Predictors of long-term event-free survival and of freedom from restenosis after percutaneous balloon mitral commissurotomy

Background Most long-term studies after balloon mitral commissurotomy (BMC) were from industrialized countries. Less is known about the long-term results of BMC from developing countries where patients are younger with fewer mitral valve deformities. Methods Between December 1987 and December 1998, we performed BMC in 654 patients whose mean age was 33 +/- 13, years. Baseline and postprocedural variables were evaluated to identify predictors of event-free survival (survival without repeat BMC or mitral valve replacement) and of freedom from restenosis defined as a mitral valve area (MVA) greater than or equal to1.5 cm(2) after BMC and <1.5 cm(2) at follow-up. Results The actuarial survival rates were 98%, 98%, and 97%. at 5, 7, and 10 years, respectively. The 5-, 7-, and 10-year event-free survival rates were 85%, 81%, and 72%. Multivariate predictors of a higher 10-year event-free survival rate were lower echocardiographic score (79% for a score <less than or equal to>8, 61% for a score of 9 to 11, 62% for a score greater than or equal to 12, P < .001) and cardiac sinus rhythm (P = .04) before BMC, lower mean left atrial pressure (P < .001), lower mitral valve gradient (P < .001), and less than or equal to grade 2 mitral regurgitation (P = .036) after BMC. Restenosis occurred in 16% of patients. The restenosis-free rates were 88%, 80%, and 66% at 5, 7, and 10 years, respectively. A higher freedom from restenosis at 10 years was associated with a lower score (77% for a score <less than or equal to>8, 45% for a score of 9-11 and 50% for a score greater than or equal to 12, P = .03) and a larger MVA before BMC (P = .03), a larger MVA (P < .001), and a lower mitral valve gradient (P = .04) after BMC. Conclusions BMC produces excellent 10-year results in patients with pliable mitral stenosis and good results in patients with semipliable or calcified mitral stenosis. BMC is the procedure of choice in patients with pliable valves and it is a reasonable treatment option in young patients with unfavorable mitral valve anatomy.