Prognostic value of dipyridamole SPECT imaging in low-risk patients after myocardial infarction.

BACKGROUND: The prognostic value of perfusion imaging was assessed in low-risk patients after myocardial infarction (MI) and compared with clinical and angiographic variables. METHODS AND
RESULTS: Rest thallium and dipyridamole technetium 99m sestamibi single photon emission computed tomography imaging was performed in 203 (91%) low-risk patients 3 to 21 days after MI who were enrolled in a trial of low-dose warfarin sodium and aspirin. Patients were considered low risk with planned nonintervention, on the basis of an uncomplicated course after MI, negative submaximal stress electrocardiography, and the absence of significant angiographic disease requiring revascularization. During a minimum follow-up of 12 months, 69 patients (34%) had clinical events: 1 cardiac death, 7 MIs, 26 admissions for unstable angina, 18 coronary bypass grafting, and 17 angioplasty. Univariate analysis identified the extent of significant angiographic stenoses (> or =70%) and the extent of scintigraphic defect as predictive of future events. On multivariate analysis, the presence of any scintigraphic reversibility had the strongest correlation with clinical events, with better predictive value than angiographic multivessel stenoses (P =.0006 vs P =.003).
CONCLUSIONS: In the low-risk population after MI, scintigraphic reversibility remains a strong predictor of cardiac events, with greater prognostic value than angiographic data. The extent of scintigraphic reversibility was directly correlated with clinical events. Therefore scintigraphic imaging remains clinically relevant for risk stratification in the current low-risk population after MI.