Automatic quantitative measurement of left atrial pressure using mitral regurgitation spectrum：Clinical study on comparison with floating cathete

Automatic quantitative measurement of left atrial pressure using mitral regurgitation spectrum：Clinical study on comparison with floating cathete | 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 Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Automatic quantitative measurement of left atrial pressure using mitral regurgitation spectrum：Clinical study on comparison with floating cathete Yan Jin, Chao-yang Wen, Fengjie Yue, Huishan Wang, Liancheng Yin, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1996717/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 7 You are reading this latest preprint version Abstract To explore how to measure LAP Ep accurately and quantitatively, that is, the left atrial pressure (LAP) measured and calculated by equation method using mitral regurgitation spectrum. Methods The mitral regurgitation spectrum, pulmonary arteriolar wedge pressure (PAWP) and invasive arterial systolic pressure of radial artery of 28 patients were collected simultaneously, including 3 patients with rheumatic heart disease, 15 patients with mitral valve prolapse and 10 patients with coronary artery bypass grafting, patients with moderate or above aortic stenosis were excluded. LAP Bp (Doppler sphygmomanometer method), LAP Eq (Equation method) and LAP C (Catheter method) were measured synchronously, and the measurement results of the three methods were compared and analyzed. We designed a special intelligent Doppler spectrum analysis software to accurately measure LAP Eq . Results Found that there was no significant statistical difference between the measurement results of LAP C and LAP Eq (t = 0.954, P = 0.348),and significant correlation between the two methods [r = 0.908(0.844,0.964), P < 0.001]. Although the measurement results of LAP C and LAP BP are consistent in some patients, there are significant differences in the overall case and weak correlation between the two methods [r = 0.210, (−0.101, 0.510), P = 0.090]. In MVP patients with P1 or P3 prolapse, the peak pressure difference of MR was underestimated due to the serious eccentricity of MR, which affected the accuracy of LAP BP measurement. This study had been approved by the ethics committee of the northern theater general hospital ( K-2019-17), applied prospectively for clinical trial (No. Chictr 190023812) and invention patent application (No. 202210711862.X). Conclusions This study shows that there is a good correlation between LAP Eq and LAP C , which verifies that the noninvasive and direct quantitative measurement of left atrial pressure based on mitral regurgitation spectrum is feasible and has a good application prospect. Left atrial pressure Pulmonary arteriole wedge pressure Mitral regurgitation spectrum Deep learning model of big data training Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Left atrial pressure (LAP) is a reliable data reflecting the left ventricular preload, which can correctly reflect the change of blood volume and sensitively reflect the left ventricular end diastolic pressure. It is an important hemodynamic parameter for adjusting the treatment plan of critically ill patients[1]. However, it is almost impossible to directly measure left atrial pressure in clinical practice. At present, pulmonary arteriole wedge pressure (PAWP) measured by floating catheter is used to replace LAP C in clinic. However, the measurement of PAWP is also invasive, and its clinical application is greatly limited[2.3]. Different degrees of mitral regurgitation (MR) often occurred in normal subjects and patients [4]. At present, there are two methods to quantitatively measure LAP according to mitral regurgitation spectrum. The first method is the "Doppler + sphygmomanometer" method [5.6], that is, the LAP BP is the left ventricular systolic pressure (P) minus the mitral regurgitation pressure difference, LAP BP = P-ΔP. If there is no aortic valve and/or left ventricular outflow tract stenosis, the arterial systolic pressure can replace the left ventricular systolic pressure. The second method is proposed by our team. According to Weiss exponential equation (P=e-t/τ+B), Simplified Bernoulli equation (ΔP=4V 2 ) and P=ΔP+LAP, Bai [7-10] used mathematical methods to derive “binary linear equations”, which have 2 variables, namely the left ventricular relaxation time constant (τ)and LAP, and LAP Ep is measured and calculated by using the decline curve of mitral regurgitation spectrum. The calculation ofτhas been verified by animal experiments [11]. In animal experiments, our team has confirmed that there is a good correlation LAP Ep and LAP C (Catheter measurement) [12]. If a non-invasive, convenient and accurate LAP quantitative measurement method can be developed, the diagnosis and treatment of heart related diseases will enter an accurate stage, which has important clinical value. We evaluated the accuracy of two methods of quantitative measurement of left atrial pressure using mitral regurgitation spectrum, and discussed how to measure LAP noninvasively, accurately and quantitatively. Methods Study design and patients Patients who needed cardiac surgery accompanied with mitral regurgitation were prospectively selected as the research objects, from June 2020 to Oct 2020. The mitral regurgitation spectrum, pulmonary arteriolar wedge pressure (PAWP) and invasive arterial systolic pressure of radial artery of 28 patients were collected simultaneously, 13 males and 15 females, including 3 patients with rheumatic heart disease, 15 patients with mitral valve prolapse and 10 patients with coronary artery bypass grafting, patients with moderate or above aortic stenosis were excluded, aged 47-78 years (62.55±7.28 years) and PAWP 7-29mmHg (15.3±4.9mmHg). Floating catheter With the assistance of intravenous anesthesia, endotracheal intubation and ventilator, the floating catheter was placed through the jugular vein and the arterial systolic pressure was measured by radial artery puncture. The position of the floating catheter was determined by transthoracic ultrasound. PAWP measured by floating catheter was used to replace LAP C . The a wave after the P wave of ECG is generated by the active contraction of left atrium, and the C wave is generated by the closure of mitral valve. The V wave after ECG T wave is generated by left ventricular relaxation and left atrial passive filling during mitral valve opening (the pressure generated by this wave cannot be used as left atrial pressure). Therefore, we take the pressure measured on the PAWP pressure curve at the end of ECG P wave as LAP C . The equipment used include: Fl-005 GE anesthesia monitor (GE Healthcare Finland), Edwards 131 F7 floating catheter (Irvine, USA), PTC-6F pressure monitoring catheter (Jingzhou Yihai Technology Co., Ltd.), etc. Echocardiography The patient was in supine position because of perioperative period. All ultrasound examinations were performed by the same echocardiographic doctors with a Philips ultrasound system (Philips iE33 ultrasound machine; Philips Healthcare, Andover Mass). The mitral regurgitation spectrum was collected under CW, and the angle between the sampling line and the mitral regurgitation beam should be less than 15°. Select different recording speeds of 100mm / s or 150mm / s according to the speed of heart rate to obtain a dull, smooth and complete spectrum. Formulas of LAP Ep According to Weiss exponential equation and simplified Bernoulli equation, the left ventricular relaxation time constant (τ) can be obtained,τ=P/(-dP/dt), Where P is the pressure in the left ventricle, and t is the time from -dp/dtmax, as shown in Figure 1. Bring in the intervals between different speeds to obtain the following formula,τ=(t1-t2)/ln((LAP+16)/(LAP+4)) andτ=(t1-t3)/ln((LAP+36)/(LAP+4)). Theoretically, LAP can be calculated by measuring the intervals between any two speeds. In order to facilitate calculation and measurement of , we selected the time t1, t2 and t3 when the descending branch velocity of mitral regurgitation spectrum was 1m/s, 2m/s and 3m/s respectively. Measurement methods of LAP Ep In order to accurately measure the intervals, t1-t2 and t1-t3, it is necessary to detect the spectrum edge firstly, so we propose an intelligent method based on deep learning to complete this task. The method consists of two parts, a basic network for coarse detection and a post-processing module for refining. We adopt BCD-Unet deep learning model, which was proposed at the ICCV conference in 2019 [13], for edge detection firstly, but there are dislocation and fracture in the detection results. So we design a post-processing module to deal with these problems. The post-processing module mainly uses the polynomial fitting method to refine the edges detected by BCD-Unet, making them clearer and smoother. The overall structure of the proposed method is shown as Figure 2. We use the data collected by the hospital to train the model Iteratively. The trained deep learning model can automatically detect the edge of mitral regurgitation spectrum. Then we encapsulated the model and built the system based on it. The system takes the mitral regurgitation spectrum as input and outputs the edge curve and LAP(directly a number), which is shown as Figure 3. The software can only measure and calculate when the descending branch of the mitral regurgitation spectrum curve is complete, and the curve between at least 1m / s and 3m / S is good. When the peak value of the curve is less than 3m / s, it will not be calculated. Statistical analysis The statistical analysis and data visualization were conducted by SPSS 26.0 statistical software. Paired t-test was used to compare and analyze the measurement results of LAP BP and LAP Eq with LAP C method. Meanwhile, correlation analysis was performed on the measurement results of LAP BP and LAP Eq with LAP C method. The difference between LAP BP and LAP C was less than 10%, which was defined as the consistency between LAP BP and LAP C , otherwise it was inconsistent. 28 patients were divided into two groups, 17 in the consistent group and 11 in the inconsistent group. The causes of inaccurate LAP BP measurement were analyzed by single factor analysis.The significant level is 0.05. Results 1. Paired t-test of the measurement results of LAP Eq and LAP BP with LAP C method A total of 95 mitral regurgitation spectra were obtained in 28 patients. LAP C , LAP Eq and LAP BP measured synchronously in 28 patients were visualized, as shown in Figure 4. The average difference between LAP C and LAP Eq was 0.353, and the 95% confidence interval was (- 1.112, 0.406). Paired t-test found no significant statistical difference between the measurement results of LAP C and LAP Eq (t = 0.954, P = 0.348). The average difference between LAP C and LAP BP was 3.332, and the 95% confidence interval was (- 5.577, -1.087). Paired t-test found no significant statistical difference between the measurement results of LAP C and LAP BP (t = 3.045, P = 0.005). Although the measurement results of LAP C and LAP BP are consistent in some patients, there are significant differences between the two methods in the overall case. As shown in Figure 4. 2. Correlation analysis of the measurement results of LAP BP and LAP Eq with LAP C method The correlation analysis of LAP C and LAP Eq shows that the results measured by the two methods are highly correlated and have significant statistical significance [r=0.908(0.844,0.964), P < 0.001]. The correlation analysis of LAP C and LAP BP shows that the results measured by the two methods show a weak correlation, but they do not have significant statistical significance[r=0.210, (-0.101, 0.510), P=0.090]. As shown in Figure 5. 3. Analysis of the difference between LAP BP and LAP C measurement Whether atrial fibrillation or not had no significant effect on the measurement results of the two methods, P > 0.05; The analysis of disease composition found that the consistency rate of the two methods in patients with coronary heart disease and rheumatic heart disease without aortic stenosis was significantly higher than that in patients with mitral valve prolapse, P=0.002. As shown in Table 1. In 11 MVP patients with P1 or P3 prolapse, the MR peak differential pressure was underestimated due to the MR severe eccentric direction. Seven MVP patients with A2 or P2 prolapse could accurately obtain the MR peak pressure difference and quantitatively measure LAP BP . Table 1 Analysis of inaccurate LAP BP measurement testvar Consistent (n=17) Inconsistent (n=11) statistic p Disease composition CABG & RHD 10(58.82) 0(0) 7.381 0.002 MVP 7(41.18) 11(100) Radial artery systolic pressure.mmHg. 111(101,119) 102(96.5,107.5) 1.248 0.212 MR Peak velocity. m/s. 4.9(4.6,5) 4.5(4.25,4.72) 1.677 0.094 Sinus rhythm 11(64.71%) 5(45.45%) 0.452 0.441 Atrial fibrillation 6(35.29%) 6(54.55%) Discussion This study is a methodological study of LAP quantitative measurement. The advantages and disadvantages of two methods of LAP quantitative measurement using mitral regurgitation spectrum are analyzed. The measurement results of LAP Ep method proposed by our team and LAP C method have good correlation. LAP BP method only has good correlation with LAP C method in some types of patients. Accurate assessment of LAP is an important determinant in the formulation of clinical treatment plan, so floating catheter must be used in many critically ill patients to replace LAP with PAWP. However, in most cases, the assessment of LAP adopts qualitative or semi quantitative