Noninvasive Detection of Collateral Flow to the Infarct-Related Coronary Artery in Patients after Myocardial Infarction by Tl-201 Tomographic Imaging

Background The determination of viability and perfusion within the infarct zone in post-myocardial infarction patients has both therapeutic and prognostic significance. Reversibility of thallium 201 uptake within the territory of the infarct-related coronary artery (IRA) as shown by single photon emission computed tomography (SPECT) is associated with a jeopardized but viable myocardium. We aimed to test the hypothesis that for post-myocardial infarction patients undergoing Tl-201 stress-redistribution SPECT, a scintigraphic pattern of distal reversibility without proximal reversibility within a defect corresponding to the IRA territory is a marker of collateral flow to the occluded culprit artery. Methods and Results We assessed Tl-201 SPECT imaging results of 78 patients with IRA occlusion as demonstrated by angiography 7 ± 1 months after myocardial infarction. Angiography demonstrated the presence of collateral flow in 57 patients and its absence in 21 patients. Distal reversibility was present in 42 of the 57 patients with collateral flow (sensitivity, 74%) and was absent in 16 of the 21 patients without collateral flow (specificity, 76%). Collateral flow to the IRA was demonstrated in 42 of 47 patients with distal reversibility (group A) (positive predictive value, 89%) and absent in 16 of 31 patients with a fixed defect without reversibility (group B) ( P < .001) (negative predictive value, 52%). Conclusions In patients after myocardial infarction, a Tl-201 SPECT redistribution pattern of distal reversibility without proximal reversibility within a defect in the IRA territory is a noninvasive marker of collateral flow to the culprit artery with a high positive predictive value that may provide valuable information on patient management. A larger prospective study in an unselected patient population is needed to further evaluate the clinical value of this marker.