IMPROVED SURVIVAL WITH MULTIPLE LEFT-SIDED BILATERAL INTERNAL THORACIC ARTERY GRAFTS

Background. Although conceptually sound, the use of multiple internal thoracic artery (ITA) bypass grafts to improve long-term clinical resu lts remains controversial. This operation typically involves grafting the left ITA to the anterior descending artery and the right ITA to th e right coronary artery. Past clinical studies of bilateral ITA operat ions have not examined comparative results associated with which coron ary arteries received the ITA bypass grafts. Because grafting a superi or conduit to an artery of lesser physiologic importance might reduce the clinical benefits, we compared the outcomes of patients receiving different configurations of bilateral ITA operations. Methods. The stu dy group was 498 consecutive bilateral ITA operations, constituting th e 10-year experience of a single surgeon. Follow-up averaged 7.1 years (mode 7.3 years), and was 94.2% complete. These patients were divided into two groups, 311 patients (group I) who underwent the traditional operation (left ITA to the left anterior descending artery, right ITA to the right coronary artery), and 187 patients (group II) who receiv ed revascularization of branches of the left coronary artery (left ITA to the circumflex system and right ITA to the left anterior descendin g artery). Results. The study groups were similar in age, severity of disease, number of bypassed arteries, ejection fraction, diabetes, hyp ertension, and duration of operation. There were more male patients in group II (91.4% versus 82.3%). A multivariate analysis showed that th e location of ITA bypass grafts influenced survival independent of gen der (p = 0.0288). Operative morbidity and mortality were similar betwe en groups. Ninety-three patients had repeat angiography with equivalen t patency rates of the ITA conduits (91.7% versus 89.6%; p = 0.67). Th e Kaplan-Meier actuarial survival estimate demonstrated a significant improvement in survival of patients in group II who received both ITA bypass grafts to left-sided arteries (p = 0.021), with the survival cu rves diverging at 6 years. More patients in group II were in New York Heart Association class I or II, but the difference was not statistica lly significant (94.6% versus 91.6%). Only 2 patients required reopera tion. Conclusions. It appears that maximum long-term benefit from bila teral ITA operations is achieved by grafting the ITA conduits to coron ary arteries that supply more left ventricular muscle. (C) 1997 by The Society of Thoracic Surgeons.