Do longer delays for coronary artery bypass surgery contribute to preoperative mortality in less urgent patients?

BACKGROUND: Priority wait lists are common for managing access to cardiac surgery in publicly funded health systems. We evaluated whether longer delays contribute to the probability of death before surgery among patients prioritized into the less urgent category.
METHODS: We studied records of 9233 patients registered for isolated coronary artery bypass graft (CABG) in British Columbia, Canada. The primary outcome was death before surgery. We estimated the probability that a patient, who could be removed from the list as a result of surgery, death, or other competing events, dies on or before a certain wait-list week.
RESULTS: Despite similar death rates in semiurgent and nonurgent groups, 0.63 (95% confidence interval, 0.46-0.80) versus 0.58 (0.36-0.80) per 1000 patient-weeks, nonurgent patients were remaining on the list longer, which contributed to higher cumulative incidence of all-cause death than in semiurgent group (adjusted odds ratio = 1.66; 1.03-2.68). By 52 weeks on the wait list, 0.9% (0.6-1.1) and 1.3% (0.8-1.8) of patients died in semiurgent and nonurgent groups, respectively (P < 0.01). Similar proportions of deaths related to cardiovascular disease estimated over wait-list time in both groups (P = 0.40) were the result of shorter delays in the semiurgent group despite a higher rate of death resulting from cardiovascular disease (0.50 [0.36-0.65] vs. 0.34 [0.17-0.51] per 1000 patient-weeks).
CONCLUSION: Queuing according to urgency of treatment contributed to a higher proportion of CABG candidates dying before surgery from all causes in the nonurgent compared with the semiurgent group despite similar weekly death rates observed in both groups. However, similar probabilities of death resulting from cardiovascular disease observed in both groups over wait-list time were the result of shorter delays in the semiurgent group despite a higher rate of cardiovascular death.