Declotting of embolized temporary vena cava filter by ultrasound and the Angiojet: comparative experimental in vitro studies.
OBJECTIVE
The authors perform an in vitro evaluation of the thrombolytic efficacy and the amount of "downstream" embolization induced by two new mechanical thrombectomy devices when applied to clots trapped in a temporary vena cava filter.


METHODS
The first device used was a 22.5-kHz prototype intravascular ultrasound device with a flexible 0.8-mm (.032-inch) titanium 2-mm ball-tipped wire probe ensheathed in a 7-French teflon guide catheter. The device was inserted through a 10-French steering catheter. Under fluoroscopic control, ultrasound energy (26 +/- 4 watts/cm2, maximal longitudinal catheter tip amplitude 54 microm) was applied to 10 Ultravist-filled porcine thrombi (mean, 3500 mg). The second device, the Angiojet catheter, was applied to five Ultravist-filled porcine thrombi (mean, 3640 mg). The thrombi were treated while trapped in a temporary Günther vena cava filter (Cook Europe, Bjaverskov, Denmark) mounted in a vena cava flow model. The resultant "downstream" emboli were trapped in two tandem filters of decreasing pore size and weighed.


RESULTS
Mean thrombus dissolution rate was 53% +/- 22% standard deviation (SD) for the ultrasound device (n = 10) and 63 % +/- 8% SD for the Angiojet (n = 5) (difference statistically significant at P = 0.03). For the ultrasound device, the mean embolic particle weight caught by the filters with mesh widths of 1 mm and 0.1 mm was 42% +/- 14% SD and 4% +/- 2% SD, respectively, of the initial thrombus weight. For the Angiojet, the respective numbers were 35% +/- 16% SD and 3% +/- 1% SD. Mean treatment time was 216 +/- 45 seconds SD for the ultrasound device and 153 +/- 21 seconds SD for the Angiojet.


CONCLUSIONS
The thrombolytic efficacy of the Angiojet was significantly greater and the treatment time was significantly shorter than that of the ultrasound device. Both systems had a high embolization rate.
Dick
A
A
Department of Diagnostic Radiology, University of Technology Aachen, Germany.
Neuerburg
J
J
Schmitz-Rode
T
T
Alliger
H
H
Günther
R W
RW
D000818:Animals; D001777:Blood Coagulation; D002404:Catheterization / Q000295:instrumentation; D066298:In Vitro Techniques; D011859:Radiography; D013552:Swine; D017131:Thrombectomy / Q000295:instrumentation / Q000379:methods*; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy*; D014464:Ultrasonic Therapy; D018084:Ultrasonography, Interventional; D016306:Vena Cava Filters / Q000009:adverse effects*