Utility of the Penn Classification in Predicting Outcomes of Surgery for Acute Type A Aortic Dissection

The Penn classification, a risk assessment system for acute type A aortic dissection (AAAD), is based on preoperative ischemic conditions. We investigated whether Penn classes predict outcomes after surgery for AAAD. Three hundred fifty-one patients with DeBakey type I AAAD treated surgically, January 1997 to January 2011, were divided into 4 groups per Penn class: Aa (no ischemia, n = 187), Ab (localized ischemia with branch malperfusion, n = 67), Ac (generalized ischemia with circulatory collapse, n = 46), and Abc (localized and generalized ischemia, n = 51). Early and late outcomes were compared between groups. In-hospital mortality was 3% (6 of 187) for Penn Aa, 6% (4 of 67) for Penn Ab, 17% (8 of 46) for Penn Ac, and 22% (11 of 51) for Penn Abc. Multivariate logistic regression analysis showed Penn classes Ac and Abc, operation time >6 hours, and entry in the descending thoracic aorta to be risk factors for in-hospital mortality. Incidences of neurologic, respiratory, and hepatic complications differed between groups. Five-year cumulative survival was 85% in the Penn Aa group, 74% in the Penn Ab group (p = 0.027 vs Penn Aa), 78% in the Penn Ac group, and 67% in the Penn Abc group (p <0.001 vs Penn Aa). In conclusion, morbidity and mortality are high in patients with generalized ischemia. The Penn classification appears to be a useful risk assessment system for AAAD, predictive of outcomes.