Coronary artery bypass grafting procedures done on beating hearts have 1-year outcomes similar to those for procedures done with use of a heart-lung machine, according to major new study findings published in the April 21st issue of the Journal of the American Medical Association.

In an attempt to avoid complications attributed to cardiopulmonary bypass, U.S. surgeons performed approximately 21 percent of coronary artery bypass operations as off-pump procedures in 2002. Concerns remain about the technical difficulty of off-pump coronary artery bypass (OPCAB), including the possibility of imprecise grafting and incomplete revascularization compromising patient outcomes, as well as long-term graft patency.

John D. Puskas, M.D., M.Sc., and colleagues conducted the Surgical Management of Arterial Revascularization Therapies (SMART) trial to compare graft patency, clinical outcomes, health-related quality of life, and costs in unselected patients referred for elective, isolated bypass surgery and randomized to an off-pump or on-pump procedure. 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, as well as rates for death, stroke, myocardial infarction, angina, and need for reintervention, were similar for both types of procedures at 30 days and at 1 year. There were no significant differences in health-related quality of life. The only significant difference was in cost. The authors wrote, "Mean total hospitalization cost per patient at hospital discharge was $2,272 less for OPCAB and $1,955 less at 1 year."

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

In an accompanying editorial, Eric D. Peterson, M.D., M.P.H., and Daniel B. Mark, M.D., M.P.H., wrote that early randomized comparisons such as those done in the SMART trial demonstrate the proof of concept for off-pump surgery: "In the right hands and for the right patients, off-pump coronary artery bypass grafting (OPCAB) offers safe, complete, and durable revascularization that may reduce complications relative to conventional coronary artery bypass grafting 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 under-enrolled these higher-risk subgroups," the editorialists added.