Mortality in Acute Type A Aortic Dissection: Validation of the Penn Classification

Background. Intraoperative and in-hospital mortality after surgery for acute type A dissection depends largely on preoperative conditions, specifically the presence of localized or generalized ischemia. Recently, the Penn classification of patients with acute type A aortic dissection has been described. The primary aim was to validate the Penn classification and to investigate preoperative variables related to mortality. Methods. All consecutive patients operated for acute type A aortic dissection, 1990 to 2009 (n = 360), were included in a retrospective observational study. Univariate and multivariable analyses were used to identify variables related to intraoperative and in-hospital mortality. Propensity scoring was used to adjust for treatment selection bias. Results. Overall intraoperative mortality was 7% (24 of 360) and in-hospital mortality was 19% (69 of 360). Two hundred nineteen patients (61%) were Penn class Aa (14% in-hospital mortality), 51 (14%) class Ab (24% mortality), 63 (18%) class Ac (24% mortality), and 27 (8%) class Abc (44% mortality), p =0.007. In multivariable analysis, Penn class Ac and Abc were independently related to intraoperative death (odds ratio 5.0 and 5.4, respectively), and Penn class Abc and non-Aa were independently related to in-hospital mortality (odds ratio 3.4 and 2.3, respectively). Concomitant coronary artery bypass grafting, older age, DeBakey type I dissection, and prolonged periods of cardiopulmonary bypass and hypothermic circulatory arrest were also independently associated with mortality. Conclusions. The Penn classification of acute type A aortic dissection is purposeful and its continued usage encouraged. Penn class indicating localized or generalized ischemia is independently related to intraoperative and in-hospital mortality. (Ann Thorac Surg 2011;92:1376-83) (C) 2011 by The Society of Thoracic Surgeons