Intravascular deliverable stent for reinforcement of abdominal aortic aneurysm

• US 20070168018A1
• Filed: 01/13/2006
• Published: 07/19/2007
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: St. Jude Medical Cardiology Division Incorporated (Abbott Laboratories)
• Original Assignee: AGA Medical Corporation (Abbott Laboratories)
• Inventors: Russo, Patrick, Amplatz, Kurt, Oslund, John
• Granted Patent: US 8,900,287 B2
• Time in Patent Office: Days
• US Class Current: 623/1.180
• CPC Class Codes: A61F 2/07 Stent-grafts
• CPC Class Codes: A61F 2/852 Two or more distinct overlapping stents
• CPC Class Codes: A61F 2/856 Single tubular stent with a side portal passage
• CPC Class Codes: A61F 2/90 characterised by a net-like or mesh-like structure
• CPC Class Codes: A61F 2002/061 provided with means for allowing access to secondary lumens
• CPC Class Codes: A61F 2002/075 the stent being loosely attached to the graft material, e.g. by stitching
• CPC Class Codes: A61F 2210/0014 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2250/0015 differing in density or specific weight
• CPC Class Codes: D04C 1/06 Braid or lace serving particular purposes
• CPC Class Codes: D10B 2401/046 Shape recovering or form memory
• CPC Class Codes: D10B 2509/06 Vascular grafts; stents

Abstract

A stent/graft especially designed to be used in a minimally invasive surgical procedure for treating an abdominal aortic aneurysm (AAA) comprises an innermost tubular structure of a length (L₁) formed by braiding a relatively few strands of shape memory alloy wire. The pick and pitch of the braid are such as to provide relative large fenestrations in the tubular wall. A portion of the innermost tubular structure of a length L₂<L₁ is surrounded by a further braided tubular structure having relatively many strands that occlude the fenestrations of the innermost tubular structure. The composite structure can be stretched to reduce the outer diameter of the stent/graft, allowing it to be drawn into a lumen of a delivery catheter. The catheter can then be advanced through the vascular system to the site of the AAA and then ejected, allowing it to self-expand with the portion L₂ bridging the aneurysm. The portion L₁>L₂ does not block blood flow to the renal arteries while the portion L₂ prevents the aneurysm to grown and burst.

Claims

1. A catheter deliverable stent for treating an abdominal aortic aneurysm comprising:

(a) an innermost tubular structure of a first length, the innermost tubular structure comprising a first plurality of braided wire strands of a shape memory alloy, the braid having a predetermined pick and pitch to define openings sufficiently large so as to not materially impede blood flow therethrough;

(b) at least one further tubular structure of a predetermined diameter placed in surrounding relationship with a predetermined length portion less than the first length of the innermost tubular structure, the further tubular structure comprising a second plurality of braided wire strands greater in number than said first plurality, also of a shape memory alloy, the braid of the further tubular structure having pick and pitch to define openings sufficient small so as to substantially preclude blood flow therethrough;

(c) wherein longitudinal stretching of the innermost and further tubular structures reduces an outer diameter of the stent sufficiently to allow it to be loaded into a lumen of an intravascular delivery catheter and release of the stent from the delivery catheter allows the outer diameter to expand back to said predetermined diameter.

2. The catheter deliverable stent as in claim 1 wherein a portion of the innermost tubular structure extending beyond a terminus of the further tubular structure is adapted to overlay the juncture of a patient'"'"'s renal arteries with the patient'"'"'s abdominal aorta when the further tubular structure bridges an abdominal aortic aneurysm.

3. The catheter deliverable stent as in claim 1 wherein two further tubular structures are placed in generally coaxial surrounding relationship with said predetermined length portion.

4. The catheter deliverable stent as in claim 1 wherein the shape memory alloy comprises Nitinol®

.

5. The catheter deliverable stent as in claim 1 wherein the first plurality of braided wire strands comprises 36 strands and the second plurality of braided wire strands comprises 144 strands.

6. The catheter deliverable stent as in claim 3 wherein the two further tubular structures each comprise 144 braided wire strands.

7. A method of treating an abdominal aortic aneurysm comprising the steps of:

(a) providing a stent of claim 1;

(b) releasably affixing a proximal end of the stent to a pusher catheter;

(c) drawing said stent into a lumen of an intravascular delivery catheter;

(d) advancing the delivery catheter through the vascular system until a distal end of the delivery catheter is proximate an aneurysm to be treated; and

(e) holding the stent stationary using the pusher catheter while drawing the delivery catheter proximally to eject the stent from a distal end of the delivery catheter with the stent self-expanding to engage an aortic wall while bridging the aneurysm; and

(f) releasing the proximal end of the stent from the pusher catheter.