A vascular filter comprises an emboli-capturing portion having a set of helical filter-wires joined at a central region and extending in a given direction along the blood vessel in a diverging relationship to the axis of the filter, the wires terminating in free ends constructed to engage the...http://www.google.es/patents/US5836969?utm_source=gb-gplus-sharePatente US5836969 - Vena cava filter