non-invasive methods. The combined application of tissue Doppler at atrioventricular valve annulus, mitral anterior flow spectrum and pulmonary vein spectrum can be used to qualitatively or semi quantitatively evaluate LAP [14.15], and can also be used to quantitatively estimate LAP [16], but the correlation with LAP C is only moderate [17.18]. LAP BP measured by "Doppler + sphygmomanometer" method based on mitral regurgitation spectrum is a practical quantitative measurement method of left atrial pressure. However, it is easily affected by the hemodynamics of aortic valve and mitral valve, with poor repeatability and complex operation [5].We carefully analyzed each patient and found that LAP BP method has a good correlation with LAP C method in some types of patients. The LAP BP method has clinical value in patients with central mitral regurgitation. We deduce the calculated LAP according to Weiss exponential equation and simplified Bernoulli equation. In theory, it is a method of real-time quantitative measurement of LAP. To verify the correlation between LAP Eq and LAP C , the mitral regurgitation spectrum (TTE) and PAWP were collected simultaneously when the floating catheter had been placed in cardiac surgery patients before thoracotomy. The LAP C of our subjects is between 8-29mmhg. Paired t- test showed that there was no significant statistical difference between LAP Eq and LAP C (t = 0.954, P = 0.348). There was a high correlation between the results of the two measurement methods (r=0.908, P＜0.001). It shows that LAP Eq can quantitatively measure LAP Eq , that is, two different intervals of the descending branch of the mitral regurgitation spectrum can be brought into the equation calculation, and the specific value of left atrial pressure can be obtained. This method of measuring left atrial pressure is accurate. Animal experiments and clinical trials have proved that the quantitative measurement of left atrial pressure can be carried out by using mathematical equation. Our theoretical derivation is reasonable. However, there are two preconditions: One, a certain amount of mitral regurgitation is needed to measure left atrial pressure by this method; Second, it is necessary to accurately outline the edge of mitral regurgitation spectrum, which is the key to improve the repeatability of LAP Eq measurement. We measured LAP Eq and LAP BP for the same mitral regurgitation spectrum. Compared with LAP C method, it was found that LAP BP method was easily affected by the eccentricity of mitral regurgitation and underestimated the MR peak pressure difference. LAP Eq method measures the decrease rate of left ventricular pressure, whether the mitral regurgitation spectrum is eccentric or not has little effect on the accuracy of this method. LAP Eq method can accurately measure left atrial pressure. In this study, the deep learning model of big data training is adopted, and the software with the ability of automatic tracking envelope and automatic calculation is established to improve the repeatability of LAP Eq measurement. For cases with relatively large mitral regurgitation, the software shows good repeatability; For the cases with relatively few mitral regurgitation, we first sketch the edge manually, then draw the curve of mitral regurgitation spectrum with software, and measure and calculate the LAP, so as to improve the repeatability of this measurement method. The method we used was the quantitative measurement of left atrial pressure directly, while the floating catheter method measured is PAWP. In some cases, PAWP is not equal to left atrial pressure, such as mechanical ventilation with Peep, endotoxin shock[19], pulmonary embolism[20], ARDS, etc. Therefore, the LAP Ep method based on the descending branch of mitral regurgitation spectrum is a direct quantitative measurement method of left atrial pressure with good repeatability, which is worthy of further promotion. Limitations The application software used in LAP Ep measurement in this study can only identify the Doppler spectrum of transthoracic echocardiography, but can not identify the Doppler spectrum of transesophageal echocardiography. Conclusions This study shows that there is a good correlation between LAP Eq and LAP C , which verifies that the noninvasive and direct quantitative measurement of left atrial pressure based on mitral regurgitation spectrum is feasible and has a good application prospect. Declarations This study had been approved by the ethics committee of the northern theater general hospital ( K-2019-17), applied prospectively for clinical trial (No. Chictr 190023812) and invention patent application (No. 202210711862.X). All authors have contributed significantly, and all authors are in agreement with the content of the manuscript. Availability of data and materials had consent for publication. The authors declare that they have no competing interests. .Funding: This work was supported by the National Natural Science Foundation of China (No. 81771833, A study on the method of noninvasive measuring left atrial pressure by using the continuous Doppler spectrum mitral regurgitation). YJ and FY collected and measured the initial data of mitral regurgitation spectrum method and catheter method. YJ was one of major contributors in writing the manuscript. CW was another major contributor in writing the manuscript. HW was the subject designer and the main reviewer. LY and KM had designed proprietary application software to achieve accurate measurement of Doppler spectrum. FX was responsible for statistical analysis of data. All authors read and approved the final manuscript. Acknowledge Not applicable References Thomas L, Abhayaratna WP. Left Atrial Reverse Remodeling: Mechanisms, Evaluation, and Clinical Significance. JACC Cardiovasc Imaging 2017;10:65–77. Liu M, Fang F, Yu C M. Noncardiac comorbidities in heart failure with preserved ejection fraction - commonly ignored fact[J]. Circ J, 2015, 79(5): 954–959. Nadruz W, Shah A M, Solomon S D. Diastolic Dysfunction and Hypertension[J]. Med Clin North Am, 2017, 101(1): 7–17. 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Krahmer RL, Fang HK, Vitello J, Rypins EB, Law WR. Pulmonary capillary wedge pressure estimates of left ventricular preload are inaccurate in endotoxin shock: contribution of Starling resistor forces to septic pulmonary hypertension. Shock. 1994 Nov;2(5):344 – 50. doi: 10.1097/00024382-199411000-00008 . PMID: 7743360. Entress JJ, Dhamee MS, Olund T, Aggarwal A, Hopwood M, Olinger GN. Pulmonary artery occlusion pressure is not accurate immediately after cardiopulmonary bypass. J Cardiothorac Anesth. 1990 Oct;4(5):558 – 63. doi: 10.1016/0888-6296(90)90404-4 . PMID: 2132134. