From 2010 to 2019, 1192 patients with degenerative mitral valve regurgitation underwent surgery at our hospital. Patients who were younger than 18 years old, concomitant with congenital heart disease (CHD), and had heart surgery previously were excluded. And 1069 patients were identified. Patients were divided into PLP, ALP, and BLP groups according to their mitral valve pathology.

All procedures were performed through a median sternotomy. Aorta and superior and inferior vena cava intubations were used to establish cardiopulmonary bypass. The mitral valve was exposed through a right atrium, atrial septal, or atrial sulcus incision. Before surgery, TEE was performed conventionally to further explore the structure of MV, help us better establish the surgical plans.

PLP was corrected through quadrangular or triangular resection and involved the use of the sliding technique if further resection was needed. Due to the importance of the recent “respect rather than resect” principle, the leaflet folding and polytetrafluoroethylene chordae were also adapted, especially for patients with isolated P2 prolapse. For commissural prolapse, the commissural closure or folding was used.

ALP repair is considered more challenging than PLP repair. Therefore, for patients with ALP, polytetrafluoroethylene chordae, commissural closure and triangular resection were adopted. Additionally, the size of annuloplasty ring or band was according to the surface area of the anterior leaflet.

Transoesophageal echocardiography was routinely performed to evaluate the quality of the repair. If there were residual moderate MR, it would be re-repaired.

Othe procefures were also performed as required.

The patients were followed up at 3, 6, and 12 months, and then annually. The outcomes include the long term survival, recurrent mitral valve regurgitation and mitral valve reoperation. The degree of regurgitation was classified as mild (effective regurgitate orifice area (EROA) 0.2 cm${}^2$), moderate (0.2–0.39 cm${}^2$), or severe ($\ge$0.4 cm${}^2$) [5]. Patients with more than moderate mitral valve regurgitation were considered to have recurrent mitral valve regurgitation. The pulmonary hypertension was diagnosed by the pulmonary artery systolic pressure (PASP) measured by the echocardiography using the modified Bernoulli equation on the transtricuspid continuous-wave Doppler signal while adding right atrium (RA) pressure. And patients were divided into 3 groups: normal pulmonary hypertension (PH), mild PH (35 to 44 mmHg), moderate PH (45 to 59 mmHg) and severe PH ($\ge$60 mmHg) [6].

Data are presented as mean $\pm$ SD for continuous variables while the differences among groups were expressed using the the analysis of variance (ANOVA). For categorical variables, data are presented as frequencies and percentages, and the differences among groups were tested using the chi-square analysis (Pearson).

Cox’s proportional hazard regression model was used to evaluate the effects of multiple potential factors on long-term survival. Kaplan–Meier analysis was used to assess the differences in survival among the groups. The log-rank test determined statistical significance among the risk categories for all Kaplan–Meier analyses. Data analysis was performed using SPSS version 22 (SPSS, Inc. Chicago, IL, USA) and R 3.6.1 using the cmprsk package (R Foundation for Statistical Computing, 169 Vienna, Austria).

In total, 1069 patients were identified in this study, among whom 273 (25.5%) had ALP, 148 (13.8%) had BLP, and 648 (60.6%) had PLP. A total of 90 patients underwent MVR, among whom 27 had ALP, 30 had PLP, and 33 had BLP. The total repair rate was nearly 92%, with 91% for ALP, 95% for PLP, and 82% for BLP. Patients with ALP or BLP had a higher probability of repair failure than patients with PLP.

60 patients were considered to have Barlow’s disease. Most patients with ALP (65.7%) were female, while males constituted the majority of patients with ALP (35.5%) and BLP (35.1%). Patients with PLP were the oldest (56.30 $\pm$ 10.96 years old), followed by patients with BLP (50.46 $\pm$ 14.09 years old) and ALP (53.33 $\pm$ 13.08 years old). Patients with PLP and ALP had the highest prevalence of hypertension and atrial fibrillation (AF), respectively. Patients with PLP had the smallest left atrial diameter and left ventricular end-diastolic and end-systolic diameters (Table 1).

The Maze procedure was more common for ALP repair. BLP repair had longer cardiopulmonary bypass (CPB) and aortic cross-clamp durations than PLP and ALP repairs (p 0.05). 10 patients died in-hospital, 5 patients had PLP, 3 had ALP, and 2 had BLP (Table 2).

