Patent Application
20200107925
The present invention relates generally to implantable medical devices, and specifically to implantable stent-grafts.
Endovascular prostheses are sometimes used to treat aortic aneurysms. Such treatment includes implanting a stent or stent-graft within the diseased vessel to bypass the anomaly. An aneurysm is a sac formed by the dilation of the wall of the artery. Aneurysms may be congenital, but are usually caused by disease or, occasionally, by trauma. Aortic aneurysms which commonly form between the renal arteries and the iliac arteries are referred to as abdominal aortic aneurysms (“AAAs”). Other aneurysms occur in the aorta, such as thoracic aortic aneurysms (“TAAs”) and aortic uni-iliac (“AUI”) aneurysms. A TAA may occur downstream the aortic arch, i.e., in the descending aorta. Alternatively, a TAA may occur in the aortic arch itself, where the aorta branches to supply the brachiocephalic, left carotid and subclavian arteries, or may occur in the ascending aorta.
Endo-Vascular Aneurysm Repair (EVAR) has transformed the practice of treatment of aortic aneurysms from an open surgical approach to a much less invasive surgical approach. The first step of an endovascular intervention usually requires introducing a delivery system into the vasculature of a subject. If the crossing profile, i.e., the external diameter, of the delivery system is 24 Fr or lower (3 Fr=1 millimeter), a true percutaneous approach may be used, because vascular closure devices are available for proper closure of such puncture sites.
Blood vessels occasionally weaken or even rupture. For example, in the aortic artery, the vascular wall can weaken or tear, resulting in dangerous conditions such as aneurysm and dissection. Treatment of such conditions can be performed by implanting a stent-graft within the vascular system using minimally-invasive surgical procedures. An endoluminal stent-graft typically includes one or more stents affixed to graft material and is delivered to the treatment site by endovascular insertion. Once the endoluminal stent-graft is radially enlarged, it should remain in place indefinitely by self-attachment to the vessel wall, acting as a substitute vessel for the flow of blood or other fluids.
Aortic dissection is a tear or partial tear in the inner wall of the aorta, which causes blood to flow between the layers of the wall of the aorta, forcing the layers apart. Aortic dissections may be divided into two types in accordance with the Stanford classification. Type A dissections involve the ascending aorta and/or aortic arch, and possibly the descending aorta. Type B dissections involve the descending aorta or the arch (distal to right brachiocephalic artery origin), without involvement of the ascending aorta.
Embodiments of the present invention provide an endovascular stent-graft, which comprises struts and a fluid flow guide, which is fixed to first and second subsets of the struts. The struts of the first and the second subsets are elastic such that, when the stent-graft assumes the radially-expanded state:
For some applications, the bulge is configured to reduce the likelihood of long-term leakage (i.e., blood flow) through gutters, i.e., the residual intravascular space disposed outside the lumens of the endovascular stent-graft and branching stent-grafts disposed alongside the endovascular stent-graft. Alternatively or additionally, the bulge may reduce the likelihood of blood flow between the endovascular stent-graft and features of the anatomy of the blood vessel wall, such as isolated regions of plaque, calcifications, or thrombus, all of which alter the circularity of the blood vessel wall and might otherwise present issues for good sealing between the stent-graft and the blood vessel wall. As a result, the likelihood of type 1 endoleak is reduced.
For some applications, the struts of the second subset have an average wall thickness, measured radially, that is no more than 80% (e.g., no more than 60%) of an average wall thickness of the struts of the first subset, measured radially. Such a lower wall thickness may contribute to a lower spring constant of the struts of the second subset than the struts of the first subset, which may facilitate more local deformation (indentation) of the bulge around a branching stent-graft, without unnecessarily crushing the branching stent-graft, or necessitating internally reinforcement of the branching stent-graft with additional metallic stents.
For some applications, the struts of the first subset are arranged as a plurality of circumferential cells in circumferentially-continuous rings, which cause the fluid flow guide to define the plurality of substantially cylindrical tubular portions. For some applications, the struts of the second subset define tip portions. For some of these applications, the number of tip portions of the struts of the second subset that define the bulge is at least 30% (typically at least 50%) greater than the average number of the circumferential cells in the two the circumferentially-continuous rings proximally and distally adjacent the bulge, such as least 175% greater, no more than 250% greater, and/or between 175% and 250% (e.g., 200%) of the average number of the circumferential cells. Providing such a relatively large number of tip portions may facilitate more local deformation (indentation) of the bulge around a branching stent-graft, without unnecessarily crushing the branching stent-graft, or necessitating internally reinforcement of the branching stent-graft with additional metallic stents.
