Water-Soluble Adhesive Coating for Vascular Grafts
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Solution Overview
Problem
Existing vascular grafts, particularly those made of expanded polytetrafluoroethylene (ePTFE), face challenges with neointimal hyperplasia and restenosis due to tissue ingrowth and biomechanical forces, leading to low patency rates in small diameter vessels and inadequate performance in infrapopliteal interventions.
Innovation Solution
A water-soluble polymerization product is formed from a composition of volatile solvents and hydrophilic monomers, which is applied to ePTFE grafts to create a delivery vehicle for therapeutic agents like rapamycin, inhibiting neointimal hyperplasia and restenosis without altering the graft's mechanical properties or causing thrombosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ePTFE grafts are used as vascular substitutes, then structural integrity and resistance to biomechanical forces are improved, but neointimal hyperplasia and thrombosis occur leading to low patency rates
Solution Approach 1:
The adhesive coating is applied to the ePTFE graft surface before implantation, pre-equipping the graft with therapeutic agents (antiproliferative drugs, anticoagulants, anti-infective agents) that will be released in situ to prevent neointimal hyperplasia and thrombosis, thereby improving patency without compromising structural integrity
Solution Approach 2:
A hydrophilic adhesive coating serves as an intermediary layer between the ePTFE graft and the biological environment, delivering therapeutic agents that mediate the interaction between the graft and host tissue to prevent pathological responses while maintaining the graft's mechanical properties
2Reliability
If stents are used to overcome elastic recoil and negative arterial remodeling, then vessel patency is improved, but restenosis occurs due to continued pressure stimulation
Solution Approach 1:
The adhesive coating acts as an intermediary drug delivery system that releases antiproliferative therapeutic agents at the site of vessel injury, mediating the response to stent pressure and preventing the proliferative response that leads to restenosis
Solution Approach 2:
The therapeutic agents embedded in the adhesive coating convert the harmful proliferative response stimulated by stent pressure into a beneficial controlled response, where drug release counteracts the proliferative stimulus and prevents restenosis
3Reliability
If coatings are applied to ePTFE grafts to deliver therapeutic agents, then neointimalhyperplasia is reduced, but handling characteristics and thrombogenicity may be altered
Solution Approach 1:
The adhesive composition parameters are optimized to ensure the coating is sufficiently thin and hydrophilic to maintain the underlying ePTFE graft's handling characteristics and non-thrombogenic properties, while still providing adequate drug delivery capacity to prevent neointimalhyperplasia
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces neointimal hyperplasia and preserves anastomotic diameter, maintaining graft patency and preventing infection, with rapamycin elution demonstrating reduced neointimal formation and increased graft longevity in small diameter vessels.
Implementation Method 1
one or more volatile solvents
Implementation Method 2
a first hydrophilic monomer component, and a second hydrophilic monomer component that is different from the first hydrophilic monomer component, wherein the first and second hydrophilic monomer components form a water-soluble polymerization product upon contact
Data Source
AI summary
Water-soluble polymeric adhesive compositions and their use as delivery vehicles for carrying therapeutic agents on implantable devices, such as vascular grafts, are disclosed. Use of drug-coated vascular grafts is demonstrated for delivery of the therapeutic agents in vivo, thereby inhibiting restenosis or neointimal hyperplasia of the vascular graft and inhibiting infection at the vascular graft site. Methods of forming the adhesive and making the coated vascular grafts are also disclosed.