Assessment of prosthetic vascular graft thrombogenicity using the technetium-99m labeled glycoprotein IIb/IIIa receptor antagonist DMP444 in a dog model

Abstract Introduction: Prosthetic graft patency greatly depends on graft thrombogenicity. The concept of graft thrombogenicity is poorly understood and difficult to measure or quantify. In a study we tested the experimental radiopharmaceutical DMP444 and developed a suitable dog model. This agent is a radiolabelled ( 99m Technetium) glycoprotein IIb/IIIa receptor antagonist with a high affinity for activated platelets. It binds to platelets that are intimately involved in thrombus formation. The agent does not affect thrombocyte function, when used in a dose necessary for imaging. DMP444 does not require platelet harvesting and processing. Early imaging of thrombocyte aggregation sites such as vascular prostheses is possible within 4 hours after injection. Material and methods: Adult Beagle dogs weighing 12–15 kg were used for the experiments. In 16 dogs a prosthetic patch was sewn onto the abdominal aorta (Bovine pericard: n =4, Dacron: n =6, Human Umbilical Vein: n =6). Imaging cycles after injection of 99m Technetium-labelled DMP444 were performed on days 1, 7, 14 and 28 after surgery. Results: We noticed differences in thrombus formation on the tested graft materials. The bovine pericard patches ( n =4) showed a relatively high rate of thrombocyte aggregation. In the Dacron patches ( n =6) aggregation was not seen. In 1 of 6 cases of human umbilical vein patches a measurable focal aggregation was recorded. Conclusion: The method outlined in this study is a relatively simple and reproducable method to visualize thrombocyte aggregation.