Restrictive Atrial Septum Defect Becomes a Risk Factor for Norwood Palliation of Hypoplastic Left Heart Syndrome Only When It Is Combined with Mitral or Aortic Atresia

Abstract

Restrictive atrial septal defect (ASD) is described as risk factor for Norwood procedure because of elevated pulmonary resistance. We hypothesized that it invariably could not cause pulmonary hypertension, unless it was combined with mitral valve or aortic valve atresia. We investigated how restrictive ASD influenced survival of patients with hypoplastic left heart syndrome (HLHS) who underwent Norwood operation. A total of 118 HLHS patients who underwent surgery between January 2005 and December 2012 were grouped into three groups. Group 1 included 31 patients with restrictive ASD combined with mitral or aortic atresia; Group 2 composed of 12 patients with restrictive ASD and mitral and aortic stenosis; Group 3 (n = 75) had no ASD restriction. Survival was determined for each group. Multivariate analysis was conducted to test risk factors for mortality. Mean follow-up was 26.3 ± 24.1 months. Survival was 78.7% ± 4.2% at 30-month interval and onward after Norwood procedure for the whole cohort; it was 43.8% ± 10.0%, 91.7% ± 8.0%, and 77.3% ± 5.0% for Group 1, 2, and 3, respectively. The difference was significant between Group 1 and Group 2 and 3: p < 0.001. Survival was similar for Group 2 and Group 3: p = 0.45. Combination of restrictive ASD and mitral or aortic atresia was found to be the sole risk factor for early and late mortality (odds ratio: 3.5, 95% confidence interval: 1.8-7.1, p < 0.001). Restrictive ASD only affects survival of HLHS patients following Norwood procedure if it is associated with mitral or aortic atresia.