There is therefore provided, in accordance with an Inventive concept 1 of the present invention, apparatus for use with a delivery catheter, the apparatus including an endovascular stent-graft, which is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, and which includes:
struts; and
a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to first and second subsets of the struts, wherein the first and the second subsets do not include any common struts,
wherein the struts of the first and the second subsets are elastic such that, when the stent-graft assumes the radially-expanded state:
wherein the bulge is a first bulge,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state:
wherein all of the struts of the second subset are structurally integral with at least one of the struts of the first subset,
wherein none of the struts of the second subset is directly connected to any of the other struts of the second subset, and
wherein none of the struts of the second subset is indirectly connected to any of the other struts of the second subset by any struts other than the struts of the first subset.
Inventive concept 20. The apparatus according to Inventive concept 18, wherein, for at least a first one of the tip portions of first one of the struts of the second subset, an angle is defined by (a) the central longitudinal axis and (b) a line defined by (i) the first one of the tip portions and (ii) a junction between the first one of the struts of the second subset and the second one of the struts of the first subset, and the angle is between 5 and 60 degrees.
Inventive concept 21. The apparatus according to Inventive concept 20, wherein the angle is between 10 and 30 degrees.
Inventive concept 22. The apparatus according to any one of Inventive concepts 1-16,
wherein the stent-graft further includes sutures that secure the struts of the first and the second subsets to the fluid flow guide, and
wherein, for at least a first one of the tip portions of the first one of the struts of the second subset
wherein the first plurality of the struts of the second subset originate at proximal-most sites of the one of the undulating circumferentially-continuous rings, and
wherein the second plurality of the struts of the second subset originate at distal-most sites of the one of the undulating circumferentially-continuous rings.
Inventive concept 28. The apparatus according to Inventive concept 23, wherein a first plurality of the struts of the second subset originate at two or more axially different locations of one of the undulating circumferentially-continuous rings.
Inventive concept 29. The apparatus according to any one of Inventive concepts 1-16, wherein at least one of the struts of the second subset is not structurally integral with any of the struts of the first subset.
Inventive concept 30. The apparatus according to any one of Inventive concepts 1-16,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to define a flared axial portion that extends to one end of the fluid flow guide, the flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than a radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion.
Inventive concept 31. The apparatus according to Inventive concept 30,
wherein the flared axial portion is a first flared axial portion, and the one end of the fluid flow guide is a first end of the fluid flow guide, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to additionally define a second flared axial portion that extends to a second end of the fluid flow guide, the second flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than an average radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion.
Inventive concept 32. The apparatus according to any one of Inventive concepts 1-16,
wherein the stent-graft further includes sutures that secure the struts of the first and the second subsets to the fluid flow guide, and
wherein at least 80% of a surface area of the struts of the first subset is within 3 mm of at least one of the sutures that secure the struts of the first subset to the fluid flow guide.
Inventive concept 33. The apparatus according to Inventive concept 32, wherein no more than 50% of the surface area of the struts of the second subset is within 3 mm of at least one of the sutures that secure the struts of the second subset to the fluid flow guide.
Inventive concept 34. The apparatus according to any one of Inventive concepts 1-16, wherein respective circumferences of all substantially cylindrical tubular portions of the fluid flow guide vary by less than 10%.
Inventive concept 35. The apparatus according to any one of Inventive concepts 1-16, wherein a circumference of a first one of the substantially cylindrical tubular portions is at least 10% greater than a circumference of a second one of the substantially cylindrical tubular portions.
Inventive concept 36. The apparatus according to any one of Inventive concepts 1-16, wherein when the endovascular stent-graft is removably disposed in the delivery catheter in the radially-compressed state, the struts of the first subset do not coincide with the struts of the second subset.
Inventive concept 37. The apparatus according to any one of Inventive concepts 1-16,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define any fenestrations or scallops, and
wherein the apparatus further includes one or more branching stent-grafts.
Inventive concept 38. The apparatus according to any one of Inventive concepts 1-16,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define one or more openings selected from the group of openings consisting of: fenestrations, scallops, and fenestrations and scallops, and
wherein the apparatus further includes a number of branching stent-grafts, the number greater than a number of the openings.
There is further provided, in accordance with an Inventive concept 39 of the present invention, apparatus for use with a delivery catheter, the apparatus including an endovascular stent-graft, which is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, and which includes:
struts; and
a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to first and second subsets of the struts, wherein the first and the second subsets do not include any common struts,
wherein the struts of the first and the second subsets are elastic such that, when the stent-graft assumes the radially-expanded state:
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define one or more openings selected from the group of openings consisting of: fenestrations, scallops, and
fenestrations and scallops, and
wherein the apparatus further includes a number of branching stent-grafts, the number greater than a number of the openings.
Inventive concept 55. The apparatus according to any one of Inventive concepts 39-52, wherein the struts of the second subset have an average wall thickness, measured radially, that is no more than 80% of an average wall thickness of the struts of the first subset, measured radially.
Inventive concept 56. The apparatus according to Inventive concept 55, wherein the average wall thickness of the struts of the second subset, measured radially, is no more than 60% of the average wall thickness of the struts of the first subset, measured radially.