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Major revision 12 Sep, 2022 Reviews received at journal 12 Sep, 2022 Reviewers agreed at journal 09 Sep, 2022 Reviewers invited by journal 06 Sep, 2022 Editor assigned by journal 06 Sep, 2022 Submission checks completed at journal 05 Sep, 2022 First submitted to journal 25 Aug, 2022 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 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-1996717","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":134194986,"identity":"0d82036f-64f0-40d3-b65b-419fc898644d","order_by":0,"name":"Yan Jin","email":"","orcid":"","institution":"General Hospital of Northern Theater Command","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yan","middleName":"","lastName":"Jin","suffix":""},{"id":134194990,"identity":"c1cd0078-5636-43cd-beff-11402178977a","order_by":1,"name":"Chao-yang Wen","email":"","orcid":"","institution":"Peking University International 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3","display":"","copyAsset":false,"role":"figure","size":785882,"visible":true,"origin":"","legend":"\u003cp\u003eLAPEp measured by mitral regurgitation spectrum intelligent analysis system\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-1996717/v1/b1eb9a579fb8de76e5386cc4.png"},{"id":26216108,"identity":"3d7bade2-2ba1-48aa-9c4f-efa36a4f5107","added_by":"auto","created_at":"2022-09-08 16:49:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":73189,"visible":true,"origin":"","legend":"\u003cp\u003ePaired t-test of the measurement results of LAPEq and LAPBP with LAPC method\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-1996717/v1/821bb6c981d89bf305ca68a3.png"},{"id":26216109,"identity":"216517b8-2e3c-406a-804b-22e9af7418a6","added_by":"auto","created_at":"2022-09-08 16:49:46","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":78861,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation analysis of the measurement results of LAPBPand LAPEq with LAPC method\u003c/p\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-1996717/v1/e27d9059fdb56cb881f39267.png"},{"id":26216839,"identity":"56d5a028-c733-4d56-956f-c3e8a24e8753","added_by":"auto","created_at":"2022-09-08 16:54:50","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1426114,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1996717/v1/97d1f838-a315-4f99-a4ad-9ddf95ffbebe.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Automatic quantitative measurement of left atrial pressure using mitral regurgitation spectrum：Clinical study on comparison with floating cathete ","fulltext":[{"header":"Introduction","content":"\u003cp\u003eLeft atrial pressure (LAP) is a reliable data reflecting the left ventricular preload, which can correctly reflect the change of blood volume and sensitively reflect the left ventricular end diastolic pressure. It is an important hemodynamic parameter for adjusting the treatment plan of critically ill patients[1]. However, it is almost impossible to directly measure left atrial pressure in clinical practice. At present, pulmonary arteriole wedge pressure (PAWP) measured by floating catheter is used to replace LAP\u003csub\u003eC\u003c/sub\u003e in clinic. However, the measurement of PAWP is also invasive, and its clinical application is greatly limited[2.3].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eDifferent degrees of mitral regurgitation (MR) often occurred in normal subjects and patients [4]. At present, there are two methods to quantitatively measure LAP according to mitral regurgitation spectrum. The first method is the \u0026quot;Doppler + sphygmomanometer\u0026quot; method [5.6], that is, the LAP\u003csub\u003eBP\u003c/sub\u003e is the left ventricular systolic pressure (P) minus the mitral regurgitation pressure difference, LAP\u003csub\u003eBP\u003c/sub\u003e = P-\u0026Delta;P. If there is no aortic valve and/or left ventricular outflow tract stenosis, the arterial systolic pressure can replace the left ventricular systolic pressure. The second method is proposed by our team. According to Weiss exponential equation (P=e-t/\u0026tau;+B), Simplified Bernoulli equation (\u0026Delta;P=4V\u003csup\u003e2\u003c/sup\u003e) and P=\u0026Delta;P+LAP, Bai [7-10] used mathematical methods to derive\u0026nbsp;\u0026ldquo;binary linear equations\u0026rdquo;, which have 2 variables, namely the left ventricular relaxation time constant (\u0026tau;)and LAP, and LAP\u003csub\u003eEp\u003c/sub\u003e is measured and calculated by using the decline curve of mitral regurgitation spectrum. The calculation of\u0026tau;has been verified by animal experiments [11]. In animal experiments, our team has confirmed that there is a good correlation LAP\u003csub\u003eEp\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e (Catheter measurement) [12].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIf a non-invasive, convenient and accurate LAP quantitative measurement method can be developed, the diagnosis and treatment of heart related diseases will enter an accurate stage, which has important clinical value. We evaluated the accuracy of two methods of quantitative measurement of left atrial pressure using mitral regurgitation spectrum, and discussed how to measure LAP noninvasively, accurately and quantitatively.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003eStudy design and patients\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients who needed cardiac surgery accompanied with mitral regurgitation were prospectively selected as the research objects, from June 2020 to Oct 2020. The mitral regurgitation spectrum, pulmonary arteriolar wedge pressure (PAWP) and invasive arterial systolic pressure of radial artery of 28 patients were collected simultaneously, 13 males and 15 females, including 3 patients with rheumatic heart disease, 15 patients with mitral valve prolapse and 10 patients with coronary artery bypass grafting, patients with moderate or above aortic stenosis were excluded, aged 47-78 years (62.55\u0026plusmn;7.28 years) and PAWP 7-29mmHg (15.3\u0026plusmn;4.9mmHg).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFloating catheter\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWith the assistance of intravenous anesthesia, endotracheal intubation and ventilator, the floating catheter was placed through the jugular vein and the arterial systolic pressure was measured by radial artery puncture. The position of the floating catheter was determined by transthoracic ultrasound. PAWP measured by floating catheter was used to replace LAP\u003csub\u003eC\u003c/sub\u003e. The a wave after the P wave of ECG is generated by the active contraction of left atrium, and the C wave is generated by the closure of mitral valve. The V wave after ECG T wave is generated by left ventricular relaxation and left atrial passive filling during mitral valve opening (the pressure generated by this wave cannot be used as left atrial pressure). Therefore, we take the pressure measured on the PAWP pressure curve at the end of ECG P wave as LAP\u003csub\u003eC\u003c/sub\u003e. The equipment used include: Fl-005 GE anesthesia monitor (GE Healthcare Finland), Edwards 131 F7 floating catheter (Irvine, USA), PTC-6F pressure monitoring catheter (Jingzhou Yihai Technology Co., Ltd.), etc.