Antithrombotic potencies of enoxaparin in microvascular surgery: influence of dose and administration methods on patency rate of crushed arterial anastomoses.

This study evaluated the influence of the dose and administration methods of enoxaparin, a low-molecular-weight heparin, on the patency rate of crushed rat femoral arteries following anastomosis. An impact crush with a 25-kg magnitude was applied to a 2-mm segment of 100 rat femoral arteries, followed by anastomosis. The arteries were divided into five groups: group 1 received systemic enoxaparin alone with a relatively high dose (45 IU) twice a day for 3 days; groups 2 and 3 received topical irrigation with a lower (15 IU/mL) concentration and a higher (45 IU/mL) concentration, respectively; group 4 received systemic and topical application at a lower (15 IU) dose and concentration (15 IU/mL); and group 5 received systemic and topical application at a higher (45 IU) dose and concentration (45 IU/mL). The results of this study demonstrate the following: (1) topical irrigation with enoxaparin at a concentration of 45 IU/mL-three times higher than that recommended for clinical use adjusted by body weight (15 IU/mL)-is effective for antithrombotic action; (2) a combination of systemic and local application does not offer additional benefit in the patency rate when compared to local irrigation alone; (3) systemic administration alone does not prevent thrombus formation; and (4) enoxaparin is potentially useful to enhance the patency rate in compromised microvessels.