Segmental Plethysmography for Endothelial Dysfunction Detection
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Solution Overview
Problem
Current methods for detecting endothelial dysfunction and reactive hyperemia are limited in their ability to provide early and accurate measurements, which are crucial for predicting vascular events and monitoring the effectiveness of treatments like statin therapy.
Innovation Solution
A method combining segmental volume plethysmography and oscillometry to generate arterial compliance and pressure-area curves over the entire transmural pressure range, using non-linear mathematical functions to calculate cuff compliance and measure reactive hyperemia, allowing for the detection and monitoring of endothelial dysfunction and cardiovascular diseases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional plethysmography methods are used to measure blood flow, then basic blood pressure and clot detection are achieved, but early detection of endothelial dysfunction and reactivehyperemia is limited
Solution Approach 1:
The patent applies parameter changes by measuring arterial compliance across multiple pressure points (0-300 mmHg in 25 mmHg increments) rather than at a single pressure level. This multi-pressure approach captures the nonlinear pressure-area relationship, enabling detection of endothelial dysfunction and reactivehyperemia that conventional single-point methods miss. The systematic variation of pressure parameters reveals subtle vascular responses indicative of early endothelial impairment.
2Measurement precision
If segmental volume plethysmography is performed with standard cuff inflation, then blood pressure measurement is achieved, but reactivehyperemia assessment is not possible
Solution Approach 1:
The patent implements periodic action through a structured two-phase cuff inflation protocol: baseline phase (0-300 mmHg over 3-5 minutes) followed by hyperemic phase (300 mmHg held for 5 minutes, then deflated). This periodic cycling of cuff pressure creates controlled ischemia-reperfusion cycles that elicit reactivehyperemia responses. The rhythmic application and release of occlusive pressure enables measurement of post-ischemic blood flow surge, which is the hallmark of reactivehyperemia assessment.
Solution Approach 2:
The patent applies preliminary action by performing baseline arterial compliance measurements across the full pressure range (0-300 mmHg) before inducing hyperemia. This preliminary characterization of the pressure-area relationship establishes a reference state against which hyperemic responses can be compared. The baseline data, collected during normal perfusion conditions, provides the necessary control measurements to quantify subsequent reactivehyperemia magnitude and assess endothelial function.
3Measurement precision
If arterial compliance is measured at single pressure points, then quick assessment is possible, but accurate endothelial dysfunction detection is limited
Solution Approach 1:
The patent implements continuity of useful action by continuously recording pressure and area measurements throughout the entire cuff inflation and deflation process rather than taking discrete snapshots. Data collection occurs at multiple pressure points (0-300 mmHg in 25 mmHg increments) continuously tracked over time. This continuous measurement approach captures the dynamic pressure-area relationship and enables construction of complete compliance curves, providing comprehensive endothelial function assessment without requiring multiple separate measurement sessions.
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
Enables early detection of endothelial dysfunction, prediction of vascular events, and monitoring of treatment efficacy, providing real-time, non-invasive measurements of cardiac output and vascular tone, thus aiding in the management of cardiovascular diseases and pre-eclampsia.
Implementation Method 1
a first compliant cuff 102 and a second compliant cuff 102 are placed about a first limb segment 101 and a second limb segment 101, respectively
Data Source
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AI summary
A method for measuring reactive hyperemia in a subject is disclosed. The method includes performing a first segmental cuff plethysmography to generate a baseline arterial compliance curve and/or a baseline pressure-area (P-A) curve, performing a second segmental cuff plethysmography to generate a hyperemic arterial compliance curve and/or a hyperemic P-A curve, and calculating an area between the baseline and the hyperemic curves. The size of the area can be used as an indication of endothelial dysfunction (ED) and ED-related diseases.