Does Use of Bilateral Internal Mammary Artery Grafting Reduce Long-Term Risk of Repeat Coronary Revascularization? A Multicenter Analysis.

BACKGROUND: Although previous studies have demonstrated that patients receiving bilateral internal mammary artery (BIMA) conduits during coronary artery bypass grafting have better long-term survival than those receiving a single internal mammary artery (SIMA), data on risk of repeat revascularization are more limited. In this analysis, we compare the timing, frequency, and type of repeat coronary revascularization among patients receiving BIMA and SIMA. METHODS: We conducted a multicenter, retrospective analysis of 47 984 consecutive coronary artery bypass grafting surgeries performed from 1992 to 2014 among 7 medical centers reporting to a prospectively maintained clinical registry. Among the study population, 1482 coronary artery bypass grafting surgeries with BIMA were identified, and 1297 patients receiving BIMA were propensity-matched to 1297 patients receiving SIMA. The primary end point was freedom from repeat coronary revascularization. RESULTS: The median duration of follow-up was 13.2 (IQR, 7.4-17.7) years. Patients were well matched by age, body mass index, major comorbidities, and cardiac function. There was a higher freedom from repeat revascularization among patients receiving BIMA than among patients receiving SIMA (hazard ratio [HR], 0.78 [95% CI, 0.65-0.94]; CONCLUSIONS: BIMA grafting was associated with a reduced risk of repeat revascularization and an improvement in long-term survival and should be considered more frequently during coronary artery bypass grafting

Coronary Revascularization With Single Versus Bilateral Mammary Arteries: Is It Time to Change?

BACKGROUND: Arterial conduits are preferred to venous conduits for coronary artery bypass grafting because of longer patency. A single internal mammary artery (SIMA) is used routinely. Bilateral internal mammary arteries (BIMA) are used less frequently. We sought to determine whether BIMA were superior to SIMA. METHODS: From our regional registry of consecutive open heart operations, we identified 47,984 patients who underwent isolated coronary artery bypass grafting from 1992 to 2014. Of the 1,482 BIMA patients, 1,297 were propensity matched to a cohort of SIMA patients. Short-term outcomes were compared using standard statistical techniques. Long-term survival was compared using Kaplan-Meier estimators and compared using a log-rank test. RESULTS: BIMA patients were younger and had fewer comorbid conditions than SIMA patients. After propensity weighting, BIMA and SIMA patients were well matched. There was no difference in in-hospital outcomes for BIMA versus SIMA patients for mortality (1.2% [n = 15] vs 0.8% [n = 10], p = 0.315), stroke (0.7% [n = 9] vs 0.7% [n = 9), p = 1.000), bleeding (2.2% [n = 28] vs 2.8% [n = 36], p = 0.311), or mediastinitis (0.8% [n = 10] vs 0.9% [n = 12], p = 0.667). The median follow-up was 12 years. Survival was better for BIMA than SIMA (adjusted hazard ratio, 0.79; 95% confidence interval, 0.69 to 0.91; p \u3c 0.001). Survival curves began to separate after 5 years. At 15 years, the absolute difference in survival was 8.4%. CONCLUSIONS: In a large regional experience, BIMA is associated with no upfront risk of adverse events and improved long-term survival compared with SIMA. Our results indicate that BIMA conduits should be considered more frequently during coronary artery bypass grafting due to their demonstrated survival advantage

Should Diabetes Be a Contraindication to Bilateral Internal Mammary Artery Grafting?

BACKGROUND: This study evaluates the influence of bilateral internal mammary artery (BIMA) versus single internal mammary artery (SIMA) grafting on postoperative morbidity and long-term survival among diabetic patients undergoing coronary artery bypass grafting (CABG). METHODS: A multicenter, retrospective analysis of 47,984 consecutive CABGs performed from 1992 to 2014 at 7 medical centers was conducted. Among the study population, 1,482 CABGs with BIMA were identified, and 1,297 BIMA patients were propensity-matched to 1,297 SIMA patients. The study cohort for this analysis, drawn from matched data, included 430 diabetic patients: 217 SIMA and 213 BIMA. The primary endpoint was long-term survival. Secondary endpoints included postoperative morbidity, length of stay, and in-hospital mortality. RESULTS: The median duration of follow-up was 9.3 (range, 4.3 to 13.9) years. Among propensity-matched diabetic patients, there was no significant difference in age, body mass index, or major baseline comorbidities. The groups were also well matched on the number of diseased coronary arteries and number of distal anastomoses performed. There was no difference in the rate of mediastinitis or sternal dehiscence (p = 0.503) or in-hospital mortality (p = 0.758) between groups. Both groups had a similar median length of stay of 5 (range, 4 to 7) days. Diabetic patients who received a BIMA had significantly improved long-term survival when compared with SIMA patients (hazard ratio 0.75 [95% confidence interval 0.57 to 0.98], p = 0.034). CONCLUSIONS: Among diabetics undergoing CABG, use of BIMA grafting does not result in increased in-hospital morbidity or mortality and confers a long-term survival advantage when compared with SIMA grafting. Thus, diabetic patients should be considered for BIMA grafting more frequently