Quantitative effects of antiplatelet therapy on healing of the endarterectomized canine aorta

This study was designed to quantitatively evaluate the effects of an antiplatelet agent, ibuprofen, on mural thrombus formation and pseudointimal development in the endarterectomized canine aorta. A 3 cm segment of abdominal aorta was endarterectomized in 18 dogs. Nine dogs served as controls and nine dogs were treated with ibuprofen (12.5 mg/kg) given intravenously 1 hour preoperatively and orally (7.5 mg/kg) three times a day in the postoperative period. Three dogs were killed from each group at 7, 14, and 21 days. Healing of the endarterectomized aortic segment was assessed by means of computer-assisted surface morphometry, light microscopy, and both scanning and transmission electron microscopy. One week postoperatively, the thrombus-free surface in the treated dogs was 75 percent, compared with 20 percent in control animals; at 2 weeks 97 percent, compared with 38 percent and at 3 weeks 98 percent, compared with 38 percent (p less than 0.01 for each group). The thickness of the pseudointima was 9 percent of the aortic wall thickness in treated dogs compared with 60 percent in control animals 1 week postoperatively (p less than 0.001); at 2 weeks 24 percent in treated animals and 64 percent in control animals (p less than 0.001); and at 3 weeks 31 percent in treated animals and 55 percent in control animals (p less than 0.05). Partial reendothelialization was observed 1 week postoperatively and complete reendothelialization at 3 weeks in both the control and treated animals. These data suggest that administration of preoperative and maintenance therapy with ibuprofen significantly reduces mural thrombus formation and pseudointimal thickness in the endarterectomized canine aorta.