Multilayer Vascular Graft Structure for Small-Vessel Patency
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Solution Overview
Problem
Current vascular grafts face challenges such as limited availability of autologous veins, high failure rates due to aneurysm, calcification, thrombosis, and thrombosis, especially for small-diameter vessels, leading to significant clinical needs for durable and versatile grafts with improved patency.
Innovation Solution
A multilayer vascular graft device with porous structures and biofragmentable materials that facilitate endothelialization and remodeling, featuring macropores for microvessel development, and layers with varying durometers and thicknesses to provide strength and kink resistance, gradually fracturing to integrate with host tissue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If synthetic PTFE grafts are used for large-diameter vessels, then graft availability is improved, but patency rate deteriorates due to aneurysm, calcification, and thrombosis
Solution Approach 1:
The graft comprises a porous structure with interconnected pores allowing tissue ingrowth and endothelialization. The porous scaffold enables host tissue integration while maintaining mechanical integrity, preventing the complications associated with synthetic PTFE grafts.
Solution Approach 2:
The graft combines biofragmentable porous scaffold material with bioactive components to create a composite structure that provides both mechanical support and biological functionality. This composite approach enables simultaneous achievement of graft availability and improved patency through tissue integration.
2Adaptability or versatility
If decellularized bovine xenografts or human allograft vessels are used, then graft availability is improved, but reliability deteriorates due to aneurysm, calcification, and thrombosis
Solution Approach 1:
The graft uses biofragmentable materials with controlled degradation rates and tuned mechanical properties. The material parameters are optimized to provide initial structural support while gradually transferring load to regenerated host tissue, preventing aneurysm formation and maintaining long-term patency.
Solution Approach 2:
The porous architecture facilitates rapid tissue ingrowth and vascularization, enabling the graft to become integrated with host tissue. This prevents the complications of aneurysm and thrombosis by establishing functional host-vessel continuity.
3Reliability
If autologous saphenous vein is used, then patency rate is improved, but graft availability deteriorates due to limited availability
Solution Approach 1:
The biofragmentable porous scaffold acts as a temporary intermediary structure that provides mechanical support during the critical healing period. As host tissue regenerates and integrates, the scaffold gradually degrades, transferring function to the newly formed vessel while maintaining patency.
Solution Approach 2:
The graft is pre-formed with optimized porous architecture and mechanical properties before implantation. The preliminary structure is designed to facilitate immediate tissue ingrowth and vascularization, ensuring long-term patency without requiring autologous vein harvest.
4Adaptability or versatility
If small-diameter vessels are required, then clinical applicability is improved, but reliability deteriorates due to unacceptably low patency rates of synthetic grafts and allografts
Solution Approach 1:
The porous structure with controlled pore size and interconnectivity enables efficient tissue ingrowth and vascularization in small-diameter grafts. This facilitates rapid endothelialization and integration, achieving patency rates comparable to or exceeding autologous vessels in small-diameter applications.
Solution Approach 2:
The composite structure combines biofragmentable scaffold material with bioactive components optimized for small-diameter applications. The material composition and architecture are tuned to provide adequate mechanical strength while facilitating rapid tissue integration, overcoming the limitations of synthetic and allograft small-diameter vessels.
Data Source
AI summary
Provided herein our graft devices for a patient comprising one or more layers, such as an inner layer and an outer layer. The inner layer comprises a first porous arrangement of fibers defining a first tube comprising an inner wall and an outer wall. The outer layer comprises a second porous arrangement of fibers defining a second tube comprising an inner wall and an outer wall. The second tube surrounds the first tube. A plurality of macropores extend through at least the inner and outer wall of the first tube. The inner and/or the outer layer can comprise a biofragmentable material configured to mechanically fracture into one or more fragments over time. Methods of creating graft devices are also disclosed.