Bilateral internal thoracic artery grafting is superior to other forms of multiple arterial grafting in providing survival benefit after coronary bypass surgery

Abstract

The objective of this study was to examine the effect of arterial grafting on long-term coronary artery bypass grafting mortality. Consecutive coronary artery bypass grafting surgeries performed at a single tertiary care center between 1995 and 2007 were reviewed. Long-term survival was compared among patients according to the type of arterial grafts used: no internal thoracic artery, single internal thoracic artery, single internal thoracic artery with other arterial graft, or bilateral internal thoracic artery. Cox proportional hazard models were generated to examine the association of arterial grafting with mortality. A total of 8264 isolated coronary artery bypass grafting operations were performed and followed for a median time of 4.7 years (interquartile range, 2.1-7.5). A single internal thoracic artery was used in the majority of patients (79%), multiple arterial grafts were used in 24% of patients, and bilateral internal thoracic artery grafts were used in 13% of patients. Patients who received multiple arterial grafts were more likely to be younger, to be male, and to undergo non-urgent surgery. After adjusting for these differences, patients who received bilateral internal thoracic artery grafts were found to have a significant survival advantage when compared with all other patients, including those who received a single internal thoracic artery plus other arterial grafts (hazard ratio, 0.818; confidence interval, 0.672-0.996). Survival at 10 years was 71% for patients with bilateral internal thoracic artery grafts compared with 66% for patients with single internal thoracic artery grafts and 58% for patients with no internal thoracic artery graft. Patients with bilateral internal thoracic artery grafts had significantly better freedom from readmission for acute coronary syndrome (hazard ratio, 0.802; confidence interval, 0.668-0.963). After adjusting for relevant clinical differences, only multiple arterial grafting using the bilateral internal thoracic artery was able to offer a long-term survival advantage over single internal thoracic artery grafting in patients undergoing coronary artery bypass grafting.