Parachute mitral valve: morphologic descriptors, associated lesions, and outcomes after biventricular repair

In "true" parachute mitral valve, mitral valve chordae insert into one papillary muscle. In parachute-like asymmetric mitral valve, most or all chordal attachments are to one papillary muscle. This study compared morphologic features, associated lesions, and palliation strategies of the two parachute mitral valve and dominant papillary muscle types and examined interventions and midterm outcomes in patients with biventricular circulation.

Echocardiography and autopsy databases were reviewed to identify patients with "true" parachute mitral valve or parachute-like asymmetric mitral valve from January 1987 to January 2006. Predictors of palliation strategy in the entire cohort, mitral stenosis on initial echocardiogram, and mortality in the biventricular cohort were determined with logistic regression.

Eighty-six patients with "true" parachute mitral valve (n = 49) or parachute-like asymmetric mitral valve (n = 37) were identified. Chordal attachments to the posteromedial papillary muscle were more common (73%). The presence "true" parachute mitral valve (P = .008), hypoplastic left ventricle (P < .001), and two or more left-sided obstructive lesions (P = .002) predicted univentricular palliation. Among 49 patients maintaining biventricular circulation at follow-up, 8 died median follow-up 6.4 years (7 days-17.8 years). Multivariate analysis revealed that "true" parachute mitral valve was associated with mitral stenosis on initial echocardiogram (P = .03), and "true" parachute mitral valve (P = .04) and conotruncal anomalies (P = .0003) were associated with mortality. Progressive mitral stenosis was found in 11 patients; 2 underwent mitral valve interventions, and 1 died.

Nearly two thirds of this parachute mitral valve cohort underwent biventricular palliation. Some progression of mitral stenosis occurred, although mitral valve intervention was rare. "True" parachute mitral valve was associated with mitral stenosis on initial echocardiogram. "True" parachute mitral valve and conotruncal anomalies were associated with mortality in the biventricular population.