title: Preoperative anaemia is a risk factor for mortality and morbidity following aortic valve surgery.
abstract: OBJECTIVE
  The impact of anaemia on patients undergoing aortic valve surgery has not been well studied. We sought to evaluate the effect of anaemia on early outcomes following aortic valve replacement (AVR).
  
  
  METHODS
  All patients undergoing non-emergent aortic valve surgery (n = 2698) with or without other concomitant procedures between 1997 and 2010 were included. Preoperative anaemia was defined as per World Health Organization guidelines as haemoglobin (Hb) < 130 g/l in men and Hb < 120 g/l in women. Multivariable analyses were used to determine the association between preoperative anaemia and postoperative outcomes.
  
  
  RESULTS
  The prevalence of preoperative anaemia was 32.2%. Patients with anaemia were older (71 ± 12 vs 66 ± 13 years, P < 0.001), more likely to have urgent surgery, recent MI, higher creatinine level and impaired preoperative left ventricular function. Overall unadjusted mortality was 2.8% in non-anaemic patients vs 8% in anaemic patients. Anaemic patients were more likely to require renal replacement therapy (11 vs 3%, P < 0.0001) and prolonged ventilation (24 vs 10%, P < 0.0001). Following multivariable adjustment, lower preoperative Hb was an independent predictor of mortality (odds ratio 1.19, 95% CI: 1.04-1.34, P = 0.007) and composite morbidity (odds ratio 1.36, 95% CI: 1.05-1.77, P = 0.02) after AVR. Mortality and composite morbidity were significantly higher with lower levels of preoperative Hb.
  
  
  CONCLUSIONS
  Preoperative anaemia is a common finding in patients undergoing aortic valve surgery and is an important and potentially modifiable risk factor for postoperative morbidity and mortality.
authors.affiliation: Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON, Canada.
authors.forename: Elsayed
authors.initials: E
authors.lastname: Elmistekawy
authors.forename: Fraser
authors.initials: F
authors.lastname: Rubens
authors.forename: Chris
authors.initials: C
authors.lastname: Hudson
authors.forename: Bernard
authors.initials: B
authors.lastname: McDonald
authors.forename: Marc
authors.initials: M
authors.lastname: Ruel
authors.forename: Khanh
authors.initials: K
authors.lastname: Lam
authors.forename: Thierry G
authors.initials: TG
authors.lastname: Mesana
authors.forename: Munir
authors.initials: M
authors.lastname: Boodhwani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000740:Anemia / Q000097:blood / Q000503:physiopathology*; D001021:Aortic Valve / Q000601:surgery*; D005260:Female; D006349:Heart Valve Diseases / Q000097:blood* / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D006454:Hemoglobins / Q000378:metabolism; D017052:Hospital Mortality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D057234:Preoperative Period; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
chemical_list: D006454:Hemoglobins
keywords: Aortic valve replacement; Morbidity; Mortality; Preoperative anaemia