[Coronary revascularization evaluated by thallium-201 myocardial scintigraphy: a follow-up study]

To elucidate changes with time in T1-201 scintigraphy after coronary revascularization, T1-201 stress myocardial scintigraphy was performed at least twice during the follow-up period (from one to 12 months) in 58 patients with ischemic heart disease (12 with angina, and 46 with myocardial infarction) who had undergone PTCA or A-C bypass surgery. The perfusion defects were classified in 4 grades, and scintigraphic changes over grade 1 were judged significant. We evaluated; 1) time of scintigraphic improvement after revascularization, 2) presence of reverse redistribution, and 3) assessment of coronary restenosis. Scintigraphic improvement was observed in 21 of 58 patients during a 3- to 12- month follow-up period, 7 of whom improved within one month. Reverse redistribution after coronary revascularization was observed in 8 of the 58 patients (14%), including 6 who showed scintigraphic improvement in 3 to 12 months (2 were not examined). Among 29 patients whose coronary angiogram and Tl-201 scintigram were compared, 11 had angiographic evidence of restenosis and 4 of them showed deterioration of scintigraphic findings (sensitivity 57%, specificity 68%, and accuracy 66%). In conclusion, scintigraphic improvement was observed over various periods (immediately after and up to 12 months) after coronary revascularization. Reverse redistribution appears to be a predictor of good prognosis. Coronary restenosis cannot always be reliably assessed by Tl-201 scintigraphy.