltrasonic index\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eExperimental group (n=22)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eControl group (n=24)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003et-value/\u0026chi;2-value\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eP-value\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eLVFV (m/s)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.6\u0026plusmn; 0.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2.4\u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.942\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eLVP (mmHg)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.3\u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12.3\u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.933\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eIST (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8.8\u0026plusmn; 0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.5\u0026plusmn; 0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.912\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eSAM (n, %)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 (9.09)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 (20.83)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.861\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.006\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eIDLV (mm)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e30.7\u0026plusmn; 5.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e24.9\u0026plusmn; 4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.257\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e\u0026lt;0.001\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e\u003cstrong\u003eAR rate (%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6.7\u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9.5\u0026plusmn; 0.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.134\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.013\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003eNote: LVFV, left ventricular flow velocity. LVP, left ventricular outflow tract pressure difference. IST, interventricular septal thickness. SAM, systolic anterior motion. IDLV, inner diameter of the left ventricular outflow tract. AR, aortic regurgitation.\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003cem\u003eComparison of the incidence of complications between the two groups.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the experimental group, deep venous thrombosis occurred in 1 case. In the control group, 1 case of incision infection and 2 cases of deep venous thrombosis occurred. There was no significant difference between the experimental group (6.25%) and the control group (11.36%) (\u0026chi;2=0.579, P =0.447).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe Morrow operation is the gold standard for the treatment of HCM. Although Lekaditi Dimitra and others believe that medical drug treatment can improve the outcome, the effect is not as clear as that of the operation \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Havndrup, O et al. believe that compared with other treatments, the Morrow operation is still the best in terms of postoperative effects \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. In experienced hospitals, the mortality rate with experienced cardiac surgeons is less than 1%. After the operation, they can obtain immediate and permanent improvement of clinical symptoms, a decrease in the LVOT pressure difference and improvement of the exercise stress response. The life span of patients in the operation group was essentially the same as that of normal individuals, which was better than that yielded by any other treatment method for obstruction.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eWhy 3D printing?\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe risk of Morrow surgery is increased due to the relatively poor visualization of the left ventricular cavity and the heterogeneity of the LVOT anatomy. The incidence of postoperative complications of the Morrow operation for doctors who have not yet acquired experience is relatively high; such complications include injury to the conduction tract, damage to the atrioventricular wall, coronary artery injury, valve injury and even the occurrence of new-onset postoperative atrial fibrillation(POAF)\u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eIn recent years, 3D printing technology has been increasingly widely used in complex heart disease surgery. Lee, M et al. believed that a 3D-printed heart model can be used to reconstruct the coronary artery anatomy and improve the understanding of coronary artery abnormalities \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. It has been proven that 3D printing technology can be widely used in congenital heart disease surgery. In the treatment of coronary heart disease and acquired valve disease, the curative effect is satisfactory \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Jivanji, SGM, et al. studied the repair of aneurysm neck occluders and right ventricular outflow tract Venus P valves using a 3D-printed heart model. The encouraging findings of the simulation enabled them to plan complex surgical procedures effectively and achieve successful results \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/sup\u003e. 3D printing can visually display the geometric relationship between the hypertrophic myocardium, papillary muscle, ventricular muscle band and mitral annulus with different colors and simulate myocardial resection in a 3D model to better grasp the scope of hypertrophic septum resection, define the position and length of the papillary muscle and abnormal ventricular muscle band, and formulate a better operation plan \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe intraoperative effect of 3D printing.