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEchocardiography\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe patient was in supine position because of perioperative period. All ultrasound examinations were performed by the same echocardiographic doctors with a Philips ultrasound system (Philips iE33 ultrasound machine; Philips Healthcare, Andover Mass). The mitral regurgitation spectrum was collected under CW, and the angle between the sampling line and the mitral regurgitation beam should be less than 15\u0026deg;. Select different recording speeds of 100mm / s or 150mm / s according to the speed of heart rate to obtain a dull, smooth and complete spectrum.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFormulas of LAP\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003eEp\u003c/strong\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003eAccording to Weiss exponential equation and simplified Bernoulli equation, the left ventricular relaxation time constant (\u0026tau;) can be obtained,\u0026tau;=P/(-dP/dt), Where P is the pressure in the left ventricle, and t is the time from -dp/dtmax, as shown in Figure 1. Bring in the intervals between different speeds to obtain the following formula,\u0026tau;=(t1-t2)/ln((LAP+16)/(LAP+4)) and\u0026tau;=(t1-t3)/ln((LAP+36)/(LAP+4)). Theoretically, LAP can be calculated by measuring the intervals between any two speeds. In order to facilitate calculation and measurement of , we selected the time t1, t2 and t3 when the descending branch velocity of mitral regurgitation spectrum was 1m/s, 2m/s and 3m/s respectively.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMeasurement methods of LAP\u003c/strong\u003e\u003csub\u003e\u003cstrong\u003eEp\u003c/strong\u003e\u003c/sub\u003e\u003c/p\u003e\n\u003cp\u003eIn order to accurately measure the intervals, t1-t2 and t1-t3, it is necessary to detect the spectrum edge firstly, so we propose an intelligent method based on deep learning to complete this task. The method consists of two parts, a basic network for coarse detection and a post-processing module for refining. We adopt BCD-Unet deep learning model, which was proposed at the ICCV conference in 2019 [13], for edge detection firstly, but there are dislocation and fracture in the detection results. So we design a post-processing module to deal with these problems. The post-processing module mainly uses the polynomial fitting method to refine the edges detected by BCD-Unet, making them clearer and smoother. The overall structure of the proposed method is shown as Figure 2.\u003c/p\u003e\n\u003cp\u003eWe use the data collected by the hospital to train the model Iteratively. The trained deep learning model can automatically detect the edge of mitral regurgitation spectrum. Then we encapsulated the model and built the system based on it. The system takes the mitral regurgitation spectrum as input and outputs the edge curve and LAP(directly a number), which is shown as Figure 3. The software can only measure and calculate when the descending branch of the mitral regurgitation spectrum curve is complete, and the curve between at least 1m / s and 3m / S is good. When the peak value of the curve is less than 3m / s, it will not be calculated.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe statistical analysis and data visualization were conducted by SPSS 26.0 statistical software. Paired t-test was used to compare and analyze the measurement results of LAP\u003csub\u003eBP\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e with LAP\u003csub\u003eC\u003c/sub\u003e method. Meanwhile, correlation analysis was performed on the measurement results of LAP\u003csub\u003eBP\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e with LAP\u003csub\u003eC\u003c/sub\u003e method. The difference between LAP\u003csub\u003eBP\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e was less than 10%, which was defined as the consistency between LAP\u003csub\u003eBP\u0026nbsp;\u003c/sub\u003eand LAP\u003csub\u003eC\u003c/sub\u003e, otherwise it was inconsistent. 28 patients were divided into two groups, 17 in the consistent group and 11 in the inconsistent group. The causes of inaccurate LAP\u003csub\u003eBP\u003c/sub\u003e measurement were analyzed by single factor analysis.The significant level is 0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003e1. Paired t-test of the measurement results of LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eBP\u0026nbsp;\u003c/sub\u003ewith LAP\u003csub\u003eC\u0026nbsp;\u003c/sub\u003emethod\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 95 mitral regurgitation spectra were obtained in 28 patients. LAP\u003csub\u003eC\u003c/sub\u003e, LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eBP\u0026nbsp;\u003c/sub\u003emeasured synchronously in 28 patients were visualized, as shown in Figure 4. The average difference between LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e was 0.353, and the 95% confidence interval was (- 1.112, 0.406). Paired t-test found no significant statistical difference between the measurement results of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e (t = 0.954, P = 0.348). The average difference between LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e was 3.332, and the 95% confidence interval was (- 5.577, -1.087). Paired t-test found no significant statistical difference between the measurement results of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e (t = 3.045, P = 0.005). Although the measurement results of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e are consistent in some patients, there are significant differences between the two methods in the overall case. As shown in Figure 4.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2. Correlation analysis of the measurement results of LAP\u003csub\u003eBP\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e with LAP\u003csub\u003eC\u003c/sub\u003e method\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe correlation analysis of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e shows that the results measured by the two methods are highly correlated and have significant statistical significance [r=0.908(0.844,0.964), P \u0026lt; 0.001]. The correlation analysis of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e shows that the results measured by the two methods show a weak correlation, but they do not have significant statistical significance[r=0.210, (-0.101, 0.510), P=0.090]. As shown in Figure 5.