Inventive concept 57. The apparatus according to any one of Inventive concepts 39-52,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to define a flared axial portion that extends to one end of the fluid flow guide, the flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than a radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion.
Inventive concept 58. The apparatus according to Inventive concept 57,
wherein the flared axial portion is a first flared axial portion, and the one end of the fluid flow guide is a first end of the fluid flow guide, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to additionally define a second flared axial portion that extends to a second end of the fluid flow guide, the second flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than an average radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion.
There is still further provided, in accordance with an Inventive concept 59 of the present invention, apparatus for use with a delivery catheter, the apparatus including an endovascular stent-graft, which is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, and which includes:
struts; and
a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to first and second subsets of the struts, wherein the first and the second subsets do not include any common struts, and wherein the struts of the second subset have an average wall thickness, measured radially, that is no more than 80% of an average wall thickness of the struts of the first subset, measured radially,
wherein the struts of the first and the second subsets are elastic such that, when the stent-graft assumes the radially-expanded state:
wherein the struts of the first subset have a first average cross-sectional area, measured perpendicular to respective axes of the struts of the first subset,
wherein the struts of the second subset have a second average cross-sectional area, measured perpendicular to respective axes of the struts of the second subset, and
wherein the second average cross-sectional area is no more than 80% of the first cross-sectional area.
Inventive concept 62. The apparatus according to Inventive concept 59, the fluid flow guide is arranged such that all of the fabric defines the lumen when the stent-graft assumes the radially-expanded state.
Inventive concept 63. The apparatus according to Inventive concept 59,
wherein the bulge is a first bulge,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and wherein the struts of the third subset have an average wall thickness, measured radially, that is no more than 80% of the average wall thickness of the struts of the first subset, measured radially, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to define a second bulge having a greatest bulge radius from the central longitudinal axis, which greatest bulge radius is at least 5% greater than an average radius of the substantially cylindrical tubular portions proximally and distally adjacent the second bulge.
Inventive concept 64. The apparatus according to Inventive concept 59, wherein the struts of the first and the second subsets are arranged and shaped such that the struts of the first subset apply a radially-outward force that is at least 20% greater than a radially-outward applied by the struts of the second subset.
Inventive concept 65. The apparatus according to Inventive concept 64, wherein the struts of the first and the second subsets are arranged and shaped such that the struts of the first subset apply the radially-outward force that is at least 40% greater than the radially-outward applied by the struts of the second subset.
Inventive concept 66. The apparatus according to Inventive concept 59, wherein the struts of the first and the second subsets are superelastic.
Inventive concept 67. The apparatus according to Inventive concept 59, wherein the bulge completely circumferentially encircles the stent-graft.
Inventive concept 68. The apparatus according to any one of Inventive concepts 59-67, wherein at least a first one of the struts of the second subset is structurally integral with at least a second one of the struts of the first subset.
Inventive concept 69. The apparatus according to Inventive concept 68,
wherein all of the struts of the second subset are structurally integral with at least one of the struts of the first subset,
wherein none of the struts of the second subset is directly connected to any of the other struts of the second subset, and
wherein none of the struts of the second subset is indirectly connected to any of the other struts of the second subset by any struts other than the struts of the first subset.
Inventive concept 70. The apparatus according to Inventive concept 68,
wherein the first one of the struts of the second subset defines a first tip portion, and
wherein an angle is defined by (a) the central longitudinal axis and (b) a line defined by (i) the first tip portion and (ii) a junction between the first one of the struts of the second subset and the second one of the struts of the first subset, and the angle is between 5 and 60 degrees.
Inventive concept 71. The apparatus according to Inventive concept 70, wherein the angle is between 10 and 30 degrees.
Inventive concept 72. The apparatus according to Inventive concept 68,
wherein the first one of the struts of the second subset defines a first tip portion,
wherein the first one of the struts of the second subset has a length measured along the first one of the struts of the second subset between (a) the first tip portion and (b) a junction between the first one of the struts of the second subset and the second one of the struts of the first subset,
wherein a far half of the first one of the struts of the second subset extends from the first tip portion along 50% of the length of the first one of the struts of the second subset,
wherein the stent-graft further includes sutures that secure the struts of the first and the second subsets to the fluid flow guide, and
wherein none of the sutures are disposed along at least 50% of the far half of the first one of the struts of the second subset.
Inventive concept 73. The apparatus according to any one of Inventive concepts 59-67,
wherein the struts of the first subset are arranged in a plurality of undulating circumferentially-continuous rings having alternating peaks and troughs, and
wherein a first plurality of the struts of the second subset originate in a proximal half of one of the undulating circumferentially-continuous rings, and a second plurality of the struts of the second subset originate in a distal half of the one of the undulating circumferentially-continuous rings.
Inventive concept 74. The apparatus according to Inventive concept 73, wherein the first plurality of the struts of the second subset originate in a proximal 20% of an axial height of the one of the undulating circumferentially-continuous rings.
