| 摘要 |
PURPOSE: To prevent a large clot or a thrombus from reaching from the heart from the leg veins through the descending vena cava by using a filter so constructed that first leg parts radiated from the head closely surround a central member, the head is formed by metal of the ends of the first leg parts, and the central member becomes a lateral fulcrum when the legs are compressed to be united into one body. CONSTITUTION: Six legs 12 projected from a head 14 are formed by a wire made of a biocompatible titanium alloy, and the respective legs are formed in such a manner that a first straight leg part 13 is parallel to an axis E of a filter having a length HN of 1mm, it is provided with a nose bending 15, and a second bent leg part 16 longer than the first straight leg part is bent from the first leg end part outside the axis E to form an imaginary cone at the base 20 with the other second leg parts and have an outward hook 22. The second leg part 16 is formed by a series of individual straight segments and is substantially tangential to the plane of the imaginary cone to increase the efficiency of a filtering effect. A hexagonal pattern is formed centering round the straight line leg part 13 central segment 24, and the end parts of all legs are joined to the head by fusion.
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