Impact of Mitral Stenosis and Aortic Atresia on Survival in Hypoplastic Left Heart Syndrome

Abstract

Aortic atresia has been implicated as a risk factor for decreased survival after stage 1 palliation. Prior studies evaluating the association of anatomic subtypes and mortality report conflicting results. Our objective was to determine if mitral valve patency with aortic atresia is associated with increased mortality in hypoplastic left heart syndrome (HLHS). All patients (n = 72) with classic HLHS born between August 1996 and May 2002, who underwent stage I Norwood palliation, had presenting echocardiograms reviewed for patency of the mitral and aortic valves. The cohort was divided into three groups: aortic atresia-mitral atresia (AA-MA), aortic stenosis-mitral stenosis (AS-MS), and aortic atresia-mitral stenosis (AA-MS). Analysis included analysis of variance techniques for continuous variables and the 2-tailed Fisher exact test for categoric variables. Survival analysis was performed using the Kaplan-Meier method with log-rank testing. Of the 72 patients, 36 had AA-MA, 17 had AS-MS, and 19 had AA-MS. The stage 1 hospital survival was 92% for the entire cohort, 97% for AA-MA, 94% for AS-MS, and 79% for AA-MS (p = 0.05). Interstage mortality was 8% (6 of 72) overall, but was 21% (4 of 19) for AA-MS versus 6% (2 of 36) for AA-MA and 0% for AS/MS. Overall survival to date was 79% for the entire cohort but was 58% for AA-MS, 86% for AA/MA, and 88% for AA-MS (p = 0.015). Aortic atresia alone was not associated with increased mortality (p = 0.2). In patients with HLHS, aortic atresia was associated with increased mortality only in the presence of a patent mitral valve. The highest incidence of death was observed primarily during the interstage period.