Two-year assessment by exercise Thallium scintigraphy of myocardial revascularization using bilateral internal mammary and gastroepiploic arteries

Objective: To assess the blood flow supply offer ed to the myocardium by su rgical revascularization using bilateral internal mammary (IMAs) and gastro epiploic (GEA) arteries, Methods: Two-year assessment by exercise thallium myocardial scintigraphy without medical treatment was performed in 122 pati ents (mean age 61 +/- 9 years) who underwent coronary artery bypass graftin g (CABG) with exclusive use of IMAs and GEA. Usually, the right IMA was use d to bypass the left anterior descending coronary artery, and the left IMA to bypass the diagonal and the marginal arteries as a sequential graft if r equired. The GEA was used to bypass the right coronary artery (RCA) in 50 p atients and its posterior branches in 72 patients. Results: During maximal or submaximal exercise stress testing, 119 patients (98%) were asymptomatic and 26 patients (21%) exhibited moderate ischemic ECG modifications which were correlated (P < 0.01) with incomplete revascularization and with the u se of GEA to bypass the RCA, A third of patients had moderate ischemic thal lium defects on exercise reversible after redistribution (anterior, 10; lat eral, 2; inferior, 28), Silent residual myocardial ischemia detected by tha llium scintigraphy was correlated (P < 0.001) with ECG modifications and in complete revascularization; and inferior thallium defects were more frequen t when GEA bypassed the RCA (P < 0.05), However, 26% of patients had residu al ischemia despite a complete revascularization, and in at least 18% of ca ses for GEA and 8% for light TMA, arterial graft blood flow was insufficien t at maximum exercise level and caused silent residual myocardial ischemia detected by thallium scintigraphy. Conclusions: Myocardial revascularizatio n using bilateral IMAs and GEA offers a satisfactory myocardial perfusion i n the majority of cases; however silent residual myocardial ischemia was de tected in a third of patients and was related to incomplete revascularizati on and to insufficient blood flow supply probably due to small diameter of the arterial grafts. (C) 1999 Elsevier Science B.V, All rights reserved.