the centering catheter of the present invention is designed to facilitate access to a treatment site in a lumen of a vessel through tortuous anatomy , and to facilitate uniform stent deployment at the treatment site . the centering catheter of the present invention comprises an elongated catheter body having a proximal end and a distal end , and at least one centering device attached near the distal end of the catheter . the centering device comprises a proximal end and a distal end , and at least two struts extending therebetween . the centering device has a smaller first diameter for insertion into the lumen , a larger second diameter for expanding to substantially equal the diameter of the lumen of the vessel , and a plurality of intermediate diameters therebetween . the centering device may be employed in any type of flexible elongated medical device product , including catheters , cannulae , guidewires and scopes . although the centering catheter may be utilized in conjunction with any type of device , for ease of explanation , the exemplary embodiments described below will refer to a balloon catheter and stent delivery system . while the present invention may be realized in a number of exemplary embodiments , for ease of explanation , two exemplary embodiments will be described in detail . referring to the figures , there is illustrated in fig1 a centering catheter 10 made in accordance with the present invention . the distal end of the centering catheter 10 comprises an inner member 20 , which extends longitudinally through the centering catheter 10 ; a catheter tip 25 ; at least one centering device 40 attached to the circumference of the inner member 20 ; and an angioplasty balloon 30 attached to the inner member 20 proximal to the at least one centering device 40 . each centering device 40 comprises a proximal end 42 and a distal end 44 and at least two struts 50 extending therebetween . the struts 50 may be equally or unequally spaced . the struts 50 may be longitudinal , as illustrated in fig1 , or circumferential , or any number of other suitable configurations . as illustrated in fig1 , the centering device 40 has a larger diameter that substantially equals the diameter of the lumen , and substantially exceeds the diameter of the inner member 20 . therefore , the centering device 40 may center the tip 25 of the centering catheter 10 in the lumen during and throughout insertion into the vessel , until the treatment location is reached . the at least one centering device 40 may be made from any number of suitable materials , and is preferably made from a superelastic alloy such as nitinol . the struts 50 may alternatively be hingedly connected struts . the centering device 40 may be coated with any number of suitable materials , and is preferably coated with a lubricious or biologically compatible coating . the centering device 40 may be removably or permanently attached to the inner member 20 . the centering catheter may be any suitable configuration catheter , and may preferably be an over the wire or rapid exchange catheter . as illustrated in fig1 , the centering catheter may be advanced into the lumen of a vessel with the centering device 40 expanding to make contact with the walls of the lumen . the centering device 40 thus serves to center the distal end of the catheter 10 and its inner member 20 as it is pushed through the vasculature to the treatment site . the struts 50 are compressible and allow the centering device 40 to vary its diameter as the lumenal diameter varies , while always keeping the catheter tip 25 of the centering catheter 10 centered in the lumen . this may facilitate the pushability and trackability of the centering catheter 10 as it traverses the vasculature . fig2 illustrates another exemplary made in accordance with the present invention . in this exemplary embodiment , a centering catheter 10 is a stent delivery system which comprises an inner member 20 , which extends longitudinally through the catheter 10 ; a catheter tip 25 ; at least one centering device 40 attached to the circumference of the inner member 20 ; an angioplasty balloon 30 attached to the inner member 20 proximal to the at least one centering device 40 ; and a stent 60 mounted on the angioplasty balloon 30 . each centering device 40 comprises a proximal end 42 and a distal end 44 and at least two struts 50 extending therebetween . the struts 50 may be equally or unequally spaced . the struts 50 may be longitudinal , as illustrated in fig2 , or circumferential , or any number of other suitable configurations . as illustrated in fig2 , the centering device 40 has a larger diameter that substantially equals the diameter of the lumen , and substantially exceeds the diameter of the inner member 20 . therefore , the centering device 40 may center the catheter tip 25 of the centering catheter 10 in the lumen during and throughout insertion into the vessel , and during stent deployment . another centering device may also be added to the centering catheter 10 at the proximal end of the stent 60 to facilitate uniform stent deployment . the at least one centering device 40 may be made from any number of suitable materials , and is preferably made from a superelastic alloy such as nitinol . the chronic outward force of the nitinol may be increased , and / or the diameter of the centering device may be increased to enhance the stabilization of the system during stent deployment . the struts 50 may alternatively have hinges near their midpoints . the centering device 40 may also be coated with any number of suitable materials , and is preferably coated with a lubricious or biologically compatible coating . the centering device 40 may be removably or permanently attached to the inner member 20 . the centering catheter 10 may be any suitable configuration catheter , and may preferably be an over the wire or rapid exchange catheter . the stent 60 may be a balloon expandable stent , as illustrated in fig2 , or a self - expanding stent . as illustrated in fig2 , the centering catheter 10 may be a stent delivery system that is advanced into the lumen of a vessel , with the centering device 40 expanding to make contact with the walls of the lumen . the centering device 40 thus serves to center the distal end of the catheter 10 and its inner member 20 as it is pushed through the vasculature to the treatment site . the struts 50 are compressible and allow the centering device 40 to vary its diameter as the lumen diameter varies , while always keeping the catheter tip 25 of the centering catheter 10 centered in the lumen . this may facilitate the pushability and trackability of the centering catheter 10 as it traverses the vasculature . when the treatment site is reached , the centering device 40 may stabilize the stent delivery system in the lumen of the vessel to insure uniform stent 60 deployment . there is illustrated in fig3 a non - centering catheter 100 in an irregular and narrowed lumen of a tortuous vessel 200 . the lumen may be narrowed by plaques and other deposits 210 on the lumenal surface . the tip 110 of the non - centering catheter 100 may therefore become uncentered and may “ catch ” on the lumenal surface . delivery of the noncentering catheter 110 to the targeted position in the lumen of the vessel may be difficult . in addition , deployment of a stent 120 ( shown mounted on a balloon 130 ) may not be perfectly uniform . there is illustrated in fig4 a centering catheter 10 with the at least one centering device 40 on a stent delivery system in an irregular and narrowed lumen of a tortuous vessel 200 . the lumen may be narrowed by plaques and other deposits 210 on the lumenal surface . delivery of the centering catheter 10 to the targeted position in the lumen of the vessel may be facilitated by the presence of the at least one centering device 40 , which tends to center the tip of the catheter 25 in the lumen of the vessel 200 . deployment of a stent 60 , shown mounted on a balloon 30 , may be facilitated by the presence of the at least one centering device 40 , which tends to center the catheter 10 within the vessel and facilitate uniform stent deployment . although shown and described are what are believed to be the preferred embodiments , it is apparent that departures from specific designs and methods described and shown will suggest themselves to those skilled in the art and may be used without departing from the spirit and scope of the invention . the present invention is not restricted to the particular constructions described and illustrated , but should be constructed to cover all modifications that may fall within the scope of the appended claims .
a catheter with at least one centering device attached near a distal end of the catheter . the centering device has at least two struts extending between a proximal end and a distal end . the centering device has a variable diameter and tends to center the distal end of the catheter , steering the catheter away from the vessel wall during insertion through the vasculature and toward the treatment site . the centering catheter may facilitate access to tortuous anatomy by preventing the catheter tip from catching on irregularities in the lumenal surface . the centering catheter may also facilitate uniform stent expansion by stabilizing the catheter during stent deployment .