This single-center study evaluated 305 Chinese patients who presented to our hospital between January 2008 and December 2018 and were eligible for inclusion in this retrospective study. We included patients who: (i) were diagnosed with nonrheumatic isolated PMPL confirmed by echocardiography or transesophageal echocardiography (TEE) and (ii) had only undergone surgery with CR or QR. We excluded patients if they (i) had a history of surgery for mitral valve disease, (ii) were diagnosed with mitral valve prolapse (MVL) due to ischemic cardiomyopathy or endocarditis, (iii) were diagnosed with mitral stenosis and congenital mitral valve disease, and (iv) had anterior or bileaflet prolapse.
This retrospective study was approved by the ethics committee of Union Hospital of Fujian Medical University and conformed to the Declaration of Helsinki. The requirement for informed consent was waived owing to the retrospective nature of the study.
The data collected included baseline characteristics, preoperative conditions, operative details, postoperative outcomes, and follow-up data. Baseline characteristics included sex, age, body mass index, heart function classification (NYHA), acute left heart failure, hydrothorax, coronary heart disease, hypertension, diabetes mellitus, atrial fibrillation, chronic obstructive pulmonary disease, left ventricular ejection fraction (LVEF), left atrial diameter, left ventricular end-diastolic/systolic diameter (LVEDD/LVESD), and mitral regurgitation (MR) grade. Operative details included operative approach, operative time, cardiopulmonary bypass (CPB) time, aorta-clamping time, and MVP failure. Postoperative outcomes included 30-day mortality and major adverse outcomes, including hemolysis, acute renal failure, gastrointestinal hemorrhage, multiple organ dysfunction, mechanical ventilation, intensive care in the ICU, and hospitalization time. Follow-up data included follow-up time, death, LVEF, left atrial diameter, LVED/LVESD, acute heart failure, chronic heart failure, new-onset atrial fibrillation, recurrent MR (+++/++++), reoperation for recurrent MR, and the interval between the initial operation and reoperation. Postoperative hemolysis was defined by progressive anemia and dark urine after MVP in a patient with no history of hemolysis before MVP, and the observation of residual mitral regurgitation byechocardiography .
Intraoperatively, all patients were under general anesthesia, and TEE was routinely performed. TEE confirmed the location and extent of MPL. Thoracoscopic or conventional median sternal incision or partial incision of the lower sternum was used to access the pericardial cavity. After heparinization with 3 mg/kg heparin sodium, CPB was established when the activated clotting time of whole blood was > 480 s. When the nasopharyngeal temperature dropped to 30–32℃, the aorta was cross-clamped, and myocardial protective cardioplegia fluid was injected through the ascending aortic root perfusion tube. Carbon dioxide was used to flood the surgical field. The left atrium was accessed via the atrial septum or atrioventricular sulcus, and the mitral valve was exposed, with a detailed examination of the mitral valve, subvalvular structure, and papillary muscles. Valve competency was tested using a bulb syringe, and the location and extent of MPL were determined. CR or QR procedure was then performed.
The CR procedure was performed using artificial chordae tendineae Gore-tex sutures (W. L. Gore & Associates, Inc, Elkton, Maryland) sewn through the posterolateral papillary muscle 16. The artificial chordae were brought up and sewn through the prolapsed posterior mitral valve a few millimeters from the edge of the valve. Multiple artificial chordae were used when necessary. Valve competency was tested by filling the left ventricle with a saline solution using a bulb syringe to determine the length of the chordae. With the length of the chordae adjusted, a titanium clip was placed on the chordae to avoid sliding the knot while tying the chordae. The valve competency was again tested with a bulb syringe. If the result of the valve competency was satisfactory, the mitral valvuloplasty ring (BalMedic, Beijing Bairen Medical Technology Co., Ltd. Beijing), Edwards (Lifesciences Corp., Irvine, CA, USA), St Jude (St. Jude Medical, St. Paul, Minnesota, USA), or Medtronic (Medtronic Inc. Minneapolis, Minnesota, USA) was selected according to the size of the measured annulus and was sutured to the annulus.
The QR procedure adopted the techniques described in Carpentier’s report after careful examination of the diseased valve 4. Valve repair proceeded with QR of the prolapsed portion of the posterior leaflet with the corresponding annular plication, followed by suture reapproximation of the free leaflet edges. The valve competency was tested, and the mitral valvuloplasty ring was sutured to the annulus. The surgical incision was closed, the cross-clamped ascending aorta was opened, and the heart resumed beating. Valve competency was reassessed by TEE after CPB was stopped. If the results were satisfactory, the operation was completed. If the valve competency was unsatisfactory, or the mitral valve still had moderate or more regurgitation, then re-repair surgery was conducted.
After discharge, patients were followed-up in the outpatient clinic, follow-up room, through telephone, or WeChat, and warfarin was administered orally every day for 3 months. Before discharge and 3 months after surgery, patients underwent transthoracic echocardiography, which was then performed annually. The patients were followed-up until December 2021.
Data are presented as numbers or percentages for categorical variables, whereas median and interquartile range or mean ± standard deviation were used for continuous variables according to whether they followed a Gaussian distribution. T-test or Mann–Whitney U test for continuous variables and χ2 test for categorical variables. The survival curve was determined using the Kaplan–Meier curve and log-rank test to assess group differences. The analysis was performed using SPSS version 19.0 (IBM Corp., Armonk, NY, USA). The threshold for significance was set at P < 0.05.