Bilateral Internal Mammary Artery Grafting Enhances Survival in Diabetic Patients: A 30-Year Follow-Up of Propensity Score–Matched Cohorts

Study Questions:

What are the long-term results of bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) grafting in a large population of diabetic patients in whom BIMA grafting was broadly applied?


Between February 1972 and May 1994, 1,107 consecutive diabetic patients underwent coronary artery bypass grafting with either SIMA (n = 646) or BIMA (n = 461) grafting. Optimal matching with the propensity score was used to create matched SIMA (n = 414) and BIMA (n = 414) cohorts. Cross-sectional follow-up (6 weeks to 30.1 years; mean, 8.9 years) determined long-term survival.


There was no difference in operative mortality, sternal wound infection, or total complications between matched SIMA and BIMA groups (operative mortality, 10 of 414 [2.4%] vs. 13 of 414 [3.1%]; p = 0.279; sternal wound infection, 7 of 414 [1.7%] vs. 13 of 414 [3.1%]; p = 0.179; total complications, 71 of 414 [17.1%] vs. 71 of 414 [17.1%]; p = 1.000). Late survival was significantly enhanced with the use of BIMA grafting (median survival: SIMA, 9.8 years vs. BIMA, 13.1 years; p = 0.001). Use of BIMA was found to be associated with late survival on Cox regression (p = 0.003).


The authors concluded that compared with SIMA grafting, BIMA grafting in propensity score–matched patients provides diabetics with enhanced survival without any increase in perioperative morbidity or mortality.


This study reported an enhanced long-term survival advantage for BIMA grafting in a large cohort of consecutive multigraft diabetic CABG patients in whom BIMA grafting was liberally applied. Given the documented benefits of CABG in diabetic patients with extensive multivessel coronary artery disease, BIMA grafting appears to be the procedure of choice in those patients in whom the operation is technically feasible. An adequately powered randomized study of SIMA versus BIMA grafting in diabetics will help validate these findings and further encourage use of BIMA grafts.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease

Keywords: Coronary Artery Disease, Internal Mammary-Coronary Artery Anastomosis

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