Apparatus, system and methods for measuring a blood pressure gradient
Inventors
Caron, Eric • Bilodeau, Luc • Paquette, Michel
Assignees
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Publication Number
US-9149230-B2
Publication Date
2015-10-06
Expiration Date
Abstract
An apparatus (100), control system (150) and methods are provided for directly measuring a pressure gradient, i.e. by real-time pressure measurements, with particular application for in situ measurement of transvalvular blood pressure gradients for the aortic valve and other heart valves, using minimally-invasive techniques. The apparatus takes the form of a multi-sensor assembly, e.g. enclosed within a micro-catheter or a steerable guidewire, and comprises a plurality of optical pressure sensors (10) is arranged along a length of the distal end portion (101), for measuring pressure simultaneously at each sensor location. For example, four MOMS optical pressure sensors (10), and optionally, a flow sensor (20), are incorporated into a distal end portion (101) having a diameter of 0.89 mm or less, and preferably 0.46 mm or less. Beneficially, all sensors are optically coupled, via respective optical fibers (11), to an optical coupler (112) at the proximal end of the multi-sensor apparatus, without requiring electrical connections.
Core Innovation
The disclosed invention provides an apparatus for measuring an intravascular blood pressure gradient, including a transvalvular blood pressure gradient for a heart valve. The apparatus includes a multi-sensor assembly arranged within a tubular covering layer that comprises a micro-catheter or a coil of a steerable guidewire having a proximal end and a distal end with a flexible distal tip. The distal portion contains a sensor arrangement for pressure measurement at sensor locations spaced apart along a length of 4 cm to 7 cm of the distal end portion of the tubular covering layer.
The multi-sensor assembly includes an optical fiber bundle with a plurality of optical fibers and a plurality of optical sensors, where each optical sensor is attached and optically coupled to a respective optical fiber. The distal ends of the optical fibers are arranged so that the optical sensors have sensor locations spaced apart lengthwise. The proximal ends of the optical fibers are optically coupled to an optical input/output end for connection to a control system, and the sensor arrangement provides measurement of pressure at each sensor location so the control system determines a blood pressure gradient.
Fluid contact with each sensor is enabled by an aperture in the covering layer adjacent each optical sensor, and at least one marker is provided for locating the sensor arrangement. The distal end portion of the covering layer has an outer diameter suitable for introduction intravascularly or intraluminally through a micro-catheter into the heart. The disclosed system optionally enables simultaneous pressure-gradient measurement and flow-velocity measurement using an optical thermoconvection flow sensor.
Claims Coverage
The partial document provides one independent claim (clm-00001). It covers an intravascular transvalvular blood pressure gradient apparatus using spaced optical pressure sensors in a distal portion of a micro-catheter or steerable guidewire, with optical fibers coupled to an optical input/output end for determination by a control system; it further specifies fluid-contact apertures, a locating marker, and an intravascularly introducible distal end portion. It includes inventive feature refinements that introduce sensor count/spacing and optional flow/temperature-related sensing through dependent claims.
Intravascular blood pressure gradient apparatus with transvalvular sensing
An apparatus for measuring an intravascular blood pressure gradient, including a transvalvular blood pressure gradient for a heart valve.
Multi-sensor assembly in a tubular covering layer
A multi-sensor assembly contained within a tubular covering layer comprising a micro-catheter or a coil of a steerable guidewire, having a proximal end and a distal end with a flexible distal tip, with the multi-sensor assembly extending within the tubular covering layer from the proximal end into a distal end portion adjacent the distal end.
Optical fiber bundle coupled to spaced optical pressure sensors
An optical fiber bundle comprising a plurality of optical fibers and a plurality of optical sensors, where each optical sensor is attached and optically coupled to a respective distal end of a fiber; distal ends arranged to form a sensor arrangement with sensor locations spaced apart lengthwise from each other.
Distal sensor arrangement for pressure-gradient determination over 4 cm to 7 cm
The sensor arrangement comprising the plurality of optical sensors located within the distal end portion for measuring pressure at respective sensor locations spaced apart along a length of 4 cm to 7 cm of the distal end portion of the tubular covering layer, and providing measurement of pressure at each sensor location for determination by the control system of a blood pressure gradient.
Fluid-contact apertures adjacent each optical sensor and locating marker
An aperture in the covering layer adjacent each optical sensor for fluid contact, and at least one marker for locating the sensor arrangement.
Intravascular introducible distal end portion suitable for introduction through a micro-catheter
At least the distal end portion of the covering layer having an outer diameter suitable for introduction intravascularly or intraluminally through a micro-catheter into the heart.
Across the provided independent claim, the core claim coverage is directed to an intravascular/transvalvular blood pressure gradient apparatus having a distal sensor arrangement of multiple optical pressure sensors coupled to optical fibers and optically read by a control system, with pressure measured at spaced locations over a 4 cm to 7 cm region inside a micro-catheter/steerable guidewire covering layer, including fluid-contact apertures and a locating marker.
Stated Advantages
Reduced disruption due to the device being ≤0.89 mm (preferably ≤0.46 mm) in diameter.
Simultaneous upstream and downstream sensing to avoid sequential errors.
Optical immunity to EMI/humidity.
Potential to estimate cardiac output and valve area.
Documented Applications
Measurement of transvalvular gradients across aortic, mitral, tricuspid, and pulmonary valves in a heart-model and in a minimally-invasive intravascular procedure context.
Cardiac catheterization using an intravascular or intraluminally introduced multi-sensor wire/micro-catheter into the heart.
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