Abstract
The effect of intravenous administration of urokinase on the rate and time of thrombolysis was investigated in 22 dogs with an occlusive coronary artery thrombus induced by placement of a copper coil in the left anterior descending artery. One hour after angiographic confirmation of complete coronary artery occlusion, an intravenous bolus of urokinase was administrated in a dose of either 1.2×106 units (Group 1, n=7); 0.6×106 units (Group 2, n=9) or 0.3×106 units (Group 3, n=6). Reperfusion occurred in all 7 (100%) Group 1 dogs, in 7 of 9 (78%) group 2 dogs and in 3 of 6 (50%) group 3 dogs (p=0.07 for Group 1 vs Group 3). There was no residual intra-arterial thrombus in any group 1 (high dose) dog but 4 of the 10 reperfused Group 2 or Group 3 (intermediate or low dose) dogs had small thrombus in the distal left anterior descending artery (3.5±4.0 mg) and all 5 non-reperfused dogs had thrombus in the coil (26.1±6.2 mg). The frequency of residual thrombus was significantly less in Group 1 compared to Group 2 and 3 (P < 0.01). We conclude that intravenous administration of urokinase has a dose dependent efficacy for lysing intracoronary thrombus in the canine model.
