Internal thoracic artery grafting in the elderly patient undergoing coronary artery bypass grafting: Room for process improvement?

Abstract

Objective: The acute and long-term benefits of internal thoracic artery grafting are clear in younger patients undergoing coronary artery bypass grafting. The elderly, however, face higher surgical risks and have shorter life expectancy, and thus the use of internal thoracic artery grafting in this age group has been debated. This study examined the use, complication risks, and operative (30-day) mortality associated with internal thoracic artery grafting in patients 75 years of age and older. Methods: Between 1996 and 1999, 522,656 patients in the Society of Thoracic Surgeons National Cardiac Database underwent primary, nonemergency-salvage coronary artery bypass grafting; of these, 99,942 were 75 years of age or older. The influence of internal thoracic artery use on operative mortality and 5 major complications in this elderly group was examined by means of (1) risk adjustment (adjusting for 28 baseline risk factors and site) and (2) a treatment propensity score analysis that compares patients with similar baseline likelihood for receiving an internal thoracic artery graft. Results: In the National Cardiac Database 77.4% of patients aged 75 to 84 years received an internal thoracic artery graft compared with 93.5% for those aged 55 years or less. In this elderly group use of the internal thoracic artery was strongly associated with decreased operative mortality (unadjusted mortality, 6.20% vs 4.05%; P < .0001) that persisted after controlling for baseline risk and provider effects (adjusted odds ratio, 0.85; 95% confidence intervals, 0.79-0.91). This mortality benefit was seen among those with low-to-high baseline propensity for receiving an internal thoracic artery graft. Conclusions: Use of the internal thoracic artery in elderly patients undergoing coronary artery bypass grafting provides an acute survival benefit. This benefit is similar to that seen in younger patients and persists after adjusting for both patient and provider selection factors. The internal thoracic artery appears to be underused in elderly patients undergoing bypass grafting and is a potential area for quality improvement.