Patient Selection

All patients undergoing MVR at the study hospital from January 2015 to December 2022 (N = 218) were reviewed. Patients who underwent concomitant MVR with coronary artery bypass graft surgery (n = 33) or aortic valve replacement (n = 35) were not included. Patients with infective endocarditis (n = 7) and patients who had previously undergone MVR (n = 3) were also excluded. Accordingly, 127 patients were included in the study. (Curiously, 13 patients were not included because no SVA preservation method was used.) These patients were allocated to 1 of 2 groups according to the techniques used to preserve the SVA. In group 1, which comprised patients undergoing PLP, the anterior leaflet was completely resected and the posterior leaflet was preserved. In group 2, which comprised patients with severe leaflet extension and subvalvular fusion treated with ACI, the mitral valve was excised completely and substituted with artificial chordae.

The same team operated on all patients. Informed consent was obtained from each patient or a responsible relative. The study was conducted in line with the Declaration of Helsinki and was approved by the hospital's ethics committee (No. E-71522473-050.01.04-249192-174, dated May 23, 2023). All relevant preoperative, intraoperative, and postoperative data were recorded. In addition, operative data were ret-rospectively extracted from medical records, surgery notes, and the computerized database of the institution's Department of Cardiac Surgery.

Surgical Techniques

The surgical approach involved conventional median sternotomy in all patients. Following aortobicaval cannulation, surgeries were performed under cardiopulmonary bypass with moderate hypothermia (28-32 °C). Cardiac arrest was achieved with a cold blood cardioplegia infusion via antegrade delivery. After a left atriotomy was performed, the mitral valve was evaluated. If it was not suitable for repair, the decision was made to replace it. In 31 (24.4%) patients, a transseptal approach was used. The choice of subvalvular preservation technique was based on the surgeons’ judgment and the patient's mitral valve structure. Techniques for mitral valve subvalvular preservation have evolved over the years. In 63 (50.0%) patients, MVR with PLP was performed. For patients with extensive rheumatic mitral valve disease, following resection of both leaflets, restricted primary chords were also resected. In such cases, the native chordae were substituted with artificial chordae, which involved using 2 pairs of 3-0 polytetrafluoroethylene sutures placed on the heads of the anterolateral and posteromedial papillary muscles. The suture for the anterolateral papillary muscle was placed at the 9 to 10 o'clock position on the mitral annulus, while the suture for the posteromedial papillary muscle was placed at the 2 to 3 o'clock position on the mitral annulus. The level of the zone of opposition was adjusted according to the level of the annulus. Prosthetic mitral valves were implanted using several pledgeted mattress sutures, with pledgets on the atrial side. Following valve replacement, the movement of the prosthetic leaflets was observed to ensure that the leaflets were not entrapped by the 3-0 expanded polytetrafluoroethylene sutures. The current study included 54 patients with atrial fibrillation (AF); the left atrial appendage was ligated in all these patients, and left atrial ablation was performed in 47 of them. Intraoperative transesophageal echocardiography was routinely used for intraoperative assessment following cardiopulmonary bypass.

Follow-Up

Follow-up data were analyzed using cardiology and cardiac surgery outpatient follow-up notes, primary care records, and entries in the institutional computerized database as well as telephone interviews. Echocardiographic findings were recorded in the computerized database of the hospital. The mean (SD) duration of follow-up until the last echocardiogram was 59.97 (23.63) months (range, 6-99 months). Clinical parameters recorded during the follow-up period included early (<30 days) and late (≥30 days) mortality after surgery. All patients received anticoagulant treatment with warfarin sodium for 3 months following placement of a bioprosthetic valve or permanently if they had AF or a mechanical heart valve.

Statistical Analysis

Data analysis was performed using IBM SPSS Statistics, version 25.0, for Windows (Microsoft Corp). Several methods were employed to evaluate whether the variables adhered to normal distribution, including visual analysis (eg, histograms, probability plots) and analytical analysis (eg, Kolmogorov-Smirnov test, Shapiro-Wilk test). Continuous variables were expressed as mean (SD) or as median (IQR), depending on the normality of their distribution. The Pearson χ² test or Fisher exact test, as applicable, was used to compare discrete variables, while the independent t test was used for comparisons of continuous variables between the groups. Comparisons between preoperative and postoperative echocardiographic markers by group were based on paired t tests. Two-tailed P <.05 was considered statistically significant.

