Extravascular cuff
Inventors
Verkaik, Josiah • Joseph, Jeffrey I. • VAN HELMOND, Noud
Assignees
Thomas Jefferson University • RTM Vital Signs LLC
Publication Number
US-11751771-B2
Publication Date
2023-09-12
Expiration Date
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Abstract
An implantable extravascular pressure sensing system including a cuff having a first brace portion, a second brace portion, and a plurality of biasing members movably coupling the first brace portion and the second brace portion to each other, the first brace portion defining a fluid chamber, the fluid chamber defining a recessed aperture, a flexible diaphragm coupled to the fluid chamber and sealing the recessed aperture, a fluid disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the flexible diaphragm, and a pressure sensor coupled to the first brace portion, the pressure sensor being configured to measure a change in the hydraulic pressure when a force is imparted on the flexible diaphragm.
Core Innovation
The invention provides an implantable extravascular pressure sensing system including a cuff having a first brace portion, a second brace portion, and a plurality of biasing members movably coupling the first brace portion and the second brace portion to each other. The first brace portion defines a fluid chamber and the fluid chamber defines a recessed aperture, a flexible diaphragm coupled to the fluid chamber and sealing the recessed aperture, a fluid disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the flexible diaphragm, and a pressure sensor coupled to the first brace portion, the pressure sensor being configured to measure a change in the hydraulic pressure when a force is imparted on the flexible diaphragm.
The cuff is configured so the biasing members movably couple the first and second brace portions to allow the brace portions to move with respect to each other in accordance with a pressure applied by the blood vessel, and the biasing members act as a spring-like element to provide suspension and vary the distance between the brace portions to accommodate blood vessels of varying size and to translate with respect to each other in response to a force applied by the blood vessel. The diaphragm is a compliant diaphragm configured to be mechanically coupled against a wall of the blood vessel to facilitate transduction of blood pressure through the vessel wall, and the design maintains mechanical coupling of the diaphragm with a wall of the blood vessel during vasoconstriction/dilation.
Additional disclosed features include an electronic circuit disposed between the flexible diaphragm and the fluid chamber with apertures to allow fluid communication to the pressure sensor, a sealing member adjacent the flexible diaphragm, sidewall ports in fluid communication with the fluid chamber for filling and venting, a casing surrounding folds of the biasing members to limit tissue integration, and a blood vessel securing region in the brace portions having transition regions, cylindrical support surfaces, and a centralized planar region adapted to contact a flattened portion of a blood vessel wall.
Claims Coverage
The patent includes one independent claim from which six main inventive features are extracted.
movable cuff with biasing members
A cuff including a first brace portion, a second brace portion, and at least two biasing members, each biasing member having a pair of opposing ends with at least one fold disposed between the pair of opposing ends, the pair of opposing ends for each of the at least two biasing members movably coupling the first brace portion and the second brace portion to each other to allow the first brace portion and the second brace portion to move with respect to one another in accordance with a pressure applied by the blood vessel to the first brace portion and the second brace portion.
first brace portion defining a fluid chamber
The first brace portion defining a fluid chamber and also defining a recessed aperture that is proximate the fluid chamber where the recessed aperture is in fluid communication with the fluid chamber.
flexible diaphragm sealing the recessed aperture
A flexible diaphragm coupled to the fluid chamber and sealing the recessed aperture.
fluid in chamber exhibiting hydraulic pressure
A fluid disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the flexible diaphragm.
pressure sensor measuring hydraulic pressure change
A pressure sensor coupled to the first brace portion, the pressure sensor being configured to measure a change in the hydraulic pressure when a force is imparted on the flexible diaphragm.
biasing members permitting translation with vessel pressure
At least two biasing members configured so the brace portions move with respect to one another in accordance with a pressure applied by the blood vessel, enabling the cuff to translate in response to forces from the blood vessel.
The independent claim covers an implantable extravascular cuff assembly that combines movably coupled brace portions via folded biasing members with a fluid-filled chamber sealed by a flexible diaphragm and monitored by a pressure sensor to transduce hydraulic pressure changes caused by forces on the diaphragm.
Stated Advantages
An extravascular pressure sensor that does not breach the vessel wall has fewer safety risks as compared to a more-invasive extravascular tonometer, including reduced blood flow obstructions and reduced potential for thrombus formation.
The biasing members provide suspension and vary the distance between brace portions to accommodate blood vessels of varying size and adjust for dilation and constriction while maintaining mechanical coupling of the diaphragm with a vessel wall.
The transitional geometry of the abutment structure is adapted to minimize stress imposed on the blood vessel during forced transition from a circular geometry to constrained flattening for applanation and accurate pressure transduction.
A casing surrounding the biasing members limits tissue integration to preserve the mechanical integrity and overall stiffness of the cuff.
Concave casing features and protrusions assist in centering the blood vessel and reduce movement and misalignment due to transverse or tilting loads.
The design isolates the diaphragm from external forces and movement of the cuff to protect the diaphragm and improve measurement stability.
Documented Applications
An implantable extravascular blood pressure sensing system for implantation to at least partially surround a blood vessel without breaching or significantly obstructing the blood vessel to measure blood pressure.
An implantable extravascular cuff for attachment around a blood vessel to obtain blood pressure measurements and perform additional or alternative medical diagnostics.
An attachment element or lock (female body and male body with retention element) adapted to couple the cuff to a blood vessel to secure the cuff during implantation.
Use as a blood pressure sensor employing applanation of the blood vessel wall to transduce blood pressure through the vessel wall to the diaphragm.
Measuring blood pressure in arteries and veins as an implantable sensor alternative to more-invasive tonometers or intravascular sensors.
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