Vascular grafts and method for preserving patency of the same
Inventors
Marshall, Andrew J. • Maginness, Max • Oda, Adrienne • Scanlan, Brandt
Assignees
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Publication Number
US-12263077-B2
Publication Date
2025-04-01
Expiration Date
Abstract
This disclosure provides prosthetic arteriovenous grafts having a blood-contacting layer; an intermediate layer; and a tissue-interface layer formed of a microporous biomaterial with a textured microporous surface, the prosthetic arteriovenous grafts providing vascular access for hemodialysis and being capable of reducing perigraft fibrotic capsular formation, and a method of maintaining the patency of the prosthetic arteriovenous grafts.
Core Innovation
The invention relates to prosthetic vascular grafts, particularly implanted arteriovenous hemodialysis grafts, having a layered construction that includes a blood-contacting microporous layer, a nonporous intermediate layer, and a tissue-interface layer formed from a second microporous biomaterial. The tissue-interface layer includes a textured microporous surface intended to reduce the tissue response that constricts the graft and thereby leads to neointimal hyperplasia.
The textured microporous surface comprises interconnected pores and inter-pore openings within specified size ranges, and includes peaks and valleys such that peaks can be greater than 200 µm and less than 1000 µm. The asserted functional effect of this surface texture is suppression of fibrotic capsular formation and capsular contraction, thereby preserving radial compliance and attenuating stenosis, neointimal hyperplasia and thrombus while maintaining graft patency.
The disclosure also includes a patency-maintenance method in which the microporous blood-contacting layer is pre-hydrated to remove air and the graft is directly implanted by connecting the graft to native vessels. Experimental support is described using ovine AV shunt and small-caliber arterial bypass models, where modified microporous silicone and modified ePTFE grafts are reported to show improved flow stability, reduced capsule thickness and loosening, reduced bacterial colonization, improved peak velocity ratio and lumen patency, diminished lumen occlusion, increased compliance, and better survival and patency compared with unmodified controls.
Claims Coverage
The partial content includes two independent claims covering reducing or preventing stenosis caused by neointimal hyperplasia and reducing or preventing development of neointimal hyperplasia. Both independent claims rely on a tissue-interface layer having a textured microporous surface defined by interconnected pore sizes and inter-pore openings, in the context of connecting an implanted vascular graft to native blood vessels.
Textured microporous tissue-interface layer with interconnected pore and inter-pore opening ranges
The vascular graft includes a tissue-interface layer having a textured microporous surface that reduces constriction from the tissue response to a degree that reduces neointimal hyperplasia, wherein the tissue-interface layer comprises interconnected pores larger than 20 microns and smaller than 200 microns, and adjacent pores have inter-pore openings larger than 5 microns and smaller than 50 microns.
Connecting an implanted vascular graft to native blood vessels for neointimal hyperplasia reduction
The method comprises connecting a vascular graft to one or more native blood vessels to provide the implanted vascular graft in tissue, where the vascular graft has a tissue-interface layer with a textured microporous surface defined by interconnected pores larger than 20 microns and smaller than 200 microns and adjacent inter-pore openings larger than 5 microns and smaller than 50 microns.
Across both independent claims, the core inventive coverage is the reduction or prevention of neointimal hyperplasia associated stenosis and constriction by connecting the graft to native vessels and providing a tissue-interface layer with a textured microporous surface defined by specific interconnected pore and inter-pore opening ranges.
Stated Advantages
Reduces neointimal hyperplasia.
Prevents development of neointimal hyperplasia.
Reduces constriction from the tissue response to the implanted vascular graft.
Attenuates stenosis, neointimal hyperplasia and thrombus while maintaining graft patency.
Suppresses fibrotic capsular formation and capsular contraction.
Preserves radial compliance.
Maintains lumen patency and improves peak velocity ratio.
Diminishes lumen occlusion.
Reduces bacterial colonization.
Documented Applications
Hemodialysis vascular access using implanted prosthetic arteriovenous grafts, including reducing stenosis caused by neointimal hyperplasia within or near either end of an implanted vascular graft.
Ovine AV shunt model use for evaluating improved flow stability, reduced capsule thickness and loosening, reduced bacterial colonization, improved peak velocity ratio and lumen patency, diminished lumen occlusion, increased compliance, and better survival and patency versus unmodified controls.
Small-caliber arterial bypass model use for evaluating improved flow stability and patency-related outcomes versus unmodified controls.
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