Assessment of Catheter-Directed Thrombolysis and Histotripsy Treatment for Deep Vein Thrombosis.

Purpose: The hypothesis of this study was histotripsy, an ultrasound therapy that disrupts tissue mechanically through the action of bubble clouds, increases the short-term rate of acute thrombus clearance for catheter-directed thrombolysis (CDT) in an animal model.

Materials And Methods: Thrombi formed in the femoral vein of pigs were treated with CDT, histotripsy, or CDT and histotripsy (histotripsy+). Ultrasound (B-mode and color Doppler) and contrast fluoroscopy imaging data were scored by four observers for semi-quantitative evaluation of each arm with ordinal regression models. Further, B-mode images were manually annotated by three observers to quantify the thrombus clearance rate.

Results: A total of 27 thrombi (2.0 ± 0.4 cm in length) in 27 animals were considered in this study (N = 8 for CDT, N = 9 for histotripsy, and N = 10 for histotripsy+). The mean treatment duration was 20.2 ± 1.3 min. The ordinal regression models indicated the thrombus clearance rate was increased for histotripsy+ relative to CDT based on B-mode and color Doppler, but not fluoroscopy (p = 0.015, 0.001, and 0.900, respectively). Manual annotation of B-mode images denoted histotripsy+ had an increased thrombus clearance rate relative to CDT and histotripsy (p = 0.001 and 0.022, respectively). Petechial hemorrhage was present in the perivascular soft tissue for two cases with histotripsy and one case with histotripsy+.

Conclusions: The clearance of acute thrombus was similar for treatment with CDT or histotripsy. Combining these individual approaches further increased the rate of thrombus clearance based on multiple imaging metrics.