Catch members for occluder devices

Abstract

Devices and techniques for modifying and maintaining a configuration of an occlusion device for the closure of physical anomalies, such as an atrial septal defect, a patent foramen ovale (PFO), and other septal and vascular defects are described. The devices and techniques relate particularly to, but are not limited to, modifying and maintaining a configuration of a PFO occluder made from a polymer tube. The proximal portion of a catch member may be provided with one or more protrusions, or arms, or bump or other raised element for securing the occluder in a partial or fully deployed configuration, either temporarily or permanently.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This Application claims the benefit of priority to U.S. Provisional Application Ser. No. 60 / 753,681, filed Dec. 22, 2005, the disclosure of which is incorporated by reference herein.FIELD OF THE INVENTION [0002] This invention relates generally to occlusion devices for the closure of physical anomalies, such as an atrial septal defect, a patent foramen ovale, and other septal and vascular defects. The invention also relates to mechanisms for deploying such devices and securing them in the deployed position. BACKGROUND OF THE INVENTION [0003] A patent foramen ovale (PFO), illustrated in FIG. 1, is a persistent, one-way, usually flap-like opening in the wall between the right atrium 11 and left atrium 13 of the heart 10. Because left atrial (LA) pressure is normally higher than right atrial (RA) pressure, the flap usually stays closed. Under certain conditions, however, right atrial pressure can exceed left atrial pressure, creating the p...

AI Technical Summary

Benefits of technology

[0014] Catch members may be used to deploy and keep the device in place. According to some embodiments, the catch member maintains a reduced axial length of the device when the device is in the deployed configuration. Also, varied constructions could be used to maintain the axial dimension of the device, such as different locking mechanisms. Preferably, the catch member secures both sides of the device in the reduced profile configuration with a single element. Generally, during the delivery stage, the catch member has a smaller diameter at its proximal end compared to the diameter of the proximal end of the occluder. This configuration allows the proximal end of the occluder to slide over the proximal end of the catch member during deployment sequence. This may be achieved by compression of the proximal end of the catch member, by expansion of the proximal end of the occluder, or a combination of both. In a catching configuration, the catch member generally has a greater diameter at its proximal end compared to the diameter of the proximal end of the occluder, which keeps the occluder in its deployed configuration.

[0017] According to at least some embodiments, the catch member is formed from a tube. According to some embodiments, the tube includes a material selected from the group consisting of metals, shape memory materials, alloys, polymers, bioabsorbable polymers, and combinations thereof. In particular embodiments, the tube includes a shape memory polymer. In particular embodiments, the tube includes nitinol. In some embodiments, the tube is formed by rolling a flat piece of material into a tubular form. According to some embodiments, the catch member is formed by cutting the tube. The catch member is placed in its deployment configuration by fixing the axial length of the device, for example by preventing the proximal end of the device from sliding over the proximal catch element.

[0020] In certain embodiments, the catch member may include a bump and pre-curved tabs at its proximal side. The bump is interrupted by a largely planar lumen slicing through the proximal side of the catch member. The lumen allows compression of the catch member with the delivery wire attached to provide a temporary catch configuration. In some embodiments, after the delivery wire is removed, the tabs automatically slide into the lumen to prevent or reduce compressibility of the catch member, thus providing a permanent catch configuration.

Problems solved by technology

While there is currently no definitive proof of a cause-effect relationship, many studies have confirmed a strong association between the presence of a PFO and the risk for paradoxical embolism or stroke.

In addition, there is significant evidence that patients with a PFO who have had a cerebral vascular event are at increased risk for future, recurrent cerebrovascular events.

These patients are commonly treated with oral anticoagulants, which potentially have adverse side effects, such as hemorrhaging, hematoma, and interactions with a variety of other drugs.

However, umbrella devices and the like that are designed for ASDs are not optimally suited for use as PFO closure devices.

Currently available septal closure devices present drawbacks, including technically complex implantation procedures.

Additionally, there are significant complications due to thrombus, fractures of the components, conduction system disturbances, perforations of heart tissue, and residual leaks.

Many devices have high septal profile and include large masses of foreign material, which may lead to unfavorable body adaptation of a device.

Given that ASD devices are designed to occlude holes, many lack anatomic conformability to the flap-like anatomy of PFOs.

Thus, when inserting an ASD device to close a PFO, the narrow opening and the thin flap may form impediments to proper deployment.

Even if an occlusive seal is formed, the device may be deployed in the heart on an angle, leaving some components insecurely seated against the septum and, thereby, risking thrombus formation due to hemodynamic disturbances.

Finally, some septal closure devices are complex to manufacture, which may result in inconsistent product performance.

The unique design of these tube-made devices, however, requires an additional catch mechanism to catch the devices in their deployed configurations.

Making such catch members capable of forming a temporary lock during partial deployment and a more secure permanent lock after full deployment has proved challenging.

Some designs are not sufficiently reliable and other designs cannot be manufactured effectively.

Finally, some designs, while workable on paper, do not perform satisfactorily in the human body.

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