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe results of this study showed that the operation time, cardiopulmonary bypass time, intraoperative blood loss and hospitalization time of the experimental group were significantly lower than those of the control group, suggesting that 3D printing of a heart model for extracorporeal simulation surgery for patients with LVOT obstruction is helpful to shorten the operation time and reduce surgical blood loss. The specific location, depth, direction and the best resection method for the stenosis can be determined before the operation, and the Morrow operation can be simulated on this basis. Surgeons can repeatedly test the resection on the model to determine the best resection range and depth.The simulation results can help to shorten the time of lesion resection in the actual operation and are also helpful for avoiding unnecessary exposure of the surgical field and the excessive anatomical bleeding caused by the formal operation, thus shortening the time necessary to search for the best resection site and depth in the operation \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe postoperative effect of 3D printing.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eThe results showed that the values of the LVFV, LVP, IST, AR rate and SAM-sign positive rate were lower in the experimental group than in the control group, and the IDLV was larger than that of the control group (P \u0026lt; 0.05). It is suggested that 3D printing of a cardiac model for in vitro simulated resection of a hypertrophic myocardium for the Morrow operation is helpful for patients with outflow tract obstruction to recover a better morphology and physiological anatomy and achieve an ideal long-term effect \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe advantage of fat stem cell treatment in patients with coronary heart disease.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIt has been reported that the incidence rate of adult HOCM combined with CAD accounts for approximately 20% of HOCM. Huang, CH, et al. suggested that the risk of coronary heart disease with obstructive heart disease is higher whether interventional therapy or surgical treatment is applied \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. The sudden death rate and total mortality of HOCM with severe CAD were significantly higher than those of HOCM alone. For patients with HOCM, CAD often aggravates the symptoms of angina pectoris and affects the prognosis of surgery. For patients with severe CAD, CABG should be performed at the same time. However, due to the hypertrophic myocardium, it is difficult to check the coronary artery and free blood vessels, so 3D printing technology can be used for preoperative evaluation \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe treatment advantage of fat stem cells in valvular disease.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eFor patients with HOCM complicated with valvular disease, hypertrophic ventricular muscle leads to valve changes. The common mitral valve problem is due to LVOT obstruction. The SAM of the mitral valve can contact the ventricular septum and produce dynamic subaortic occlusion. This problem can be solved by the Morrow operation. Lefebvre, XP and others studied the mechanism of mitral valve systolic forward motion in HCM under the condition of stable blood flow, which greatly facilitates completion of the Morrow operation \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. However, valvular disease (such as valve calcification) requires surgical treatment to correct the valve, which cannot be simply removed as myocardial tissue can \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. Therefore, preoperative 3D printing technology can simplify the repair of valvular disease by clarifying the scope and severity of the disease and simulating the operation \u003cstrong\u003e(\u003c/strong\u003eFigure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e\u003cstrong\u003e)\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe treatment advantage of fat infarction patients with atrial fibrillation.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eWe previously described a patient who had atrial fibrillation before surgery and needed modified maze surgery \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. For the preoperative evaluation of patients with fat infarction, it is necessary not only to evaluate the extent of resection but also to understand the shape of the nerve tracts in patients with fat infarction. Because fat infarction patients are different from general heart patients, their nerve path is different because of the change in the heart state, such as the wrong ablation position, which may affect the surgical effect. Therefore, 3D printing before surgery poses certain advantages for understanding the overall shape of the heart and the patient\u0026apos;s nerve path.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003ePostoperative cardiac function.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eIn the past, many experts have said that too much cardiac tissue resection may lead to postoperative cardiac dysfunction \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. However, this study found that the LVOT diameter and wall thickness of the two groups were significantly improved compared with those of the control group (P \u0026lt; 0.05), but there was no significant difference in cardiac function between the two groups (P \u0026gt; 0.05). However, improvement of the LVOT can change the incidence of diseases related to the risk of an insufficient blood supply (e.g., stroke, myocardial insufficiency). Therefore, during the Morrow operation, with the aid of 3D printing technology, more cardiac tissue can be removed as much as possible without affecting the heart function of patients.