Death risk increases with 'excessive' CABG surgery waiting times

In the Canadian healthcare system, patients with longer than recommended waitlist times for coronary artery bypass graft (CABG) surgery are at increased risk of dying in the hospital, reports Medical Care. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

The risk of death is one-third lower for patients with shorter delays to CABG surgery, compared to those with "excessive delays," according to the new report by Boris G. Sobolev, PhD, of the University of British Columbia and colleagues. They write, "Our results have implications for health systems that provide universal coverage and that budget the annual number of procedures."

Risk Increases with 'Excessive' CABG Waiting Times
The researchers analyzed data on approximately 9,600 patients undergoing CABG surgery in British Columbia between 1992 and 2006. All procedures were performed on an elective basis—that is, not as an urgent or emergency procedure—after the patient was registered on a waiting list.

Waitlist time was analyzed for association with the risk of in-hospital death, accounting for the role of other known risk factors. Risk was compared for patients with:
•Short delays—within two weeks for "semiurgent" and 6 weeks for "nonurgent" procedures—as recommended by the Canadian Cardiac Society (CCS).
•Prolonged delays—within 6 to 12 weeks—as recommended by British Columbia provincial guidelines.
•Excessive delays—longer than either set of recommendations.

Overall, about 12.5 percent of patients had short delays to CABG surgery, 21.5 percent had prolonged delays, and 66 percent had excessive delays. Patients with shorter delays tended to be sicker and to have more risk factors.

The absolute risk of in-hospital death was relatively small: 1.2 percent. However, risk increased from 0.6 percent for patients with short delays, to 1.1 percent for those with prolonged delays, to 1.3 percent for those with excessive delays.

Once other risk factors were taken into account, the odds of death were about two-thirds lower for the patients with short versus excessive delays. There was no significant difference in risk for patients in the prolonged delay category.

In the Canadian healthcare system and similar systems, limited capacity requires "budgeting" the number of CABG surgeries (and other complex procedures) within a given time. Guidelines for CABG waitlist times were made on the basis of expert opinion—with "little evidence to support the recommended target times," the authors note.

The new study supports the stricter CCS guidelines for performing elective CABG surgery. "We found that among patients who underwent the operation within the CCS target times, in-hospital death was one-third as likely among those who had to wait longer than provincial guidelines," Dr Sobolev and colleagues write. However, they note that two-thirds of patients had waiting times exceeding even the less-stringent provincial guidelines.

Dr Sobolev and colleagues believe their study provides evidence to inform decisions regarding capacity planning versus access time for CABG, with the goal of minimizing adverse outcomes associated with excessive waitlist time. The results also have implications for other models of government-sponsored medicine providing universal coverage for eligible patients—including the U.S. Veterans Administration system.