Methods and apparatus for treating embolism
A method and apparatus for treating a clot in the blood vessel of a patient, and particularly the treatment of a pulmonary embolism is disclosed. The treatment includes restoring flow through the clot followed by clot removal, either partially or substantially completely. The clot treatment device is expandable into the blood vessel and may contain radial extensions that assist in restoring flow as well as in removing clot material.
1. A device for treating a pulmonary embolism that at least partially restricts blood flow through a pulmonary vessel, the device comprising:
an elongated shaft having a proximal region and a distal region;
an expandable braid attached to the distal region of the elongated shaft, the braid having a plurality of radially extending portions and at least one cylindrical portion, and the radially extending portions and the cylindrical portion being configured to move from a compressed state sized to fit in a delivery catheter to an expanded state;
wherein the cylindrical portion is between a pair of the radially extending portions, and in the expanded state the cylindrical portion is configured to press radially outward against the pulmonary embolism;
wherein the radially extending portions extend radially outward from the cylindrical portion in the expanded state such that portions of the pulmonary embolism are retained between the radially extending portions; and
wherein the cylindrical portion has a first length along a longitudinal direction of the braid in the expanded state and the radially extending portions have a second length along the longitudinal direction of the braid in the expanded state that is less that the first length.
2. The device of claim 1 wherein at least a portion of the individual radially extending portions is disk-shaped.
3. The device of claim 1 wherein the individual radially extending portions include a curved portion and a linear portion.
4. The device of claim 1 wherein, in the expanded state, an exterior surface area of the device is at least two times to four times greater than the surface area of a uniformly cylindrical device.
5. The device of claim 1 wherein the braid includes a plurality of filaments, and wherein:
in the delivery state, the filaments form a first angle with respect to an axis of the device; and
in the expanded state, the filaments form a second angle with respect to an axis of the device that is different than the first angle.
6. The device of claim 1 wherein at least one of the radially extending portions is tapered.
7. The device of claim 1 wherein at least one of the radially extending portions is generally cylindrical.
8. The device of claim 1 wherein the individual radially expanding portions have a first diameter and a second diameter different than the first diameter.
9. The device of claim 1 wherein the expandable braid comprises metallic filaments of Nitinol.
10. The device of claim 1 wherein the expandable braid comprises a cobalt chrome alloy.
11. The device of claim 1 wherein at least one generally cylindrical portion forms a conical lumen.
12. The device of claim 1 wherein individual radially extending portions have a flare-shaped cross-section with a concave proximal surface.
13. The device of claim 1 wherein at least one of the radially extending portions has a generally triangular cross-section.