Hemodialysis access method for a patient
View Patent ↗An elastic dialysis stent comprises a central restrictor segment located between two tapered segments. The tapered segments are tapered from a larger diameter suitable for joining to tubular graft segments or attaching the stent in a graft or fistula, to the narrower diameter of the elastic central restrictor segment which provides a stenosis. The central restrictor is made of an elastic material which enables the stent to be radially expanded by a balloon catheter to a larger diameter for passage of endovascular devices through the stent for repair of blockages on the venous side of the stent. When the balloon catheter is deflated and removed, the elastic properties of the stent cause it to retract to its original stenotic configuration.
1 . A hemodialysis access method for a patient, comprising:
deploying a dialysis stent within an arterial venous (AV) fistula or graft, the dialysis stent having an expandable restriction and comprising a shunt tube and at least one elastic restrictor, the shunt tube having an inlet end, an outlet end, and a central opening extending from the inlet end to the outlet end such that the central opening has a first diameter, the at least one elastic restrictor extending around a portion of the shunt tube located between the inlet end and the outlet end, the at least one elastic restrictor narrowing the central opening in order to create a stenosis in the shunt tube that acts as a flow restrictor for allowing the shunt tube to elastically shunt blood flow from an extremity of the patient, and in order to create a reduced diameter section of a second diameter in the shunt tube that is elastically adjustable from the second diameter, which is less than the first diameter, to a third diameter that is greater than the second diameter such that the stenosis expands when the shunt tube moves from having the second diameter to having the third diameter; and
elastically adjusting the at least one elastic restrictor from the second diameter to the third diameter responsive to a balloon inflating to expand the at least one elastic restrictor, and from the third diameter back to the second diameter responsive to the balloon subsequently deflating.
2 . The method according to claim 1 , further comprising elastically reforming the at least one elastic restrictor from an expanded state to an original state when adjusting from the third diameter back to the second diameter.
3 . The method according to claim 2 , further comprising exerting radial pressure on the shunt tube by the at least one elastic restrictor both when the shunt tube has the second diameter and when the shunt tube has the third diameter.
4 . The method according to claim 3 , further comprising providing an elastic material of the at least one elastic restrictor as being different than a material of the shunt tube in order to create a radially inward pressure on the shunt tube and to allow the shunt tube to have smooth inner and outer surfaces proximate the at least one elastic restrictor.
5 . The method according to claim 3 , further comprising providing the at least one elastic restrictor as having a first thickness greater than a second thickness of the shunt tube in order to create a radially inward pressure on the shunt tube and to allow the shunt tube to have smooth inner and outer surfaces proximate the at least one elastic restrictor.
6 . The method according to claim 3 , wherein the at least one elastic restrictor comprises an elastic band.
7 . The method according to claim 3 , wherein the at least one elastic restrictor comprises an elastic covering material.
8 . The method according to claim 3 , being performed without folding of the at least one elastic restrictor.
9 . The method according to claim 3 , wherein the third diameter is the same as the first diameter.
10 . The method according to claim 3 , wherein the at least one elastic restrictor is expandable from the third diameter to a fourth diameter, and wherein the fourth diameter is greater than the third diameter.
11 . The method according to claim 3 , wherein elastically adjusting is performed without an additional medical procedure in a manner wherein the at least one elastic restrictor is a sole force for radially contracting the shunt tube back to the second diameter.
12 . The method according to claim 3 , further comprising providing each of the shunt tube and the at least one elastic restrictor with a middle disposed midway between the inlet and outlet ends of the shunt tube.
13 . The method according to claim 3 , further comprising connecting an artery of the patient to a vein of the patient with the AV fistula or graft before deploying the dialysis stent within the AV fistula or graft, wherein elastically adjusting further comprises radially expanding the shunt tube outwardly when the shunt tube adjusts from the second diameter to the third diameter.
14 . The method according to claim 1 , further comprising:
providing the shunt tube with an elastic central restrictor segment, and a first tapered segment and a second tapered segment each having a central lumen and extending from a corresponding end of the elastic central restrictor segment;
providing each of the first and second tapered segments with a corresponding end spaced from the elastic central restrictor segment, the corresponding end having a corresponding diameter configured to be greater than the first diameter and the second diameter; and
moving the first and second tapered segments radially in concert with movement of the corresponding end of the elastic central restrictor segment to which they are attached.
15 . The method according to claim 14 , further comprising:
elastically expanding the elastic central restrictor segment radially when radially expansive pressure is applied within the elastic central restrictor segment; and
elastically contracting the elastic central restrictor segment to the second diameter when the radially expansive pressure is removed.
16 . The method according to claim 14 , further comprising providing the first and second tapered segments as being made of a first material and the elastic central restrictor segment as being made of a second material different than the first material.
17 . The method according to claim 16 , further comprising providing the first material as being a metallic material.
18 . The method according to claim 14 , further comprising providing an outer covering for covering at least an exterior surface of each of the central elastic segment and each of the first and second tapered segments.
19 . The method according to claim 14 , further comprising concentrically surrounding the outer covering at the elastic central restrictor segment with an elastic sleeve for maintaining a stenotic configuration of the dialysis stent.
20 . The method according to claim 14 , further comprising receiving within the elastic central restrictor segment an endovascular medical device in order to allow stent repair to be performed in the AV fistula or graft.
21 . The method according to claim 14 , further comprising integrating at least a first structure and a second structure with a corresponding one of the first and second tapered segments, wherein the first and second structures are each made of a material different than a material of the first and second tapered segments.
22 . The method according to claim 14 , further comprising expanding each of the first and second tapered segments when the dialysis stent is deployed within the AV fistula or graft in order to retain the dialysis stent in a predetermined location therein.
23 . The method according to claim 1 , further comprising providing the at least one elastic restrictor with a structural framework and a covering material lining the structural framework, wherein the covering material is configured to move with the structural framework when the at least one elastic restrictor is elastically adjusted in order to elastically shunt the blood flow from the extremity of the patient.
24 . The method according to claim 23 , further comprising providing the covering material as being lined on an inside of the structural framework.
25 . The method according to claim 24 , further comprising providing another covering material lining an outside of the structural framework, wherein the another covering material is configured to move with the structural framework when the at least one elastic restrictor is elastically adjusted in order to elastically shunt the blood flow from the extremity of the patient.