Preventing lower extremity distal embolization using embolic filter protection: Results of the PROTECT registry

Purpose: To report the results from a single-center prospective registry (PROTECT) established to evaluate the safety and effectiveness of embolic filter protection (EFP) in reducing distal embolization during percutaneous lower extremity interventions. \ Methods: Patients undergoing angioplasty, stenting, or SilverHawk atherectomy and adjunctive balloon angioplasty for infrainguinal occlusive disease were eligible if the lesion(s) met one or more of these angiographic criteria: (1) moderate or severe calcification of any length, (2) total occlusions of any length, (3) a filling defect, (4) irregular (ulcerated) lesions at least 30 mm in length, and/or (5) smooth, non-ulcerated lesions at least 50 mm in length. The primary angiographic outcome was the ability of the filter to prevent angiographically visible distal embolization, slow flow, and loss of distal tibial runoff with or without capturing macrodebris. Results: Forty patients (23 men; mean age 71.4 +/- 11.5 years) with 56 lesions (42 de novo and 14 restenotic) underwent treatment with angioplasty/stenting (group A, n=29; 43 lesions) or SilverHawk atherectomy (group B, n=11; 13 lesions). One filter was used per patient (25 SpiderFX and 15 EmboShield). Macroembolization occurred in 22 (55.0%) patients, 11 (37.9%) in group A and 11 (100%) in group B (p < 0.001). Clinically significant (>= 2 mm in diameter) macrodebris was found in 18 (45.0%) patients: 8 (27.6%) in group A and 10 (90.9%) in group B (p < 0.001). All filters were retrieved successfully with no complications. One side-branch embolization occurred proximal to the filter. In another case, the filter was overfilled, resulting in no distal flow; it was retrieved, with subsequent tibial embolization when the procedure was continued without protection. Conclusion: Macroembolization is very frequent in patients undergoing lower extremity interventions, particularly with SilverHawk atherectomy. EFP appears to be very effective in capturing macrodebris, and its use is associated with good acute angiographic outcome. The clinical significance of these findings needs to be determined in future studies.