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eThe disadvantages of 3D printing.\u003c/em\u003e\u003c/p\u003e\n\u003cp\u003eHowever, because the current 3D printing technology is caused by vascular perfusion imaging, the nerve conduction bundle cannot be displayed. Lau, IWW and other researchers found that even if 3D printing is perfect, it is still a serious defect to be unable to display the shape of the micro-nerve bundle \u003csup\u003e[\u003cspan class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. When we try to remove hypertrophic myocardial tissue, it is difficult to detect the shape of the conduction beam and block conduction after the operation. This is a problem that 3D printing technology cannot solve. Therefore, in the experimental group and the control group, we found that there was no significant difference in the conduction block between the two groups (P \u0026gt; 0.05).\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003e3D printing of the heart model can enable the doctor to more instinctively understand the patient's heart condition and make the operation more intuitive. The optimal scheme simulation before the operation can help to reduce the damage to adjacent nerves, blood vessels and other tissues during the operation and can decrease the surgical risk. In conclusion, a 3D-printed heart model for in vitro simulation surgery is conducive to creating a more reasonable surgical plan, which can reduce surgical trauma and operation time and is conducive to the recovery and maintenance of the heart.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003cstrong\u003e: \u003c/strong\u003eFor data sharing, please contact the corresponding author of this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003cstrong\u003e: \u003c/strong\u003eThe project was supported by the Beijing Municipal Science \u0026amp; Technology Commission (Z191100006619005), Peking University International Hospital Research Grant YN2019ZD01, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, and Nanjing Medical University Research Grant GSRCKY20210101. The funders had no role in the study design, data collection or analysis, decision to publish, or preparation of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical statement\u003c/strong\u003e\u003cstrong\u003e: \u003c/strong\u003eThis study has been approved by the Hospital Ethics Committee, with the approval No.: ks2585. Patients in this study have signed written informed consent and obtained relevant reports and attached pictures from patients. All methods were performed in accordance with the relevant guidelines and regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement\u003c/strong\u003e\u003cstrong\u003e: \u003c/strong\u003eThis work was supported by the Beijing Municipal Science \u0026amp; Technology Commission (Z191100006619005), Peking University International Hospital Research Grant (YN2019ZD01) and The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, and Nanjing Medical University Research Grant( GSRCKY20210101).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003cstrong\u003e: \u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of conflict of interest: \u003c/strong\u003eNone.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eTen Cate, FJ. Prognosis of hypertrophic cardiomyopathy.J Insur Med.1996 ;28(1):42\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMirza, SJ, Radaideh, GA. Pattern of left ventricular hypertrophy seen on transthoracic echo in patients with hypertensive cardiomyopathy when compared with idiopathic hypertrophic cardiomyopathy. J Pak Med Assoc.2013 Jan;63(1):16\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEidem, BW, Lindor, NM, Driscoll, DJ. Resolution of neonatal hypertrophic cardiomyopathy in an infant with an affected mother. Pediatr Cardiol.1999;20(3):208\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee, S; Squelch, A; Sun, Z. Quantitative Assessment of 3D Printed Model Accuracy in Delineating Congenital Heart Disease. Biomolecules.2021 02 12;11(2).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFrank, DO, Zanation, AM, Dhandha, VH, McKinney, KA, Fleischman, GM, Ebert, CS, et al. Quantification of airflow into the maxillary sinuses before and after functional endoscopic sinus surgery. Int Forum Allergy Rhinol.2013 Oct;3(10):834\u0026ndash;40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSaltman, AE; Lahey, SJ; Francalancia, NA; Tselentakis, EV. Origin of atrial fibrillation in a patient who had undergone septal myectomy. J Cardiovasc Electrophysiol.2003 Jul;14(7):786; author reply 786-7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLekaditi, D; Sakellaropoulos, S. Myosin Modulators: The New Era of Medical Therapy for Systolic Heart Failure and Hypertrophic Cardiomyopathy. Cardiology ResearchVolume 12, Issue 3. 2021. PP 146\u0026ndash;148.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHavndrup, O, Bundgaard, H, Hansen, FV, Pietersen, AH, Kelbaek, HS. Treatment of hypertrophic cardiomyopathy. Ugeskr Laeger.1998 Sep 14;160(38):5495\u0026ndash;500.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMaaroos, M, Pohjant\u0026auml;hti-Maaroos, H, Halonen, J, V\u0026auml;h\u0026auml;mets\u0026auml;, J, Turtiainen, J, Rantonen, J, et al. New onset postoperative atrial fibrillation and early anticoagulation after cardiac surgery. Scand Cardiovasc J.2017 Dec;51(6):323\u0026ndash;326.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee, M, Moharem-Elgamal, S, Beckingham, R, Hamilton, M, Manghat, N, Milano, EG, et al. Evaluating 3D-printed models of coronary anomalies: a survey among clinicians and researchers at a university hospital in the UK. BMJ Open.2019 03 08;9(3):e025227.