Post thrombotic syndrome is a frequent complication of deep venous thrombosis, associated with high morbidity. Treatments currently available are invasive. Pulsed cavitational ultrasound therapy (PCUT) is a new technique to destroy remotely soft tissue. We demonstrated that PCUT was able to recanalize non-invasively in in-vitro model of human blood clot.

We aim to test the safety and efficacy of venous recanalization by non-invasive PCUT in vivo swine model of acute venous thrombosis.

All the experiments were performed on White large X Landrace swine. We induced an acute femoral deep venous thrombosis by using endovascular approach combined with local injection of thrombin. A 3cm length occlusive thrombosis was obtained after 2hours. Swine were divided in three groups: one with PCUT without follow-up (n=11), one with PCUT and follow-up at 14days (n=8), and a control group also followed for 14days (n=5). Acutely and during follow up all swine received curative anticoagulation. To achieve PCUT, a 2.25MHz transducer (Imasonic©) centered by a linear probe was used and cavitation was obtained in the centre of the vein. Effectiveness of recanalization was evaluated by echo-Doppler and phlebography. Safety was assessed by Doppler ultrasound and by histological analysis of vein, artery and lungs.

Among the 24swine, we obtained 22occlusive venous thromboses and 2 partials. The median length of the thrombus was 26±4.4mm. Acutely, thrombosis recanalization was obtained among the 19swine with PCUT with median treatment duration of 33min. After a 14-day follow-up, 75% of recanalisation remains permeable vs. 0% of vein permeable in the no therapy group (P=0.008). Residual diameter was 2.6±1.2mm, 50% of the venous diameter. No embolism or pulmonary infarction was observed in all pigs (Fig. 1).

We have demonstrated in vivo the safety and the efficacy of PCUT for non-invasive venous recanalization, persistent after 2weeks.