Diagnostic accuracy of tomographic myocardial imaging for evaluation of coronary artery bypass graft patency

Introduction and objectives. Conventional ergometry has limitations in the evaluation of coronary artery bypass graft patency. The aim of the present study was to determine the efficacy of exercise single photon emission tomo graphy with Tc-99m-compounds for the diagnosis of coronary artery bypass gr afts disease. Patients and methods. The state of sixty-seven coronary artery bypass graft s (31 with mammary artery, 36 with safein vein; 35 to left descending anter ior artery, 15 to circumflex and 17 to right coronary artery) were analyzed retrospectively in 38 patients (mean age 63 +/- 8.7; 35 men). The time tha t elapsed betwen the coronary surgery and the exercise tomography was 9,7 y ears. In 16 cases, exercise tomography was performed with Tc-99m-MIBI and i n the 22 remaining with Tc-99m-tetrofosmin. In 6 cases, dipiridamol was adm inistred simultaneously during an insufficient exercise test. Results. Sensitivity (73.1%), specificity (93%), positive predictive value (86.3%), negative predictive value (84.4%), global value (85%), positive li kelihood ratio (10.4) and negative likelihood ratio (0.29) of exercise tomo graphy were significantly (p < 0.01) better than those obtained with the ex ercise test alone (53.8%, 43.6%, 38.9%, 58.6%, 47.7%, 0.95 and 1.06, respec tively). Conclusions. Exercise tomography with Tc-99m-compounds is a highly effectiv e for the detection of coronary artery bypass grafts disease.