Fiberoptic study on the effects of transluminal angioplasty in experimental occlusive arterial thrombosis.

Percutaneous transluminal coronary angioplasty has been proposed as definitive therapy for coronary recanalization of occluded coronary arteries in patients with acute myocardial infarction (AMI). The effects of transluminal angioplasty (TA) on experimental occlusive canine arterial thrombi that closely simulated the clinical condition was examined by a fiberoptic method. Experimental arterial thrombosis was produced by endothelial denudation and induction of luminal stenosis. Eighteen dogs that showed total occlusion of the iliac artery with thrombi were evaluated. Seven dogs (group A) with 6-hour-old thrombi received 20,000 IU/kg intravenous urokinase (UK) but did not show recanalization. TA was performed with a Gruentzig or Simpson-Robert balloon catheter and its effect was evaluated by a vascular fibroscope. Eight dogs (group B) with 6-hour-old thrombi underwent primary TA. After TA, less than 50% luminal obstruction with residual thrombi was visualized in five dogs (71%) of group A and four dogs (50%) of group B. Residual thrombi showed a doughnut-like or globular type shape and consisted of dense fibrin networks and compact platelet aggregates. All dogs in group B received 20,000 IU/kg intravenous UK after TA, but most of them showed progression of thrombus size despite UK infusion. In conclusion, the results suggest (1) that TA is effective in recanalization of an occluded artery with aged thrombus that is resistant to thrombolytic therapy and (2) that vascular fiberscope is a useful method for evaluation of the effects of TA on occlusive arterial thrombus.