Patients and Surgical Data

In total, 127 patients were enrolled in this study, in line with inclusion criteria. A total of 63 patients were analyzed in group 1 (treatment with PLP), while 64 patients were analyzed in group 2 (treatment with ACI). The mean (SD) ages of patients in group 1 and group 2 were 63.1 (9.65) and 57.1 (12.3) years, respectively (P = .003). Group 1 included 38 women (60.3%), and group 2 included 39 women (60.9%; P = .943). Baseline characteristics of all patients are summarized in Table I. There were no statistically significant differences between the groups with respect to diabetes, hypertension, chronic kidney failure, chronic obstructive pulmonary disease, preoperative AF, or cerebrovascular disease (P >.05). Etiology of valve pathology and lesions were identified by the surgeon on inspection of the valve during surgery and based on echocardiographic findings. The distribution of mitral valve pathologies is shown in Table I. Most patients (n = 91) had mitral valve regurgitation. All 127 operations were performed via median sternotomy. Tricuspid ring annuloplasty was required in 96 (75.6%) patients who had tricuspid valve insufficiency. Left atrial ablation (Cox-maze IV procedure) was performed in 47 (37%) patients with preoperative AF. Operative data from all patients are summarized in Table II. The mitral valve was replaced with a bioprosthetic tissue valve in 66 (52%) patients and a mechanical valve in 61 (48%) patients.

TABLE I. Demographics of All Patients

View Fullscreen

TABLE II. Operative Data

View Fullscreen

Early and Late Outcomes

Patients’ early and late postoperative outcomes are presented in Table III. Early (<30 days) mortality rates in groups 1 and 2 were 6.3% (n = 4) and 9.4% (n = 6), respectively (P = .53). Five patients had low cardiac output syndrome (observed on postoperative days 2, 4, 4, 5, and 6, respectively), 1 patient died of acute kidney failure, 3 patients died as a result of respiratory distress syndrome, and 1 patient died following a cerebrovascular accident. The groups did not differ in terms of rates of postoperative complications (P > .05).

TABLE III. Early and Late Morbidity and Mortality

View Fullscreen

Mean (SD) follow-up time was 59.97 (23.63) months (range, 6-99 months), and late (≥30 days) postoperative outcomes were as follows: 9 (7.1%) patients died—3 (2.4%) of cardiac causes and 6 (4.7%) of other causes. The causes of late cardiac death were congestive heart failure, sudden death, and myocardial infarction, each in a single patient. Other causes of late death were cerebrovascular accident (2 patients in group 1 and 1 patient in group 2), tumor (1 patient in each group), and unknown (1 patient in group 1). Prosthetic valve endocarditis developed in 2 patients (1 in each group). Two patients underwent a follow-up surgery to address prosthetic valve endocarditis (1 patient in group 2) and severe paravalvular leakage (1 patient in group 1).

Echocardiographic Follow-Up

Preoperative and postoperative echocardiographic data are shown in Table IV. Left ventricular end-diastolic diameter (LVEDD) decreased significantly following ACI (P < .001) and insignificantly following PLP (P = .20). In both groups, there was a statistically significant reduction (P < .001) in left ventricular end-systolic diameter (LVESD) and left atrium diameter during the postoperative period compared with their respective preoperative levels. During follow-up, left ventricular ejection fraction (LVEF) was found to have increased beyond preoperative levels in both groups, but these differences were not statistically significant (P > .05). Systolic pulmonary artery pressure decreased insignificantly in group 1 (P = .25) and significantly in group 2 (P = .039).

TABLE IV. Changes in Late Echocardiographic Parameters of Cardiac Functions in All Patients

View Fullscreen

Study Limitations

This study has several limitations. First, it was limited by its retrospective cohort design and the small number of patients followed over an 8-year period. Second, the study was performed in a single center. To determine ideal techniques for the preservation of left ventricular performance following MVR, more rigorous and standardized research must be undertaken in future large, multicenter studies with comprehensive and lengthy follow‐up; then, final conclusions can be drawn regarding first‐line options when MVR is indicated. Finally, patients in this study had various valvular pathologies, and some patients were followed for only a short time. Although multivariate analysis could not be conducted because of this study's small sample size, the lack of between‐group differences in all baseline data, except age and operative factors, reduced the potential confounding effects.