Comprehensive Aristotle Score: Implications for the Norwood Procedure

Background Aristotle score is emerging as a reliable tool to measure surgical performance. We estimated the comprehensive Aristotle score for the Norwood procedure, correlated it with survival, and considered its impact on surgical management of hypoplastic left heart syndrome. Methods Comprehensive Aristotle score was retrospectively calculated for 39 consecutive Norwood procedures performed from 2001 to 2004. Survival was estimated by the Kaplan-Meier method. Results The Aristotle scores ranged from 14.5 to 23.5 (mean, 19.12 ± 2.52; median, 19.5). The score was 20 or greater in 44% (17 of 39) of cases. The most frequent patient-adjusted factors were aortic atresia (n = 16), interrupted aortic arch (n = 9), mechanical ventilation to treat cardiorespiratory failure (n = 19) and shock resolved at time of surgery (n = 13). Hospital mortality was 58.8% (10 of 17) in case of score of 20 or more and 9.1% (2 of 22) for score less than 20 (p = 0.0014). From 2003 on, all patients with a score less than 20 survived. Actuarial estimate of survival at 1 year is 56.2% ± 7.9% and there have been no late deaths after 1 year. One-year survival is much lower (p = 0.001) for patients with scores of 20 or greater (29.4% ± 11.05%) compared with those whose scores were less than 20 (77.3% ± 8.9%). Conclusions This study shows significant correlation of comprehensive Aristotle score with hospital mortality and late survival after Norwood palliation. It suggests that operative survival on the order of 90% may be achieved in patients with comprehensive complexity scores of less than 20. Efforts should be devoted to improve survival of high-risk patients (score ≥ 20).