Non-invasive Endothelial Function Assessment via Reactive Hyperemia
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Solution Overview
Problem
Current methods for assessing endothelial function are invasive, expensive, difficult to perform, and poorly tolerated by patients, and do not accurately quantify the stimulus delivered to the endothelium, leading to variability in test results.
Innovation Solution
A diagnostic system that measures changes in arterial volume by analyzing component pulse waves before and after a stimulus, using a cuff to occlude the artery and a Doppler transducer to quantify blood flow, and adjusts for anthropomorphic and demographic variables to provide an endothelial function indicator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ultrasound imaging technique is used to assess brachial artery dilation, then non-invasive measurement is achieved, but the magnitude of arterial dilation is not sufficient to be reliably determined and requires specialized vascular laboratories
Solution Approach 1:
The patent replaces the mechanical ultrasound imaging system with a pneumatic oscillometry system that uses pressure oscillations to detect arterial volume changes. This substitution maintains non-invasiveness while improving measurement reliability through more sensitive detection of volume changes.
Solution Approach 2:
The patent changes the measurement parameter from arterial diameter (ultrasound) to arterial volume (oscillometry). This parameter change enables more reliable detection because volume changes are larger and more easily measured than diameter changes, especially in smaller arteries.
2Measurement precision
If invasive intra-coronary or intra-brachial infusions of vasoactive agents are used, then accurate detection of endothelial dysfunction is achieved, but the highly invasive nature limits their use
Solution Approach 1:
The patent replaces invasive chemical stimulation (vasoactive agent infusion) with mechanical stimulation (cuff occlusion inducing reactive hyperemia). This substitution eliminates the need for invasive procedures while maintaining the ability to accurately detect endothelial dysfunction through flow-mediated dilation assessment.
Solution Approach 2:
The patent uses the body's own physiological response (reactive hyperemia) instead of external vasoactive agents. The occlusion-stimulated blood flow naturally activates endothelial nitric oxide production, eliminating the need for exogenous substances while maintaining diagnostic accuracy.
3Ease of operation
If existing non-invasive techniques are used, then ease of operation is improved, but they do not quantify the stimulus delivered to the endothelium nor account for other sources of nitric oxide, leading to variability in test results
Solution Approach 1:
The patent incorporates feedback by measuring blood flow velocity and calculating the stimulus magnitude delivered to the endothelium. This feedback allows the system to account for variations in individual physiological responses and normalize the data, improving result consistency while maintaining operational simplicity.
Solution Approach 2:
The patent performs preliminary measurements of blood flow velocity and other physiological parameters before and during the occlusion stimulus. This preliminary action enables the system to quantify the actual stimulus delivered and adjust for confounding factors, reducing variability in test results.
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
The system provides a non-invasive, cost-effective, and patient-friendly method to assess endothelial function by accurately measuring relative changes in arterial volume, correlating with brachial artery dilation, and improving the reliability of endothelial dysfunction diagnosis.
Implementation Method 1
a Doppler transducer to quantify blood flow
Implementation Method 2
using a cuff to occlude the artery
Data Source
AI summary
A medical diagnostic system and method for assessing endothelial function comprise adjusting a reactive hyperemia indicator, measured in response to a stimulus, based on an anthropomorphic and/or demographic variable. The adjusted reactive hyperemia indicator provides a more accurate reflection of endothelial function and can be communicated to a clinician.