Devices and methods for pressure-responsive shaping of blood vessels

Abstract

A device for controlling blood flow through a vein is provided. The device includes a device body configured for implantation in or around the vein. The device body is capable of reducing flow through the vein in response to an increase in tissue pressure around the vein.

1 . (canceled) 
     
     
         2 . A system for controlling blood flow through a vein, said system comprising:
 an applicator comprising an applicator body having a distal tip;   a needle cannula fixed to and extending distally from the distal tip of the applicator body;   an over tube mounted within the applicator body, said over tube having a lumen and extending coaxially over a proximal portion of the needle cannula;   a mandrel mounted within the applicator body, said mandrel extending coaxially through a lumen the needle cannula; and   a coil implant comprising a plurality of coils, said coil implant positioned coaxially over the needle cannula, wherein a first plurality of the coils are disposed within the lumen of the over tube lumen and a second plurality of the coils extend beyond a distal end of the over tube and are attached to a distal end of the mandrel;   wherein the over tube is configured to be reacted to release the first plurality of coils and the mandrel is configured to be distally pushed to release the second plurality of coils.   
     
     
         3 . The system of  claim 2 , further comprising a sliding knob on the applicator body configured to draw the over tube proximally to release the first plurality of the coils. 
     
     
         4 . The system of  claim 3 , further comprising a push knob on the applicator body configured to push the mandrel distally to release the second plurality of the coils. 
     
     
         5 . The system of  claim 2 , wherein the coil implant is configured to elastically recoil and foreshorten to form an upper flange configured to engage an upper wall of the vein and a lower flange configured to engage a lower wall of the vein. 
     
     
         6 . The system of  claim 2 , wherein the coil implant is wrapped tightly about an outer surface of the needle cannula in a delivery configuration. 
     
     
         7 . The system of  claim 2 , wherein said coil implant is fabricated from a shape memory material capable of assuming a tissue compressive shape following delivery. 
     
     
         8 . The system of  claim 2 , wherein said coil implant is configured for facilitating collapse of said vein under external pressure applied thereto. 
     
     
         9 . The system of  claim 8 , wherein the coil implant is configured to elastically recoil so that a length of the elongated coil foreshortens, and the diameter of individual coils increases. 
     
     
         10 . The system of  claim 5 , wherein the needle cannula has a diameter of about 0.5 mm and the clip has about six to eight coils which extend over a length of about 3 mm to 4 mm. 
     
     
         11 . The method of controlling blood flow through a vein comprising:
 a coil implant having a first plurality of coils and a second plurality of coils through an upper wall and a lower wall of the vein, wherein the coils are constrained in a straightened configuration;   releasing the first plurality of coils beneath the lower wall of the vein so that the coils expand to assume a coiled shape to engage the lower wall; and   releasing the second plurality of coils over the upper wall of the vein so that the coils expand to assume a coiled shape to engage the upper wall;   wherein the coil implant elastically recoils and foreshortens to compress the vein and reduce flow therethrough.   
     
     
         12 . The method of  claim 11 , wherein said clip is configured for facilitating collapse of said vein under external pressure applied thereto. 
     
     
         13 . The method of  claim 11 , wherein the clip is initially constrained over an outer surface of a needle cannula and wherein delivering the coil implant comprises penetrating the needle cannula through the walls of the vein to partially collapse the walls prior to releasing the coils. 
     
     
         14 . The method of  claim 13 , wherein releasing the first plurality of coils comprises proximally retracting an over tube that radially constrains the first plurality of coils. 
     
     
         15 . The method of  claim 14 , wherein releasing the second plurality of coils comprises distally advancing a mandrel that axially constrains the second plurality of coils. 
     
     
         16 . The method of  claim 11 , wherein the coil implant elastically recoils and foreshortens to compress the vein so that open lumens are left on each side of the vein to provide controlled blood flow.