Equivalent Patencies of the Radial Artery, Right Internal Thoracic Artery and Saphenous Vein Beyond 5 Years: Surprising Results from the Radial Artery Patency and Clinical Outcomes Trial
Philip Hayward1, Mark Horrigan2, David L. Hare2, Ian Gordon3, George Matalanis2, Brian F. Buxton2; 1Cardiothoracic Surgery, Essex Cardiothoracic Centre, Basildon, United Kingdom; 2Austin Hospital, Melbourne, VIC, Australia; 3University of Melbourne Statistical Consulting Centre, Melbourne, VIC, Australia
Comment on this Abstract
Objective: To investigate the optimum conduit for coronary targets other than the left anterior descending artery, long-term patencies of the radial artery, right internal thoracic artery and saphenous vein were evaluated, in parallel with clinical data, through the Radial Artery Patency and Clinical Outcomes (RAPCO) trial.
Methods: As part of a 10-year prospective, randomised, single-centre trial, patients undergoing primary coronary surgery were allocated to radial artery (n=198) or free right internal thoracic artery (n=196), if aged less than 70 years (Group 1), or radial artery (n=112 or saphenous vein (n=112) if aged at least 70 years (Group 2). All patients received a left internal thoracic artery graft to the LAD, and the randomised conduit was used to graft the second largest target. Protocol-directed angiography has been performed at randomly assigned intervals weighted towards the end of the study period, with an additional optional restudy at 5 and 10 years. All angiograms are independently reported by 3 assessors. Grafts are defined as failed if there was occlusion, string sign, or <80% stenosis. Analysis is by study conduit utilised, rather than by intention.
Results: At mean follow up of 5.2 and 5.4 years, protocol angiography has been performed in groups 1 and 2 in 212 and 102 patients respectively. There are no significant differences within each group in preoperative comorbidity, age or urgency. Figure 1 shows similar patencies for either of the 2 conduits in each group (log rank analysis, p=0.70 for group 1, p=0.40 for group 2). Alternative analysis by intention to treat does not influence this finding.
Conclusion: At mean 5-year angiography in largely asymptomatic patients, the selection of arterial or venous conduit for the second graft has not impacted on patency. This finding from the most comprehensive assessment of the radial artery offers surgeons, for now, enhanced flexibility in planning revascularisation.
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