Aspirin therapy in small-caliber arterial prostheses: long-term experimental observations

To study the therapeutic effects of 3 mg/kg aspirin given at the time of surgery and postoperatively, Dacron carotid grafts with an internal diameter of 4 mm and a length of 6 cm were implanted bilaterally in mongrel dogs. Sixteen control grafts in eight subjects and 20 grafts in 10 subjects treated with aspirin were followed by serial angiograms until consecutive studies showed stable patency rates in both groups. Platelet aggregations, malondialdehyde production, serum salicylate levels, and thromboxane A2 and prostacyclin secretion (measured as thromboxane B2 and 6-keto-prostaglandin F1 alpha) were monitored prior to and throughout the experiment. Surface mapping, indium-111 uptake, factor VIII-related antigen staining, and scanning and transmission electron microscopy were performed on the grafts at sacrifice. This study demonstrates a protective effect on the early patency of small-caliber prostheses in the canine model with daily oral aspirin administration. The degree and duration of this effect depends on the preoperative baseline ratio of thromboxane to prostacyclin in each subject.