Repair of left ventricular inflow tract lesions in Shone's anomaly: valve growth and long-term outcome.

Background: The degree of involvement of left ventricular inflow tract obstruction is the predominant factor determining outcome in Shone's anomaly. In this series of patients with Shone's anomaly, we evaluated the impact of mitral valve (MV) repair strategies performed to correct the components of this anomaly on growth of the valve and long-term functional outcome in children.

Methods: In the last 25 years, 45 children, mean age 5.16 ± 5.0 years (median, 3.9; range, 2 months-16.8 years), underwent surgical correction of Shone's anomaly. Coarctation of the aorta was found in 40%, subaortic stenosis due to fibromuscular hypertrophy was found in 55%, and subvalvar membrane was found in 66% of these patients. Left ventricular inflow tract obstruction was brought about by fused commissures with dysplastic and shortened chordae in 53.3%, valve hypoplasia in 11.1%, supravalvar mitral ring in 100%, and parachute valve in 17.8 of patients%.

Results: Various repair strategies were performed according to the presenting morphologic characteristics in patients with either previously corrected or concomitant correction of the left-sided obstructive lesions. Mean duration of follow-up was 17.5 ± 1.5 years. Freedom from reoperation was 52.8% ± 11.8%, wherein 23 patients underwent repeated MV repair and 1 patient underwent MV replacement after failed attempts at repair. The cumulative survival rate was 70.3% ± 8.9% at 15 years. Severity and type of mitral abnormalities, left ventricular outflow tract lesions, and pulmonary hypertension are risk factors for reoperation and mortality (p < 0.05).

Conclusions: Repair allowed growth of the MV. Long-term outcome of MV repair in Shone's anomaly is related to the degree that the obstructive lesions can be relieved.