Thrombolysis in Acute Peripheral Arterial Occlusion: Predictors of Immediate Success

Thrombolytic therapy is frequently used for the treatment of peripheral arterial occlusion, but clinical predictors of success have not yet been defined. We prospectively evaluated 80 consecutive patients receiving intra-arterial urokinase for acute (< 14 days) ischemia. Fifty-five patients (69%) were treated for bypass graft occlusion and 25 patients (31%) for native arterial occlusion. Two primary outcome measures were evaluated using multivariate techniques (stepwise logistic regression) to determine the independent predictors of immediate arteriographic success: Successful (>80%) thrombolysis and avoidance of adjuvant operative or endovascular procedures. Independent variables examined included age, sex, comorbid conditions, severity, duration, etiology and location of the ischemic process, and positioning of the infusion catheter and guidewire. Overall, successful lysis was achieved in 57 patients (71%) and adjuvant procedures were avoided in 22 patients (28%). Successful outcome was more frequent in prosthetic graft (78%) and native arterial (72%) occlusions than in vein graft occlusions (53%. p = 0.017) and in nondiabetics than in diabetics (80% vs. 52%, p = 0.031). Lysis was dependent on placement of the catheter into the substance of the thrombus (85% vs. 0% success, p = 0.004) and passage of a guidewire through the occlusive process (92% vs. 10% success, p = 0.001). The only parameter independently predictive of successful outcome without the use of adjuvant procedures was the location of the occlusion; additional procedures were necessary in 88% of aortoiliac and 82% of infrainguinal occlusions vs. only 17% of upper extremity occlusions ( p =0.005). Thus specific parameters can be identified that predict those patients in whom success, as determined by arteriographic criteria, is most likely to be achieved. Appropriate patient selection is important since unsuccessful thrombolysis protracts the ischemic process and increases the risk of bleeding complications.