Inventive concept 75. The apparatus according to Inventive concept 74, wherein the first plurality of the struts of the second subset originate at proximal-most sites of the one of the undulating circumferentially-continuous rings.
Inventive concept 76. The apparatus according to Inventive concept 74, wherein the second plurality of the struts of the second subset originate in a distal 20% of the axial height of the one of the undulating circumferentially-continuous rings.
Inventive concept 77. The apparatus according to Inventive concept 76,
wherein the first plurality of the struts of the second subset originate at proximal-most sites of the one of the undulating circumferentially-continuous rings, and
wherein the second plurality of the struts of the second subset originate at distal-most sites of the one of the undulating circumferentially-continuous rings.
Inventive concept 78. The apparatus according to Inventive concept 73, wherein a first plurality of the struts of the second subset originate at two or more axially different locations of one of the undulating circumferentially-continuous rings.
Inventive concept 79. The apparatus according to any one of Inventive concepts 59-67, wherein at least one of the struts of the second subset is not structurally integral with any of the struts of the first subset.
Inventive concept 80. The apparatus according to any one of Inventive concepts 59-67,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to define a flared axial portion that extends to one end of the fluid flow guide, the flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than an average radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the flared axial portion.
Inventive concept 81. The apparatus according to Inventive concept 80,
wherein the flared axial portion is a first flared axial portion, and the one end of the fluid flow guide is a first end of the fluid flow guide, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to additionally define a second flared axial portion that extends to a second end of the fluid flow guide, the second flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than an average radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion.
Inventive concept 82. The apparatus according to any one of Inventive concepts 59-67,
wherein the stent-graft further includes sutures that secure the struts of the first and the second subsets to the fluid flow guide, and
wherein at least 80% of a surface area of the struts of the first subset is within 3 mm of at least one of the sutures that secure the struts of the first subset to the fluid flow guide.
Inventive concept 83. The apparatus according to Inventive concept 82, wherein no more than 50% of the surface area of the struts of the second subset is within 3 mm of at least one of the sutures that secure the struts of the second subset to the fluid flow guide.
Inventive concept 84. The apparatus according to any one of Inventive concepts 59-67, wherein respective circumferences of all substantially cylindrical tubular portions of the fluid flow guide vary by less than 10%.
Inventive concept 85. The apparatus according to any one of Inventive concepts 59-67, wherein a circumference of a first one of the substantially cylindrical tubular portions is at least 10% greater than a circumference of a second one of the substantially cylindrical tubular portions.
Inventive concept 86. The apparatus according to any one of Inventive concepts 59-67, wherein an axial length of the bulge equals between 10% and 40% of a difference between (a) the greatest bulge radius and (b) the average radius of the substantially cylindrical tubular portions proximally and distally adjacent the bulge.
Inventive concept 87. The apparatus according to any one of Inventive concepts 59-67, wherein when the endovascular stent-graft is removably disposed in the delivery catheter in the radially-compressed state, the struts of the first subset do not coincide with the struts of the second subset.
Inventive concept 88. The apparatus according to any one of Inventive concepts 59-67,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define any fenestrations or scallops, and
wherein the apparatus further includes one or more branching stent-grafts.
Inventive concept 89. The apparatus according to any one of Inventive concepts 59-67,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define one or more openings selected from the group of openings consisting of: fenestrations, scallops, and fenestrations and scallops, and
wherein the apparatus further includes a number of branching stent-grafts, the number greater than a number of the openings.
There is additionally provided, in accordance with an Inventive concept 90 of the present invention, apparatus for use with a delivery catheter, the apparatus including an endovascular stent-graft, which is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, and which includes:
struts; and
a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to first, second, and third subsets of the struts, wherein the first, the second, and the third subsets do not include any common struts,
wherein the struts of the first, the second, and the third subsets are elastic such that, when the stent-graft assumes the radially-expanded state:
wherein the flared axial portion is a first flared axial portion, and the one end of the fluid flow guide is a first end of the fluid flow guide, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to additionally define a second flared axial portion that extends to a second end of the fluid flow guide, the second flared axial portion having (a) a greatest flared radius from the central longitudinal axis, which greatest flared radius is at least 5% greater than a radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion, and (b) an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion axially adjacent the second flared axial portion.
Inventive concept 92. The apparatus according to Inventive concept 90,
wherein the bulge is a first bulge,
wherein the fluid flow guide is fixed to the first subset of the struts, the second subset of the struts, and a third subset of the struts so as to define the lumen, wherein the first, the second, and the third subsets do not include any common struts, and
wherein the struts of the third subset are elastic such that, when the stent-graft assumes the radially-expanded state, the struts of the third subset cause the fluid flow guide to define a second bulge having a greatest bulge radius from the central longitudinal axis, which greatest bulge radius is at least 5% greater than an average radius of the substantially cylindrical tubular portions proximally and distally adjacent the second bulge.
