Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Arterial prosthesis – Including valve
Reexamination Certificate
2001-06-08
2003-03-04
DeMille, Danton D. (Department: 3764)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Arterial prosthesis
Including valve
C623S001190
Reexamination Certificate
active
06527800
ABSTRACT:
BACKGROUND
1. Technical Field
This application relates to a vascular device and more particularly to a vascular device for approximating vein valve leaflets for treating venous valve insufficiency.
2. Background of Related Art
Veins in the body transport blood to the heart and arteries carry blood away from the heart. The veins have one-way valve structures in the form of leaflets disposed annularly along the inside wall of the vein which open to permit blood flow toward the heart and close to prevent back flow. That is, when blood flows through the vein, the pressure forces the valve leaflets apart as they flex in the direction of blood flow and move towards the inside wall of the vessel, creating an opening therebetween for blood flow. The leaflets, however, do not normally bend in the opposite direction and therefore return to a closed position to prevent blood flow in the opposite, i.e. retrograde, direction after the pressure is relieved. The leaflet structures, when functioning properly, extend radially inwardly toward one another such that the tips contact each other to block backflow of blood.
In the condition of venous valve insufficiency, the valve leaflets do not function properly as they thicken and lose flexibility, resulting in their inability to extend sufficiently radially inwardly to enable their tips to come into sufficient contact with each other to prevent retrograde blood flow. The retrograde blood flow causes the buildup of hydrostatic pressure on the residual valves and the weight of the blood dilates the wall of the vessel. Such retrograde blood flow, commonly referred to as reflux, leads to swelling and varicose veins, causing great discomfort and pain to the patient. Such retrograde blood flow, if left untreated can also cause venous stasis ulcers of the skin and subcutaneous tissue. There are generally two types of venous valve insufficiency: primary and secondary. Primary venous valve insufficiency is typically a condition from birth, where the vein is simply too large in relation to the leaflets so that the leaflets cannot come into adequate contact to prevent backflow. More common is secondary venous valve insufficiency which is caused by clots which gel and scar, thereby changing the configuration of the leaflets, i.e. thickening the leaflets creating a “stub-like” configuration. Venous valve insufficiency can occur in the superficial venous system, such as the saphenous veins in the leg, or in the deep venous system, such as the femoral and popliteal veins extending along the back of the knee to the groin.
A common method of treatment of venous valve insufficiency is placement of an elastic stocking around the patient's leg to apply external pressure to the vein, forcing the walls radially inwardly to force the leaflets into apposition. Although sometimes successful, the tight stocking is quite uncomfortable, especially in warm weather, as the stocking must be constantly worn to keep the leaflets in apposition. The elastic stocking also affects the patient's physical appearance, thereby potentially having an adverse psychological affect. This physical and/or psychological discomfort sometimes results in the patient remove the stocking, thereby preventing adequate treatment.
Another method of treatment has been developed to avoid the discomfort of the stocking. This method involves major surgery requiring the implantation of a cuff internally of the body, directly around the vein. This surgery requires a large incision, resulting in a long patient recovery time, scarring and carries the risks, e.g. anesthesia, inherent with surgery.
Another invasive method of surgery involves selective repairing of the valve leaflets, referred to as valvuloplasty. In one method, sutures are utilized to bring the free edges of the valve cusp into contact. This procedure is complicated and has the same disadvantages of the major surgery described above.
It would therefore be advantageous to provide a method and device to minimally invasively treat venous valve insufficiency without requiring an outer stocking or internal cuff. Such device would thereby avoid the physical and psychological discomfort of an external stocking as well as avoid the risk, complexity and expense of surgically implanted cuffs. Such device would advantageously be inserted minimally invasively, i.e. intravascularly, and function to effectively bring the valve leaflets into apposition.
SUMMARY
The present invention overcomes the problems and deficiencies of the prior art by providing an intravascular device which brings the vessel wall adjacent the vein valve radially inwardly to bring valve leaflets into apposition. The present invention, in one aspect, provides a vascular device movable from a collapsed insertion position having a first diameter to an expanded position having a second larger diameter. A plurality of vessel engaging members extend outwardly from the device for securely engaging the internal wall of a vessel upon expansion of the device to the second expanded position. The vessel engaging members pull the internal wall of the vessel radially inwardly upon movement of the device from the second expanded position toward a first expanded position having a third diameter greater than the first diameter and smaller than the second diameter.
The device is preferably composed of shape memory material and the first expanded position preferably substantially corresponds to the memorized position of the device. In one embodiment, the device is initially movable from the collapsed position to the first expanded position in response to exposure to body temperature and is subsequently movable to the second expanded position by mechanical means or an inflatable balloon positioned within the device. In another embodiment, the device is movable from the collapsed position to the second expanded position by substantial simultaneous exposure to body temperature and expansion by an expandable member.
The vessel engaging members preferably extend from the distal and proximal portions of the device and have sharp ends to limit axial movement of the vessel wall and barbs to limit radial movement of the vessel wall to enhance retention (securement) of the vessel. The vessel engaging members preferably extend substantially parallel to a longitudinal axis of the device in the collapsed position and substantially perpendicular to the longitudinal axis in the extended position.
In one embodiment, in the collapsed position the middle portion of the device includes a plurality of longitudinal strips with a gap between adjacent strips. In this embodiment, the vessel engaging member is formed by a cut in the respective longitudinal strip and the longitudinal strips buckle radially outwardly upon movement of the device to the first expanded position.
In another embodiment of the present invention, the device includes a plurality of longitudinal strips, each terminating at opposing ends in one of the vessel engaging members. A substantially straight slot can be formed in each of the longitudinal strips in the collapsed position of the device, each slot preferably transforming to a substantially diamond shape when the device is moved to the first expanded position.
In another aspect of the present invention, a vascular device is provided comprising a tubular-like member expandable from a collapsed configuration to an expanded configuration and having a plurality of hooks extending from the tubular member at the proximal end and the distal end. The hooks extend substantially parallel to the longitudinal axis in the collapsed position and substantially perpendicular to the longitudinal axis in the extended position. Barbs may be provided adjacent the hooks for limiting radial movement of a vessel wall engaged by the barbs.
In another aspect of the present invention, a vascular device is provided comprising a tubular-like member expandable from a collapsed configuration to an expanded configuration. A plurality of vessel engaging members with penetrating tips extend from the proximal, distal and inter
Briganti Richard T.
McGuckin, Jr. James F.
DeMille Danton D.
Gershon Neil D
Rex Medical, L.P.
Thanh Quang D
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