Limited data exist on outcomes for patients with mitral stenosis (MS) who have previously undergone percutaneous mitral commissurotomy (PMC) and later require surgical mitral valve replacement (MVR). This study evaluates the impact of prior PMC on clinical outcomes in rheumatic MS patients undergoing surgical MVR. We retrospectively compared rheumatic MS patients with and without a history of PMC who underwent surgical MVR between 2010 and 2020. The primary outcome was 5-year all-cause mortality, while secondary outcomes included mitral reintervention, rehospitalization for heart failure (HHF), stroke/transient ischemic attack (TIA), and major bleeding over 5 years. Among 1,137 patients with rheumatic MS undergoing surgical MVR, 77 (6.8%) had a history of prior PMC. Compared with patients without prior PMC, patients with prior PMC were more often female and presented with a lower baseline mitral valve pressure gradient. No significant difference in 5-year mortality was observed between patients with and without prior PMC (20.5% vs 17.6%; log-rank p = 0.614). Multivariate analysis confirmed no association between prior PMC and mortality risk (HR: 1.42; 95% CI: 0.82–2.46; p = 0.212). Secondary outcomes of HHF and major bleeding were not different between the 2 groups, although rates of mitral reintervention and stroke/TIA were higher in the prior PMC group (3.9% vs 0.8%; p = 0.014 and 5.2% vs 0.9%; p = 0.002, respectively). In conclusion, in patients with rheumatic MS undergoing surgical MVR, prior PMC did not increase long-term mortality, indicating its safety as an initial treatment. However, the increased risk of mitral reintervention and stroke/TIA suggests the need for long-term monitoring.
Mitral stenosis (MS) is a narrowing of the mitral valve, usually caused by rheumatic heart disease, leading to commissural fusion, leaflet thickening, and chordae tendineae calcification. The primary treatment for severe rheumatic MS consists of either percutaneous mitral commissurotomy (PMC) or surgical intervention, with the decision guided by valve anatomy and surgical risk. , Evidence indicates that PMC is comparable to surgery in appropriately selected patients. ,,,,, However, restenosis may occur following PMC, necessitating subsequent surgical intervention in some cases. , Although evidence remains limited, it has been postulated that patients undergoing surgery for recurrent MS following PMC may experience worse outcomes compared to those without a prior history of PMC. This could be attributed to more severe valve pathology, as residual valve injury from the initial commissurotomy may lead to commissural calcification. Many surgeons suggest that this may contribute to higher rates of morbidity and mortality in this patient group. Currently, limited data exist regarding the impact of prior PMC on the mortality and morbidity of patients with rheumatic MS who undergo surgical treatment for restenosis. Therefore, this study aimed to investigate the characteristics of patients with a history of PMC and evaluate its effect on clinical outcomes in those undergoing mitral valve surgery for rheumatic MS.
Methods
We retrospectively reviewed medical records of consecutive patients with severe rheumatic MS who underwent their first surgical mitral valve intervention and performed surgical mitral valve replacement (MVR) at Queen Sirikit Heart Center of the Northeast, Khon Kaen University in Thailand, between January 2010 and December 2020, and included them in our MS database. We excluded patients if transthoracic echocardiography (TTE) data from within 6 months prior to the procedure were unavailable or if the transthoracic echocardiography (TTE) image quality was poor. The remaining cohort constituted the study population and was categorized into 2 groups based on prior PMC history. The study protocol conforms to the ethical guidelines of the 1975 Declaration of Helsinki as reflected in a priori approval by the Khon Kaen University Institutional Review Board, with a waiver of informed consent obtained due to the study’s retrospective nature.
Baseline and perioperative clinical characteristics were collected for all patients. Echocardiographic evaluations were conducted by experienced level-III trained echocardiologists following current guidelines. , Rheumatic MS was defined as a narrowing mitral valve orifice characterized by commissural fusion, leaflet thickening, and chordae tendineae calcification. MS severity was assessed by measuring the mitral valve orifice area (MVA) through planimetry in the parasternal short-axis view or by pressure half-time (PHT) using continuous-wave (CW) Doppler, with severe MS defined as MVA <1.5 cm². , In cases of atrial fibrillation, which may introduce significant beat-to-beat variability, PHT was averaged over 3 beats. Wilkins’ score was calculated to characterize the mitral valve apparatus. Right ventricular systolic pressure (RVSP) was estimated by combining the peak systolic tricuspid regurgitation pressure gradient with the estimated right atrial pressure derived from the inferior vena cava width. Significant concomitant valve disease was defined as the presence of moderate or greater stenosis or regurgitation in any other valves, while significant coronary artery disease was diagnosed by coronary angiography if there was >70% stenosis in a major epicardial artery or >50% stenosis in the left main coronary artery. Treatment decisions, including PMC or surgical MVR, were made by the heart team. All PMC procedures were performed using an Inoue balloon via an anterograde trans-septal approach, with balloon size in millimeters calculated by the formula (height in cm/ 10) + 10; optimal results were determined by the interventionists’ judgment. For surgical MVR, the valve type, size, and surgical technique were determined at the discretion of experienced cardiac surgeons.
