Tapered Prosthetic Heart Valve Frame for Lower Pressure Gradients
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Solution Overview
Problem
Existing prosthetic heart valves with cylindrical frames experience increased pressure gradients due to eddies and turbulence, leading to prosthesis-patient-mismatch and worsened hemodynamic function, particularly when using mechanical actuators for expansion.
Innovation Solution
A radially expandable and compressible frame design with curved, pivotably connected struts and a tapered shape, allowing for self-expansion and compression without permanent deformation, and a delivery apparatus with actuators and a crimping mechanism for controlled deployment and retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cylindrical frame is used in existing prosthetic heart valves, then the valve can be manufactured with standard components, but the effective outflow orifice becomes narrower than the inflow orifice causing eddies and turbulence downstream
Solution Approach 1:
The frame transitions from a symmetric cylindrical shape to an asymmetric tapered shape where the outflow orifice is larger than the inflow orifice. This asymmetry eliminates the narrow outflow restriction that causes eddies and turbulence, while the tapered geometry can still be manufactured using standard forming processes by controlling the radial dimension variation along the longitudinal axis.
2Ease of operation
If additional components such as actuators are placed adjacent to the outflow end of the frame, then the valve can be mechanically expanded, but the pressure gradient across the prosthetic valve increases
Solution Approach 1:
The actuators are repositioned from the traditional outflow-end location to the inflow end of the frame, utilizing the inflow dimension for actuator placement. This dimensional relocation moves the expansion mechanism away from the outflow path, preventing interference with blood flow and reducing the pressure gradient while maintaining full mechanical expansion functionality.
3Adaptability or versatility
If the effective outflow orifice is made narrower to match patient anatomy, then prosthesis-patient-mismatch is reduced, but eddies and turbulence increase leading to worsened hemodynamic function
Solution Approach 1:
The frame employs asymmetric tapering where the outflow orifice diameter is intentionally made larger than the inflow orifice diameter. This asymmetric geometry allows the valve to adapt to various patient anatomies while preventing the formation of eddies and turbulence that would occur with a narrow outflow, thereby improving hemodynamic function without compromising prosthesis-patient-mismatch alignment.
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
Reduces pressure gradients and paravalvular leakage, improving hemodynamic function and survival rates by optimizing the prosthetic valve's fit within the patient's anatomy.
Implementation Method 1
Each strut can be curved helically with respect to a first, longitudinal axis of the frame and each strut can be curved with respect to a second axis that is perpendicular to the first, longitudinal axis of the frame
Implementation Method 2
Each strut of the first set of struts can be pivotably connected to at least one strut of the second set of struts
Data Source
AI summary
An implantable prosthetic device can include a radially expandable and compressible frame comprising a plurality of struts each comprising a first portion including one or more first segments and a second portion including one or more second segments, wherein the first segments are closer to an outflow end of the frame than the second segments, and a valvular structure mounted in the frame such that a majority of the volume is disposed in the portion of the frame comprising the second portions of the struts. The one or more first segments have a first width and the one or more second segments have a second width narrower than the first width.