Percutaneous mitral balloon valvotomy: six-year follow-up

Percutaneous mitral valvotomy (PMV) is an alternative to the surgical treatment of mitral stenosis. Results obtained with PMV appear to depend on the echocardiographical characteristics of the valvular apparatus. The purpose of this study was to report the immediate and late-term results with PMV. The incidence of late events (restenosis, mitral valve replacement and death), and their correlation with echocardiographic score (Wilkin's score) are also discussed.

Between December 1987 and August 1999, a total of 160 PMVs were performed at our institution. Ninety-six patients with a minimum of 6 months follow-up and echocardiographic evaluation of the mitral valve (Wilkin's score) before and after the procedure were selected for this study. Follow-up was available for 99% of the patients, with a mean follow-up of 33 +/- 22 months (range, 6 months to 11 years). Hazard ratio (HR) and Cox's regression were used for statistical analyses.

PMV was successfully performed in 97% of the cases; in 84%, the result was considered optimal. The incidence of complications related to the procedure was 10%; no mortality was observed due to PMV. Severe mitral regurgitation was observed in 7% of the patients, but only 3% of the total group developed ventricular dysfunction or worsened their New York Heart Association functional class. Eight-four percent of the patients were free of late events at the end of the follow-up period. A restenosis rate of 34% was observed during follow-up; this rate did not correlate with age, functional class or atrial fibrillation. Restenosis was associated with pulmonary hypertension (HR 2.85; 95% confidence interval, 0.68-11.80). Also, Wilkin's score was not useful to predict the development of restenosis or clinical events in the mid- to long-term.

In our series, PMV had a high immediate success rate and a low incidence of complications due to the procedure. Incidence of late events was also low and was unrelated to the Wilkin's score; however, recurrence of stenosis was observed in one-third. Pulmonary hypertension should be considered to be an important clinical predictor of restenosis.