The primary outcome was 5-year all-cause mortality, while secondary outcomes included rates of mitral reintervention, rehospitalization for heart failure (HHF), stroke/transient ischemic attack (TIA), and major bleeding at 5 years. All-cause mortality data were extracted from the National Death Certification database, whereas all secondary outcomes were reviewed through medical records.
Continuous variables were tested for normality using the Shapiro-Wilk test and were reported as mean ± standard deviation or median with interquartile range (IQR), as appropriate. Comparisons of continuous variables were made using the Student’s t-test or the Mann-Whitney U-test, depending on the distribution. Categorical variables were presented as counts and percentages and were compared using Pearson’s Chi-square test or Fisher’s exact test, as appropriate. Time to first event for primary and secondary outcomes over a 5-year period was estimated using Kaplan–Meier analysis and assessed using the log-rank test. The Cox proportional hazards model, with hazard ratios (HR) and 95% confidence intervals (CI), was used to examine the impact of clinical characteristics on outcomes. Univariate analyses were conducted, and variables with significant p-values were further analyzed through multivariate analysis to assess associations with the primary outcome. A p-value of <0.05 was considered statistically significant. All statistical analyses were performed using SPSS version 26 (SPSS Inc., Chicago, IL, USA).
Results
We identified 1,292 consecutive patients with severe rheumatic MS undergoing surgical MVR during the study period. One hundred and fifty-five patients were excluded from the study, and the remaining 1,137 patients constituted our study population, in which 77 (6.8%) patients had a history of prior PMC. The study flow diagram is presented in Figure 1 . The baseline and postoperative characteristics are provided in Tables 1 and 2 , respectively. Compared with patients without prior PMC, patients with prior PMC were more likely to be female (74% vs 62%; p = 0.035), had lower creatine (0.8 (IQR: 0.7–1.0) vs 0.9 (IQR: 0.8–1.1) mg/dL; p = 0.013), and had lower mitral valve mean pressure gradient (8.5 (IQR: 6.3–10.9) vs 10.2 (IQR: 7.5–13.8) mmHg; p <0.001) at baseline. At postprocedure, patients with prior PMC had higher rates of postoperative stroke (2.6% vs 0.3%; p = 0.003) and hospital-acquired pneumonia (9% vs 4%; p = 0.017) compared with patients without prior PMC. However, the length of hospital stay was comparable between the 2 groups (13.5 (IQR: 10–21) vs 14 (IQR: 11–18) days; p = 0.964). Notably, higher rates of penicillin V prescription at discharge were observed in the prior PMC group (10% vs 4%; p = 0.006).
Study flow diagram. MS = mitral stenosis; MVR = mitral valve replacement; PMC = percutaneous mitral commissurotomy; TTE = transthoracic echocardiography.
