[Evaluation of the graft flow reserve after coronary artery bypass grafting by stress 201T1 myocardial SPECT: comparison between arterial grafts and venous grafts].

We performed stress 201T1 myocardial SPECT to evaluate ischemia and perfusion reserve after coronary artery bypass grafting (CABG). A total of 103 patients was performed stress 201T1 myocardial SPECT one month after CABG. Each patient's myocardium was divided into 9 segments and visually evaluated using five grade scoring system (0 = defect, 1 = severe decrease, 2 = moderate decrease, 3 = mild decrease, 4 = normal uptake). Eleven of 133 (8.27%) segments covered by patent venous grafts showed reversible 201T1 defect, however, 36 of 117 (30.8%) segments which covered by patent arterial grafts showed reversible 201T1 defect. This finding was observed more significantly in arterial grafts than in venous grafts (p < 0.001). These finding suggests that arterial grafts have lower flow capacity than venous grafts at peak exercise.