Embolic filter device and related systems and methods

An embolic filter system includes a filter device that is adapted to be positioned over a guidewire and locked onto the guidewire at the position. The filter device may be locked over the guidewire outside of the patient, and then the locked assembly is advanced within a delivery sheath to the desired filtering location where the filter is adjusted to an expanded configuration to filter emboli there. Or, the filter device in a radially collapsed configuration may be advanced over an indwelling guidewire by back-loading the guidewire into a guidewire lumen associated with the filter device. Once delivered to the desired filtering location along the guidewire, the filter is locked onto the guidewire and then expanded to the radially expanded configuration for filtering the emboli. A control system cooperates with the embolic filter device to selectively lock the embolic filter device onto the guidewire and to selectively adjust the filter assembly between radially collapsed and expanded configurations for delivery and filtering, respectively. The control system includes a locking system, which in one beneficial embodiment has at least one shape memory member that is adapted to be heated and reshaped to thereby lock onto the guidewire.