Analysis of particulate debris after superficial femoral artery atherectomy

To evaluate the occurrence, size and composition of embolized debris captured during routine directional atherectomy using the SilverHawk device.

15 consecutive eligible patients with a nonocclusive superficial femoral artery (SFA) were enrolled. Patients were included if they were > 18 years of age and had > or = 70% stenosis in the SFA. All lesions underwent plaque excision with the SilverHawk atherectomy device. A FilterWire EZ was used for distal protection and retrieval of embolized material. Specimens were collected separately from the filter basket and the SilverHawk atherectomy device's nosecone and were studied by a pathologist for number, size and composition.

Visible debris captured in the filter was found in the majority of patients 14/15 (93%). Clinically-significant debris was found in 7/15 (47%) patients. The proportion of captured debris ranged from 0.1-0.4 cm. Microscopy revealed that the shaved particles consisted predominantly of collagen, fibrin, lipid-laden macrophages, cholesterol and calcium. Analysis of the embolized material revealed a different composition, mostly consisting of collagen with fibrosis, cholesterol and macrophages.

In this single-center comparative study we have shown that during SilverHawk atherectomy of SFA lesions, distal embolization is universal. The debris captured in the filter is different in overall composition from the captured material in the nosecone of the SilverHawk device. Debris large enough to cause clinically-significant embolization, no-reflow and ischemia following SFA interventions occurred in nearly 50% of cases.