Inventive concept 93. The apparatus according to Inventive concept 90, wherein an axial length of the bulge equals between 10% and 40% of a difference between (a) the greatest bulge radius and (b) the average radius of the substantially cylindrical tubular portions proximally and distally adjacent the bulge.
Inventive concept 94. The apparatus according to Inventive concept 90, wherein a circumference of a first one of the substantially cylindrical tubular portions is at least 10% greater than a circumference of a second one of the substantially cylindrical tubular portions.
Inventive concept 95. The apparatus according to Inventive concept 90, wherein the bulge completely circumferentially encircles the stent-graft.
Inventive concept 96. The apparatus according to Inventive concept 90, wherein the struts of the first and the second subsets are superelastic.
Inventive concept 97. The apparatus according to any one of Inventive concepts 90-96,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define any fenestrations or scallops, and
wherein the apparatus further includes one or more branching stent-grafts.
Inventive concept 98. The apparatus according to any one of Inventive concepts 90-96,
wherein the stent-graft is a main stent-graft,
wherein the fluid flow guide is not shaped so as to define one or more openings selected from the group of openings consisting of: fenestrations, scallops, and fenestrations and scallops, and
wherein the apparatus further includes a number of branching stent-grafts, the number greater than a number of the openings.
There is yet additionally provided, in accordance with an Inventive concept 99 of the present invention, a method including:
advancing, into a main artery of a subject, an endovascular stent-graft, which is removably disposed in a delivery catheter in a radially-compressed delivery state, and includes (a) a main stent-graft, which includes (i) elastic struts and (ii) a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to first and second subsets of the struts, wherein the first and the second subsets do not include any common struts;
deploying the endovascular stent-graft from the delivery catheter such that the endovascular stent-graft assumes a radially-expanded state in which (a) the fluid flow guide defines a lumen having a central longitudinal axis, (b) the struts of the first subset are arranged as a plurality of circumferential cells in circumferentially-continuous rings, which cause the fluid flow guide to define a plurality of substantially cylindrical tubular portions, (c) the struts of the second subset cause the fluid flow guide to define a bulge having a greatest bulge radius from the central longitudinal axis, which greatest bulge radius is at least 5% greater than an average radius of the substantially cylindrical tubular portions proximally and distally adjacent the bulge, (d) the struts of the second subset define tip portions, and (e) the number of the tip portions of the struts of the second subset that define the bulge is at least 50% greater than the average number of circumferential cells in the two circumferentially-continuous rings proximally and distally adjacent the bulge; and
deploying one or more branching stent-grafts partially alongside the main stent-graft and partially in respective branching arteries that branch from the main artery, such that portions of the branching stent-grafts contact the bulge.
There is also provided, in accordance with an Inventive concept 100 of the present invention, apparatus for use with a delivery catheter, the apparatus including an endovascular stent-graft, which is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, and which includes:
struts;
a fluid flow guide, which includes at least one biologically-compatible substantially blood-impervious fabric, and which is fixed to the struts; and
one or more bulges, which bulge radially outward and are arranged as one or more respective circumferential helices, wherein each of the circumferential helices circumscribes at least 0.3 complete turns around the endovascular stent-graft.
Inventive concept 101. The apparatus according to Inventive concept 100, wherein each of the one or more circumferential helices circumscribes at least 0.5 complete turns around the endovascular stent-graft.
Inventive concept 102. The apparatus according to Inventive concept 101, wherein each of the one or more circumferential helices circumscribes at least 1.5 complete turns around the endovascular stent-graft.
Inventive concept 103. The apparatus according to Inventive concept 100, wherein the one or more bulges is exactly one bulge.
Inventive concept 104. The apparatus according to Inventive concept 100, wherein the one or more bulges is a plurality of bulges, arranged as a plurality of helices.
Inventive concept 105. The apparatus according to Inventive concept 104, wherein the plurality of helices are arranged as an n-tuple helix.
Inventive concept 106. The apparatus according to any one of Inventive concepts 100-105, wherein each of the one or more bulges has a greatest bulge radius from a central longitudinal axis of the fluid flow guide, which greatest bulge radius is at least 5% greater than an average radius of substantially cylindrical tubular portions of the endovascular stent-graft.
Inventive concept 107. The apparatus according to any one of Inventive concepts 100-105, wherein the struts are shaped so as to define a lumen of the fluid flow guide, and wherein the one or more bulges are defined by the fabric of the fluid flow guide and the struts that are shaped so as to define the lumen of the fluid flow guide.
Inventive concept 108. The apparatus according to any one of Inventive concepts 100-105, wherein each of the one or more bulges includes at least one biologically-compatible substantially blood-impervious fabric, distinct from the fabric of the fluid flow guide.
Inventive concept 109. The apparatus according to Inventive concept 108, wherein each of the one or more bulges further includes one or more springs that provide structure to the one or more bulges.
Inventive concept 110. The apparatus according to Inventive concept 109, wherein the one or more springs include helical springs, and the fabric of the one or more bulges surrounds a portion of the springs, such that the springs are disposed between the fabric of the one or more bugles and the fluid flow guide.
