Refractory Alloy Heart Valve Frame for Smaller Crimping Diameter
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Solution Overview
Problem
Current medical devices, particularly cardiovascular implants like stents and transcatheter aortic valves, face issues with recoil, limited crimping diameters, metal ion release, and complications such as mispositioning and paravalvular leak, which restrict their use in smaller profiles and higher-risk patients.
Innovation Solution
A medical device partially or fully formed from a refractory metal alloy, such as MoRe or ReW, with improved properties like reduced recoil, enhanced strength, and lower ion release, allowing for smaller crimping diameters and improved biocompatibility, is developed. This alloy is used in a prosthetic heart valve with a radially collapsible and expandable frame and an inner skirt to minimize tissue damage and ensure proper implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional metal alloys (stainless steel, cobalt-chromium) are used to maintain frame strength, then the device can retain its expanded shape, but the crimping diameter cannot be reduced sufficiently
Solution Approach 1:
The patent changes the material parameters by introducing refractory metal alloys (molybdenum, rhenium, niobium, tantalum, or tungsten) with specific compositional ranges. These material parameter changes enable both reduced crimping diameter and maintained frame strength, resolving the contradiction between size reduction and strength retention
Solution Approach 2:
The patent employs composite alloy formulations combining refractory metals with other elements (e.g., Mo-Re, W-Re, Mo-Ta) to achieve superior mechanical properties. These composite materials provide both the reduced crimping diameter capability and the frame strength retention, simultaneously addressing both requirements
2Length of moving object
If the frame size and thickness are reduced to achieve smaller crimping diameter, then the device can be inserted into smaller blood vessels, but the strength after expansion is compromised
Solution Approach 1:
By changing the material composition to refractory metal alloys with specific weight percentages (e.g., 20-80% molybdenum, 10-50% rhenium), the patent achieves enhanced strength-to-size ratio. This allows the frame to be thinner and smaller at crimped state while maintaining sufficient strength after expansion
Solution Approach 2:
The composite refractory metal alloys provide a synergistic effect where the combination of elements (e.g., Mo-Re, W-Ta) creates a material that is both smaller in dimension and stronger in performance, simultaneously achieving reduced crimping diameter and maintained frame strength
3Ease of manufacture
If traditional alloys are used, then the device can be manufactured with current technology, but metal ion release and biocompatibility issues occur
Solution Approach 1:
The patent changes the chemical composition parameters by using refractory metals (molybdenum, rhenium, niobium, tantalum, tungsten) that inherently exhibit lower ion release and improved biocompatibility compared to traditional alloys, while remaining manufacturable with existing medical device fabrication technologies
Solution Approach 2:
The patent converts the traditionally expensive and difficult-to-manufacture refractory metals into a benefit by demonstrating their superior biocompatibility and reduced ion release, transforming a manufacturing challenge into a clinical advantage
4Length of moving object
If the device is designed for smaller profile to access smaller blood vessels, then it can treat more patients, but recoil and mispositioning complications increase
Solution Approach 1:
By changing the material parameters to refractory metal alloys with optimized mechanical properties (elastic modulus, strength, ductility), the patent reduces recoil while maintaining small device profile, thereby improving positioning accuracy without sacrificing accessibility
Data Source
AI summary
A medical device that is at least partially formed of a refractory metal alloy, and a method for inserting the medical device in a patient.