Method and apparatus for stenting

Abstract

A method and an apparatus to create a more favorable flow regime in a lumen. An artificial shape in the lumen is created to at least one of eliminate flow disturbances and enhance aspects of fluid flow through a treatment site.

What is claimed is:  
     
         1 . A method to create a more favorable flow regime in a lumen, comprising creating an artificial shape in the lumen to at least one of eliminate flow disturbances and enhance aspects of fluid flow through a treatment site.  
     
     
         2 . The method according to  claim 1  comprising creating an artificial shape in the lumen which minimizes flow separation.  
     
     
         3 . The method according to  claim 1  comprising creating an artificial shape that enhances aspects of fluid flow relative to both a pre-treatment diseased shape and a post-treatment shape than would result with conventional stents.  
     
     
         4 . The method according to  claim 1  comprising creating an artificial shape in a bifurcation in the lumen.  
     
     
         5 . The method according to  claim 4  wherein said artificial shape comprises a taper.  
     
     
         6 . The method according to  claim 1  comprising creating an artificial shape in a straight vessel where tapering was non-existing prior to the treatment  
     
     
         7 . The method according to  claim 6  wherein said artificial shape comprises a taper.  
     
     
         8 . The method according to  claim 1  comprising creating said artificial shape in the lumen with a stent.  
     
     
         9 . The method according to  claim 8  comprising using an existing stent design that was originally made to have a uniform shape to create said artificial shape.  
     
     
         10 . The method according to  claim 8  comprising using a stent that is designed to create said artificial shape in a lumen.  
     
     
         11 . The method according to  claim 8  wherein said stent comprises a self-expanding stent which, when expanded has a non-uniform shape.  
     
     
         12 . The method according to  claim 11  wherein said stent has at least two sections with different cross-sectional areas, and a tapered section connecting the two sections with different cross-sectional areas to one another.  
     
     
         13 . The method according to  claim 8  wherein said stent comprises a balloon expandable stent and said method includes implanting said stent with a delivery balloon which is constructed such as to cause the stent to deploy to a predetermined non-uniform shape.  
     
     
         14 . The method according to  claim 13  wherein said non-uniform shape is a tapered shape.  
     
     
         15 . The method according to  claim 8  wherein said stent comprises a self-expanding stent and said method includes delivering a self-expandable stent in a conventional manner and with said stent expanded to a uniform diameter, and then reconfiguring said stent, after delivery, with a tapered balloon to introduce a non-uniform shape to the stent.  
     
     
         16 . The method according to  claim 15  wherein said non-uniform shape is a tapered shape.  
     
     
         17 . The method according to  claim 13  comprising positioning the non-uniform shape in the stent at a bifurcation.  
     
     
         18 . The method according to  claim 13  comprising positioning the non-uniform shape in the stent at a sensitive area in a straight vessel.  
     
     
         19 . The method according to  claim 13  wherein said sensitive area is the area of a previous lesion.  
     
     
         20 . The method according to  claim 13  wherein said sensitive area is an area that was traumatized by an angioplasty procedure.  
     
     
         21 . The method according to  claim 1  wherein said artificial shape comprises a non-uniformity about the axis of the stent.  
     
     
         22 . A stent for implantation in a lumen to create a more favorable flow regime, comprising a stent being configured for establishing an artificial shape in the lumen for altering flow characteristics to at least one of eliminate flow disturbances and enhance aspects of fluid flow through a treatment site.  
     
     
         23 . The stent according to  claim 22  wherein said non-uniform shape is selected to minimize flow separation  
     
     
         24 . The stent according to  claim 22  wherein said stent is tapered such as to create an artificial taper in a bifurcation in the lumen.  
     
     
         25 . The stent according to  claim 22  wherein said stent is tapered such as to create an artificial taper in a straight vessel where tapering was non-existing prior to the treatment  
     
     
         26 . The stent according to  claim 22  wherein said stent comprises a self-expanding stent having a non-uniform shape when expanded.  
     
     
         27 . The stent according to  claim 26  wherein said stent has at least two sections with different cross-sectional areas, and a tapered section connecting the two sections with different cross-sectional areas to one another.  
     
     
         28 . The stent according to  claim 22 , wherein said stent is a balloon expandable stent and further including a delivery balloon expandable to a non-uniform shape to configure said stent such as to have a non-uniform shape.  
     
     
         29 . The stent according to  claim 28  wherein said non-uniform shape comprises a shape with a taper.  
     
     
         30 . The stent according to  claim 22  wherein said stent comprises a self-expanding stent having a uniform shape when delivered and expanded and further including a balloon expandable to a non-uniform shape to reconfiguring said stent, after delivery, such as to have a non-uniform shape.  
     
