Age cut-off for the loss of benefit from bilateral internal thoracic artery grafting.

OBJECTIVES To identify the age-related benefit of single and bilateral internal thoracic artery (ITA) grafting on long-term cardiac-related survival in patients who survived from primary isolated coronary artery bypass grafting (CABG). METHODS A unicenter study was conducted on 12,231 consecutive survivors from primary isolated CABG who received single (n=9566 patients) or bilateral (n=1388 patients) ITA grafts, or vein grafts only (n=1277 patients) between 1992 and 2005. Data was collected prospectively. The Cox regression model estimates the hazard ratio of each independent variable on cardiac-specific survival over the entire length of follow-up. Age was a significant covariate into the statistical model. The mean follow-up was 5.7+/-3.7 years and 100% complete as of December 2005. The date and cause of death were obtained from the regional statistical institute. RESULTS After adjustments for different risk factors, the cardiac-related survival benefit in patients undergoing CABG with two ITAs was superior to that of single ITA grafting up to 60 years of age, displaying a constant decrease over time. The use of a single ITA was beneficial on cardiac-related survival in all age groups, including octogenarians, compared to patients receiving only vein grafts. CONCLUSIONS The use of at least one ITA is associated with increased long-term cardiac-specific survival in all age groups compared to venous-only CABG, even in octogenarians. The additional survival benefit of using a second ITA decreases gradually with age, and is lost after 60 years of age.