Nanodroplet-mediated intravascular sonothrombolysis: Cavitation study

Nanodroplets mediated sonothrombolysis has the potential to improve thrombolytic outcomes and minimize the need for thrombolytic drugs. Our group has developed a forward-viewing intravascular transducer which can perform contrast agent mediated sonothrombolysis. Most applications of nanodroplets mediated sonothrombolysis are applied by an external transducer, which cannot access locations blocked by bones or gassy organs, thus greatly limiting its usage. The purpose of our study was to demonstrate the feasibility of using nanodroplets with our small aperture intravascular transducers, which would allow access to a wide range of locations. Passive cavitation detection was performed to determine the minimum peak negative pressure output necessary for nanodroplet mediated sonothrombolysis and initial clot lysis tests were performed. The stable cavitation dose increased with increasing peak negative pressure output, with there being a higher stable cavitation dose at 0.9 MPa and 1.2 MPa compared to controls. The inertial cavitation dose was higher at 0.6 and 0.9 MPa compared to the control group. In our proof-of-concept demonstration, nanodroplets mediated sonothrombolysis presented a mass decrease of 55 ± 1% compared to 29 ± 6% for the control group (p=0.02). We demonstrated that it was feasible to deliver nanodroplet mediated sonothrombolysis using the small aperture intravascular transducers.