Off-pump and on-pump coronary artery bypass grafting are associated with similar graft patency, myocardial ischemia, and freedom from reintervention: long-term follow-up of a randomized trial

Background: The Surgical Management of Arterial Revascularization Therapies trial was conceived to rigorously compare completeness of revascularization, clinical outcomes and resource utilization in unselected patients referred for elective, primary coronary artery bypass grafting randomly assigned to undergo off-pump (OPCAB) or conventional on-pump coronary artery bypass grafting using cardiopulmonary bypass (CPB). The goal of this follow-up study was to compare long-term survival, graft patency, myocardial ischemia, and clinical outcomes among survivors who volunteered to return for clinical evaluation and imaging studies.

Methods: Two hundred unselected patients with multivessel coronary artery disease were randomly assigned to OPCAB or CPB coronary artery bypass grafting between March 2000 and August 2001. All-cause mortality was determined by individual patient contact and referencing the Social Security Death Master File. Of 140 survivors, 87 volunteered to return after a minimum of 6.8 years (maximum, 8.4 years; mean, 7.5 years) for assessment of graft patency (computed tomographic angiography) and myocardial ischemia (cardiac positron emission tomography and 12-lead electrocardiogram). Age at follow-up ranged from 38 to 90 years (mean, 68 years).

Results: There were 26 deaths from all causes among OPCAB patients and 31 among CPB patients as of March 30, 2009. Graft patency was similar between groups among 622 grafts assessed by angiography before hospital discharge (99% OPCAB versus 97.7% CPB; p=0.22, Fisher's exact test), among 511 grafts assessed by angiography at 1 year (93.6% OPCAB versus 95.8% CPB; p=0.33), and among 190 grafts assessed by computed tomographic angiography at late follow-up (76% OPCAB versus 83.5% CPB; p=0.44). Twelve of 34 OPCAB (35.3%) and 16 of 39 CPB patients (41.0%) had any ischemia on positron emission tomography scanning (p=0.62). Four OPCAB patients (11.8%) and 9 CPB patients (23.1%) had an ischemic region in excess of 10% of myocardium (p=0.21). At late follow-up, recurrent angina had occurred in 11 of 43 (25.6%) OPCAB patients and 5 of 44 (11.4%) CPB patients (p=0.09). Percutaneous reintervention had been performed at the discretion of blinded local cardiologists in 1 of 43 (2.3%) OPCAB patients and 1 of 44 (2.3%) CPB patients (p=1.0). No patient in either group has undergone repeat CABG.

Conclusions: In this randomized trial, off-pump and on-pump coronary artery bypass grafting were associated with similar early and late graft patency, incidence of recurrent or residual myocardial ischemia, need for reintervention, and long-term survival.