Body lumen closure

#This invention relates to body lumen closure.

#A venous valve functions to prevent retrograde flow of blood and allow only antegrade flow of blood to the heart. Referring to FIG. 1A, a healthy venous valve 12 is illustrated in a vessel 10. The valve is bicuspid, with opposed cusps 14. In the closed condition, the cusps 14 are drawn together to prevent retrograde flow (arrow 16) of blood. Referring to FIG. 1B, if the valve is incompetent, the cusps 14 do not seal properly and retrograde flow of blood occurs. Incompetence of a venous valve is thought to arise from at least the following two medical conditions: varicose veins and chronic venous insufficiency.

#In a first aspect, the invention features an implantable medical closure device. The device includes a flexible strand defining an arcuate form. The strand is deformable upon implantation from a large cross-section condition to a small cross-section condition and has at least two anchoring portions disposed along the strand. The anchoring portions are configured to penetrate a wall of a body lumen such that when the strand is deformed to the small cross-section condition, the wall of the body lumen is disposed inwardly.

#FIG. 1A is a cross-sectional schematic of a vessel including a competent venous valve while FIG. 1B is a schematic of a vessel including an in competent venous valve.

#FIG. 2A is a longitudinal cross section of a vessel including a closure device, while FIG. 2B is a radial cross section of the vessel including the closure device.

#FIGS. 3A and 3B are longitudinal and radial cross-sectional views, respectively, illustrating delivery of a closure device using a catheter.

#Like reference symbols in the various drawings indicate like elements.

#Referring to FIGS. 2A and 2B, a valve closure device 20 is illustrated in position about a vessel 22 at the location of a valve 24 including cusps 26. The closure device 20 is an arcuate, open-ended, filament-form defining an arc that includes a body 28 which is located in the lumen of the vessel and two anchoring portions 30 which extend into the walls 32 of the vessel. The device 20 provides a force (arrows 34) that draws the vessel walls inward, enhancing the function of the valve 24. As evident, the closure device 20 does not substantially impede the flow of blood through the vessel. The body portion 30 is thin and conforms closely to the vessel wall, outside of central portions of the vessel, where flow volume and rate is greatest.

#Referring to FIGS. 3A and 3B, the closure device 20 can be positioned at a treatment site in vessel 22 using a catheter 36, which may be delivered into the vessel percutaneously. The catheter 36 includes a long, flexible body adapted for delivery through the vessel and has near its distal end an expander 38, such as an inflatable balloon. Suitable balloon catheters include angioplasty balloon catheters and balloon catheters adapted for delivering stents. An example utilizing a coextruded balloon is described in Hamilton et al., U.S. Pat. No. 5,797,877, the entire contents of which is incorporated herein by reference. The catheter may be delivered over a guidewire (not shown). The device 20 may be friction fit over the catheter. A retractable sheath may be used to cover the device and balloon during delivery.