The effect of prolonged aspirin therapy on experimental balloon-catheter arterial wall injury.

Indications for aspirin following percutaneous transluminal angioplasty are not well defined. Although aspirin's early antithrombotic effect is believed to be beneficial, the long-term influence of aspirin on myointimal proliferative response following balloon-catheter angioplasty is still being investigated. This study quantitates arterial wall thickening, including intimal hyperplasia, at 4 months following balloon-catheter aortic injury in New Zealand white rabbits (n = 12), comparing aspirin treatment (30 mg/kg) with controls. Aspirin was administered daily for 1 month prior and 4 months following aortic injury. Myointimal proliferation was noted in both groups. The mean area of the intima and media as well as the maximum thickness of the intima were similar (p greater than .05) in both the aspirin treatment and control groups. Cellular hyperplasia was evaluated by media smooth muscle cell counts using an ocular reticle. There was a trend toward higher cell counts with aspirin treatment, although there was no significant difference between the two groups. Prolonged aspirin therapy did not alter the degree of myointimal hyperplasia at 4 months postinjury in our model.