P2765Efficacy of venous recanalization by noninvasive pulsed cavitational ultrasound therapy on swine model of acute deep venous thrombosis

Abstract

Abstract Background Post thrombotic syndrome is a frequent complication of deep venous thrombosis and is associated with high morbidity and hospitalization. Treatments currently available are invasive, involve use of endovenous procedures with stents and balloons, and frequently require general anesthesia. Pulsed cavitational ultrasound therapy (PCUT) emerged recently as a new technique to destroy remotely soft tissue. We recently demonstrated that PCUT was able to recanalize non-invasively in in vitro model of acute venous thrombosis (human blood clot). Purpose We aim to test the safety and efficacy of venous recanalization by noninvasive PCUT in vivo swine model of acute venous thrombosis. Methods All the experiments were performed on White large X Landrace swine. We induced an acute femoral deep venous thrombosis by using occlusive balloons introduced from jugular and popliteal vein combined with local injection of 50 IU of human thrombin. A 3 cm length occlusive thrombosis was obtained after 2 hours. Swines were divided in three groups: one with PCUT without follow-up (n=11), one with PCUT and follow-up at 14 days (n=8), and a control group also followed for 14 days (n=5). Acutely and during the follow up all swines received curative anticoagulation. To achieve PCUT, a 2.25 MHz transducer centered by a linear probe was used and cavitation was obtained in the center of the vein (Figure). After manual determination of thrombus location, a robotic arm was used to automatically move the transducer along the thrombus. Effectiveness of recanalization was evaluated by echo-Doppler and phlebography. Safety was assessed by Doppler ultrasound of the insonified area (artery, veins and surrounding tissue) and by histological analysis (local femoral vein and artery and lungs for pulmonary embolism). Results Among the 24 swines, we obtained 22 occlusive venous thromboses and 2 partial. The median length of the thrombus was 26±4.4 mm with vein diameter of 8.5±1.6 mm. Acutely, thrombosis recanalization was systematically obtained among the 19 swine with PCUT with median treatment duration of 33 minutes with residual diameter of 2.9±0.9 mm. No extravasation of contrast material or hematoma was observed after the therapy. After a 14-day follow-up, 75% of recanalisation remain permeable vs. 0% of vein permeable in the no therapy group (p=0.008). Residual diameter was 2.6±1.2 mm, which correspond to 50% of the venous diameter. No vein or artery damage and no embolism or pulmonary infarction was observed in all pigs. Figure 1 Conclusion We have demonstrated in vivo the safety and the efficacy of PCUT for non-invasive venous recanalization, persistent after 2 weeks. Acknowledgement/Funding French society of cardiology