Oral acetylsalicylic acid improves patency rates in small-vessel anastomoses

Because platelet aggregation is the critical step in vascular thrombosis, this study investigated the possibility that acetylsalicylic acid given orally would improve patency of anastomoses in small arteries. Under clean conditions, in male Sprague-Dawley rats, the superficial femoral arteries were divided and reanastomosed using the sleeve technique with 10-0 nylon suture. Fifty-one rats received a full laboratory diet and acetylsalicylic acid in their drinking water (1.08 mg/ml), before and after operation. A control group of 54 rats was matched for weight, water intake and duration of vessel occlusion. Vessel patency was assessed on postoperative day 7, at sacrifice, by dye angiography. In the experimental group 7 (13.7%) anastomoses became occluded, compared with 20 (37.0%) in the control group (chi 2 = 5.99, df = 1, p less than 0.025). Serum thromboxane B2 levels in five rats given acetylsalicylic acid orally (33.1 +/- 6.1 ng/ml) were significantly (p less than 0.001) lower than in five control rats (86.6 +/- 49.1 ng/ml). The authors concluded that acetylsalicylic acid administered in the drinking water to Sprague-Dawley rats improved the patency rate of femoral artery anastomoses probably because of a reduction in platelet aggregation. Orally administered acetylsalicylic acid may be of clinical benefit to patients who undergo small-vessel anastomoses.