Abstract 354: Enhanced Coronary Thrombolysis by Three-dimensional Transthoracic Ultrasound and Intravenous Non-Targeted Microbubbles
High mechanical index (MI) ultrasound impulses from a diagnostic transducer combined with intravenous (IV) microbubbles (MB) have recanalized vessel thromboses in animal studies. In acute coronary syndromes, transthoracic ultrasound (TTU) has the potential to also improve microvascular flow by applying the high MI impulse to the thrombosed risk area (RA) downstream from the coronary thrombus. Since the spatial distribution of the risk area is large, we hypothesized that a guided three dimensional (3D) TTU beam would be more effective than a two dimensional beam.
Methods: In 36 pigs with acute left anterior descending (LAD) thrombotic occlusions, either 3D or 2D guided TTU (Philips iE 33) were applied during the infusion of IV non-targeted MB (NVX-008, NuvOx), or no MB. All pigs received half dose recombinant pro-urokinase, heparin and aspirin. High MI applications from the 2D or 3D transducer were guided by low MI imaging of the RA. When MB were visualized within the RA microvasculature, brief high MI (>1.1) impulses were applied. Angiographic recanalization rates, wall thickening recovery and ST segment elevation resolution were analyzed at 60 minutes into treatment.
Results: Pigs treated with 3D TTU and IV MB had significantly higher epicardial recanalization rates (83% versus 40% for 2D TTU and 21% for control pigs; p<0.05; Figure⇓). ST segment resolution occurred in 80% of pigs treated with 3D TTU.
Conclusions: Intravenous non-targeted MBs combined with guided 3D high MI TTU impulses can be utilized to enhance microvascular and epicardial recanalization rates in acute ST segment elevation myocardial infarction.