Extravascular cuff with displaceable lateral restraint
Inventors
Verkaik, Josiah • Joseph, Jeffrey I
Assignees
Thomas Jefferson University • RTM Vital Signs LLC
Publication Number
US-11759114-B2
Publication Date
2023-09-19
Expiration Date
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Abstract
An implantable extravascular pressure sensing system includes a cuff including a first brace portion affixed to a second brace portion and defining a longitudinal axis therebetween. The first brace portion defines a fluid chamber, the fluid chamber defining a recessed aperture. A first lateral restraint and a second lateral restraint are disposed between the first brace and the second brace, the first lateral restraint and the second lateral restraint being configured to be displaceable in a direction orthogonal to the longitudinal axis. A diaphragm is coupled to the fluid chamber and sealing the recessed aperture. A fluid is disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the diaphragm. A pressure sensor is 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 diaphragm.
Core Innovation
The present invention is an implantable extravascular pressure sensing system that includes a cuff having a first brace portion affixed to a second brace portion and defining a longitudinal axis therebetween, the first brace portion defining a fluid chamber that further defines a recessed aperture sealed by a diaphragm. A fluid is disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the diaphragm, and a pressure sensor coupled to the first brace portion is configured to measure a change in the hydraulic pressure when a force is imparted on the diaphragm.
The system further includes a first lateral restraint and a second lateral restraint disposed between the first brace portion and the second brace portion, the first lateral restraint and the second lateral restraint being configured to be displaceable in a direction orthogonal to the longitudinal axis, and the first bracket and the second bracket are disposed on opposite sides of the pressure sensor and configured to affix the first brace portion to the second brace portion. The lateral restraints are described as pliable and configured to contour a blood vessel restrained between them and in some aspects substantially enclose a blood vessel receiving volume.
The background identifies the problem that existing tonometers or implanted sensors either severely deform the blood vessel during applanation or necessitate significant hardware inside the blood vessel that may be hazardous, with rigid tonometers generating internal blood vessel wall stress that may compromise the vessel over time and cause measurement errors. The invention addresses the need for an extravascular pressure sensor that does not breach the vessel wall and that accommodates vessel dilation and constriction while maintaining mechanical coupling of the diaphragm with the vessel wall for accurate hydraulic pressure transduction.
Claims Coverage
Three independent claims were identified (claims 1, 10, and 18). The following inventive features were extracted from those independent claims.
First and second brace portions defining a longitudinal axis
A cuff including a first brace portion affixed to a second brace portion and defining a longitudinal axis therebetween.
Fluid chamber with recessed aperture sealed by a diaphragm
The first brace portion defining a fluid chamber, the fluid chamber defining a recessed aperture, and a diaphragm coupled to the fluid chamber and sealing the recessed aperture.
Displaceable lateral restraints with bore
A first lateral restraint and a second lateral restraint each defining a bore there through and being disposed between the first brace portion and the second brace portion, the first lateral restraint and the second lateral restraint being configured to be displaceable in a direction orthogonal to the longitudinal axis.
Fluid exhibiting hydraulic pressure in communication with the diaphragm
A fluid disposed within the fluid chamber for exhibiting a hydraulic pressure in communication with the diaphragm.
Pressure sensor coupled to first brace portion 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 diaphragm.
Brace affixed at a fixed distance defining blood vessel receiving volume
A cuff including a first brace portion affixed to a second brace portion at a fixed distance and defining a longitudinal axis and a blood vessel receiving volume therebetween.
Pliable lateral restraints substantially enclosing the blood vessel receiving volume
First and second lateral restraints disposed between the first brace portion and the second brace portion, the first lateral restraint and the second lateral restraint each defining a bore there through and being pliable and configured to be displaceable in a direction orthogonal to the longitudinal axis and to substantially enclose the blood vessel receiving volume.
Brackets on opposite sides of the pressure sensor affixing brace portions
A first bracket and a second bracket, the first bracket and the second bracket being disposed on opposite sides of a pressure sensor and configured to affix the first brace portion to the second brace portion.
Lateral restraint first portion contacts vessel and second portion moves within bracket
Each lateral restraint including a first portion configured to contact a blood vessel when a blood vessel is disposed within the blood vessel receiving volume; a second portion spaced a distance from the first portion by a necked portion, the second portion being configured to move within a portion of a respective one of the first bracket and the second bracket; and a bore extending through the first portion.
The independent claims collectively recite an implantable extravascular cuff characterized by paired brace portions defining a blood vessel receiving volume, a fluid chamber and diaphragm with hydraulic fluid sensed by a pressure sensor, and pliable, displaceable lateral restraints that interact with brackets to accommodate vessel motion while maintaining mechanical coupling for hydraulic pressure transduction.
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.
The first and second brackets and lateral restraints assist the cuff in accommodating blood vessels of varying size and adjust for dilation and constriction while maintaining mechanical coupling of an outer surface of a diaphragm with a wall of the blood vessel in applanation.
The design minimizes stress imposed on the blood vessel during the forced transition from a circular geometry to a constrained flattening for achieving applanation and accurate blood pressure transduction through the blood vessel wall.
The securing region and abutment structures maintain long-term alignment of the housing axis with an axis of the blood vessel to prevent misalignment that could cause sensor tilt or displacement.
Documented Applications
Measuring blood pressure from a blood vessel disposed within the cuff.
Performing additional or alternative medical diagnostics when the cuff is implanted.
Implantation within a patient, such as a human or animal patient, to at least partially surround and measure a blood vessel.
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