[Effect of argatroban on flap survival length]

The effect of argatroban, an anti-thrombin agent, on a 1.5 x 6.0 cm caudally-based flap raised on the backs of Wistar female rats was studied. Argatroban was administered to one group via an implanted osmotic pump, and nothing was administered to a control group. In experiment 1, the effect was evaluated by survival length (ratio of length to width) and a statistically significant difference (p < 0.01) was found between the argatroban group and the control group. In experiment 2, at 3 spots along the midline (M1, M2, M3) in each group, ISO2 (a parameter of oxygen saturation) and IHb (a parameter of hemogrobin concentration) were measured with a reflectance spectrophotometer, and FLOW (a parameter of blood flow) and MASS (a parameter of blood mass) were measured with a laser Doppler flowmeter. M1 was a distal spot of flap, M2 was a proximal spot on the flap and M3 was a spot beside the flap used as a control. At M1, flaps in both groups became necrotic. At M2, flaps in the argatroban group survived, whereas those in the control group became necrotic, and each parameter indicated improvement in blood circulation only in the argatroban group. Thus, argatroban, which antagonizes thrombin, can improve microvascular circulation in congestive tissue and consequently help the flap survive. Argatroban has advantages over other agents that have been given to increase the length of the surviving experimented flap. In comparison with heparin, the coagulation time is easier to control. Also argatroban does not dilate peripheral vessels, which may be a demerit of alprostadil. Argatroban also promotes the reaction of plasminogen activator. The serum concentration of argatroban in this study was almost equal to that used clinically. Therefore, argatroban may be useful when elevating a flap clinically.