Chances of late surgery in relation to length of wait lists

Evaluation of supply-side initiatives to improve access to coronary bypass surgery

Background

Guided by the evidence that delaying coronary revascularization may lead to symptom worsening and poorer clinical outcomes, expansion in cardiac surgery capacity has been recommended in Canada. Provincial governments started providing one-time and recurring increases in budgets for additional open heart surgeries to reduce waiting times. We sought to determine whether the year of decision to proceed with non-emergency coronary bypass surgery had an effect on time to surgery.

Methods

Using records from a population-based registry, we studied times between decision to operate and the procedure itself. We estimated changes in the length of time that patients had to wait for non-emergency operation over 14 calendar periods that included several years when supplementary funding was available. We studied waiting times separately for patients who access surgery through a wait list and through direct admission.

Results

During two periods when supplementary funding was available, 1998–1999 and 2004–2005, the weekly rate of undergoing surgery from a wait list was, respectively, 50% and 90% higher than in 1996–1997, the period with the longest waiting times. We also observed a reduction in the difference between 90th and 50th percentiles of the waiting-time distributions. Forty percent of patients in the 1998, 1999, 2004 and 2005 cohorts (years when supplementary funding was provided) underwent surgery within 16 to 20 weeks following the median waiting time, while it took between 27 and 37 weeks for the cohorts registered in the years when supplementary funding was not available. Times between decision and surgery were shorter for direct admissions than for wait-listed patients. Among patients who were directly admitted to hospital, time between decision and surgery was longest in 1992–1993 and then has been steadily decreasing through the late nineties. The rate of surgery among these patients was the highest in 1998–1999, and has not changed afterwards, even for years when supplementary funding was provided.

Conclusions

Waiting times for non-emergency coronary bypass surgery shortened after supplementary funding was granted to increase volume of cardiac surgical care in a health system with publicly-funded universal coverage for the procedure. The effect of the supplementary funding was not uniform for patients that access the services through wait lists and through direct admission.

Delay in admission for elective coronary-artery bypass grafting is associated with increased in-hospital mortality

BACKGROUND

Many health care systems now use priority wait lists for scheduling elective coronary artery bypass grafting (CABG) surgery, but there have not yet been any direct estimates of reductions in in-hospital mortality rate afforded by ensuring that the operation is performed within recommended time periods.

METHODS

We used a population-based registry to identify patients with established coronary artery disease who underwent isolated CABG in British Columbia, Canada. We studied whether postoperative survival during hospital admission for CABG differed significantly among patients who waited for surgery longer than the recommended time, 6 weeks for patients needing semi-urgent surgery and 12 weeks for those needing non-urgent surgery.

RESULTS

Among 7316 patients who underwent CABG, 97 died during the same hospital admission, for a province-wide death rate at discharge of 1.3%. The observed proportion of patients who died during the same admission was 1.0% (27 deaths among 2675 patients) for patients treated within the recommended time and 1.5% (70 among 4641) for whom CABG was delayed. After adjustment for age, sex, anatomy, comorbidity, calendar period, hospital, and mode of admission, patients with early CABG were only 2/3 as likely as those for whom CABG was delayed to experience in-hospital death (odds ratio 0.61; 95% confidence interval [CI] 0.39 to 0.96). There was a linear trend of 5% increase in the odds of in-hospital death for every additional month of delay before surgery, adjusted OR = 1.05 (95% CI 1.00 to 1.11).

CONCLUSION

We found a significant survival benefit from performing surgical revascularization within the time deemed acceptable to consultant surgeons for patients requiring the treatment on a semi-urgent or non-urgent basis.

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.