Flow Graft
OwnerSeshadri Rajuinventor
Life of this patent
Estimating the term…
Abstract
The invention includes an improved flow graft. The graft has a portion where the radius r expands with length L over the portion, so that rn/L is a constant in that portion, where n≥4.0, or 1<n<4. the graft may have a beginning section that has constant diameter. The invention also includes a method of designing such an expanding graft to suit the application, such as in the venous system, the arterial system, or for dialysis. The invention also includes near constant conductance stents stacks where each stent in the stack has a radius r that grows with length, so that Rn/L is constant where n≥4.
Claims29
A improved flow graft of length L comprising a structure of non-elastic material having a tubular shape when expanded, where the expanded shape includes a radius r at each length l of the graft, such that when expanded, the graft has a portion where the radius r at each point of the length in the portion, is such that rn/l is a constant at each point in the portion, where n=4, or where the growth of the radius r at each point of the length in the portion is monotonic with the length in the portion, but where the growth of r with length is less rapid then that of r4/l=constant.
An improved flow graft comprising a series of tubular segments Si, each segment Si having a radius r at each length L for each segment, each segment having a starting radius and an ending radius such that each starting radius and ending radius is such at rn/L is constant at the starting and ending radius, where n>4.0 or 1<n<4 and where the radius between the starting and ending radius grows monotonically with length in the segment and length L is measured from a beginning of the improved flow graft.
A method of designing a graft, where the graft has a radius r at each length L of the graft, comprising the steps of choosing a starting radius rs of the graft and a desired ending radius re of the graft, where re>rs, selecting a length L of the graft, set the radius of the graft constant for a first portion of the graft, and selecting an N such that N≥4.0 so that rN/L is a constant from the end of the first portion, to the end of the graft, and where the ending radius of the graft is a value closest to re.
An expanding sleeve system comprising a tubular shaped non-elastic sleeve, the sleeve having a radius r at each point of a length l of the sleeve, and the shape further comprising a portion where rn/l is a constant in that portion, where n>4.0.
A stent balloon comprising a balloon having a shape when expanded, the shape having a radius r at each point 1 of a length of the expanded balloon, such that when expanded, the balloon has a portion where the radius r at each point 1 of the length in the portion, is such that rn/l is a constant at leach point in the portion, where n≥4.0.
An expandable sleeve system comprising a tubular shaped non-elastic sleeve, the sleeve having a radius r at each point of a length l of the sleeve, and the shape further comprising a portion where r. n/l is a constant is that portion, where n≥4.0.
An expandable stent system comprising a series of expandable stent segments Si, each segment Si having a radius at each point of a length of the segment Si when expanded, where L is measured from a beginning of the expandable stent system, each segment having a starting radius and an ending radius such that rn/l is constant, n>4, and where the stent segments radius between the starting and ending segment radius grows with length of the expandable stent, where the growth is not R4.
A method of stenting an occlusion in a vein comprising the step of positioning a unitary balloon adjacent the occlusion, where the unitary balloon comprises a tubular shape when expanded having a radius at each point of a length of the unitary balloon, the shape comprising a portion wherein rn/l is constant, where n≥4, the portion is positioned adjacent the occlusion so that the largest radius of the portion, when expanded, is positioned downstream in the vein, and then the step of expanding the unitary balloon;
- and then the step of collapsing the unitary balloon followed by the step of withdrawing the collapsed unitary balloon, followed by the step of positioning an expandable stent in the vein, the stent, when expanded having a tubular shape having a radius at each point of a length of the stent, the shape further comprising a unitary like portion wherein rn/l is constant, where the stent is positioned so that the unitary like porting is positioned adjacent the occlusion, and then the step of expanding the stent.
An expanding stent stack comprising at a series of expandable stents, configured to overlap to form a long stent stack formed of overlapping adjacent stents, each stent in the stack when expanded forming a tubular shape having a radius at each point 1 of a length of each respective stent, the radius of each adjacent stent in the overlapped region matching when expanded, the stent stack configured to have a portion where the radius in that portion grows with length, measured from a start of the stent stack, where fluid in that portion, when flowing, is constant conductance flow or near constant conductance flow.
An improved flow graft comprising a series of tubular segments Si, each segment Si having a radius r at each length L for each segment, each segment having a starting radius and an ending radius such that each starting radius and ending radius is such at rn/L is constant at the starting and ending radius, where n≥4.0 or 1<n<4 and where the radius between the starting and ending radius grows monotonically with length in the segment.
Dependencies are inferred from the claim text.