Independent factors associated with outcomes of parachute mitral valve in 84 patients.

BACKGROUND Parachute mitral valve (PMV) is defined as a unifocal attachment of the mitral valve chordae to a single or dominant papillary muscle and may cause subvalvar obstruction. We sought to determine factors associated with outcomes. METHODS AND RESULTS Patients (n=84; 64% male) who presented between 1977 and 2001 at a median age of 3 days (range, birth to 5.4 years) were assessed with PMV (without atrioventricular septal defect). Associated cardiac anomalies in 99% included aortic coarctation in 68%, atrial septal defect in 54%, ventricular septal defect in 46%, aortic valve stenosis in 32%, subaortic stenosis in 20%, and left ventricular hypoplasia in 19%, with complex anomalies in 14%. Noncardiac anomalies were noted in 32%. Survival (n=18 deaths) was 82% at 1 year and 79% at 10 years, with independent risk factors including left ventricular hypoplasia (P<0.001) and atrial septal defect (P<0.003). Freedom from surgical mitral valvotomy (n=11 patients) was 95% at age 6 months and 80% at 10 years, with independent risk factors including the absence of aortic coarctation (P<0.02) and the presence of subaortic stenosis (P<0.04). There was no significant increase in mean gradient of the PMV over time, but higher gradient was independently associated with the presence of supravalvar mitral stenosis (P<0.001), absence of atrial septal defect (P<0.04), presence of ventricular septal defect (P<0.02), and subsequent mitral valvotomy (P<0.01). CONCLUSIONS Outcomes for patients with PMV are dependent on the spectrum of associated cardiac lesions. The degree of mitral valve obstruction remains stable, and the majority will not require valvotomy.