Methods for deployment of medical devices
Methods for delivering a medical device loaded onto a catheter include positioning a first tube relative to a second concentric tube such that sheathing material having a first end affixed to the first tube and a second end affixed to the second tube forms an inner layer and an outer layer having at least one inversion point, such that no portion of the first tube is between any portion of the inner and outer layers of the sheathing material. Upon positioning the catheter at a desired target site the first tube can be moved relative to the second tube so that the inversion point moves to expose the medical device, thereby permitting expansion of the medical device at the target site.
1. A method of delivering a medical device, the method comprising:
loading the medical device onto a catheter, the catheter comprising:
an inner tube,
an outer tube concentric with the inner tube, the outer tube having an exterior surface for receiving the medical device thereon, and
a sheathing material having a first end affixed to the outer tube and a second end affixed to the inner tube such that the sheathing material forms an inner layer and an outer layer having at least one inversion point;
moving the inner tube in a first direction relative to the outer tube so that the medical device is covered at least partially by a portion of the sheathing material and is disposed between the inner layer of the sheathing material and the outer surface of the outer tube by axial movement of the inversion point;
delivering the catheter within a patient so that the medical device is positioned relative to a desired target site of therapy; and
moving the inner tube in a second direction relative to the outer tube so that the inversion point moves in such a way as to expose the medical device when it is desired to expand the device, thereby permitting expansion of the medical device at the target site.
2. The method of claim 1 , wherein movement of the inner tube in the first direction relative to the outer tube causes the inversion point to move in the first direction, and wherein movement of the inner tube in the second direction relative to the outer tube causes the inversions point to move in the second direction.
3. The method of claim 1 , wherein movement of the inner tube in the first direction relative to the outer tube causes the inversion point to move in the second direction, and wherein movement of the inner tube in the second direction causes the inversion point to move in the first direction.
4. The method of claim 1 , wherein the first end of the sheathing material is affixed to the outer surface of the outer tube.
5. The method of claim 4 , wherein the sheathing material extends around a distal end of the outer tube from the inner tube to the outer surface of the outer tube.
6. The method of claim 1 , wherein the inner layer of the sheathing material is adjacent to the outer layer of the sheathing material.
7. The method of claim 1 , wherein the sheathing material comprises a lubricious coating.
8. The method of claim 1 , wherein the medical device is a self-expanding device.
9. The method of claim 1 , wherein the medical device is a heart valve prosthesis.
10. The method of claim 1 , wherein the catheter further includes a distal cap coupled to a distal end of the outer tube.