title: Should obese patients undergo on- or off-pump coronary artery bypass grafting?
abstract: OBJECTIVE
  To determine if on- or off-pump coronary artery bypass grafting (CABG) makes a difference to in-hospital mortality and long-term survival in obese patients.
  
  
  METHODS
  Analysis of consecutive patients on a validated prospective cardiac surgery database was performed for patients undergoing isolated CABG. Obesity was defined as a body mass index (BMI) >30 kg/m(2). Uni- and multivariate analyses were performed for in-hospital mortality and long-term survival. A propensity analysis was also performed.
  
  
  RESULTS
  The overall mortality rate was 2.1% (N = 284) for all cases, N = 13 369. The mortality rate for obese patients (N = 4289) was 2.3%, and for non-obese patients (N = 9080) it was 2.0%; P = 0.4. The median follow-up was 7.0 (interquartile range 4.1-10.1) years. Univariate analysis identified that in-hospital mortality was significantly lower in obese patients undergoing off-pump CABG; P = 0.01. No significant difference existed with regard to non-obese patients; P = 0.55. Kaplan-Meier survival analysis identified that off-pump CABG was associated with improved survival in obese patients; P = 0.01. Multivariate analysis of non-obese patients did not identify on- or off-pump CABG as a significant factor determining in-hospital mortality or long-term survival. Multivariate analysis of obese patients identified off-pump CABG as being associated with significantly reduced in-hospital mortality (odds ratio [OR] 0.56, 95% confidence interval [CI] 0.34-0.93, P = 0.03), and significantly improved long-term survival (hazard ratio 0.81, 95% CI 0.67-0.98, P = 0.03). In-hospital mortality and long-term survival were significantly affected by the era of surgery, regardless of patients' BMI. Propensity matching of non-obese patients (N = 6088, 1:1 matching) did not identify on- or off-pump CABG as a significant factor determining in-hospital mortality or long-term survival. Propensity matching of obese patients (N = 2980, 1:1 matching) identified on-pump CABG as a significant factor determining in-hospital mortality (OR 0.50, 95% CI 0.26-0.98, P = 0.04), but having no effect on long-term survival.
  
  
  CONCLUSIONS
  Univariate, multivariate and propensity matching suggest that obese patients undergoing CABG have reduced in-hospital mortality if they undergo revascularization with the off-pump technique.
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Pullan
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Bilal H
authors.initials: BH
authors.lastname: Kirmani
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Thomas
authors.initials: T
authors.lastname: Conley
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Aung
authors.initials: A
authors.lastname: Oo
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Shaw
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK.
authors.forename: James
authors.initials: J
authors.lastname: McShane
authors.affiliation: Liverpool Heart and Chest Hospital, Liverpool, UK mpoullis@hotmail.com.
authors.forename: Michael
authors.initials: M
authors.lastname: Poullis
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001026:Coronary Artery Bypass / Q000379:methods* / Q000401:mortality*; D047549:Coronary Artery Bypass, Off-Pump; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000453:epidemiology* / Q000401:mortality; D057216:Propensity Score; D055815:Young Adult
keywords: Coronary; Mortality; Obesity; Off pump; Survival