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e3. Analysis of the difference between LAP\u003csub\u003eBP\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e measurement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhether atrial fibrillation or not had no significant effect on the measurement results of the two methods, P \u0026gt; 0.05; The analysis of disease composition found that the consistency rate of the two methods in patients with coronary heart disease and rheumatic heart disease without aortic stenosis was significantly higher than that in patients with mitral valve prolapse, P=0.002. As shown in Table 1. In 11 MVP patients with P1 or P3 prolapse, the MR peak differential pressure was underestimated due to the MR severe eccentric direction. Seven MVP patients with A2 or P2 prolapse could accurately obtain the MR peak pressure difference and quantitatively measure LAP\u003csub\u003eBP\u003c/sub\u003e.\u003c/p\u003e\n\u003cp\u003eTable 1 Analysis of inaccurate LAP\u003csub\u003eBP\u003c/sub\u003e measurement\u003c/p\u003e\n\u003cdiv align=\"center\"\u003e\n \u003ctable border=\"0\" cellpadding=\"0\" cellspacing=\"0\" width=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" width=\"33.333333333333336%\"\u003e\n \u003cp\u003etestvar\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.658206429780034%\"\u003e\n \u003cp\u003eConsistent\u0026nbsp;(n=17)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.165820642978005%\"\u003e\n \u003cp\u003eInconsistent\u0026nbsp;(n=11)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.690355329949238%\"\u003e\n \u003cp\u003estatistic\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.152284263959391%\"\u003e\n \u003cp\u003ep\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" width=\"13.028764805414552%\"\u003e\n \u003cp\u003eDisease composition\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"20.304568527918782%\"\u003e\n \u003cp\u003eCABG \u0026amp; RHD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.658206429780034%\"\u003e\n \u003cp\u003e10(58.82)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.165820642978005%\"\u003e\n \u003cp\u003e0(0)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" width=\"12.690355329949238%\"\u003e\n \u003cp\u003e7.381\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" width=\"10.152284263959391%\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"31.662269129287598%\"\u003e\n \u003cp\u003eMVP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"33.773087071240106%\"\u003e\n \u003cp\u003e7(41.18)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"34.56464379947229%\"\u003e\n \u003cp\u003e11(100)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" width=\"33.333333333333336%\"\u003e\n \u003cp\u003eRadial artery systolic pressure.mmHg.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.658206429780034%\"\u003e\n \u003cp\u003e111(101,119)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.165820642978005%\"\u003e\n \u003cp\u003e102(96.5,107.5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.690355329949238%\"\u003e\n \u003cp\u003e1.248\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.152284263959391%\"\u003e\n \u003cp\u003e0.212\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" width=\"33.333333333333336%\"\u003e\n \u003cp\u003eMR Peak velocity. m/s.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.658206429780034%\"\u003e\n \u003cp\u003e4.9(4.6,5)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.165820642978005%\"\u003e\n \u003cp\u003e4.5(4.25,4.72)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"12.690355329949238%\"\u003e\n \u003cp\u003e1.677\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"10.152284263959391%\"\u003e\n \u003cp\u003e0.094\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" width=\"33.333333333333336%\"\u003e\n \u003cp\u003eSinus rhythm\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"21.658206429780034%\"\u003e\n \u003cp\u003e11(64.71%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"22.165820642978005%\"\u003e\n \u003cp\u003e5(45.45%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" width=\"12.690355329949238%\"\u003e\n \u003cp\u003e0.452\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" width=\"10.152284263959391%\"\u003e\n \u003cp\u003e0.441\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" width=\"43.20175438596491%\"\u003e\n \u003cp\u003eAtrial fibrillation\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.07017543859649%\"\u003e\n \u003cp\u003e6(35.29%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.728070175438596%\"\u003e\n \u003cp\u003e6(54.55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis study is a methodological study of LAP quantitative measurement. The advantages and disadvantages of two methods of LAP quantitative measurement using mitral regurgitation spectrum are analyzed. The measurement results of LAP\u003csub\u003eEp\u003c/sub\u003e method proposed by our team and LAP\u003csub\u003eC\u003c/sub\u003e method have good correlation. LAP\u003csub\u003eBP\u003c/sub\u003e method only has good correlation with LAP\u003csub\u003eC\u0026nbsp;\u003c/sub\u003emethod in some types of patients.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAccurate assessment of LAP is an important determinant in the formulation of clinical treatment plan, so floating catheter must be used in many critically ill patients to replace LAP with PAWP. However, in most cases, the assessment of LAP adopts qualitative or semi quantitative non-invasive methods.\u0026nbsp;The combined application of tissue Doppler at atrioventricular valve annulus, mitral anterior flow spectrum and pulmonary vein spectrum can be used to qualitatively or semi quantitatively evaluate LAP [14.15], and can also be used to quantitatively estimate LAP [16], but the correlation with LAP\u003csub\u003eC\u0026nbsp;\u003c/sub\u003eis only moderate [17.18].\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eLAP\u003csub\u003eBP\u003c/sub\u003e measured by \u0026quot;Doppler + sphygmomanometer\u0026quot; method based on mitral regurgitation spectrum is a practical quantitative measurement method of left atrial pressure. However, it is easily affected by the hemodynamics of aortic valve and mitral valve, with poor repeatability and complex operation [5].We carefully analyzed each patient and found that LAP\u003csub\u003eBP\u003c/sub\u003e method has a good correlation with LAP\u003csub\u003eC\u003c/sub\u003e method in some types of patients. The LAP\u003csub\u003eBP\u003c/sub\u003e method has clinical value in patients with central mitral regurgitation.