Direct non-invasive techniques for assessing coronary bypass graft patency.

Venous digital subtraction angiography (vDSA) and computed tomography (CT) are two non-invasive techniques that allow direct imaging of coronary grafts. Neither of them is 100% accurate when compared to selective angiography. We studied 52 patients with 107 coronary grafts (101 saphenous and 6 mammary artery grafts) by CT and vDSA. Fifty patients had control selective angiography and 2 had control digital arterial aortography. CT correctly diagnosed 88 of the 95 patent grafts and 8 out of the 12 occluded grafts (in 1 patient 3 patent grafts could not be well analyzed owing to artifacts from pacemaker wires). vDSA correctly identified 93 patent grafts and the 12 occluded grafts, allowing the correct diagnosis of the 11 non/or misdiagnosed CT grafts. CT allowed the correct identification of the 2 misdiagnosed vDSA grafts. These results show that when there was agreement between CT and vDSA there were no diagnostic errors and that the combination of these two non-invasive techniques may avoid selective angiography for studying coronary bypass graft patency.