Which Arterial Conduit? Radial Artery Versus Free Right Internal Thoracic Artery: Six-Year Clinical Results of a Randomized Controlled Trial

Background To investigate the optimum revascularization conduit for coronary territories other than that of the left anterior descending artery, long-term clinical outcomes after use of a radial artery or right internal thoracic artery were evaluated as part of the Radial Artery Patency and Clinical Outcomes (RAPCO) study. Methods As part of a 10-year prospective randomized single-center trial, patients aged less than 70 years undergoing primary coronary surgery were randomly allocated to the use of the radial artery (n = 198) or free right internal thoracic artery (n = 196) for grafting the largest target other than the left anterior descending artery. Annual follow-up documented death, myocardial infarction, or revascularization as primary endpoints. Analysis was on an intention-to-treat basis. Results There were no significant differences in the preoperative status of the two groups including age, sex, diabetes mellitus, hypertension, and urgency of surgery. One hundred eighty-six of 198 patients in the radial artery group and 179 of 196 patients in the right internal thoracic artery group received the intended conduit. Mean number of grafts was 3.1 ± 0.8 and 3.2 ± 0.9 in the radial artery and the right internal thoracic artery groups, respectively. During surveillance of as long as 10.4 years (mean, 6.0), absolute survival and event-free survival were equivalent between groups, with 13 versus 18 deaths and 24 versus 37 events (death, myocardial infarction, or revascularization) in the radial artery and the right internal thoracic artery groups, respectively (log rank: p = 0.36 for survival, p = 0.08 for event-free survival). Conclusions These two arterial conduits may yield equivalent clinical outcomes at 5 or more years. That finding will be compared with mean 5-year angiographic patency when available. For now, equivalent clinical results offer surgeons flexibility in planning revascularization.