Radial Artery as a Coronary Artery Bypass Conduit
What are the results of radial artery (RA) grafts used for coronary artery bypass grafting (CABG) and the effects of RA removal on forearm circulation?
The investigators reported the results of the prospective 20-year follow‐up of the first 100 consecutive patients who received the RA as a coronary bypass conduit at their institution. Competing risk analysis was used to estimate the cumulative incidence function for late graft occlusion for the different conduits.
Follow-up was 100% complete. There were 64 deaths, 23 (35.9%) from cardiovascular causes. Kaplan-Meier 20-year survival was 31%. Thirty-three of 36 survivors (91.6%) underwent RA graft control at a mean of 19.0 ± 2.5 years after surgery. The RA was found to be patent in 24 cases (84.8% patency). In the overall population, probability of graft failure at 20 years was 19.0% ± 0.2% for the left internal thoracic artery (ITA), 25.0% ± 0.2% for the RA, and 55.0% ± 0.2% for the saphenous vein (SV) (p = 0.002 for RA vs. SV, 0.11 for RA vs. ITA, and < 0.001 for ITA vs. SV). Target vessel stenosis >90%, but not location of distal anastomosis, significantly influenced long-term RA graft patency. No patients reported hand or forearm symptoms. The ulnar artery diameter was increased in the operated arm (2.44 ± 0.43 mm vs. 2.01 mm ± 0.47 mm; p < 0.05) and correlated with the peak systolic velocity of the second palmar digital artery (Pearson’s coefficient, 0.621; p < 0.05).
The authors concluded that the 20‐year patency rate of RA grafts is good, and not inferior to the left ITA.
This study reports that the 20‐year angiographic outcome of RA conduits used for CABG is not inferior to that of the gold standard left ITA. While the location of the target vessel does not influence graft status, the severity of the coronary stenosis appears to be a major determinant of patency. Furthermore, after harvesting of the RA, the ulnar collateral circulation provides sufficient flow to the arm and clinically evident forearm or hand ischemia does not occur, even at extended follow-up. Randomized trials are indicated to verify these findings and compare short- and long-term outcomes of revascularization using the RA with alternative vascular conduits in patients with less severe stenosis undergoing CABG.
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