Yuanjia Zhu1, Bharathi Lingala1, Hanjay Wang1, Y Joseph Woo2. 1. Department of Cardiothoracic Surgery, Stanford University, Stanford, California. 2. Department of Cardiothoracic Surgery, Stanford University, Stanford, California. Electronic address: joswoo@stanford.edu.
Abstract
BACKGROUND: The use of the bilateral internal mammary artery (BIMA) in coronary artery bypass grafting remains controversial. The objective of this study was to investigate the long-term outcomes using the BIMA vs the single internal mammary artery (SIMA) in the United States. METHODS: Medicare beneficiaries who underwent primary isolated coronary artery bypass surgery using the SIMA or BIMA from 1999 to 2010 were included in this retrospective study, with follow-up through 2014. Greedy matching algorithms were used for 1:4 matching on propensity score based on age, gender, year of surgery, and comorbidities. Kaplan-Meier survival analyses were performed. The primary outcome was death from any cause. RESULTS: A total of 1,156,339 and 25,005 patients who were 72 ± 7.6 years of age and 70.3 ± 7.9 years of age underwent primary isolated coronary artery bypass surgery using SIMA and BIMA, respectively. Matching created comparable groups with 95,780 SIMA and 24,160 BIMA patients. Matched median survival using SIMA vs BIMA was 11.8 vs 12.4 years (P < .001) and 9.6 vs 10 years in diabetic patients (P = .006), respectively. At 10 years of follow-up, the respective survival rates of using SIMA vs BIMA were 58.3% vs 61.1%, respectively. The stratified matched median survival using SIMA vs BIMA with 1, 2, 3, and 4 or more aortocoronary bypasses were 11.8 vs 12.3 years (P = .005), 11.7 vs 12.5 years (P < .001), 11.9 vs 12.3 years (P = .01), and 11.4 vs 12 years (P = .02), respectively. CONCLUSIONS: Primary isolated coronary artery bypass surgery using the BIMA rather than the SIMA was associated with improved long-term survival. This survival advantage was independent of aortocoronary bypass grafts or patient diabetes status.
BACKGROUND: The use of the bilateral internal mammary artery (BIMA) in coronary artery bypass grafting remains controversial. The objective of this study was to investigate the long-term outcomes using the BIMA vs the single internal mammary artery (SIMA) in the United States. METHODS: Medicare beneficiaries who underwent primary isolated coronary artery bypass surgery using the SIMA or BIMA from 1999 to 2010 were included in this retrospective study, with follow-up through 2014. Greedy matching algorithms were used for 1:4 matching on propensity score based on age, gender, year of surgery, and comorbidities. Kaplan-Meier survival analyses were performed. The primary outcome was death from any cause. RESULTS: A total of 1,156,339 and 25,005 patients who were 72 ± 7.6 years of age and 70.3 ± 7.9 years of age underwent primary isolated coronary artery bypass surgery using SIMA and BIMA, respectively. Matching created comparable groups with 95,780 SIMA and 24,160 BIMApatients. Matched median survival using SIMA vs BIMA was 11.8 vs 12.4 years (P < .001) and 9.6 vs 10 years in diabeticpatients (P = .006), respectively. At 10 years of follow-up, the respective survival rates of using SIMA vs BIMA were 58.3% vs 61.1%, respectively. The stratified matched median survival using SIMA vs BIMA with 1, 2, 3, and 4 or more aortocoronary bypasses were 11.8 vs 12.3 years (P = .005), 11.7 vs 12.5 years (P < .001), 11.9 vs 12.3 years (P = .01), and 11.4 vs 12 years (P = .02), respectively. CONCLUSIONS: Primary isolated coronary artery bypass surgery using the BIMA rather than the SIMA was associated with improved long-term survival. This survival advantage was independent of aortocoronary bypass grafts or patientdiabetes status.