Vascular Endothelial Function Evaluation Using Dual-Cuff Pulse Wave Analysis
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Solution Overview
Problem
Existing techniques for evaluating vascular endothelial function, such as those using ultrasonic echo systems, are complex, require large apparatus, and are influenced by blood pressure, leading to inaccurate measurements due to ischemia and sympathetic control effects.
Innovation Solution
An apparatus comprising two cuffs, a cuff pressure controller, a pressure detector, and a pulse wave detector, which performs continuous pressure stimulation and analyzes pulse waves before and after occlusion to evaluate vascular endothelial function without the need for ultrasonic systems, using statistical processing to minimize blood pressure influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic echo system is used to measure vessel diameter, then measurement precision is improved, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The patent replaces the ultrasonic echo system (acoustic field) with a pressure-based mechanical measurement system using cuffs and pressure sensors. This substitution maintains measurement capability while dramatically simplifying the apparatus, eliminating the need for complex ultrasonic equipment and specialized operator skills.
Solution Approach 2:
The patent uses pressure pulse wave measurements as a proxy copy for direct vessel diameter measurement. By measuring the pressure pulse wave characteristics that reflect vessel diameter changes, the system achieves indirect measurement of vascular endothelial function without requiring direct visualization or complex imaging equipment.
2Measurement precision
If cuff pressure is maintained at predetermined pressure higher than maximal blood pressure, then vascular endothelial function evaluation is enabled, but subject burden increases due to vein blood flow blockage
Solution Approach 1:
The patent divides the measurement process into distinct phases: a pressurization phase for vascular stimulation and a measurement phase for pulse wave detection. By separating these functions and controlling the timing, the system achieves accurate measurement while minimizing the duration and intensity of ischemic conditions, thereby reducing subject burden.
Solution Approach 2:
The patent employs periodic pressure application and release cycles to stimulate vascular endothelial function. The cuff pressure is periodically increased to induce vasodilation and then released to allow recovery, creating rhythmic stimulation that enhances measurement accuracy while preventing prolonged ischemia and reducing subject burden through controlled intermittent occlusion.
3Measurement precision
If blood pressure is high, then vessel wall compliance decreases, but measurement accuracy is improved by statistical processing
Solution Approach 1:
The patent incorporates statistical processing that analyzes pulse wave characteristics in relation to blood pressure variations. By continuously monitoring and statistically evaluating the relationship between pressure changes and pulse wave responses, the system compensates for blood pressure-induced compliance changes, maintaining measurement accuracy despite variations in vessel wall stability.
Solution Approach 2:
The patent measures pulse wave parameters at multiple different cuff pressure levels and uses statistical analysis to determine vessel compliance. By changing the pressure parameter and observing how pulse wave characteristics change across different pressure states, the system calculates compliance as a derived parameter, thereby accounting for and compensating for blood pressure effects on vessel wall mechanics.
Data Source
AI summary
An apparatus for evaluating a vascular endothelial function using a first cuff that occludes an artery of a patient, measuring pulse waves from pressure of a second cuff at a different position than the first cuff, and evaluating the vascular endothelial function using the pulse waves.