Observational study of mortality risk stratification by ischemic presentation in patients with acute type A aortic dissection: the Penn classification

Background Acute type A aortic dissection is a surgical emergency, with an operative mortality as high as 25%. Ischemia is a known predictor of mortality. We tested the efficacy of a classification system-the Penn classification, which is based on ischemic pattern at clinical presentation to stratify operative mortality risk and identify high-risk groups of patients for further intervention and study. Methods In this prospective observational study, patients underwent a standard aortic dissection repair protocol at the University of Pennsylvania, Philadelphia, PA, from 1993 to 2004. Patients were classified as having no ischemia, branch vessel malperfusion with localized organ ischemia, generalized ischemia with circulatory collapse, with or without cardiac involvement, or a combination of localized and generalized ischemia. Results The cohort comprised 221 patients. The mean age was 61.6 (+/- 14.8) years and 66.5% were male. At presentation 57.9% of patients had no ischemia, 17.6% had localized ischemia, 15.4% had generalized ischemia, and 9.0% had both localized and generalized ischemia. Overall, 28 (12.7%) patients died during the perioperative period. All-cause mortality differed significantly between groups (no ischemia 3.1%, localized ischemia 25.6%, generalized ischemia 17.6%, combined ischemia 40.0%), yielding an overall 8.3-fold difference for no compared with any ischemia (3.1% versus 25.8%, P = 0.0001). Ischemic presentations together accounted for 85.7% of all deaths. Conclusion The Penn classification of acute type A aortic dissection enabled stratification of patients by operative mortality risk. The system requires further validation, but might facilitate new ways to analyze mortality data for this disorder.