Dual-Sensor Catheter for Fractional Flow Reserve
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Solution Overview
Problem
Current methods for assessing coronary artery disease, such as coronary angiography, are limited in evaluating the functional significance of intermediate coronary lesions due to high intra- and inter-observer variability and lack of correlation with physiologic severity, necessitating a more accurate and functional measure of stenosis severity.
Innovation Solution
A method and device using at least two sensors positioned within a luminal organ near a stenosis to determine fractional flow reserve (FFR) by measuring flow velocity and cross-sectional area, with the introduction of a fluid with different properties to temporarily displace blood, allowing for accurate calculation of FFR based on flow velocity, mean aortic pressure, and cross-sectional areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual interpretation of coronary anatomy is used, then device complexity is reduced, but measurement precision deteriorates due to high intra- and inter-observer variability
Solution Approach 1:
The patent replaces visual interpretation methods with quantitative physiological measurements using pressure wires and flow sensors. This substitution of mechanical/physical measurement systems for subjective visual assessment resolves the contradiction by providing objective, precise measurements of stenosis severity through pressure gradients and flow reserve calculations.
Solution Approach 2:
The patent introduces physiological parameters (pressure gradients, flow velocity, coronary flow reserve) as intermediaries between anatomical structure and functional significance. These intermediary measurements bridge the gap between visual anatomy and actual blood flow impact, enabling accurate assessment without relying on subjective visual grading.
2Measurement precision
If Doppler guidewire is used to measure blood velocity, then measurement capability is improved, but reliability deteriorates due to difficulty in aligning the piezo-electric crystal with flow direction
Solution Approach 1:
The patent replaces Doppler-based acoustic measurement with direct pressure and flow sensing using micromachined pressure sensors and flow velocity sensors. This substitution eliminates the alignment problem inherent in Doppler methods by using sensors that measure pressure and flow directly without requiring directional alignment with blood flow.
Solution Approach 2:
The patent uses pressure gradients and flow velocity as intermediary measurements to calculate coronary flow reserve, replacing direct velocity measurement with Doppler. This approach achieves reliable flow assessment through pressure-based calculations that are independent of sensor alignment with flow direction.
3Measurement precision
If multiple sensors are introduced to improve measurement accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines pressure sensing and flow velocity sensing capabilities into an integrated catheter system. By merging multiple sensor functions into a single device platform, the patent achieves high measurement precision while managing device complexity through integration rather than separate components.
Solution Approach 2:
The patent creates a multi-functional sensor system that can measure pressure, flow velocity, and calculate coronary flow reserve within a single device. This universal approach allows multiple measurements to be obtained simultaneously, improving precision without proportionally increasing complexity through shared hardware resources.
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
This approach provides a simple, accurate, and cost-effective means to determine coronary blood flow, enabling better differentiation between ischemia-producing and non-ischemia-producing intermediate coronary lesions, thereby improving the assessment of coronary artery disease.
Implementation Method 1
devices for determining flow velocity and volumetric flow in a body organ based on an introduced fluid having a different conductivity than the native fluid
Data Source
AI summary
Devices, systems, and methods to determine fractional flow reserve. At least one method for determining fractional flow reserve of the present disclosure comprises the steps positioning a device comprising at least two sensors within a luminal organ at or near a stenosis, wherein the at least two sensors are separated a predetermined distance from one another, operating the device to determine flow velocity of a second fluid introduced into me luminal organ to temporarily displace a first fluid present within the luminal organ, and determining fractional flow reserve at or near the stenosis based upon the flow velocity, a mean aortic pressure within the luminal organ, and at least one cross-sectional area at or near the stenosis. Devices and systems useful for performing such exemplary methods are also disclosed herein.