\u003c/p\u003e\n\u003cp\u003eWe deduce the calculated LAP according to Weiss exponential equation and simplified Bernoulli equation. In theory, it is a method of real-time quantitative measurement of LAP. To verify the correlation between LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e, the mitral regurgitation spectrum (TTE) and PAWP were collected simultaneously when the floating catheter had been placed in cardiac surgery patients before thoracotomy. The LAP\u003csub\u003eC\u003c/sub\u003e of our subjects is between 8-29mmhg. Paired t- test showed that there was no significant statistical difference between LAP\u003csub\u003eEq\u0026nbsp;\u003c/sub\u003eand LAP\u003csub\u003eC\u0026nbsp;\u003c/sub\u003e(t = 0.954, P = 0.348). There was a high correlation between the results of the two measurement methods (r=0.908, P＜0.001). It shows that LAP\u003csub\u003eEq\u003c/sub\u003e can quantitatively measure LAP\u003csub\u003eEq\u003c/sub\u003e, that is, two different intervals of the descending branch of the mitral regurgitation spectrum can be brought into the equation calculation, and the specific value of left atrial pressure can be obtained. This method of measuring left atrial pressure is accurate.\u003c/p\u003e\n\u003cp\u003eAnimal experiments and clinical trials have proved that the quantitative measurement of left atrial pressure can be carried out by using mathematical equation. Our theoretical derivation is reasonable. However, there are two preconditions: One, a certain amount of mitral regurgitation is needed to measure left atrial pressure by this method; Second, it is necessary to accurately outline the edge of mitral regurgitation spectrum, which is the key to improve the repeatability of LAP\u003csub\u003eEq\u003c/sub\u003e measurement.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eWe measured LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e for the same mitral regurgitation spectrum. Compared with LAP\u003csub\u003eC\u003c/sub\u003e method, it was found that LAP\u003csub\u003eBP\u003c/sub\u003e method was easily affected by the eccentricity of mitral regurgitation and underestimated the MR peak pressure difference. LAP\u003csub\u003eEq\u0026nbsp;\u003c/sub\u003emethod measures the decrease rate of left ventricular pressure, whether the mitral regurgitation spectrum is eccentric or not has little effect on the accuracy of this method. LAP\u003csub\u003eEq\u0026nbsp;\u003c/sub\u003emethod can accurately measure left atrial pressure.\u003c/p\u003e\n\u003cp\u003eIn this study, the deep learning model of big data training is adopted, and the software with the ability of automatic tracking envelope and automatic calculation is established to improve the repeatability of LAP\u003csub\u003eEq\u003c/sub\u003e measurement. For cases with relatively large mitral regurgitation, the software shows good repeatability; For the cases with relatively few mitral regurgitation, we first sketch the edge manually, then draw the curve of mitral regurgitation spectrum with software, and measure and calculate the LAP, so as to improve the repeatability of this measurement method.\u003c/p\u003e\n\u003cp\u003eThe method we used was the quantitative measurement of left atrial pressure directly, while the floating catheter method measured is PAWP. In some cases, PAWP is not equal to left atrial pressure, such as mechanical ventilation with Peep, \u0026nbsp;endotoxin shock[19], pulmonary embolism[20], ARDS, etc. Therefore, the LAP\u003csub\u003eEp\u003c/sub\u003e method based on the descending branch of mitral regurgitation spectrum is a direct quantitative measurement method of left atrial pressure with good repeatability, which is worthy of further promotion.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLimitations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe application software used in LAP\u003csub\u003eEp\u003c/sub\u003e measurement in this study can only identify the Doppler spectrum of transthoracic echocardiography, but can not identify the Doppler spectrum of transesophageal echocardiography.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThis study shows that there is a good correlation between LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e, which verifies that the noninvasive and direct quantitative measurement of left atrial pressure based on mitral regurgitation spectrum is feasible and has a good application prospect.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThis study had been approved by the ethics committee of the northern theater general hospital ( K-2019-17), applied prospectively for clinical trial (No. Chictr 190023812) and invention patent application (No. 202210711862.X). All authors have contributed significantly, and all authors are in agreement with the content of the manuscript. Availability of data and materials had consent for publication. The authors declare that they have no competing interests. .Funding: This work was supported by the National Natural Science Foundation of China (No. 81771833, A study on the method of noninvasive measuring left atrial pressure by using the continuous Doppler spectrum mitral regurgitation). YJ and FY collected and measured the initial data of mitral regurgitation spectrum method and catheter method. YJ was one of major contributors in writing the manuscript. CW was another major contributor in writing the manuscript. HW was the subject designer and the main reviewer. LY and KM had designed proprietary application software to achieve accurate measurement of Doppler spectrum. FX was responsible for statistical analysis of data. All authors read and approved the final manuscript.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledge \u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eThomas L, Abhayaratna WP. Left Atrial Reverse Remodeling: Mechanisms, Evaluation, and Clinical Significance. JACC Cardiovasc Imaging 2017;10:65\u0026ndash;77.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu M, Fang F, Yu C M. Noncardiac comorbidities in heart failure with preserved ejection fraction - commonly ignored fact[J]. Circ J, 2015, 79(5): 954\u0026ndash;959.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNadruz W, Shah A M, Solomon S D. Diastolic Dysfunction and Hypertension[J]. 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Escalera, Bi-Directional ConvLSTM U-Net with Densley Connected Convolutions[J]. arXiv:1909.00166v1 [eess.IV] 31 Aug 2019.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSmallhorn J F, Freedom R M, Olley P M. Pulsed Doppler echocardiographic assessment of extraparenchymal pulmonary vein flow[J]. J Am Coll Cardiol, 1987, 9(3): 573\u0026ndash;579.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGeske J B, Sorajja P, Nishimura R A, et al. Evaluation of left ventricular filling pressures by Doppler echocardiography in patients with hypertrophic cardiomyopathy: correlation with direct left atrial pressure measurement at cardiac catheterization[J]. Circulation, 2007, 116(23): 2702\u0026ndash;2708.