Coronary angiography and thallium-201 single photon emission computed tomography in single vessel coronary artery disease.

Polar presentations of selective coronary angiography and myocardial 201T1 SPECT were compared in 49 patients with single vessel disease. Twenty-six lesions were located in LAD, 8 in LCX and 15 in RCA. Perfusion defects were found within the supply area of 44 stenotic and 20 non-stenotic arteries. 201T1 SPECT detected coronary disease in 45 patients (92%) and the obstructed artery in 44 (90%). Single vessel disease was correctly indicated in 28 patients (57%) where the perfusion defects did not extend significantly outside the area supplied by the stenotic artery. Extensive perfusion defects could be explained by 'collateral steal', myocardial disease, LV aneurysm or spasm in 9 patients (18%). The absence of perfusion defect related to the stenotic artery could be explained by a moderate degree of stenosis or well developed collateral vessels in 5 patients (10%). Proximal LAD lesions resulted in larger perfusion defects than distal.