Effects of thrombolysis and venous thrombectomy on valvular competence, thrombogenicity, venous wall morphology, and function

Purpose: The experiments were designed to compare the effects of thrombolytic therapy (TL) and balloon-catheter thrombectomy (TX) on valvular competence, thrombogenicity, venous wall morphology, and function after acute deep venous thrombosis (DVT) in canine veins. Methods: The femoral veins of male mongrel dogs were ligated proximally and distally for 48 hours to induce DVT. The thrombosed veins were treated with either TL (n = 5) or TX (n = 9), or no treatment was rendered (n = 6). Sham-operated dogs were used as controls. TL was performed with catheter-directed infusion of urokinase at 4000 u/min for 90 minutes. Three hours after the treatment, the valvular competence was determined with duplex scanning, thrombogenicity determined with deposition of radio-labeled platelet and fibrin, and function determined with response to contractile and relaxing agonists in organ chambers. The structural integrity of the endothelial layer was assessed by means of scanning electron microscopy. Results: The removal or lysis of the thrombus was successful in all cases. The valvular competence did not differ among the groups. The platelet deposition was the highest after TX (P < .05), and the fibrin deposition was not significantly different among the groups. In the organ chamber experiments, relaxations to adenosine diphosphate and nitric oxide were reduced after TX (P < .05). The contractions to serotonin were enhanced after TX. Scanning electron microscopy results showed a comparable (51% to 75%) endothelial loss with either treatment. Conclusions: After experimental acute DVT, the TL and the TX at 3 hours had similar effects on the valvular competence and the endothelial morphology. However, the TL reduced thrombogenicity, which is consistent with the preserved endothelial responses to platelet products. These data suggest that TL may preserve vein function after DVT and may reduce the long-term potential for recurrent DVT and post-thrombotic syndrome.