Systems and methods for treating septal defects

This application is a divisional of co-pending U.S. patent application Ser. No. 11/175,814, filed Jul. 5, 2005, which claims the benefit of co-pending U.S. patent application Ser. No. 10/847,747, filed on May 7, 2004, which is a continuation-in-part of U.S. patent application Ser. No. 10/734,670, filed Dec. 11, 2003, which is a division of Ser. No. 09/948,453, filed Sep. 7, 2001, now U.S. Pat. No. 6,702,835 and which is a continuation-in-part of Ser. No. 09/948,502, filed Sep. 6, 2001, now U.S. Pat. No. 6,776,784, which is fully incorporated herein by reference.

The present invention relates generally to systems and methods for closing internal tissue defects, and more particularly to systems and methods for closing a patent foramen ovale or other septal defect.

By nature of their location, the treatment of internal tissue defects is inherently difficult. Access to a defect through invasive surgery introduces a high level of risk that can result in serious complications for the patient. Access to the defect remotely with a catheter or equivalent device is less risky, but treatment of the defect itself is made more difficult given the limited physical abilities of the catheter. The difficulty in accessing and treating tissue defects is compounded when the defect is found in or near a vital organ. For instance, a patent foramen ovale (“PFO”) is a serious septal defect that can occur between the left and right atria of the heart and a patent ductus arteriosus (“PDA”) is an abnormal shunt between the aorta and pulmonary artery.

During development of a fetus in utero, oxygen is transferred from maternal blood to fetal blood through complex interactions between the developing fetal vasculature and the mother\'s placenta. During this process, blood is oxygenated within the fetal lungs. In fact, most of the fetus\' circulation is shunted away from the lungs through specialized vessels and foramens that are open during fetal life, but typically closed shortly after birth. Occasionally, however, these foramen fail to close and create hemodynamic problems, which, in extreme cases, can ultimately prove fatal. During fetal life, an opening called the foramen ovale allows blood to pass directly from the right atrium to the left atrium (bypassing the lungs). Thus, blood that is oxygenated via gas exchange with the placenta may travel through the vena cava into the right atrium, through the foramen ovale into the left atrium, and from there into the left ventricle for delivery to the fetal systemic circulation. After birth, with pulmonary circulation established, the increased left atrial blood flow and pressure causes the functional closure of the foramen ovale and, as the heart continues to develop, this closure allows the foramen ovale to grow completely sealed.

In some cases, however, the foramen ovale fails to close entirely. This condition, known as a PFO, can allow blood to continue to shunt between the left and right atria of the heart throughout the adult life of the individual. PFO\'s can pose serious health risks for the individual, including strokes and migraines. The presence of PFO\'s have been implicated as a possible contributing factor in the pathogenesis of migraine. Two current hypothesis that link PFO\'s with migraine include the transit of vasoactive substances or thrombus/emboli from the venous circulation directly into the left atrium without passing through the lungs where they would normally be deactivated or filtered respectively. Other diseases that have been associated with PFO\'s (and which could benefit from PFO closure) include but are not limited to depression and affective disorders, personality and anxiety disorders, pain stroke, TIA, dementia, epilepsy, and sleep disorders.

Still other septal defects can occur between the various chambers of the heart, such as atrial-septal defects (ASD\'s), ventricular-septal defects (VSD\'s), and the like. To treat these defects as well as PFO\'s, open heart surgery can be performed to ligate and close the defect. Alternatively, catheter-based procedures have been developed that require introducing umbrella or disc-like devices into the heart. These devices include opposing expandable structures connected by a hub or waist. Generally, in an attempt to close the defect, the device is inserted through the natural opening of the defect and the expandable structures are deployed on either side of the septum to secure the tissue surrounding the defect between the umbrella or disc-like structure.

These devices suffer from numerous shortcomings. For instance, these devices typically involve frame structures that often support membranes, either of which may fail during the life of the patient, thereby introducing the risk that the defect may reopen or that portions of the device could be released within the patient\'s heart. These devices can fail to form a perfect seal of the septal defect, allowing blood to continue to shunt through the defect. Also, the size and expansive nature of these devices makes safe withdrawal from the patient difficult in instances where withdrawal becomes necessary. The presence of these devices within the heart typically requires the patient to use anti-coagulant drugs for prolonged periods of time, thereby introducing additional health risks to the patient. Furthermore, these devices can come into contact with other portions of the heart tissue and cause undesirable side effects such as an arrhythmia, local tissue damage, and perforation.

Accordingly, improved systems and methods for closing internal tissue defects within the heart are needed.

Improved systems and methods for closing internal tissue defects, such as septal defects and the like, are provided herein by the way of exemplary embodiments. These embodiments are examples only and are not intended to limit the invention.

In one exemplary embodiment, an implantable apparatus for treating a septal defect is provided having a body with a first end portion, a second end portion and a central portion located therebetween. Preferably, the first end portion is configured to engage a first septal surface, the second end portion is configured to engage a second septal surface and the central portion is configured to fit within an opening in a septal wall.

In another exemplary embodiment, a treatment system is provided having a first elongate member and a second elongate delivery member having a distal end rotatably coupled with the first elongate member, wherein the orientation of the distal end is adjustable from a first orientation to a second orientation upon advancement of the elongate member in a distal direction.

In another exemplary embodiment, a treatment system is provided having an elongate tubular member having an inner lumen configured to slidably receive and interact with an inner elongate member. Preferably, the inner elongate member is configured to deploy a grasping device through an aperture in the elongate tubular member upon movement of the elongate inner member with respect to the elongate tubular member.

In yet another exemplary embodiment, a treatment system is provided having a flexible positioning member having a distal end and an elongate support member having an inner lumen configured to slidably receive the flexible positioning member. Preferably, the inner lumen has a distal end configured to abut the distal end of the flexible positioning member and an open portion located proximal to the distal end of the lumen. The flexible positioning member is also preferably configured to extend from the open portion upon advancement of the flexible positioning member distally against the distal end of the inner lumen.

In another exemplary embodiment, a method of treating a septal defect is provided, the method including abutting a limbus of a septum secundum with an abutment of a medical device, creating a hole in the septum secundum with the limbus as a point of reference, and using the hole to facilitate delivery of a device configured to treat a septal defect.

In another exemplary embodiment, a treatment system is provided having an implantable treatment device, a flexible elongate delivery device configured to deliver the implantable treatment device, a stabilization device insertable within an opening in a septum, or tunnel between two septa, and configured to stabilize an elongate body member, and the elongate body member configured for insertion within the vasculature of a patient, the body member configured to slidably receive the delivery device and stabilization device.

Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. It is also intended that the invention is not limited to require the details of the example embodiments.