BACKGROUND: The causes for restenosis following percutaneous balloon mitral valvotomy (PBMV) vary according to the population undergoing this technique. The aim of this study was to compare the immediate and long-term results of patients undergoing a second and third PBMV to patients submitted to a single dilatation of the mitral valve for the treatment of severe mitral stenosis. METHODS: Patients were divided into two groups: group A with 90 patients who, due to clinical and echocardiographic restenosis, were submitted to more than one procedure, and group B with 90 patients, selected by a random sample who underwent a single successful procedure. The echocardiographic variables analyzed to compare the results in the same group and between groups A and B were mitral valve area (MVA), maximal and mean diastolic gradients, left atrial diameter and incidence and time to restenosis. RESULTS: In group A, the first dilatation was successfully performed in 87 (96.7%) patients. Mean MVA after the first dilatation was smaller in group A patients than in group B patients (1.97 ± 0.17 cm² vs. 2.10 ± 0.33 cm²; P = 0.011). In both groups there was no statistically significant difference before and immediately after the first procedure in the reduction of the maximal and mean diastolic gradients and in mean LA diameters. In group A patients, success criteria were achieved in 77 (85.5%) patients after the second procedure. Mean MVA at this time was smaller than after the first PBMV (1.83 ± 0.28 cm² vs. 1.97 ± 0.17 cm²; P < 0.005). A significant decrease was observed for the maximal and mean diastolic gradients after the first and the second dilatation in this group. A third PBMV was successfully performed in all nine patients in the same group. Improvement of echocardiographic parameters was also observed in patients submitted to a second and third PBMV. Mean time to echocardiographic restenosis between the first, second and third PBMV was 54.12, 25.23 and 29.30 months, respectively. CONCLUSIONS: Smaller MVA and earlier restenosis were observed after a second and third PBMV when compared to the first dilatation; however, these findings do not contraindicate the procedure. Although smaller, mitral valve areas achieved immediately after these procedures were still within the success range for the procedure in most of these patients and justify repeated PBMV in selected cases.
Mitral valve stenosis; Balloon dilatation; Treatment outcome
