Aims: The optimal timing of percutaneous mitral commissurotomy (PMC) remains controversial in asymptomatic patients with moderate mitral stenosis (MS). We sought to compare the long-term outcomes of early preemptive PMC and a conventional treatment strategy.
Methods and results: From 1997 to 2007, we prospectively enrolled 244 consecutive asymptomatic patients (191 women, age 51 ± 11 years) with moderate rheumatic MS who were potential candidates for early PMC. The treatment groups were not randomly assigned and the choice of early PMC or conventional treatment for each patient was at the discretion of the attending physician. The primary endpoint was defined as the composite of cardiovascular mortality, cerebral infarction, systemic embolic events, and PMC-related complications. In the PMC group, there were no procedure-related deaths and mitral valve area was increased from 1.26 ± 0.11 to 2.07 ± 0.28 cm(2) immediately after PMC (P < 0.001). During a median follow-up of 8.3 years, there were 3 cardiovascular deaths and 5 cerebral infarctions in the PMC group (n= 106) compared with 16 cardiovascular deaths, 12 cerebral infarctions, and 7 systemic embolic events in the CONV group (n = 138). The estimated actuarial 11-year event-free survival rate was 89 ± 4% in the PMC group and 69 ± 5% in the CONV group (P < 0.001) but not significantly different in those without atrial fibrillation and previous embolism (86 ± 5% in the PMC group and 79 ± 6% in the CONV group at 11 years, P = 0.28). For the 62 propensity score-matched pairs, the risk of cardiovascular endpoint was significantly lower in the PMC than in the CONV group (hazard ratio: 0.327; 95% CI: 0.112-0.954; P = 0.041).
Conclusion: In asymptomatic patients with moderate MS and favourable valve morphology, the clinical benefits of early PMC may outweigh the risks associated with early intervention, but prospective randomized trials are required to confirm the efficacy of early PMC.