title: Effect of avoiding cardiopulmonary bypass in non-elective coronary artery bypass surgery: a propensity score analysis.
abstract: OBJECTIVE
  Non-elective coronary artery surgery (emergent/salvage or urgent) carries an increased risk in most risk-stratification models. Off-pump coronary surgery is increasingly used in non-elective cases. We aimed to investigate the effect of avoiding cardiopulmonary bypass on outcomes following non-elective coronary surgery.
  
  
  METHODS
  Of the 3771 consecutive coronary artery bypass procedures performed by five surgeons between April 1997 and March 2002, 828 (22%) were non-elective and 417 (50.4%) of these patients had off-pump surgery. Multivariate logistic regression was used to assess the effect of off-pump on in-hospital outcomes, while adjusting for treatment selection bias. Treatment selection bias was controlled for by constructing a propensity score from core patient characteristics, which was the probability of avoiding cardiopulmonary bypass. The C statistic for this model was 0.8.
  
  
  RESULTS
  Off-pump patients were more likely to be hypertensive, stable, had less extensive disease and better left ventricular function. The left internal mammary artery was used in 91.8% (n=383) of off-pump patients compared to 79.3% (n=326) of on-pump cases (P<0.001). After adjusting for the propensity score, no difference in in-hospital mortality was observed between off-pump and on-pump (adjusted odds ratio (OR) 0.83 (95% confidence intervals (CI) 0.36-1.93); P=0.667). Off-pump patients were less likely to require intra-aortic balloon pump support (adjusted OR 0.44 (95% CI 0.21-0.96); P=0.039), less likely to have renal failure (adjusted OR 0.44 (95% CI 0.22-0.90); P=0.025), and have shorter lengths of stay (adjusted OR 0.51 (95% CI 0.37-0.70); P<0.001). Other morbidity outcomes were similar in both groups.
  
  
  CONCLUSIONS
  In this experience, off-pump coronary surgery in non-elective patients is safe with acceptable results. Non-elective off-pump patients have a significantly reduced incidence of renal failure, and shorter post-operative stays compared to on-pump coronary artery bypass surgery.
authors.affiliation: Department of Cardiothoracic Surgery, The Cardiothoracic Centre--Liverpool, Liverpool, UK.
authors.forename: Shishir
authors.initials: S
authors.lastname: Karthik
authors.forename: Ghassan
authors.initials: G
authors.lastname: Musleh
authors.forename: Antony D
authors.initials: AD
authors.lastname: Grayson
authors.forename: Daniel J M
authors.initials: DJ
authors.lastname: Keenan
authors.forename: Ragheb
authors.initials: R
authors.lastname: Hasan
authors.forename: D Mark
authors.initials: DM
authors.lastname: Pullan
authors.forename: Walid C
authors.initials: WC
authors.lastname: Dihmis
authors.forename: Brian M
authors.initials: BM
authors.lastname: Fabri
mesh_terms: D000368:Aged; D001026:Coronary Artery Bypass / Q000379:methods* / Q000401:mortality; D003327:Coronary Disease / Q000601:surgery*; D003953:Diagnosis-Related Groups; D004638:Emergency Treatment; D005260:Female; D006355:Heart-Lung Machine; D006801:Humans; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009017:Morbidity; D051437:Renal Insufficiency / Q000209:etiology; D018709:Statistics, Nonparametric; D016896:Treatment Outcome