Vascular prosthesis for leak prevention during endovascular aneurysm repair
Inventors
Maitland, Duncan J. • Landsman, Todd L • Horn, John • Nash, Landon • Yeh, Chung
Assignees
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Publication Number
US-11839702-B2
Publication Date
2023-12-12
Expiration Date
Abstract
An embodiment includes a process for treating an abdominal aortic aneurysm (AAA) endoleak with a shape memory polymer (SMP) foam device. First, a bifurcated stent graft is placed within the aneurysm while a micro guidewire is positioned within the aneurysm for future catheter access. Second, after placing the iliac graft extension, a catheter is introduced over wire to deliver embolic foams. Third, embolic foams expand and conform to the aneurysm wall. Fourth, embolic foams create a stable thrombus to prevent endoleak formation by isolating peripheral vessels from the aneurysm volume.
Core Innovation
The invention relates to endovascular aneurysm repair (EVAR) for an abdominal aortic aneurysm (AAA) in which endoleak is prevented by deploying polyurethane shape memory polymer (SMP) foam embolic devices into a patient. A stent graft and a wire are implanted within the patient adjacent to one another, and conduits are advanced so that SMP foams are deployed at locations in an ordered manner. The deployed SMP foams expand and conform to surrounding anatomy to form a stable thrombus that isolates peripheral vessels from the aneurysm sac to prevent endoleaks.
The described approach uses a catheter delivery strategy with reduced delivery friction for catheter delivery through small catheters. Radiopacity is provided to enable fluoroscopic visibility, including tungsten or iodine-containing formulations and radiopaque markers. Spatial placement is supported by metal structures associated with the SMP foams, enabling planes that intersect proximal portions with the metal structures and distal portions without intersecting the metal structures, so that proximal/distal relationships are controlled during deployment.
The SMP material is characterized with choices between biodurable (non-degradable) polyurethane SMP to avoid recanalization and toxic byproducts, and variants that are capable of biodegradation through degradable linkages. The description further emphasizes large volumetric expansion, flow stasis quantification, tissue infiltration with retained radiopaque particles, and favorable mechanical properties. Testing includes benchtop flow-model evaluation using simulated endoleak conditions and a pilot porcine AAA study with imaging-based assessment of endoleak presence and acute embolization.
Claims Coverage
The partial content provides one independent claim. It covers a method that implants a stent graft and adjacent wire, advances a conduit over the wire, inserts a second conduit containing simultaneously disposed, serially arranged open-cell polyurethane thermoset SMP foams that are not fixedly coupled, and deploys the first, second, and third SMP foams sequentially into respective locations using metal structures and defined proximal/distal planes to establish spatial relationships.
Sequential deployment of simultaneously disposed serially arranged open-cell polyurethane thermoset SMP foams
Implant a stent graft and a wire within a patient and adjacent one another; advance a first conduit over the wire; insert a second conduit into the first conduit in which first, second, and third open-cell, polyurethane, thermoset, shape memory polymer foams are simultaneously disposed, arranged serially with respect to each other, and not fixedly coupled to each other; deploy the first, then the second, and then the third SMP foam from the first conduit into respective first, second, and third locations.
Proximal/distal plane constraints using metal structures coupled to each SMP foam
Use planes orthogonal to each SMP foam long axis that intersect a proximal half of each SMP foam and intersect a corresponding metal structure coupled to the SMP foam, and use additional parallel planes that intersect a distal half of the SMP foam but do not intersect the metal structure; apply these plane relationships for the first, second, and third SMP foams with corresponding metal structures.
Claim coverage is grounded in sequential deployment of simultaneously disposed, serially arranged open-cell polyurethane thermoset SMP foams that are not fixedly coupled, combined with explicit spatial plane relationships relative to metal structures coupled to each foam.
Stated Advantages
Prevents endoleaks by isolating peripheral vessels from the aneurysm sac with a stable thrombus formed after SMP foam deployment.
Reduced delivery friction for catheter delivery through small catheters.
Radiopacity for fluoroscopic visibility.
Avoids recanalization and toxic byproducts by using biodurable (non-degradable) SMP.
Documented Applications
Endovascular aneurysm repair (EVAR) for an abdominal aortic aneurysm (AAA) where endoleaks are prevented by embolic deployment of polyurethane SMP foams.
Benchtop flow-model testing with simulated endoleak conditions to evaluate flow stasis and embolization behavior.
A pilot porcine AAA study assessing endoleak presence and acute embolization using imaging such as CT angiography (3D-CTA) and angiography.
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