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHachulla, AL, Noble, S, Guglielmi, G, Agulleiro, D, M\u0026uuml;ller, H, Vall\u0026eacute;e, JP. 3D-printed heart model to guide LAA closure: useful in clinical practice? Eur Radiol.2019 Jan;29(1):251\u0026ndash;258.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJivanji, SGM, Qureshi, SA, Rosenthal, E. Novel use of a 3D printed heart model to guide simultaneous percutaneous repair of severe pulmonary regurgitation and right ventricular outflow tract aneurysm. Cardiol Young.2019 Apr;29(4):534\u0026ndash;537.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHuang, CH, Chen, IC, Chiou, HC. Coronary stent graft for hypertrophic obstructive cardiomyopathy combined with coronary artery disease. J Formos Med Assoc.2003 Aug;102(8):574\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLefebvre, XP, Yoganathan, AP, Levine, RA. Insights from in-vitro flow visualization into the mechanism of systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy under steady flow conditions. J Biomech Eng.1992 Aug;114(3):406\u0026ndash;13.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOhkado, A, Kitamura, M, Hachida, M, Nishinaka, T, Hanayama, N, Sato, W. Hypertrophic obstructive cardiomyopathy with abnormalities of the mitral valve complex. J Heart Valve Dis.1997 Jan;6(1):60\u0026ndash;2.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSayed, SA, Katewa, A, Srivastava, V, Jana, S, Patwardhan, AM. Modified radial v/s biatrial maze for atrial fibrillation in rheumatic valvular heart surgery. Indian Heart J.2014;66(5):510\u0026ndash;6.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eObase Kikuko;\u0026ensp;Maemura Koji;\u0026ensp;Matsumaru Ichiro;\u0026ensp;Eishi Kiyoyuki. Left ventricular outflow tract obstruction related to systolic anterior motion of anomalous secondary chords.Eur J Cardiothorac Surg. 2021 ;7(12):255.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLau, IWW, Liu, D, Xu, L, Fan, Z, Sun, Z. Clinical value of patient-specific three-dimensional printing of congenital heart disease: Quantitative and qualitative assessments. PLoS One.2018;13(3):e0194333.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Three-dimensional printing, Left ventricular outflow tract obstruction, Cardiac surgery, Cardiac imaging ","lastPublishedDoi":"10.21203/rs.3.rs-1206928/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1206928/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eObjective:\u003c/strong\u003eThe purpose of this research was to explore the application value of a three-dimensional (3D)-printed heart in the operation for left ventricular outflow tract (LVOT) obstruction. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e From August 2019 to October 2021, 46 patients with LVOT obstruction underwent surgical treatment at Peking University International Hospital, Southwest Medical University Affiliated Hospital of Traditional Chinese Medicine and Guangyuan First People's Hospital. According to the treatment method, 22 cases were allocated to the experimental group and 24 cases to the control group . The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, postoperative ejection fraction (EF), left ventricular flow velocity (LVFV), LVOT pressure difference (LVP), postoperative interventricular septal thickness (IST), inner diameter of the left ventricular outflow tract (IDLV), systolic anterior motion (SAM), atrioventricular block rate, aortic regurgitation (AR) rate and surgical complication rate of the two groups were compared. \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e The operation time, cardiopulmonary bypass time, intraoperative blood loss, hospitalization time, LVP, postoperative IST, AR, SAM, and postoperative LVFV of the experimental group were significantly lower than those of the control group (P \u0026lt; 0.05). The IDLV was larger than that of the control group (P \u0026lt; 0.05). There was no significant difference in the postoperative EF, atrioventricular block rate or complication rate between the two groups (P \u0026gt; 0.05). \u003c/p\u003e\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e A 3D-printed heart model for in vitro simulation surgery is conducive to formulating a more reasonable surgical plan and reducing surgical trauma and operation time, thereby promoting the recovery and maintenance of the heart.\u003c/p\u003e","manuscriptTitle":"Effect of 3D-Printed Hearts Used in Left Ventricular Outflow Tract Obstruction: A Multicenter Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-01-07 21:11:42","doi":"10.21203/rs.3.rs-1206928/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-02-03T05:34:17+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-01-19T18:20:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"58082fe3-cdfd-4fb7-8028-d123ad18e4e0","date":"2022-01-06T21:34:14+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-01-06T17:06:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-01-06T13:14:40+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2022-01-06T07:12:29+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-01-06T07:03:46+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cardiovascular Disorders","date":"2021-12-27T06:12:19+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"16de676d-2d85-4304-bafb-4dd8283cbaaa","owner":[],"postedDate":"January 7th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":9601398,"name":"Cardiac \u0026 Cardiovascular Systems"}],"tags":[],"updatedAt":"2022-04-19T17:44:09+00:00","versionOfRecord":[],"versionCreatedAt":"2022-01-07 21:11:42","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1206928","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1206928","identity":"rs-1206928","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}