Deformable flap catch mechanism for occluder device
Devices, delivery systems, and delivery techniques for an occlusion device for closure of physical anomalies, such as an atrial septal defect, a patent foramen ovale (PFO), and other septal and vascular defects are described. Specifically, an occluder with a catch member that holds the occluder in the deployed, expanded profile configuration is provided within a delivery sheath. The proximal end of the catch member includes a flap that when positioned proximal to the proximal end of the occluder holds the occluder in the expanded profile configuration. The flap is sized and formed of a material that allows the flap to deform by bending back and forth in axial and radial directions. In certain embodiments, the flap has segments divided by notches. In certain embodiments, deforming the flap in the proximal direction requires a different amount of force than deforming the flap in the distal direction.
1. A collapsible medical device for occluding an aperture in a body, the medical device having a first configuration with a reduced profile and a second configuration with an expanded profile, the medical device being adapted to be delivered through a delivery system into a desired delivery location, the medical device comprising:
an occluder portion having a proximal side having a proximal end and a distal side having a distal end that cooperate to close the defect, and the occluder having a central portion disposed between the proximal side and the distal side, at least one of the proximal and distal sides of the occluder including slits axially formed in a tube to form struts, wherein adjacent slits are axially offset from each other around the circumference of the tube and the struts form petals which rotate in an orthogonal plane relative to the axis of the occluder device when the axial length of the tube is shortened into a deployed state, and wherein at least one strut joined to the central portion forms a portion of two adjacent petals extending from the at least one strut;
and
a catch system for holding the medical device in the second configuration, including a catch member having a distal end with a diameter D1 and a proximal end having a diameter D2, wherein D2 is greater than D1, and a flap at the proximal end of the catch member having a base portion of thickness t1 and an outer portion having a thickness t2, wherein t2 is greater than t1; and wherein further the flap is bent distally when the flap is pulled through the proximal end during delivery of the device, wherein the proximal end of the device rests against a distal surface of the flap when the device is in the second configuration and the flap holds the medical device in the second configuration, and wherein further the flap fits inside an interior passage of the occluder portion in during delivery and retrieval, and wherein the flap has a first interference with the interior passage of the occluder portion during delivery and a second interference with the interior passage of the occluder portion during retrieval, and the second interference is greater than the first interference and a first force required to deform the flap for retrieval is greater than a second force required to deform the flap for deployment.
2. The medical device of claim 1 , wherein the flap includes two wings.
3. The medical device of claim 2 , wherein the circumferential coverage of the wings is separated by cutoff V-shaped notches.
4. The medical device of claim 1 , wherein the flap has a rounded shape when viewed axially.
5. The medical device of claim 1 , wherein the flap has a rounded surface at the radially outermost edge.
6. The medical device of claim 1 , wherein the flap has a thickness to width ratio of about 1 to about 2.
7. The medical device recited in claim 6 , wherein the flap has two wings with rounded surfaces at the radially outermost edge.
8. The medical device of claim 1 , wherein the proximal end of the catch member comprises threads that secure the catch member to the delivery system.
9. The medical device of claim 1 , wherein the occluder portion is bioresorbable.
10. The medical device of claim 1 , wherein the occluder portion is nitinol.