The frequency of acute ischemic graft thrombosis is increasing owing to the larger number of graft implantations. The possibility of success depends on detection of the reasons for the thrombosis and the ability to repair it. In addition lytic therapy must be considered during diagnosis followed usually by an adjunctive procedure like surgery or percutaneous transluminal angioplasty. With this kind of approach physicians are able to delay the surgery, to get more information about the vascular bed, and so to choose the most proper surgical procedure.
At present the authors are using this protocol: 100,000 U bolus of urokinase and then 35,000 U/hour. During the application of this protocol certain laboratory parameters are monitored (fibrinogen, activated partial thromboplastin time, thrombin time, fibrinogen degradation products) in order to evaluate the coagulation system during therapy. Their protocol also includes serial controls by means of clinical examination, Doppler examination, and angiography. Angiography can be considered at the end of the therapy as a means of final evaluation and can detect those cases that need adjunctive therapy.
Their experience is based on treatment of 47 graft occlusions in 44 men and 3 women, in whom they used urokinase.
They divided the patients with late graft occlusions into two subgroups according to the occlusion level. The clinical results were good in 88.6°10 of cases in proximal and 75 ~Io of cases in distal occlusion. The overall lysis as determined by angiography was 85.707o in proximal and 41.7% in distal grafts.
The authors found a significant difference in the time limit for starting efficient therapy of a thrombosed graft versus an atherosclerotic artery. In therapy of an occluded graft they were able to achieve patency by starting the thrombolytic infusion within nine hundred sixty hours after the occlusion. In terms of the Winsor index before and after therapy they noticed that the improvement was less evident than could be imagined from looking at the arteriographic results because of the pathologic status of the artery below the graft.
In conclusion they recommend the technique of "low dose" catheter-directed therapy for its good results and its lack of significant systemic effects.
