Comparison of radial artery and saphenous vein as the third conduit with bilateral internal mammary arteries in coronary bypass surgery.

OBJECTIVE: The optimal third conduit for multiarterial coronary artery bypass grafting using bilateral internal mammary arteries (BIMA) remains debated. Trial data have been confounded by crossover and frequent radial artery (RA) use in controls. We evaluated whether adding RA versus saphenous vein (SVG) to BIMA influences outcomes. METHODS: We performed a 27-year retrospective analysis of 1727 patients with BIMA grafts receiving SVG (n = 1307) or RA (n = 420). Propensity-score matching (1:1) generated 399 balanced pairs. Preoperative characteristics, intraoperative data, and in-hospital outcomes were compared. Long-term survival was assessed by Kaplan-Meier analysis, log-rank testing, and Cox proportional hazards modeling. RESULTS: Before matching, recipients of RAs had fewer comorbidities (diabetes 14.8% vs 26.0%; hypertension 62.4% vs 77.7%; renal impairment 5.5% vs 25.2%; all P < .001). In-hospital outcomes were largely comparable; however, postoperative renal complications more frequent in matched recipients of RAs (2.5% vs 0.5%; P = .042). In the unmatched cohort, 20-year survival favored BIMA+RA (log-rank χ2 = 5, P = .026). After matching, this difference was attenuated and not statistically significant (χ2 = 2.7, P = .097). Cox modeling identified RA as independently protective (hazard ratio, 0.522; 95% CI, 0.279-0.977; P = .0419); increasing age, preoperative atrial fibrillation, and ≥2 previous myocardial infarctions predicted mortality. CONCLUSIONS: RA as the third conduit alongside BIMA was associated with improved long-term survival in unmatched analyses and remained protective in multivariable modeling, but the matched cohort did not show a statistically significant survival difference, suggesting selection effects. The observed increase in postoperative renal complications warrants caution. Conduit choice should be individualized.