Table 1
Baseline characteristics
| Baseline characteristics | Total ( N = 1137) | Prior PMC ( N = 77) | No prior PMC ( N = 1060) | p-value |
|---|---|---|---|---|
| Median Age (years) | 52 (46–59) | 50 (44–55) | 52 (46–60) | 0.066 |
| Female Sex | 714 (63%) | 57 (74%) | 657 (62%) | 0.035 |
| Weight (kg.) | 54 (48–61) | 55.0 (46.4–61.8) | 54.0 (48.0–61.0) | 0.591 |
| Height (cm.) | 159 (153.0–165.0) | 155.0 (150.5–163.0) | 159.0 (153.0–165.0) | 0.216 |
| BMI (kg/m 2) | 21.5 (19.2–23.9) | 21.8 (19.4–23.8) | 21.4 (19.1–23.8) | 0.181 |
| Basic laboratories | ||||
| – Hct (%) | 37.6 (34.1–40.6) | 37.1 (33.5–40.3) | 37.8 (34.2–40.7) | 0.268 |
| – WBC (cells/mm 3) | 7100 (5900–8900) | 6800 (5735–8950) | 7100 (5950–8895) | 0.432 |
| – Platelet (cells/mm 3) | 216K (172K–269K) | 222K (169K–269K) | 215K (172K–268K) | 0.424 |
| – Creatinine (mg/dL) | 0.9 (0.8–1.1) | 0.8 (0.7–1.0) | 0.9 (0.8–1.1) | 0.013 |
| Pre-op CAG | 0.078 | |||
| – No CAG | 324 (28%) | 18 (23%) | 306 (29%) | |
| – Normal | 774 (68%) | 55 (71%) | 719 (68%) | |
| – Mild CAD | 21 (2%) | 4 (5%) | 17 (2%) | |
| – Significant CAD | 13 (1%) | 0 (0%) | 13 (1%) | |
| CAD | 34 (3%) | 4 (5%) | 30 (3%) | 0.243 |
| Valve type | 0.914 | |||
| – Mechanical valve | 806 (71%) | 55 (71%) | 751 (71%) | |
| – Tissue valve | 331 (29%) | 22 (29%) | 309 (29%) | |
| Repair or replacement of other valves | 722 (64%) | 43 (56%) | 679 (64%) | 0.148 |
| CABG | 44 (4%) | 2 (3%) | 42 (4%) | 0.549 |
| Comorbidities | ||||
| – Hypertension | 197 (17%) | 12 (16%) | 185 (17%) | 0.676 |
| – Diabetes mellitus | 107 (9%) | 6 (8%) | 101 (10%) | 0.614 |
| – Dyslipidemia | 95 (8%) | 4 (5%) | 91 (9%) | 0.299 |
| – Smoking | 286 (25%) | 14 (18%) | 272 (26%) | 0.144 |
| – Prior HF | 604 (53%) | 38 (49%) | 566 (53%) | 0.492 |
| – Atrial fibrillation | 931 (82%) | 60 (80%) | 871 (82%) | 0.350 |
| – Prior stroke | 109 (10%) | 7 (9%) | 102 (10%) | 0.878 |
| – CKD stage ≥3 | 372 (33%) | 21 (27%) | 351 (33%) | 0.292 |
| Functional class | 0.673 | |||
| – I | 41 (4%) | 2 (5%) | 39 (6%) | |
| – II | 395 (35%) | 27 (68%) | 368 (60%) | |
| – III | 204 (18%) | 10 (25%) | 194 (32%) | |
| – IV | 8 (1%) | 1 (2%) | 7 (1%) | |
| Medications | ||||
| – Warfarin | 892 (78%) | 63 (82%) | 829 (78%) | 0.457 |
| – Beta-blocker | 498 (44%) | 32 (42%) | 466 (44%) | 0.681 |
| – ACEI/ARB | 104 (9%) | 5 (6%) | 99 (9%) | 0.403 |
| – Diuretics | 915 (80%) | 62 (80%) | 853 (80%) | 0.992 |
| – Penicillin V | 32 (3%) | 2 (3%) | 30 (3%) | 0.905 |
| LVEF | 61.4 (53.9–67.9) | 62.8 (54.4–68.4) | 61.1 (53.9–67.9) | 0.524 |
| Wilkins score | 9.0 (8.0–10.0) | 8.0 (7.8–9.0) | 9.0 (8.0–10.0) | 0.143 |
| Preop Hemodynamic parameters | ||||
| – MVA by planimetry (cm 2) | 0.87 (0.64–1.10) | 0.83 (0.64–1.05) | 0.86 (0.62–1.09) | 0.825 |
| – MVA by PHT (cm 2) | 0.86 (0.68–1.11) | 0.85 (0.64–1.10) | 0.86 (0.68–1.11) | 0.967 |
| – MV mean PG (mmHg) | 10.1 (7.5–13.8) | 8.5 (6.3–10.9) | 10.2 (7.5–13.8) | < 0.001 |
| – RVSP (mmHg) | 47.2 (37.6–57.7) | 45.0 (34.4–53.9) | 47.2 (37.7–57.6) | 0.081 |
| Other valve involvement | 538 (47%) | 44 (57%) | 494 (47%) | 0.074 |
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