111In-oxine platelet imaging in hemodialysis patients: detection of platelet deposition at vascular access sites.

The value of 111In-oxine platelet imaging to assess abnormal platelet deposition at different vascular access sites was studied in 19 hemodialysis patients. Platelets were labelled immediately following dialysis and imaging was performed 2 and 48 h later; abnormal platelet deposition was defined as a localized increase in activity over time when compared to the opposite, control extremity. 10 patients had bovine grafts, 4 had arteriovenous fistulae, and 5 had Gore-Tex grafts. 111In-oxine platelet imaging demonstrated abnormal platelet deposition in 13 out of 19 patients. Positive images were obtained in some patients with each type of vascular access. Preliminary evaluation showed no clear relationship between image positivity and the history of prior graft occlusion. The imaging method provided in vivo evidence of the efficacy of treatment with the antiplatelet agent sulfinpyrazone in half of the treated patients. Following 1 week of sulfinpyrazone, 200 mg t.i.d., in 6 patients, 3 showed a definite decrease in platelet deposition, 2 showed a probable decrease, and 1 showed no change following therapy. We conclude that platelet imaging may provide organ-specific, in vivo evidence for abnormal platelet deposition in several types of vascular access sites, and may be useful in assessing the thrombogenicity of prosthetic materials and the efficacy of antithrombotic drugs.