Outflow protection filters during percutaneous recanalization of lower extremities' arterial occlusions: a pilot study.

PURPOSE: Filter devices are already employed for the protection of carotid, coronary and renal distal vascular bed during endovascular procedures. This is a pilot study investigating their feasibility, safety and distal emboli protection capability during recanalization of lower extremities' acute and subacute occlusions.

MATERIALS AND METHODS: Study population included 16 patients, 11 with a subacute arterial occlusion and 5 with an acute episode. The Trap filter (Microvena, USA) and its successor the Spider filter (EV3, USA) were utilized. Subacute occlusions were dealt with standard angioplasty and stenting procedures, while acute ones were managed primarily with Angiojet rheolytic thrombectomy. Outflow arterial tree was checked angiographically in-between consequent procedural steps. Embolic material collected after filter recovery was analyzed histopathologically. Patients' follow-up was scheduled at 1 month.

RESULTS: Seventeen filter baskets were applied in the recanalization of 16 target lesions in total. Mean length of the occluded segments was 6.1 (range: 2-15 cm; S.D. = 3.7 cm). Mean in situ time of the filters was 38.75 min (range: 20-60 min; S.D. = 12.71 min). Technical success rate of deployment and utilization of the filtration devices was 100% (17/17). Procedural success rate of the recanalization was 100% (16/16) without any clinical or angiographic evidence of periprocedural distal embolization. Macroscopic particulate debris was extracted from all the filters (17/17) containing fresh thrombus, calcification minerals, cholesterol and fibrin. Mean diameter of the largest particle per specimen was 1702.80 (range: 373.20-4680.00 microm; S.D. = 1155.12 microm). No adverse clinical events occurred at 1-month follow-up with 100% limb salvage (16/16).

CONCLUSION: The application of outflow protection filters is safe, feasible and efficacious in hindering distal embolization complications and safeguarding the distal capillary bed. Nevertheless, this is a pilot study in a limited group. Further studies have to be contacted in order to provide evidence for a more general use of these devices.