Identification of coronary thrombus with a IIb/IIIa platelet inhibitor radiopharmaceutical, technetium-99m DMP-444: A canine model

Abstract

Background - A diagnostic test that could distinguish between stable and unstable coronary atherosclerotic plaques would be useful. We tested the ability of a new glycoprotein IIb/IIIa platelet inhibitor DMP-444, labeled with technetium (Tc)-99m, to identify platelet-rich thrombus by nuclear imaging in a canine model. Methods and Results - Combinations of a flow- limiting stenosis and 0 to 15 minutes of endothelial electrical stimulation at a site in the left anterior descending coronary artery were used to induce varying amounts of thrombus formation. In 10 animals with markedly positive nuclear images after the injection of Tc-99m DMP-444, the presence of platelet-rich thrombus was confirmed postmortem by gross appearance, high nuclear counts, and abundant platelets on electron microscopy. The 10 animals with negative images had lower counts, smaller thrombus weights (P<0.05 for each), and fewer platelets by electron microscopy. Conclusions - Activated platelets participating in acute thrombus formation can be accurately detected by nuclear imaging using Tc-99 m DMP-444.