Bilateral Internal Thoracic Arteries Improve 10-Year Outcomes of Coronary Artery Bypass Grafting

Background: This observational cohort study was designed by the PRIORITY (PRedictIng long-term Outcomes afteR Isolated coronary arTery bypass surgery) steering committee to evaluate the 10-year follow-up outcome of bilateral internal thoracic arteries (BITA) versus single internal thoracic artery. Methods: The PRIORITY project was designed to evaluate long-term outcome of 2 large prospective multicenter cohort studies of coronary artery bypass grafting. Clinical data on isolated coronary artery bypass grafting were merged with administrative data to collect follow-up information. The primary endpoint was the composite outcome of major adverse cardiac and cerebrovascular events at 10-year follow-up. Secondary endpoints were individual components of major adverse cardiac and cerebrovascular events at 10 years and surgical site complications or infections. A propensity score–based inverse probability treatment weighting (IPTW) was used to overcome the selection bias related to the observational nature of the study. Results: The study population consisted of 10,988 patients who underwent isolated coronary artery bypass grafting. BITA was used in 23.5%. The use of BITA is related to lower incidence of major adverse cardiac and cerebrovascular events at 10 years (adjusted hazard ratio [HR] 0.88, 95% CI 0.79-0.98, P < .001). BITA correlated with better 10-year survival (IPTW adjusted HR 0.87, 95% CI 0.78-1.00, P = .05), re-revascularization (IPTW adjusted HR 0.83, 95% CI 0.74-0.92, P < .001), and myocardial infarction (IPTW adjusted HR 0.86, 95% CI 0.77-0.95, P = .005) but to increased incidence of surgical site complications or infections (HR 2.12, 95% CI 1.39-3.24, P < .001). Conclusions: In propensity-matched patients, use of BITA was associated with improved 10-year survival, freedom from repeat revascularization, and myocardial infarction but also higher incidence of surgical site complications.