Intravascular devices, retrieval systems, and corresponding methods
A semi-retrievable intravascular filter ( 100 ) for deployment within a vessel ( 108 ) includes a support structure ( 104 ) for deployment around an internal surface of the vessel ( 108 ) and a filter structure ( 102 ) supported by interconnection with the support structure ( 104 ). The filter structure ( 102 ) is connected to the support structure ( 104 ) so as to be selectively detachable so as to facilitate removal of the filter structure ( 102 ) without the support structure ( 104 ). Also described are various retrieval systems for retrievable or semi-retrievable intravascular devices, and intravascular filter structures.
1. A retrieval system in combination with an un-tethered intravascular device, the combination comprising:
(a) a hookable element connected to the un-tethered intravascular device, said hookable element including a threaded portion for temporary interconnection with a delivery system, and at least one projection projecting towards the un-tethered intravascular device;
(b) a retrieval catheter having a distal end for insertion to a position close to the intravascular device, said distal end having a longitudinal central axis; and
(c) a retrieval device deployed within, and advanceable beyond, said retrieval catheter, said retrieval device including a plurality of wire portions, said plurality of wire portions being configured such that, when said retrieval device is advanced to extend beyond said distal end of said retrieval catheter, each of said wire portions opens into a substantially planar loop in a plane parallel to, and lying substantially on, said longitudinal central axis, said plane of each of said loops being rotated about said longitudinal central axis relative to said planes of others of said loops,
such that, when said retrieval device is advanced beyond said distal end and moved towards the intravascular device, said hookable element passes between said wire portions so as to lie within at least one of said loops, and when said retrieval device is withdrawn, at least one of said wire portions is engageable on said at least one projection so as to catch said hookable element and to allow withdrawal of the intravascular device.
2. The retrieval system of claim 1 , wherein said retrieval device includes a number n of said wire portions, where 4≦n≦20, and wherein said planes are separated by angles which approximate to multiples 180°/n.
3. The retrieval system of claim 2 , wherein 6≦n≦10.
4. The retrieval system of claim 1 , wherein said hookable element is additionally configured as a connector for clamping at least two wires from the un-tethered intravascular device in fixed relation.
5. The retrieval system of claim 1 , wherein said hookable element has a substantially cylindrical external surface.
6. The retrieval system of claim 1 , wherein said wire portions are mechanically unconnected at their distal extremities.
7. The retrieval system of claim 6 , wherein each of said loops lies in a plane rotated relative to the plane of two others of said loops by no more than about 30 degrees.
8. The retrieval system of claim 6 , wherein each of said loops has a smooth arcuate form at its distal extremity.