title: Profound hypothermia compared with moderate hypothermia in repair of acute type A aortic dissection.
abstract: OBJECTIVE
  To determine the impact of the degree of hypothermia on surgical outcomes in patients undergoing repair of acute type A aortic dissection.
  
  
  METHODS
  Between 1990 and 2010, 211 consecutive patients underwent surgical repair of type A aortic syndrome. Patients with acute type A dissection (n = 128) were included. Circulatory arrest with profound hypothermia (PH; <20 °C) was used in 75 patients (58.6%) and circulatory arrest with moderate hypothermia (MH; 22-28 °C) in 53 patients (41.4%). Subacute or chronic dissections, intramural hematoma and penetrating aortic ulcers were excluded.
  
  
  RESULTS
  Preoperative acute kidney injury was higher in the PH group (18.9% vs 5.3%, P = .01). Axillary or direct aortic cannulation was more prevalent in the MH group (33.9% vs 11.1%, P = .01). The duration of circulatory arrest was 25.9 ± 14.3 and 28.9 ± 19.9 minutes in the MH and PH groups, respectively (P = .3). The composite outcome of mortality, low cardiac output syndrome or stroke was higher in the PH group (52.8% vs 24%, P < .001). Cardiopulmonary bypass time and blood transfusion were significantly higher in the PH group (P = .04). By multivariable analysis (C = 0.80), PH (odds ratio [OR], 7.6; 95% confidence interval [CI], 3.0-21.1) and preoperative shock (OR, 3.5; 95% CI, 1.3-10.1) were independent predictors of the composite outcome.
  
  
  CONCLUSIONS
  MH was independently associated with a lower risk of a composite outcome of mortality and major adverse cardiac and cerebrovascular events during repair of acute type A dissection. Use of moderate hypothermic circulatory arrest avoids the detrimental effects of PH without an increase in the risk of neurologic injury in this study.
authors.affiliation: King Saud University, Riyadh, Saudi Arabia; Peter Munk Cardiac Center, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Khaled D
authors.initials: KD
authors.lastname: Algarni
authors.affiliation: Peter Munk Cardiac Center, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Bobby
authors.initials: B
authors.lastname: Yanagawa
authors.affiliation: Peter Munk Cardiac Center, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Vivek
authors.initials: V
authors.lastname: Rao
authors.affiliation: Peter Munk Cardiac Center, Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada. Electronic address: khaled.algarni@utoronto.ca.
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Yau
mesh_terms: D000208:Acute Disease; D000368:Aged; D000784:Aortic Dissection / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D001014:Aortic Aneurysm / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery*; D001803:Blood Transfusion; D002303:Cardiac Output, Low / Q000209:etiology; D002315:Cardiopulmonary Bypass; D016009:Chi-Square Distribution; D050792:Circulatory Arrest, Deep Hypothermia Induced / Q000009:adverse effects / Q000401:mortality; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D009864:Ontario; D012189:Retrospective Studies; D012307:Risk Factors; D020521:Stroke / Q000209:etiology; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000401:mortality