     
         31 . The stent according to  claim 30  wherein said non-uniform shape comprises a shape with a taper.  
     
     
         32 . The stent according to  claim 22  wherein said non-uniform shape comprises a non-uniformity about the axis of the stent.  
     
     
         33 . A stent comprising: 
 a first stent segment configured to have a first stent segment cross-sectional area in an expanded state of the stent;    a second stent segment longitudinally offset with respect to the first stent segment and configured to have a second stent segment cross-sectional area in an expanded state of the stent;    a third stent segment configured to assume a tapered stent segment configuration in an expanded state of the stent, the tapered stent segment configuration connecting the first stent segment to the second stent segment, the stent being configured such that, in an expanded state thereof in a lumen, it manipulates a flow of blood in the lumen so as to induce a more favorable flow regime at a deployment location of the stent relative to a flow regime that would have been generated had a straight stent been deployed at the deployment location for reducing a risk of restenosis at the deployment location.    
     
     
         34 . The stent of  claim 33 , wherein the stent is configured for manipulating the flow of blood in the lumen so as to substantially eliminate flow disturbances at the deployment location.  
     
     
         35 . The stent of  claim 33 , wherein the second stent segment cross-sectional area is different from the first stent segment cross-sectional area.  
     
     
         36 . The stent of  claim 33 , wherein the stent is configured for one of shaping the lumen at the deployment location to an artificial tapered shape and restoring the lumen at the deployment location to an original shape thereof.  
     
     
         37 . The stent of  claim 36 , wherein the original shape corresponds to an original shape of a main branch of a bifurcated lumen, the stent being configured for restoring the lumen at the deployment location to the original shape thereof for inducing the favorable flow regime.  
     
     
         38 . The stent of  claim 33 , wherein, in an expanded state of the stent: 
 the first stent segment comprises a first right cylinder; and    the second stent segment comprises a second right cylinder.    
     
     
         39 . The stent of  claim 33 , further comprising a fourth stent segment configured to assume a diverging configuration in an expanded state of the stent, the fourth stent segment connecting the first stent segment to the third stent segment.  
     
     
         40 . The stent of  claim 33 , further comprising a fifth stent segment configured to assume a diverging configuration in an expanded state of the stent, the fifth stent segment connecting the third stent segment to the second stent segment.  
     
     
         41 . The stent of  claim 33 , wherein the third stent segment is directly connected to at least one of the first stent segment and the second stent segment.  
     
     
         42 . The stent of  claim 33 , wherein the first, second and third stent segments are configured such that, in an expanded state thereof, the stent is frustoconical.  
     
     
         43 . The stent of  claim 33 , wherein the first, second and third stent segments are configured such that, in an expanded state of the stent, an envelope of the stent is asymmetrical with respect to a longitudinal axis thereof.  
     
     
         44 . The stent of  claim 43 , wherein, in an expanded state of the stent, the envelope of the stent defines: 
 a first portion having a contour in a cross-sectional plane including the longitudinal axis of the stent that comprises one of a curved line and a straight line at an angle with respect to the longitudinal axis of the stent; and    a second portion having a contour in a cross-sectional plane including the longitudinal axis of the stent that comprises a straight line parallel to the longitudinal axis of the stent, the first portion and the second portion together defining the envelope of the stent.    
     
     
         45 . The stent of  claim 44 , wherein the first portion is quonset-shaped.  
     
     
         46 . The stent of  claim 33 , wherein a cross section of any stent segment of the stent in a plane normal to a longitudinal axis thereof is circular.  
     
     
         47 . The stent of  claim 33 , wherein the stent is one of self-expanding and balloon-expandable.  
     
     
         48 . A kit for deploying a stent comprising the stent of  claim 47 , the kit further including a delivery balloon configured to be inflated for expanding the stent in a lumen such that, in an expanded state of the stent, the first stent segment has the first stent segment cross-sectional area, the second stent segment has the second stent segment cross-sectional area, and the third stent segment assumes the tapered stent segment configuration.  
     
     
         49 . The kit of  claim 48 , wherein the balloon includes: 
 a first balloon segment configured to have a first balloon segment cross-sectional area in an inflated state of the balloon for expanding the first stent segment to the first stent segment cross-sectional area;    a second balloon segment longitudinally offset with respect to the first balloon segment and configured to have a second balloon segment cross-sectional area in an inflated state of the balloon for expanding the second stent segment to the second stent segment; and    a third balloon segment configured to assume a tapered balloon segment configuration in an inflated state of the balloon, the tapered balloon segment configuration connecting the first balloon segment to the second balloon segment, the balloon being configured such that, in an inflated state thereof in a lumen, it expands the stent to such that, in an expanded state thereof in a lumen, the stent manipulates a flow of blood in the lumen so as to induce a more favorable flow regime at a deployment location of the stent relative to a flow regime that would have been generated had a straight stent been deployed at the deployment location for reducing a risk of restenosis at the deployment location.    
     
