Mortality on the waiting list for coronary artery bypass grafting: incidence and risk factors

Insufficient capacity for coronary artery bypass grafting results in waiting times before operation, prioritization of patients and, ultimately, death on the waiting list. We aimed to calculate waiting list mortality and to identify risk factors for death on the waiting list.

The study included 5,864 consecutive patients accepted for elective coronary artery bypass grafting (78% male; mean age, 66 +/- 9 years). The patients were categorized at acceptance into three priority groups: imperative (39%), urgent (36%), or routine (25%). Waiting list mortality was calculated and compared between groups, and risk factors were identified by Poisson regression.

Median waiting time for the whole population was 55 days. Seventy-seven patients (1.3%) died, corresponding to a mortality rate of 5.8 deaths per 100 patient-years. The mortality rate per 100 patient-years was highest for those in the imperative group, 15.1 deaths, compared with 5.3 deaths in the urgent group and 3.2 in the routine group (p < 0.001). Independent risk factors were male sex (p = 0.032), Cleveland Clinic risk score (p = 0.005), impaired left ventricular ejection fraction (p = 0.007), unstable angina pectoris (p = 0.001), concomitant aortic valve disease (p = 0.002), priority group (p < 0.001), and time after acceptance (p = 0.019). The mortality risk increased with time after acceptance by 11% a month.

Long waiting lists for coronary artery bypass grafting are associated with considerable mortality. The risk of death increases significantly with waiting time. Sex, unstable angina, perioperative risk, impaired left ventricular function, and concomitant aortic valve disease are independent risk factors and should be considered at triage.