In vitro analysis of downstream particulates with mechanical thrombectomy devices: comparison of 20-kHz sonothrombolytic and rotating dispersion wire systems.
OBJECTIVE
To assess the potential of macroembolization, the authors compared the downstream particulate profile generated with use of two thrombectomy devices, a 20-kHz ultrasound-based sonothrombolytic (ST) device and a rotating dispersion wire (RDW).


METHODS
An arterial flow model was pressurized to 100 mm Hg and perfused with 1,000 mL/min normal saline. Tubing containing 7-mm x 30-cm bovine thrombus proximal to a 75% stenosis was inserted distal to a nonstenosed bypass. The effluent was passed successively through 1,000-, 500-, and 200-microm filters and a particle analyzer. The ST device and RDW were activated for 10 and 15 minutes, respectively, in randomized sequences of experimental sets with and without the use of 10-mg tissue-type plasminogen activator (tPA). Results are expressed as means and standard deviations of fraction of lysed clot in each category.


RESULTS
The ST device produced significantly fewer particulates larger than 1,000 microm (1.3% +/- 1.4) than did the RDW (16.8% +/- 8.4, P < .001) and significantly more particulates smaller than 10 microm (90.7% +/- 7.6) than did the RDW (73.9% +/- 9.5; P < .001) at comparable thrombolytic efficacy (P = .982) and without significant effect from tPA (P = .988). There were no significant differences between particles measuring 500-1,000 microm (ST device: 0.3% +/- 0.3, RDW: 0.4% +/- 0.3; P = .653) and those measuring 10-199 microm (ST device: 7.5% +/- 7.5, RDW: 8.6% +/- 3.8; P = .624). The amount of particles on the 200-microm filter after RDW activation (0.4% +/- 0.3) exceeded those trapped after use of the ST device (0.1% +/- 0.1, P = .007) but contributed relatively little overall.


CONCLUSIONS
In this in vitro model, the use of the ST device resulted in fewer large particulates than did the use of the RDW, with more clots being reduced to less than 10 microm.
Salazar
Gloria M
GM
Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, Massachusetts, USA. gmsalazar@partners.org
Faintuch
Salomao
S
Gladstone
Steve R
SR
Lang
Elvira V
EV