Mid-term results of the Radial Artery Patency and Clinical Outcomes randomized trial

Abstract

Background: The radial artery (RA), as an alternative to the saphenous vein or the right internal thoracic artery (RITA) for coronary artery bypass grafting, has gained considerable interest over the years. A randomized controlled trial was undertaken to assess the suitability of the radial artery as a conduit.

Method: The Radial Artery Patency and Clinical Outcomes (RAPCO) trial is a double-armed randomized controlled trial comparing the RA with the free RITA in a younger cohort of patients undergoing elective coronary bypass surgery, and the RA with the saphenous vein in an older group. The trial conduit was grafted to the most important coronary target after the left anterior descending artery, which received the gold standard left internal thoracic artery. Clinical outcomes and angiographic patency up to 10 years was recorded during careful follow up, with annual clinical review and a program of randomly assigned, staggered angiography. The final trial results will be available in 2014.

Results: Mid-trial results have shown equivalent survival and event-free survival and graft patency in both arms at median follow up of approximately 6 years. The demographic and clinical data, pre- and postoperative angiographic findings of the trial database have led to a number of substudies focusing on the role of lipid exposure in patency and disease progression, the fate of moderate lesions when grafted or left alone, patterns of disease regression, and patient satisfaction with graft harvest sites.

Conclusions: While the final analysis of the primary trial end points is eagerly awaited, the additional insight into the natural history of grafted coronary artery disease with modern secondary prevention will be of considerable interest.

Keywords: Randomized controlled trial; internal thoracic artery (ITA); radial artery (RA); saphenous vein (SV).

Figures

Figure 1

Flow diagrams: A. RA vs. RITA; B. RA vs. SV. Recruitment, exclusion, randomization, and follow-up in groups 1 and 2, respectively. RITA, Right internal thoracic artery; LITA, left internal thoracic artery; AMI, acute myocardial infarction; EF, ejection fraction; BMI, body mass index; FEV1, forced expiratory volume in 1 second (from: Hayward PAR, et al. Comparable patencies of the radial artery and right internal thoracic artery or saphenous vein beyond 5 years: Results from the Radial Artery Patency and Clinical Outcomes trial. J Thorac Cardiovasc Surg 2010;139:60-7.)

Figure 2

Kaplan-Meier estimates of survival by intention to treat of RA vs. RITA patients, Group 1 (from: Hayward PAR, et al. Which arterial conduit? Radial artery versus free right internal thoracic artery: six-year clinical results of a randomized controlled trial. Ann Thorac Surg 2007;84:493-7.)

Figure 3

Kaplan-Meier estimates of Event free survival of RA vs. RITA patients, Group 1 (from: Hayward PAR, et al. Which arterial conduit? Radial artery versus free right internal thoracic artery: six-year clinical results of a randomized controlled trial. Ann Thorac Surg 2007;84:493-7.)

Figure 4

Kaplan-Meier estimates of survival of RA vs. SV patients, Group 2 (from: Hayward PAR, et al. Effect of radial artery or saphenous vein conduit for the second graft on 6-year clinical outcome after coronary artery bypass grafting. Results of a randomized trial. Eur J Cardiothorac Surg 2008;34:113-7.)

Figure 5

Kaplan-Meier estimates of event-free survival of RA vs. SV patients, Group 2 (from: Hayward PAR, et al. Effect of radial artery or saphenous vein conduit for the second graft on 6-year clinical outcome after coronary artery bypass grafting. Results of a randomized trial. Eur J Cardiothorac Surg 2008;34:113-7.)

Figure 6

Kaplan-Meier estimates of graft patency by intention to treat of RA vs. RITA, Group 1 (from: Hayward PAR, et al. Comparable patencies of the radial artery and right internal thoracic artery or saphenous vein beyond 5 years: Results from the Radial Artery Patency and Clinical Outcomes trial. J Thorac Cardiovasc Surg 2010;139:60-7.)

Figure 7

Kaplan-Meier estimates of graft patency by intention to treat of RA vs. SV, Group 2 (from: Hayward PAR, et al. Comparable patencies of the radial artery and right internal thoracic artery or saphenous vein beyond 5 years: Results from the Radial Artery Patency and Clinical Outcomes trial. J Thorac Cardiovasc Surg 2010;139:60-7.)