Thrombolytic Therapy and Balloon Catheter Thrombectomy in Experimental Femoral Artery Thrombosis: Effect on Arterial Wall Morphology

To determine vessel wall architectural changes after lytic therapy and balloon catheter thrombectomy in experimentally thrombosed arteries. Bilateral 5-cm femoral artery occlusions were created by ligation in 14 dogs. Two dogs served as controls, and 12 animals underwent balloon catheter thrombectomy on the left and lytic therapy with urokinase on the right either 24 hours (group 1, n = 6) or 7 days (group 2, n = 6) after creation of the occlusion. After treatment, the area of thrombosis was subjected to light and scanning electron microscopy. The IEL was intact in all lysed arteries. IEL fractures were present in 11 of 12 arteries treated with thrombectomy. For group 1 arteries, average luminal area after thrombectomy was 5.63 mm² ± 0.66 versus 1.94 mm² ± 0.7 after lytic therapy (P < .007). Mean control artery luminal area was 2.86 mm² ± 0.52. Similar differences were found in group 2 arteries. With lytic therapy, scanning electron microscopy grading revealed surfaces to be intact in group 1, but moderate injury was exhibited in group 2. All arteries treated with thrombectomy had severe injury. Lysis of acute thrombi (group 1) preserved arterial wall architecture, with an intact IEL and no endothelial injury. Lysis of chronic thrombi (group 2) was associated with mild to moderate injury. Catheter thrombectomy caused severe injury regardless of the time of intervention. These results may help explain the poor long-term patency observed after these interventions.