Implant delivery capsule
Disclosed herein are embodiments of delivery capsules for delivering prosthetic implants around the relatively tight bends of a catheter. In particular, disclosed herein are delivery capsules including a tubular layer for holding the heart valve, a frame enclosing the tubular layer and an elongate element coupled to the frame for allowing the tubular layer and frame to expand. For example, the frame may be biased to expand and withdrawal of the elongate element from openings in the frame can release the frame to expand into a larger diameter. Another embodiment includes a helical wire wrapped around the capsule for easy delivery through bends and a second helical wire that is advanced between windings of the first helical wire to selectively stiffen the capsule for withdrawal. Other embodiments include sock-like capsules that can be crumpled into shorter lengths by pulling a pull line attached to the capsule.
1. A system for treating a defective native heart valve, comprising:
a catheter configured to extend through the vasculature and having a distal end for positioning in proximity to the native heart valve;
an expandable prosthetic heart valve coupled to the distal end of the catheter for placement within the native heart valve;
a flexible capsule defining a lumen configured to contain the prosthetic heart valve and including a tubular layer and a capsule helical wire attached to and encircling the tubular layer, wherein the capsule helical wire has a helical pitch space defined between adjacent windings of the capsule helical wire;
a torque shaft having a proximal end and a distal end; and
a proximal helical wire coupled to the distal end of the torque shaft, wherein the proximal helical wire has a diameter and pitch matching the helical pitch space and wherein rotation of the proximal end of the torque shaft rotates the proximal helical wire and axially advances the proximal helical wire into the pitch space of the capsule helical wire so as to stiffen the capsule for retrieval of the prosthetic heart valve into the lumen.
2. The system of claim 1 , wherein the tubular layer includes a thin polymer encapsulating the capsule helical wire.
3. The system of claim 2 , wherein the helical pitch space is defined on an outside surface of the tubular layer.
4. The system of claim 3 , wherein an inside surface of the tubular layer is smooth.
5. The system of claim 4 , further comprising a delivery sheath having a lumen containing the proximal end of the catheter, wherein the capsule helical wire is configured to reduce in diameter for withdrawal of the flexible capsule into the lumen of the delivery sheath.
6. The system of claim 1 , further comprising an elongate puller coupled to a distal end of the flexible capsule and configured to pull the proximal end of the flexible capsule to reduce the helical pitch space and reveal the prosthetic heart valve.