The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:
Endovascular stent-graft 10 is configured to initially be positioned in the delivery catheter in a radially-compressed state, and to assume a radially-expanded state upon being deployed from the delivery catheter, such as shown in
Endovascular stent-graft 10 comprises:
Struts 20 of first and second subsets 32 and 34 are elastic such that, when stent-graft 10 assumes the radially-expanded state, such as shown in
For some applications, bulge 42 is configured to reduce the likelihood of long-term leakage (i.e., blood flow) through gutters, i.e., the residual intravascular space disposed outside the lumens of endovascular stent-graft 10 and branching stent-grafts disposed alongside endovascular stent-graft 10. Alternatively or additionally, bulge 42 may reduce the likelihood of blood flow between endovascular stent-graft 10 and features of the anatomy of the blood vessel wall, such as isolated regions of plaque, calcifications, or thrombus, all of which alter the circularity of the blood vessel wall and might otherwise present issues for good sealing between the stent-graft and the blood vessel wall. As a result, the likelihood of type 1 endoleak is reduced.
For some applications, an axial length LB (labeled in
As used in the present application, including in the claims, the “central longitudinal axis” 38 of lumen 36 is the set of all centroids of transverse cross-sectional sections of lumen 36 along lumen 36. Thus the cross-sectional sections are locally perpendicular to central longitudinal axis 38, which runs along lumen 36. (For configurations in which lumen 36 is circular in cross-section, the centroids correspond with the centers of the circular cross-sectional sections.)
Typically, struts 20 comprise a metal, such as a flexible metal, an elastic metal, stainless steel (e.g., elastic stainless steel), cobalt-chromium, or a superelastic alloy (such as Nitinol). Fluid flow guide 30 comprises at least one biologically-compatible substantially blood-impervious fabric (e.g., one or more thin flexible sheets), which are typically arranged as a tubular structure (with a diameter that varies therealong), when stent-graft 10 is unconstrained in the radially-expanded state. The fabric may comprise, for example, a polymeric material (e.g., a polyester, or polytetrafluoroethylene (PT F E)), a textile material (e.g., polyethylene terephthalate (PET), e.g., Dacron÷, manufactured by E. I. du Pont de Nemours and Company, Wilmington, Del., USA), or expanded polytetrafluoroethylene (ePTFE), e.g., manufactured by W. L. Gore & Associates, Newark, Del., USA), natural tissue (e.g., saphenous vein or collagen), or a combination thereof.
Typically, fluid flow guide 30 is arranged such that all of the fabric defines lumen 36 when stent-graft 10 assumes the radially-expanded state (such that, for example, stent-graft 10 does not comprise any skirts that extend radially outward from fluid flow guide 30).
For some applications, struts 20 of first and second subsets 32 and 34 are arranged and shaped such that struts 20 of first subset 32 apply a radially-outward force that is at least 20% (e.g., at least 40%) greater than a radially-outward applied by struts 20 of second subset 34.
For some applications, as shown in
For some applications, bulge 42 completely circumferentially encircles stent-graft 10. For other applications, bulge 42 only partially circumferentially encircles stent-graft 10. For some applications in which fluid flow guide 30 defines a plurality of bulges, along an entire axial length of fluid flow guide 30, each circumferential angle is at least circumscribed by one bulge 42. For some applications in which fluid flow guide 30 defines a plurality of bulges, along an entire axial length of fluid flow guide 30, each circumferential angle is at least circumscribed by two bulges 42.
For some applications, at least a first one of struts 20 of second subset 34 defines a first tip portion 50. For some applications, an angle is defined by (a) central longitudinal axis 38 and (b) a line defined by (i) the first tip portion 50 and (ii) a junction between the first one of struts 20 of second subset 34 and at least a second one of struts 20 of first subset 32. The angle is between 5 and 60 degrees, such as between 10 and 30 degrees. For some applications, the first tip portion 50 is disposed axially near (e.g., within 2 mm of) an axial location 52 along stent-graft 10 corresponding with the greatest bulge radius RB, while for other applications, the first tip portion 50 axially crosses bulge 42 and terminates more than 2 mm from axial location 52. As used in the present application, including in the claims, a “tip portion” is a free end of a strut 20 of second subset 34; the free end is disposed radially outward from the substantially cylindrical tubular portion 40 from which the tip portion extends, when stent-graft 10 assumes the radially-expanded state. By “free end” it is meant a free end from other portions of struts 20; the tip portion may be sutured to fluid flow guide 30, as described hereinbelow.
