What is percutaneous mechanical thrombectomy?

Updated: Dec 10, 2019
  • Author: Donald Schreiber, MD, CM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Answer

Answer

Percutaneous mechanical thrombectomy has been developed as an attempt to shorten treatment time and avoid costly intensive care unit (ICU) stays during thrombolytic infusion. Mechanical disruption of venous thrombosis has the potential disadvantage of damaging venous endothelium and valves, in addition to thrombus fragmentation and possible pulmonary embolism. Many devices now exist and are approved for venous use.

Percutaneous mechanical thrombectomy devices are a popular adjunct to catheter-directed thrombolysis. Although these devices may not completely remove a thrombus, they are effective for debulking and for minimizing the dose and time required for infusing a thrombolytic. In patients at high risk for hemorrhagic complications, mechanical thrombectomy may obviate thrombolytic infusion. Such devices are most commonly used to initially restore antegrade flow (in cases of limb threat) or to manage a thrombus that has proved resistant to thrombolysis.

A wide variety of devices are under development or already on the market. These devices macerate thrombus by use of physical cutting blades, vortex, high-pressure or low-pressure saline jets, suction alone, or ultrasonic liquefaction.

An example is the Trellis catheter by Bacchus Vascular, which isolates the thrombosed segment with two occluding balloons and a rotating filament between that mechanically disrupts the thrombus while injecting a thrombolytic agent. After treatment, the thrombus and thrombolytic agent are aspirated and a venogram is performed. Published data include results with a 97% patency with a single treatment and no bleeding complications in a study group of over 700 patients. [11]

The most basic method for mechanical thrombectomy is thromboaspiration, or the aspiration of a thrombus through a sheath. Balloon maceration of the thrombus may be done to facilitate the procedure. The most technically advanced devices, approved primarily for interventions requiring hemodialysis access, may be divided by mechanism into categories of recirculation and fragmentation. Recirculation devices engage thrombus and destroy it by continuously mixing it by creating a hydrodynamic vortex.

Fragmentation devices leave macroscopic particulate effluent and include devices that chop, brush, or cut the clot. With these devices, concomitant lytic infusion and possible inferior vena cava filter placement are necessary to ensure PE prophylaxis.

Of recirculation devices, only the Trellis-8 Peripheral Infusion System (Bacchus Vascular, Inc., Santa Clara, CA) is FDA approved for the treatment of DVT. The AngioJet system (Possis Medical Inc., Minneapolis, MN) has the broadest FDA-approved uses, including uses in the coronary and peripheral arteries and in obtaining arteriovenous access; this is one of the most effective devices.

Reports have described use of the Arrow-Trerotola, AngioJet (Possis Medical), and Helix percutaneous thrombectomy devices for iliofemoral DVT, combined therapy (often with adjunctive thrombolysis, angioplasty and stenting, and placement of an inferior vena cava filter with the Arrow-Trerotola). These devices had 74-100% initial technical and 24-hour clinical success rates. Complete thrombus removal was variable (23-100%). The remainder improved with lytic infusion, with a mean infusion time of 6 hours.

Only one study had a 6% incidence of major bleeding complications. The primary patency rate at 1 year was 85%, and clinical success was obtained in 92%. At 9- to 12-month follow-up, 2 studies demonstrated an 8% rate of venous insufficiency, whereas two others showed repeat DVT in 15-23%.


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