title: Does retrograde cerebral perfusion affect risk factors for stroke and mortality after hypothermic circulatory arrest?
abstract: BACKGROUND
  In aortic surgery requiring hypothermic circulatory arrest (HCA), retrospective studies identify age and duration of the arrest period as predictors of stroke and mortality. Retrograde cerebral perfusion (RCP) has been reported to reduce the risk of stroke when compared with historical controls. The aim of this study was to ascertain if RCP affected mortality, stroke, or the risk factors for these end points in a consecutive series of HCA patients.
  
  
  METHODS
  We investigated the impact of RCP in 130 patients, mean age 62.7 years (range 20-84); 78 were men and 35% were emergencies. Overall mortality was 16.9% (elective 9.5%) and the incidence of stroke was 6.9%. Mean HCA time was 30.1 min (95% confidence interval [CI] 27.9-34). RCP was instituted in 96 cases for a mean of 24.4 min (95% CI 21.9-27.0).
  
  
  RESULTS
  Perioperative univariate predictors of mortality were emergency status, acute rupture, long HCA and cardiopulmonary bypass duration, and postoperative complications. For stroke, age (p = 0.007), hypertension (p = 0.05), and long HCA duration (p = 0.01) were predictive. RCP did not decrease mortality (p = 0.18, OR 0.55) or incidence of stroke (p = 0.57, OR 1.26). Mortality after stroke was 44.4% (p = 0.04, OR 4.6). Multiple logistic regression showed severe aortic atherosclerosis and RCP duration (p = 0.038) as risk factors for mortality, and myocardial ischemic time (p = 0.012) and HCA duration (p = 0.05) as risk factors for stroke. HCA and RCP groups differed in HCA duration (HCA mean 25 min [10-80], RCP mean 32 min [10-69]; p < 0.019).
  
  
  CONCLUSIONS
  Age and HCA duration remain risk factors for stroke and mortality despite RCP. However, HCA times were longer in the RCP patients, and the patients were not randomized. The role of RCP in cerebral protection requires further prospective randomized studies.
authors.affiliation: Cardiothoracic Surgical Unit, University Hospital Birmingham, Queen Elizabeth Medical Centre, United Kingdom.
authors.forename: C H
authors.initials: CH
authors.lastname: Wong
authors.forename: R S
authors.initials: RS
authors.lastname: Bonser
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation; D002561:Cerebrovascular Disorders / Q000209:etiology / Q000401:mortality / Q000517:prevention & control*; D005112:Extracorporeal Circulation / Q000379:methods*; D005260:Female; D006324:Heart Arrest, Induced / Q000009:adverse effects; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D016017:Odds Ratio; D010477:Perfusion / Q000379:methods*; D012307:Risk Factors; D016019:Survival Analysis; D013997:Time Factors