     
         50 . The kit of  claim 49 , wherein the stent is configured for manipulating the flow of blood in the lumen so as to substantially eliminate flow disturbances at the deployment location.  
     
     
         51 . The stent of  claim 49 , wherein the second stent segment cross-sectional area is different from the first stent segment cross-sectional area.  
     
     
         52 . A delivery balloon for deploying the stent of  claim 47 , the balloon being configured to be inflated for expanding the stent in a lumen such that, in an expanded state of the stent, the first stent segment has the first stent segment cross-sectional area, the second stent segment has the second stent segment cross-sectional area, and the third stent segment assumes the tapered stent segment configuration.  
     
     
         53 . The balloon of  claim 52 , wherein the balloon includes: 
 a first balloon segment configured to have a first balloon segment cross-sectional area in an inflated state of the balloon for expanding the first stent segment to the first stent segment cross-sectional area;    a second balloon segment longitudinally offset with respect to the first balloon segment and configured to have a second balloon segment cross-sectional area in an inflated state of the balloon for expanding the second stent segment to the second stent segment cross-sectional area; and    a third balloon segment configured to assume a tapered balloon segment configuration in an inflated state of the balloon, the tapered balloon segment configuration connecting the first balloon segment to the second balloon segment, the balloon being configured such that, in an inflated state thereof in a lumen, it expands the stent such that, in an expanded state thereof in a lumen, the stent manipulates a flow of blood in the lumen so as to induce a more favorable flow regime at a deployment location of the stent relative to a flow regime that would have been generated had a straight stent been deployed at the deployment location for reducing a risk of restenosis at the deployment location.    
     
     
         54 . The stent of  claim 53 , wherein the second balloon segment cross-sectional area is different from the first balloon segment cross-sectional area.  
     
     
         55 . A method of deploying a stent comprising: 
 delivering the stent to a deployment location in a lumen;    expanding the stent such that, in an expanded state thereof, the stent comprises: 
 a first stent segment having a first stent segment cross-sectional area;  
 a second stent segment longitudinally offset with respect to the first stent segment and having a second stent segment cross-sectional area; and  
 a third stent segment having a tapered stent segment configuration, the tapered stent segment configuration connecting the first stent segment to the second stent segment, the stent being configured such that, in the expanded state thereof in the lumen, it manipulates a flow of blood in the lumen so as to induce a more favorable flow regime at a deployment location thereof relative to a flow regime that would have been generated had a straight stent been deployed at the deployment location for reducing a risk of restenosis at the deployment location.  
   
     
     
         56 . The method of  claim 55 , wherein the second stent segment cross-sectional area is different from the first stent segment cross-sectional area.  
     
     
         57 . The method of  claim 55 , further comprising using the stent in the expanded state thereof to one of shape the lumen at the deployment location to an artificial tapered shape and restore the lumen at the deployment location to an original shape thereof.  
     
     
         58 . The method of  claim 57 , further comprising using the artificial tapered shape to substantially eliminate flow separation in the lumen at the deployment location.  
     
     
         59 . The method of  claim 55 , wherein: 
 delivering comprises delivering the stent to a bifurcation site of the lumen, the bifurcation site having a main branch and a side branch and further corresponding to the deployment location of the stent;    expanding comprises expanding the stent at the bifurcation site such that: 
 in an expanded state thereof, an envelope of the stent is asymmetrical with respect to a longitudinal axis thereof and defines: 
 a first portion having a contour in a cross-sectional plane including the longitudinal axis of the stent that comprises one of a curved line and a straight line at an angle with respect to the longitudinal axis of the stent; and  
 a second portion having a contour in a cross-sectional plane including the longitudinal axis of the stent that comprises a straight line parallel to the longitudinal axis of the stent, the first portion and the second portion together defining the envelope of the stent.  
 
 the second portion of the expanded stent abuts the side branch of the bifurcation site.  
   
     
     
         60 . A stent comprising: 
 a stent envelope adapted to be deployed at a deployment location in a lumen; and    means associated with the stent envelope for controlling a flow of blood in the lumen when the stent envelope is in its expanded state so as to induce a more favorable flow regime at the deployment location of the stent envelope relative to a flow regime that would have been generated had a straight stent envelope been deployed at the deployment location for reducing a risk of restenosis at the deployment location.