PREDICTORS OF LONG-TERM OUTCOME AFTER PERCUTANEOUS BALLOON MITRAL VALVULOPLASTY

Background. Percutaneous balloon mitral valvuloplasty is known to produce short-term hemodynamic and symptomatic improvement in many patients with mitral stenosis. Comprehensive assessment of the clinical usefulness of balloon valvuloplasty requires evaluation of patients' long-term outcomes. Methods. We performed balloon mitral valvuloplasty in 146 patients between October 1, 1985, and October 1, 1991. Base-line demographic, clinical, echocardiographic, and hemodynamic variables were evaluated in order to identify predictors of long-term event-free survival. Results. Balloon mitral valvuloplasty was completed successfully in 136 (93 percent) of the patients in whom the procedure was attempted; it resulted in an increase in the mean (+/-SD) mitral-valve area from 1.0+/-0.4 to 2.1+/-0.9 cm2 and a decrease in the mean transmitral pressure gradient from 14+/-5 to 6+/-3 mm Hg (P<0.001 for both comparisons). The estimated overall five-year survival rate was 76+/-5 percent, and the estimated five-year event-free survival rate (the percentage of patients without mitral-valve replacement, repeat valvuloplasty, or death from cardiac causes) was 51+/-6 percent. According to multivariate Cox proportional-hazards analysis, the independent predictors ot longer event-tree survival were a lower mitral-valve echocardiographic score (a measure ot mitral-valve deformity; range, 0 tor a normal valve to 16 tor a seriously deformed valve; P<0.001), lower left ventricular end-diastolic pressure (P = 0.001), and a lower New York Heart Association (NYHA) functional class (P = 0.04). Patients with no risk tactors tor early restenosis or only one risk factor (echocardiographic score >8, left ventricular end-diastolic pressure >10 mm Hg, or NYHA functional class IV) had a predicted five-year event-free survival rate of 60 to 84 percent, whereas patients with two or three risk factors had a predicted five-year event-free survival rate of only 13 to 41 percent. Conclusions. Balloon mitral valvuloplasty as a treatment for selected patients with mitral stenosis has good long-term results. The long-term outcome after this procedure can be predicted on the basis of patients' base-line characteristics.