Patent ID: 7972353

Claim:
A removable filter for capturing thrombi in a blood vessel having a wall, the filter comprising: a plurality of primary struts having first ends attached together along a longitudinal axis of the filter, each primary strut having a body member extending from the first end along the longitudinal axis and terminating with an anchoring hook defining a strut axis, each primary strut being configured to move along a strut path relative to the longitudinal axis between an expanded state for engaging with the blood vessel and a collapsed state for filter delivery or retrieval, the filter being retrievable in the collapsed state before, during, and after use, each anchoring hook including a bend having a constant angle of about 90 degrees relative to the strut axis, the constant angle being configured to remain constant between the expanded state, in which each anchoring hook engages with the blood vessel, and the collapsed state, in which each anchoring hook disengages from the wall of the blood vessel; and a plurality of secondary struts having connected ends attached together along the longitudinal axis, each secondary strut having a first arc extending from the connected end and a second arc extending from the first arc to a free end, the second arc being configured to engage the blood vessel to centralize the filter in the expanded state in the blood vessel, wherein the anchoring hook includes an end face, the end face being concave for migration resistance, the concave end face defining a sharpened outer periphery.