'Off-pump' bypass surgery has similar outcomes, lower cost, than conventional bypass surgery

04/15/04

Coronary artery surgery performed "off-pump", i.e., keeping the heart beating and not using the cardiopulmonary bypass machine, has similar outcomes after one year, and costs less, when compared to conventional coronary artery bypass grafting (CABG) using cardiopulmonary bypass, according to a study in the April 21 issue of The Journal of the American Medical Association (JAMA).

To try to avoid some of the complications attributable to cardiopulmonary bypass, U.S. surgeons performed approximately 21 percent of coronary artery bypass operations off-pump in 2002, according to background information in the article. In off-pump operations, the heart is kept beating, and with the help of a device, the beating heart is stabilized while the surgeon places the bypass grafts around the blocked arteries. During a conventional CABG surgery, a heart-lung machine allows the heart to stop and pumps blood throughout the body, and keeps the body stabilized. Concerns remains about the technical difficulty of off-pump coronary artery bypass (OPCAB), including the possibility of imprecise grafting and incomplete revascularization compromising patient outcomes, and long-term graft patency (keeping the graft open).

John D. Puskas, M.D., M.Sc., of the Emory University School of Medicine and Emory Center for Outcomes Research, Atlanta, and colleagues conducted the Surgical Management of Arterial Revascularization Therapies (SMART) trial, designed to compare graft patency, clinical outcomes, health-related quality of life, and costs in unselected patients referred for elective, isolated CABG surgery and randomized to OPCAB or CABG with cardiopulmonary bypass. The study included 197 patients who had follow-up at 30 days; 185 of those had follow-up at 1 year. The study was conducted between March 10, 2000, and August 20, 2001, at a U.S. academic center.

The researchers found that graft patency was similar for OPCAB and conventional CABG with cardiopulmonary bypass at 30 days and at 1 year. Rates of death, stroke, heart attack, angina, and reintervention were similar at 30 days and 1 year. "There were no significant differences in health-related quality of life. Mean total hospitalization cost per patient at hospital discharge was $2,272 less for OPCAB and $1,955 less at 1 year," the authors write.

"These results from the SMART trial demonstrate that OPCAB may provide complete revascularization that is durable and cost-effective relative to CABG with cardiopulmonary bypass when performed on unselected patients undergoing elective, isolated CABG," the researchers conclude.

(JAMA. 2004;291:1841-1849. Available post-embargo at JAMA.com)

Editor's Note: The research for this article was supported by grants from Medtronic Inc., and the Carlyle Fraser Heart Center Foundation (Atlanta). Dr. Puskas is a consultant for Medtronic Inc. (Minneapolis).

EDITORIAL: OFF-PUMP BYPASS SURGERY

In an accompanying editorial, Eric D. Peterson, M.D., M.P.H., and Daniel B. Mark, M.D., M.P.H., of the Duke Clinical Research Institute and the Department of Medicine, Duke University Medical Center, Durham, N.C., write that early randomized comparisons such as the SMART trial demonstrate the proof of concept for OPCAB.

"In the right hands and for the right patients, OPCAB offers safe, complete, and durable revascularization that may reduce complications relative to conventional CABG with cardiopulmonary bypass. The question of whether OPCAB should become the new standard for coronary bypass surgery rests on the generalizability of these findings. A large, multicenter randomized trial of CABG with cardiopulmonary bypass compared with OPCAB surgery would address many important questions.

"First, and most important, it could clarify whether the SMART trial findings may be extrapolated to the larger community of experienced cardiac surgeons in practice. Second, a larger multicenter trial could be powered to address any potential difference of these procedures on important patient outcomes, something these smaller, single-center studies were not able to do. Finally, such a study could compare results in important patient subgroups. Specifically, the observational literature suggests that the benefits of OPCAB may be greater in those with higher surgical risks (including elderly patients, those with renal impairment, and patients with significant carotid disease). However, existing trials have generally underenrolled these higher-risk subgroups," the editorialists write.

(JAMA. 2004;291:1897-1899. Available post-embargo at JAMA.com)

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