A vascular filter device (1) has a perfusion balloon (3) with a through-hole for blood flow. There is a distal filter (4) for trapping emboli, and the filter (4) is configured to filter an annular cross-sectional area extending from a vessel wall, while leaving an un-filtered central passageway. The filter (4) may be substantially frusto-conical in shape when deployed, and have a proximal tubular part (41) which is attached to the perfusion balloon or a support for the perfusion balloon. The filter has a retainer (5) to retain an end of the filter in an in-use position abutting a vessel wall. The retainer may comprise wires (5) or an inflated ring (8). The device may have an internal support (2, 12, 22, 96, 112) for the perfusion balloon (3, 11, 21, 95, 111). The balloon inflates and expands the inner arterial wall, and the filter captures emboli released during the procedure while leaving a channel that allows blood to flow to tissues distal to the blockage, maintaining antegrade flow. This may prevent the onset of an ischemic stroke or other perioperative neurological events.
