Coumadin and 111In-labeled platelet uptake on experimental thrombi in dogs. Preliminary observations

The effect of coumadin treatment upon the uptake of 111In platelets (111In-P) in dogs by experimental jugular thrombi and intravascular catheters was studied. Coumadin, in doses sufficient to raise the PT to the "therapeutic" range, did not impair scintigraphic visualization of thrombi on images obtained 4 hours after 111In-P injection. In addition, there was no obvious effect upon postmortem measurements of thrombus:blood or catheter:blood 111In activity ratios, consistent with the imaging data. However, slight delay in 111In-P accumulation on thrombi and catheters appeared to be present in dogs treated with coumadin, based on images obtained at 1, 2, and 3 hours after 111In-P injection. It is unlikely that coumadin's effect upon 111In-P uptake by thrombi would be significant in a clinical setting, although further studies would be required to confirm this.