The surgical techniques were shown in Table 3 detail. The average size of the annuloplasty ring was 32 mm. The Carpentier-Edwards Physio I/II Semirigid Annuloplasty Rings were most frequently used (n = 874). The Sorin Memo 3D Semirigid Annuloplasty Rings (n = 169) and Medtronic CG FUTURE annuloplasty rings (n = 26) were also used [7].

Table 4 shows the echocardiographic data before patient discharge. The left atrial diameter, left ventricular end-diastolic diameter; left ventricular end-systolic diameter; and ejection fraction was not significantly different between the groups.

During a mean follow-up of 5 years (5–7 years), Nearly 5% (53/1059) of patients were lost during follow-up. And 33 patients died, among whom 23 had PLP, 6 had ALP, and 4 had BLP. Cardiac deaths totaled 14 in the PLP group due to heart failure (n = 9), myocardial infarction (n = 2), sudden unexplained death (n = 2), and infective endocarditis (n = 1); 5 in the ALP group due to heart failure (n = 1), sudden unexplained death (n = 1), and infective endocarditis (n = 1); and 2 in the BLP group due to heart failure (n = 1) and infective endocarditis (n = 1).

Fig. 1 shows the long-term survival of patients with ALP, BLP, and PLP. The 10-year overall survival was 93 $\pm$ 3% for patients with PLP and 96 $\pm$ 1% for patients with ALP or BLP, which was not significantly different between the groups.

Fig. 1.

Overall survival for isolated anterior, bileaflet, and posterior leaflet prolapse repair. BLP, bileaflet prolapse; ALP, anterior leaflet prolapse; PLP, posterior leaflet prolapse.

Overall, 13 patients underwent reoperation, among whom 7 had PLP, 5 had ALP, and 1 had BLP. The long-term freedom from reoperation rates were 96.8 $\pm$ 1.6%, 98.5 $\pm$ 0.6%, and 99.5 $\pm$ 0.5% for PLP, ALP, and BLP, respectively (Fig. 2).

Fig. 2.

Cumulative incidence of reoperation for isolated anterior, bileaflet, and posterior leaflet prolapse repair. BLP, bileaflet prolapse; ALP, anterior leaflet prolapse; PLP, posterior leaflet prolapse.

119 patients had mitral valve regurgitation during follow up , including 82 patients with moderate MR and 37 patients with severe MR, among whom 61 had PLP (19 had severe MR), 42 had ALP (11 had severe MR), and 16 had BLP (7 had severe MR). The long-term freedom from recurrent MR rates for PLP, ALP, and BLP was 72.4 $\pm$ 4.7%, 85.2 $\pm$ 2.4%, and 82.7 $\pm$ 3.6%, respectively. After adjusting for confounding variables via the competitive risk model, BLP repair resulted in comparable long-term durability to ALP and PLP repairs. Notably, however, PLP repair had better durability than ALP repair.

Fig. 3 shows the cumulative incidences of recurrent MR between PLP, ALP, and BLP. ALP may be a greater risk factor for long-term recurrent MR compared to PLP.

Fig. 3.

Cumulative incidence of recurrent mitral regurgitation for isolated anterior, bileaflet, and posterior leaflet prolapse repair. BLP, bileaflet prolapse; ALP, anterior leaflet prolapse; MR, Mitral regurgitation; PLP, Posterior leaflet prolapse.

In our institution, patients were asked to have echocardiography 1 month, 6 months and 1 year after operation at our hospital. If there was nothing wrong, patients could have echocardiography once a year at the local hospitals. And 787 patients had undergone echocardiography, and 467 patients underwent echocardiography in our hospital.

Table 5 shows that the pathology of mitral valve is not a risk factor of long-term survival. Table 6 shows that after adjusting for confounding variables via the competitive risk model, the BLP repair had a comparable long-term durability to ALP and PLP repair. Notably, however, PLP repair had better long-term durability than ALP repair.

This is a retrospective observational study performed at a single center. The sample size is not large enough, especially for the patients with BLP, which may cause bias. The longest period of follow-up is 10 years, we are unabled to obtain very long-term outcomes.We also can not obtain all patients’ echocardiograms during follow-up, which may impact assessment of the duribiity of mitral valve repair. This retrospective observational study is the summary of our previous jobs. And prospective research about DMR is also underway.