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCowie B, Kluger R, Rex S, et al. Noninvasive estimation of left atrial pressure with transesophageal echocardiography[J]. Ann Card Anaesth, 2015, 18(3): 312\u0026ndash;316.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFigueras-Coll M, Sanchez-De-Toledo J, Gran F, et al. Echocardiography in the Assessment of Left Atrial Pressure After Pediatric Heart Surgery: A Comparison Study With Measurements Obtained From Left Atrial Catheter[J]. World J Pediatr Congenit Heart Surg, 2015, 6(3): 438\u0026ndash;442.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePozzoli M. Non-invasive evaluation of the hemodynamic profile in patients with heart failure: estimation of left atrial pressure. Ital Heart J Suppl. 2000 Oct;1(10):1326\u0026ndash;33. Italian. PMID: 11068716.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrahmer RL, Fang HK, Vitello J, Rypins EB, Law WR. Pulmonary capillary wedge pressure estimates of left ventricular preload are inaccurate in endotoxin shock: contribution of Starling resistor forces to septic pulmonary hypertension. Shock. 1994 Nov;2(5):344 \u0026ndash; 50. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00024382-199411000-00008\u003c/span\u003e\u003cspan address=\"10.1097/00024382-199411000-00008\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 7743360.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eEntress JJ, Dhamee MS, Olund T, Aggarwal A, Hopwood M, Olinger GN. Pulmonary artery occlusion pressure is not accurate immediately after cardiopulmonary bypass. J Cardiothorac Anesth. 1990 Oct;4(5):558 \u0026ndash; 63. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/0888-6296(90)90404-4\u003c/span\u003e\u003cspan address=\"10.1016/0888-6296(90)90404-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 2132134.\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":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Left atrial pressure, Pulmonary arteriole wedge pressure, Mitral regurgitation spectrum, Deep learning model of big data training","lastPublishedDoi":"10.21203/rs.3.rs-1996717/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1996717/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eTo explore how to measure LAP\u003csub\u003eEp\u003c/sub\u003e accurately and quantitatively, that is, the left atrial pressure (LAP) measured and calculated by equation method using mitral regurgitation spectrum.\u003c/p\u003e \u003cp\u003eMethods\u003c/p\u003e \u003cp\u003eThe mitral regurgitation spectrum, pulmonary arteriolar wedge pressure (PAWP) and invasive arterial systolic pressure of radial artery of 28 patients were collected simultaneously, including 3 patients with rheumatic heart disease, 15 patients with mitral valve prolapse and 10 patients with coronary artery bypass grafting, patients with moderate or above aortic stenosis were excluded. LAP\u003csub\u003eBp\u003c/sub\u003e(Doppler sphygmomanometer method), LAP\u003csub\u003eEq\u003c/sub\u003e (Equation method) and LAP\u003csub\u003eC\u003c/sub\u003e (Catheter method) were measured synchronously, and the measurement results of the three methods were compared and analyzed. We designed a special intelligent Doppler spectrum analysis software to accurately measure LAP\u003csub\u003eEq\u003c/sub\u003e.\u003c/p\u003e \u003cp\u003eResults\u003c/p\u003e \u003cp\u003eFound that there was no significant statistical difference between the measurement results of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eEq\u003c/sub\u003e (t\u0026thinsp;=\u0026thinsp;0.954, P\u0026thinsp;=\u0026thinsp;0.348),and significant correlation between the two methods [r\u0026thinsp;=\u0026thinsp;0.908(0.844,0.964), P\u0026thinsp;\u0026lt;\u0026thinsp;0.001]. Although the measurement results of LAP\u003csub\u003eC\u003c/sub\u003e and LAP\u003csub\u003eBP\u003c/sub\u003e are consistent in some patients, there are significant differences in the overall case and weak correlation between the two methods [r\u0026thinsp;=\u0026thinsp;0.210, (\u0026minus;0.101, 0.510), P\u0026thinsp;=\u0026thinsp;0.090]. In MVP patients with P1 or P3 prolapse, the peak pressure difference of MR was underestimated due to the serious eccentricity of MR, which affected the accuracy of LAP\u003csub\u003eBP\u003c/sub\u003e measurement. This study had been approved by the ethics committee of the northern theater general hospital ( K-2019-17), applied prospectively for clinical trial (No. Chictr 190023812) and invention patent application (No. 202210711862.X).\u003c/p\u003e \u003cp\u003eConclusions\u003c/p\u003e \u003cp\u003eThis study shows that there is a good correlation between LAP\u003csub\u003eEq\u003c/sub\u003e and LAP\u003csub\u003eC\u003c/sub\u003e, which verifies that the noninvasive and direct quantitative measurement of left atrial pressure based on mitral regurgitation spectrum is feasible and has a good application prospect.\u003c/p\u003e","manuscriptTitle":"Automatic quantitative measurement of left atrial pressure using mitral regurgitation spectrum：Clinical study on comparison with floating cathete","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-09-08 16:49:44","doi":"10.21203/rs.3.rs-1996717/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2022-09-12T14:38:42+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2022-09-12T05:50:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"5ec2c23f-7ffc-4721-b1b4-eb4b001a6d6d","date":"2022-09-10T00:26:06+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-09-06T23:06:16+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-09-06T07:35:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2022-09-05T10:07:47+00:00","index":"","fulltext":""},{"type":"submitted","content":"European Journal of Medical Research","date":"2022-08-25T07:42:58+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"european-journal-of-medical-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ejmr","sideBox":"Learn more about [European Journal of Medical Research](http://eurjmedres.biomedcentral.com)","snPcode":"40001","submissionUrl":"https://submission.nature.com/new-submission/40001/3","title":"European Journal of Medical Research","twitterHandle":"@BioMedCentral","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"267268f1-7299-4107-94c9-234e7b305605","owner":[],"postedDate":"September 8th, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2022-10-10T08:44:33+00:00","versionOfRecord":[],"versionCreatedAt":"2022-09-08 16:49:44","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1996717","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1996717","identity":"rs-1996717","version":["v1"]},"buildId":"oE6Zbj460LM0Up2FdVbMZ","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}