title: The occurrence of adverse events in relation to time after registration for coronary artery bypass surgery: a population-based observational study.
abstract: BACKGROUND
  Our objective was to evaluate the effect of delays on adverse events while waiting for coronary artery bypass grafting (CABG).
  
  
  METHODS
  An observational study that prospectively followed patients from registration on a wait list to removal for planned surgery, death while waiting, or unplanned emergency surgery. The population-based registry provided data on 12,030 patients with a record of registration on a wait list for first-time isolated CABG surgery between 1992 and 2005.
  
  
  RESULTS
  In total, 104 patients died and 382 patients underwent an emergency surgery before planned CABG. The death rate was 0.5 per 1000 patient-weeks in the semiurgent group and 0.6 per 1000 patient-weeks the nonurgent group, adjusted OR = 1.07 (95% confidence interval [CI] 0.69-1.65). The emergency surgery rate of 1.2 per 1000 patient-weeks in the nonurgent group was lower compared to 2.1 per 1000 patient-weeks in the semiurgent group (adjusted OR = 0.72, 95% CI 0.54-0.97). However, the nonurgent group had a greater cumulative incidence of preoperative death than the semiurgent group for almost all weeks on the wait list, adjusted OR = 1.92 (95% CI 1.25-2.95). The surgery rate was 1.2 per 1000 patient-weeks in the nonurgent group and 2.1 per 1000 patient-weeks in the semiurgent group, adjusted OR = 0.72 (95% CI 0.54-0.97). The cumulative incidence of emergency surgery before planned CABG was similar in the semiurgent and nonurgent groups, adjusted OR = 0.88, (95% CI 0.64-1.20).
  
  
  CONCLUSIONS
  Despite similar death rates in the semiurgent and nonurgent groups, the longer waiting times in the nonurgent group result in a greater cumulative incidence of death on the wait list compared to that in the semiurgent group. These longer waiting times also offset the lower rate of emergency surgery before planned admission in the nonurgent group so that the cumulative incidence of the emergency surgery was similar in both groups.
authors.affiliation: The University of British Columbia, 828 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada. boris.sobolev@ubc.ca
authors.forename: Boris G
authors.initials: BG
authors.lastname: Sobolev
authors.forename: Guy
authors.initials: G
authors.lastname: Fradet
authors.forename: Lisa
authors.initials: L
authors.lastname: Kuramoto
authors.forename: Basia
authors.initials: B
authors.lastname: Rogula
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000401:mortality* / Q000706:statistics & numerical data; D003324:Coronary Artery Disease / Q000401:mortality* / Q000601:surgery*; D004635:Emergency Medicine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D057234:Preoperative Period; D011446:Prospective Studies; D012044:Regression Analysis; D013997:Time Factors; D016896:Treatment Outcome; D014850:Waiting Lists / Q000401:mortality*