Isolated limb thrombolysis with extracorporeal pump and urokinase

In order to determine the effect of altering the method of delivery of lytic therapy, both hind limbs of 55 adult mongrel dogs were embolized to occlusion and divided into six different treatment groups. Each right limb received 100,000 units of urokinase (UK) intraarterially by one of six different treatment protocols: Group I (n = 10), 5-min infusion with control of arterial inflow (IC); Group II (n = 10), 5-min infusion without IC; Group III (n = 10), 30-min infusion with IC; Group IV (n = 10), 30-min infusion without IC (simulates percutaneous infusion); Group V (n = 10), isolated limb perfusion (ILP) with femoral arterial and venous cannulation and proximal tourniquet control using an extracorporeal circulating pump at a controlled rate and constant temperature (37 degrees C) for 30 min; Group VI (n = 5), underwent ILP without urokinase. A morphometric score was used to quantitate angiographic changes. Films were compared before and after treatment and the net difference for each animal was recorded. [table: see text] We conclude that maintenance of blood flow during urokinase infusion enhances its effectiveness and, contrary to previous recommendations, during intraoperative delivery, inflow should be maintained. Isolated limb perfusion alone was as effective as a 30-min infusion of urokinase without inflow control. Isolated limb perfusion plus UK was by far the most effective method of administering lytic therapy. These experiments suggest that the mechanical action of flowing blood enhances clot dissolution and significantly increases the effectiveness of pharmacologic lysis. Isolated limb fibrinolytic perfusion may have clinical potential in the surgical treatment of limb ischemia.