Abstract 9841: Microbubble Enhanced Sonothrombolytic Therapy Facilitates Reduction of Central Venous Catheter Associated Thrombi in vivo
Background We sought to investigate the therapeutic efficacy of microbubble (MB) enhanced sonothrombolysis in comparison with ultrasound (US) therapy alone for aged central venous catheter (CVC) associated thrombi in vivo
Methods A model of chronic indwelling CVC in the low superior vena cava with thrombus in situ was established after feasibility and safety testing in 7 pigs. This model was subsequently used for randomized sonothrombolytic treatments in 4 pigs. Baseline intracardiac echocardiography (ICE, 10.5F Acunav, Sequoia, Siemens), fluoroscopy and saline flushing confirmed the absence of any pre-existing CVC associated thrombus. By withdrawing 0.5-0.7 ml of blood into the CVC, a thrombus was allowed to form and age over 24 hours. The created thrombus at the distal CVC tip was localized and measured by ICE, and transthoracic guided high mechanical index (MI) two dimensional US treatments (1.6 MHz; 1.1 MI; iE33, Philips) applied intermittently whenever microbubbles were visualized near the thrombus. Total treatment time was 45 minutes. Lipid encapsulated MBs (3% MRX-801, NuvOx Pharma) were infused through both the CVC and a peripheral vein. Control pigs received transthoracic US alone. Post-treatment thrombus area determined by ICE planimetry was compared with pre-treatment measurements.
Results Eight randomized treatments were applied for CVC thrombi- 4 US+MB (Group A) and 4 US alone (Group B). Thrombus area measurements before and after treatment were 0.25 and 0.13 cm2 respectively in Group A; compared to 0.27 and 0.23 cm2 in Group B (p = 0.01). The Figure shows ICE examples of CVC thrombi before and after US+MB treatment. No alterations in oxygen saturation or hemodynamics occurred with either treatment.
Conclusions Guided high MI diagnostic US+systemic MB facilitates reduction of aged CVC associated thrombi in vivo. MB enhanced sonothrombolytic therapy may be a non-invasive safe alternative to thrombolytic agents in treating thrombotic CVC occlusions.
- © 2011 by American Heart Association, Inc.