For some applications, the first one of struts 20 of second subset 34 has a length measured along the first one of struts 20 between (a) the first tip portion 50 and (b) a junction between the first one of struts 20 of second subset 34 and the second one of struts 20 of first subset 32. A far half of the first one of struts 20 extends from the first tip portion 50 along 50% of the length of the first one of struts 20 of second subset 34. Stent-graft 10 further comprises sutures that secure struts 20 of first subset 32 and second subset 34 to fluid flow guide 30. None of the sutures are disposed along at least 50% of the far half of the first one of struts 20 of second subset 34. This configuration provides a degree of freedom of motion for the struts of the second subset. This freedom allows the struts of the second subset to better accommodate the disturbance of a branching stent-graft, which may provide better sealing between the bulge and the branching stent-graft. In this configuration, atraumatic features 84, described hereinbelow, typically do not serve as suture rings.
For some applications, as labeled in
For some applications, a first plurality 62 of struts 20 of second subset 34 originate in (i.e., are joined to and extend from) a proximal half of one of undulating circumferentially-continuous rings 56, and a second plurality 64 of struts 20 of second subset 34 originate in a distal half of the one of the undulating circumferentially-continuous rings 56. Typically, struts 20 of the first plurality 62 and the second plurality 64 extend in the same axial direction (e.g., proximally, as shown in the set of struts 20 labeled in
Alternatively, for some applications, at least one of struts 20 of second subset 34 is not structurally integral with any of struts 20 of first subset 32 (configuration not shown).
For some applications, as labeled in
For some applications, flared axial portion 72 is a first flared axial portion 72A, and the one end 74 of fluid flow guide 30 is a first end 74A of fluid flow guide 30. Struts 20 of fourth subset 70 are elastic such that, when stent-graft 10 assumes the radially-expanded state, struts 20 of fourth subset 70 cause fluid flow guide 30 to additionally define a second flared axial portion 72B that extends to a second end 74B of fluid flow guide 30, second flared axial portion 72B having a greatest flared radius from central longitudinal axis 38, which greatest flared radius is at least 5% greater than a radius of the substantially cylindrical tubular portion 40 axially adjacent second flared axial portion 72B. Typically, second flared axial portion 72B has an axial length equal to between 5% and 20% of a difference between (i) the greatest flared radius and (ii) the radius of the substantially cylindrical tubular portion 40 axially adjacent second flared axial portion 72B.
Flared axial portions 72 may serve the same function as bulges 42. Providing flared axial portions 72 at the ends of stent-graft 10, rather than bulges 42 at the ends may serve to prevent blood from pooling and circulating in the bulges, which might cause thrombosis.
For some applications, stent-graft 10 further comprises sutures that secure struts 20 of first and second subsets 32 and 34 to fluid flow guide 30, and at least 80% of the surface area of struts 20 of first subset 32 is within 3 mm of at least one of the sutures that secure struts 20 of first subset 32 to fluid flow guide 30. For some applications, no more than 50% of the surface area of struts 20 of second subset 34 is within 3 mm of at least one of the sutures that secure struts 20 of second subset 34 to fluid flow guide 30.
For some applications, such as shown in
Typically, for applications in which stent-graft 10 defines second bulge 42B, such as described hereinabove, struts 20 of third subset 44 have an average wall thickness, measured radially, that is no more than 80% of the average wall thickness of struts 20 of first subset 32, measured radially.
Reference is still made to
For some applications, each of circumferentially-continuous rings 56 is shaped so as to define between 4 and 16 circumferential cells 80. For some applications, at least 75% of circumferential cells 80 of each circumferentially-continuous ring 56 are similarly shaped. For some applications, the dimensions of circumferential cells 80 of each circumferentially-continuous ring 56 differ between circumferentially adjacent cells 80.
For some applications, tip portions 50 are directly sutured to fluid flow guide 30. For some of these applications, tip portions 50 are shaped so as to define respective atraumatic features 84 (some of which are labeled in
For some applications, circumferential cells 80 are W-shaped, V-shaped, U-shaped, or M-shaped (configurations not shown) or diamond-shaped (having a constant or varying width (configuration not shown).
Reference is now made to
In the configurations shown in
Typically, respective distal ends of branching stent-grafts 280 are disposed at or near a distal end of endovascular stent-graft 10, such as within 2 cm of the distal end of endovascular stent-graft 10 (either proximal or distal the distal end). Respective proximal ends of branching stent-grafts 280 are disposed in left and right renal arteries 152A and 152B.
In the configuration shown in
In the configuration shown in
In the configuration shown in
In the configurations shown in all of
Reference is made to
Reference is made to
For some applications, when endovascular stent-graft 10 is removably disposed in the delivery catheter in the radially-compressed state, struts 20 of first subset 32 do not coincide with struts 20 of second subset 34. In other words, if struts 20 are cut at a circumferential site of one of struts 20 of first subset 32 and laid flat, as shown in
For some applications, struts 20 of first and second subsets 32 and 34 are fabricated from a single piece of a tubular material (e.g., by laser cutting the material). For some applications, at least one of struts 20 of second subset 34 is structurally integral with at least one of struts 20 of first subset 32, such as shown in the figures. For some applications, all of struts 20 of second subset 34 are structurally integral with at least one of struts 20 of first subset 32, none of struts 20 of second subset 34 is directly connected to any of the other struts of second subset 34, and none of struts 20 of second subset 34 is indirectly connected to any of the other struts of second subset 34 by any struts other than struts 20 of first subset 34. (Struts 20 of second subset 34 are typically indirectly connected by the fluid flow guide 30.) This arrangement of struts 20 allows each circumferential portion of bulge 42 to radially expand generally separately from one another, because circumferentially-adjacent end portions of struts 20 of second subset 34 do not pull on each other.
