LONG-TERM PREDICTION OF MAJOR ISCHEMIC EVENTS BY EXERCISE TL-201 SINGLE-PHOTON EMISSION COMPUTED-TOMOGRAPHY - INCREMENTAL PROGNOSTIC VALUE COMPARED WITH CLINICAL, EXERCISE TESTING, CATHETERIZATION AND RADIONUCLIDE ANGIOGRAPHIC DATA

Objectives. This study sought to evaluate the prognostic role of exerc ise thallium-201 (Tl-201) single-photon emission computed tomography ( SPECT) in patients with known or suspected coronary artery disease. Ba ckground. Compared with planar Tl-201 scintigraphy, Tl-201 SPECT allow s enhanced assessment of myocardial perfusion abnormalities, However, the long-term prognostic value of exercise Tl-201 SPECT has not been a scertained and compared with that of other techniques of investigation . Methods. Predictors of ischemic events were sought in 217 patients w ith known or suspected coronary artery disease who underwent exercise Tl-201 SPECT, coronary angiography and rest radionuclide angiography a nd who initially received medical therapy. Predictive values were dete rmined using Cox proportional hazards regression models, Results. Duri ng a mean (+/-SD) follow-up period of 70 +/- 19 months, 29 patients ha d a major ischemic event (cardiac death or myocardial infarction), Tot al extent of exercise defects was the best independent predictor by Tl -201 SPECT of major events (p < 0.001) and provided additional prognos tic information compared with clinical, exercise testing and catheteri zation variables (p < 0.02). Extent of reversible Tl-201 SPECT perfusi on defects provided additional prognostic information compared with ex tent of irreversible defects (p < 0.001) and was the sole Tl-201 SPECT variable providing additional prognostic information compared with ra dionuclide left ventricular ejection fraction (p < 0.02). Conclusions. Total extent of exercise Tl-201 SPECT defects is a powerful long-term predictor of major ischemic events that enhances the prediction provi ded by clinical, exercise testing and coronary angiographic data. In v iew of its prognostic significance, extent of reversible Tl-201 SPECT defects might provide original information about improving prognosis b y coronary revascularization.