Patency and intimal hyperplasia: the effect of aspirin on small arterial anastomosis

This experiment evaluated the effect of aspirin (ASA) on the patency and development of intimal hyperplasia in autologous, small caliber, arterial end-to-side anastomosis. Twenty-eight adult female rabbits had their distal left external iliac artery transposed and anastomosed to the right proximal external iliac artery. Fourteen rabbits received ASA 40 mg by gavage twice in the 24 hours preceding the operation and 5 times a week postoperatively (experimental) and 14 rabbits received no ASA therapy (control). Plasma salicylate levels range from 25 to 36 micrograms per milliliter in experimental animals. Patency of the reconstruction was assessed by Doppler examination each month, confirmed by autopsy and calculated by life table analysis. Five cross sections of each patent anastomosis harvested at six and nine months were examined by light microscopy. A total of seven thromboses occurred in the control group versus two occlusions in the experimental group. Four of the thromboses in the control group occurred less than seven days after the reconstruction, whereas no such events occurred in the experimental group. Patency by actuarial methods at nine months was 45.5% versus 81.8% (p less than .05) in control and experimental groups, respectively. This improvement occurred in spite of similar values for intimal thickness and lumen-to-basement membrane ratios in both control and experimental groups. We conclude that aspirin significantly improves the nine month patency rate of small autologous end-to-side anastomosis, and its effect is most noticeable in the early postoperative period.(ABSTRACT TRUNCATED AT 250 WORDS)