The impact of diabetic status on coronary artery bypass graft patency: insights from the radial artery patency study.
BACKGROUND
Despite worse outcomes in diabetics after coronary artery bypass grafting surgery, studies have not examined graft patency in this high-risk group. This study examined the impact of diabetes on graft patency, 1-year postcoronary artery bypass grafting, using data from a multicenter randomized trial.


RESULTS
The Radial Artery Patency Study enrolled 561 patients undergoing coronary artery bypass grafting, comparing graft patency of the saphenous vein (SV) versus radial artery 1-year postcoronary artery bypass grafting. Angiographic follow-up was acquired for 440 patients (115 diabetics, 325 nondiabetics), each with a study radial artery and a control SV graft. Preoperative characteristics were similar. The proportion of small-sized target vessels was greater in diabetics (P=0.04). At 1 year, 33 of 230 study grafts (14.4%) were occluded in the diabetics versus 63 of 650 (9.7%) in the nondiabetics (P=0.052). Multivariable regression found diabetes to be a significant independent predictor of 1-year graft occlusion (relative risk, 1.45; 95% CI, 1.03 to 2.05; P=0.03) along with female gender, SV conduit, and small target-vessel size. A significantly higher proportion of SV grafts were occluded in the diabetics (19% versus 12%, P=0.04). Radial artery grafting was protective in the diabetic cohort (radial artery: 11 of 115 occluded [9.5%] versus SV: 22 of 115 occluded [19.1%], McNemar corrected P=0.05; relative risk, 0.42; 95% CI, 0.16 to 1.01) and nondiabetics (radial artery: 25 of 325 occluded [7.7%] versus SV: 38 of 325 occluded [11.7%], McNemar corrected P=0.11; relative risk, 0.63; 95% CI, 0.35 to 1.10).


CONCLUSIONS
Coronary artery bypass grafting occlusions were more common among diabetics versus nondiabetics at 1-year angiography, mainly because of more frequent SV graft failure in diabetics. Radial artery, compared with SV grafting, is protective in both diabetic and nondiabetic patients.
Singh
Steve K
SK
Divisions of Cardiac and Vascular Surgery, Sunnybrook Health Sciences Centre, Toronto, Canada.
Desai
Nimesh D
ND
Petroff
Stephanie D
SD
Deb
Saswata
S
Cohen
Eric A
EA
Radhakrishnan
Sam
S
Schwartz
Leonard
L
Dubbin
James
J
Fremes
Stephen E
SE
D000368:Aged; D017023:Coronary Angiography; D001026:Coronary Artery Bypass / Q000379:methods; D003324:Coronary Artery Disease / Q000150:complications* / Q000601:surgery*; D048909:Diabetes Complications; D005260:Female; D005500:Follow-Up Studies; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D017534:Radial Artery / Q000503:physiopathology* / Q000637:transplantation*; D012306:Risk; D012501:Saphenous Vein / Q000637:transplantation; D012737:Sex Factors; D014654:Vascular Patency