guided longer pulses from a diagnostic ultrasound and intraclot microbubble enhanced catheter-directed thrombolysis in vivo

The mechanism of ultrasound thrombolysis (ut) is generally attributed to cavitation. the insufficiency of microbubbles (mb) to serve as cavitation nuclei in the vessel-obstructing thrombi significantly reduces the effectiveness of ut. taking advantage of the widely performed catheter-directed therapy (cdt), in a thrombo-embolized rabbit ivc model with a simultaneous catheter directed rt-pa thrombolysis procedure, guided moderate mechanical index longer pulses from a modified diagnostic ultrasound transducer, combined with an intraclot infusion of mb, significantly accelerated the thrombolysis process. the higher thrombolysis efficacy score and consistent elevated post-treatment plasma concentration level of d-dimer, a product of fibrinolysis, both indicated the superiority of cdt + ut over cdt/ut alone. pathologic examination of the treated occluded ivc segments revealed an almost complete dissolution of the thrombi treated with cdt + ut. there was no evidences of thrombo-embolism or local thrombus formation in the cardiac–pulmonary vessels. combined with intraclot infusion of mb, guided longer pulse ultrasound from a diagnostic transducer is able to safely and significantly improve a catheter-directed thrombolysis procedure. it thus has the potential to achieve earlier clot removal, administration of a lower dosage of thrombolytic agent and, consequently, a lower incidence of thrombolysis-related side effects.