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Autologous platelets labeled with Indium-lll-oxine were used to examine the thrombotic process by which small diameter bypass grafts often fail. PTFE grafts were inserted into the carotid and femoral arteries of dogs, and labeled platelets were injected. Thirteen 6 cm grafts (Group I) were harvested after 3 hrs as follows: after systemic heparinization, the graft and adjacent arterial segments were perfuse-fixed in situ, cut open longitudinally, rinsed gently in saline and counted in a well counter. The flattened specimen was then placed inside an x-ray cassette for 24-48 hrs, depending on measured total activity. Fifteen 4 cm grafts (Group II) were similarly harvested, but 4 days later. All grafts included herein were patent. The autoradiograph was developed in an automatic processor and subjected to densitometry to quantitate platelet deposition. Each graft image was divided into 3 longitudinal segments.The average density in the proximal and distal artery was zero. Significant differences (p |