Reference is made to
In these configurations, struts 20 of second subset 34 are arranged as a plurality of bulge-inducing units 90 that cause fluid flow guide 30 to define bulge 42. Typically, an average circumferential width WB of bulge-inducing units 90 is no more than 25% (e.g., no more than 20%, no more than 15%, or no more than 10%) of an average circumferential width WC of circumferential cells 80 in the two circumferentially-continuous rings 56 proximally and distally adjacent bulge 42 (i.e., axially surrounding bulge 42) (only one of these two circumferentially-continuous rings 56 is shown in
For some applications, such as shown in
For some applications, the number of bulge-inducing units 90 is at least 30% (typically at least 50%) greater than the average number of circumferential cells 80 in the two circumferentially-continuous rings 56 proximally and distally adjacent bulge 42 (i.e., axially surrounding bulge 42), such as least 175% greater, no more than 250% greater, and/or between 175% and 250% (e.g., 200%) of the average number of circumferential cells 80.
For some applications, each of bulge-inducing units 90 circumscribes an arc having an angle of between 3 and 20 degrees, e.g., between 5 and 15 degrees.
As described hereinabove with reference to
Reference is again made to
Reference is made to
Reference is now made to
Typically, respective proximal ends of branching stent-grafts 280 are disposed at or near a proximal end of endovascular stent-graft 110, such as within 2 cm of the proximal end of endovascular stent-graft 110 (either proximal or distal the proximal end). Preferably, the respective proximal ends of branching stent-grafts 280 are disposed not proximally to the proximal end of endovascular stent-graft 110, because if they were disposed proximally to the proximal end of endovascular stent-graft 110, blood flow might cause them to bend, curve, and whip in accordance with the aortic systole cycle. Respective distal ends of branching stent-grafts 280 are disposed in left and right renal arteries 152A and 1528.
Optionally, endovascular system 200 includes one or more extension endovascular stent-grafts 284, which collectively bypass the aneurysmal sac to left and right iliac arteries 154A and 1548. The extension endovascular prostheses are sealingly coupled to endovascular stent-graft 110 during the deployment procedure. For some applications, main stent-graft 110, other than at bulges 42, is oversized about 15% compared to extension endovascular stent-grafts 284. As can be seen in
Reference is made to
Reference is made to
Reference is made to
In the configuration shown in
For some applications, as shown in
Reference is made to
For some applications, such as shown in
For other applications, such as shown in
For some applications, the one or more bulges 442 are configured to reduce the likelihood of long-term leakage (i.e., blood flow) through gutters, i.e., the residual intravascular space disposed outside the lumens of endovascular stent-graft 410 and branching stent-grafts disposed alongside endovascular stent-graft 410. Because the one or more bulges 442 are arranged as respective helices 448, the one or more bulges 442 contact the branching stent-grafts regardless of the circumferential location of the branching stent-grafts around endovascular stent-graft 410.
Alternatively or additionally, the one or more bulges 442 may reduce the likelihood of blood flow between endovascular stent-graft 410 and features of the anatomy of the blood vessel wall, such as isolated regions of plaque, calcifications, or thrombus, all of which alter the circularity of the blood vessel wall and might otherwise present issues for good sealing between stent-graft 410 and the blood vessel wall. As a result, the likelihood of type 1 endoleak is reduced.
For some application, such as shown in
For some applications, such as shown in
For other applications, such as shown in
It is noted that the features of this configuration shown in
Typically, each of the one or more bulges 442 has a greatest bulge radius from a central longitudinal axis of fluid flow guide 30 (labeled in
For some applications, the one or more bulges 442 extend to one or both ends of endovascular stent-graft 410, such as shown in
For some applications, the apparatus is substantially tubular on a first end portion and bifurcates to two substantially tubular sub-lumens on its second end portion, creating a continuous space between first end portion and sub-lumens on its second end portion. For some applications, an average circumference of each of its sub-lumens is between 40% and 70% of an average circumference of its first end portion.
Reference is again made to
In an embodiment, techniques and apparatus described in one or more of the following patents and patent applications, which are assigned to the assignee of the present application and are incorporated herein by reference, are combined with techniques and apparatus described herein.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.
The present application claims priority from U.S. Provisional Application 62/474,391, filed Mar. 21, 2017, which is assigned to the assignee of the present application and is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IL2018/050325 | 3/21/2018 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62474391 | Mar 2017 | US |
