The Effect of Pressure Injection of Urokinase to Reverse the "No-Reflow" Phenomenon

"No-Reflow" 현상에 대한 Urokinase 압력주입의 효과

Microsurgery has advanced beyond its nascent stages reaching success rates of 90% to 95%. However, this means that even in the best circumstances, 5% to 10% of free flaps and replants fail. Almost all failures are due to vessel thrombosis, resulting in ischemia of the transplanted tissue. Many attemps have been undertaken to treat and reverse its effects. Zdeblick and colleagues noted an improvement in the viability of amputated limbs replanted after an extended period of ischemia following intraarterial infusion of urokinase. Subsequent studies have investigated many modalities of urokinase administration in various animal models by differing ischemic periods. These studies, however, have failed to establish a definitive, generally accepted protocol for administration of urokinase in the salvage of tissue subjected to prolonged ischemia. Our clinical observations suggest that a bolus of urokinase delivered under pressure may increase the thromoblytic effect of the drug, probably by means of increased delivery to microvasculature. We intend to investigate the role of selective pressure perfusion of ischemic flaps as a new means for increasing the effectiveness of urokinase in the treatment of the "no-reflow" phenomenon. A total of 32 male New Zealand rabbits were used and divided into the four groups according to the method of infusion. After 12 hours of ischemia the flaps were injected with Hartmann's solution or with urokinase and the percent survival of the flap was determined at 7 days following flap reperfusion. As the result, the flap survival rate was highest in the pressure injection of urokinase group.