Platelet Deposition on Dacron Aortic Bifurcation Grafts in Man: Quantitation with Indium-111 Platelet Imaging

SUMMARY The interaction between platelets and chronically implanted prosthetic arterial graft sur-faces in man was assessed by imaging indium-111-labeled platelet deposition in 15 patients with Dacron aortic bifurcation grafts. Grafts had been in place for 9-120 months. These results were compared with those obtained by platelet imaging of the aortofemoral vessels of 13 normal young adults without grafts. Quantitative evaluation was performed in both groups by a graft/blood ratio that compared indium-111 platelet activity in the aortofemoral vascular region to whole blood platelet activity over a 96-hour imaging time. In addition, blinded qualitative visual interpretation was performed on all studies by comparing aortofemoral area activity with that in adjacent native arteries. The reproducibility of the technique was evaluated by repeat imaging and quantitative analysis of six patients with grafts. Quantitative evaluation of the normal subjects revealed that the mean vessel/whole blood activity ratio was 2.0 ± 0.7 ( ± SD) at 24 hours after platelet injection and remained constant for the duration of the study (1.7 ± 0.9 at 96 hours, NS). In contrast, patients with grafts had a mean graft/blood ratio of 3.0 ± 1.6 at 24 hours, which increased progressively to 7.8 + 5.0 at 96 hours (p < 0.001 vs normal subjects), documenting ongoing platelet deposition in patients with vascular grafts. Independent qualitative visual interpretation of the aortofemoral region disclosed no abnormal uptake in normal subjects, whereas 13 of 15 patients (87%