Meta-analysis of randomized trials comparing off-pump with on-pump coronary artery bypass graft patency

Off-pump coronary artery bypass graft surgery (OPCAB) is increasingly becoming a widely used technique and challenges conventional on-pump coronary artery bypass grafting as the standard surgical therapy for coronary artery disease. Little information, however, is available concerning postoperative performance of bypass grafts done with this new technique. The aim of this study is to assess differences in graft patency between OPCAB and coronary artery bypass grafting by meta-analysis of data published in randomized trials.

A literature search for the period beginning January 1990 until December 2004 supplemented with manual bibliographic review was performed for all peer-reviewed English-language publications. A systematic overview (meta-analysis) of randomized trials was conducted to assess differences between OPCAB and coronary artery bypass grafting in graft occlusion rates.

Literature search yielded five comparable randomized studies, for a total of 872 and 998 grafts performed during OPCAB and coronary artery bypass grafting procedures, respectively. Meta-analysis of these studies showed an increased risk of graft occlusion in the OPCAB group of patients, both when all the studies were analyzed together (odds ratio, 1.51; 95% confidence intervals, 1.15 to 1.99; p = 0.003), and when low-quality (odds ratio, 1.46; 95% confidence intervals, 1.05 to 2.03; p = 0.02) and high-quality (odds ratio, 1.65; 95% confidence intervals, 0.99 to 2.75; p = 0.05) studies were analyzed separately.

Cumulative analysis of the few prospective randomized studies currently available in the literature documents a reduction in postoperative patency of coronary artery bypass grafts performed during OPCAB procedures. The risk of reduced graft patency needs to be considered when choosing OPCAB as tailored strategy for selected patients.