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An Observational Study to Evaluate 2 Target Times for Elective Coronary Bypass Surgery

Sobolev, Boris G. PhD*; Fradet, Guy MD, FRCPS, MSc; Kuramoto, Lisa MSc; Rogula, Basia BSc

doi: 10.1097/MLR.0b013e31824deed2
Original Articles

Background: Guidelines for timing of elective bypass surgery were established by expert opinion; yet, there is little evidence to support the recommended target times.

Objectives: To estimate the effect of timing of the procedure on in-hospital mortality by comparing groups of patients that differ in the duration of time between decision to operate and performed procedure.

Research Design: We used a population-based registry to identify patients who underwent surgical coronary revascularization and their hospital discharge summaries to identify in-hospital death.

Subjects: We studied 9593 patients who underwent surgical revascularization between 1992 and 2006 after registration on a wait list for first-time isolated coronary artery bypass grafting on an elective basis.

Measures: The outcome was postoperative in-hospital death. The study variable was the timing of surgery, categorized as short, prolonged, and excessive delays according to the guidelines.

Methods: The probability of in-hospital death in relation to timing of surgery was modeled by logistic regression that included a precalculated risk score for in-hospital death, with weighting observations by inverse propensity scores for the 3 surgery timing groups.

Results: In-hospital death among patients with short delays was one third as likely as among those with excessive delays: adjusted odds ratio=0.32 (95% confidence interval 0.20–0.51). The protective effect was smaller and not significant for patients with prolonged delays; odds ratio=0.78 (95% confidence interval, 0.38–1.63).

Conclusions: Our findings suggest a survival benefit from performing elective surgical revascularization within the time frame recommended by the stricter of the 2 guidelines. Our results have implications for health systems that provide universal coverage and that budget the annual number of procedures.

*School of Population and Public Health

Department of Surgery, The University of British Columbia

Centre for Clinical Epidemiology and Evaluation, Vancouver Coastal Health Research Institute, Vancouver, BC, Canada

Supported by the Canada Research Chair Program and Canadian Foundation for Innovation.

The authors declare no conflict of interest.

Reprints: Boris G. Sobolev, PhD, School of Population and Public Health, The University of British Columbia, 828 West 10th Avenue, Vancouver BC V5Z 1M9, Canada. E-mail:

© 2012 Lippincott Williams & Wilkins, Inc.