title: Observational study of mortality risk stratification by ischemic presentation in patients with acute type A aortic dissection: the Penn classification.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Anesthesiology and Critical Care, Cardiothoracic and Vascular Section, Hospital of the University of Pennsylvania, Philadelphia, PA 19104-4283, USA. yiandoc@hotmail.com
authors.forename: John G T
authors.initials: JG
authors.lastname: Augoustides
authors.forename: Arnar
authors.initials: A
authors.lastname: Geirsson
authors.forename: Wilson Y
authors.initials: WY
authors.lastname: Szeto
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Walsh
authors.forename: Brittany
authors.initials: B
authors.lastname: Cornelius
authors.forename: Alberto
authors.initials: A
authors.lastname: Pochettino
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Bavaria
mesh_terms: D000208:Acute Disease; D000368:Aged; D000784:Aortic Dissection / Q000150:complications / Q000401:mortality* / Q000601:surgery; D001014:Aortic Aneurysm / Q000150:complications / Q000401:mortality* / Q000601:surgery; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000209:etiology / Q000401:mortality*; D010414:Pennsylvania / Q000453:epidemiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D018570:Risk Assessment; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000401:mortality*