Effect of hirudin on arterialized venous flap survival in rabbits

Arterialized venous flap (AVF) is limited in clinical application because its survival remains inconsistent and its exact survival mechanism is still unclear. Hirudin is an effective thrombin specific inhibitor, which is isolated from the salivary gland secretions of the leech. Our study evaluated the impact of hirudin on the viability of AVFs in rabbits. Thirty-six rabbits were randomly divided into three groups: sham group (physiological perfusion), control group (AVF), and hirudin group (AVF + hirudin). In hirudin group, 20 antithrombin units (ATU) hirudin (2.5 ml) were injected into each flap. In sham group and control group, the same amount of normal saline was injected into each flap. Status of flap survival, water content, vascular perfusion, histopathology, expression of CD34, VEGF, eNOS and HIF-1α were analyzed in each group. Analysis of oxidative stress was performed by measuring the activity of superoxide dismutase (SOD) and malondialdehyde (MDA). Compared with flaps in sham group with physiological perfusion mode, results of survival rate, perfusion status, SOD activity, expression of CD34, VEGF, and eNOS of AVFs in control group were significantly lower, while water content, MDA level and expression of HIF-1α were higher. The flap condition of AVFs injected with hirudin in hirudin group was improved significantly, and the results were similar to sham group. Our findings revealed that hirudin can effectively improve survival of AVF.