Implantable Arterial Pressure Monitoring via Wall Motion
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Solution Overview
Problem
Current methods for monitoring arterial blood pressure are invasive, impractical for chronic use, and lack continuous measurement and data logging capabilities, especially for systolic and diastolic pressure, which are essential for accurate hemodynamic assessment.
Innovation Solution
Implantable systems using electrodes to detect electrical heart activity and plethysmography sensors to measure mechanical activity, calculating peak pulse arrival time to determine systolic and diastolic pressures, allowing for continuous monitoring and wireless data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intravascular pressure transducer is used to measure arterial pressure, then measurement precision is improved, but device complexity and risk of complications increase
Solution Approach 1:
The patent uses an intermediary approach by placing a sensor on the arterial wall rather than inside the vessel. The sensor measures wall motion caused by pressure changes, serving as an intermediate measurement that indirectly reflects intravascular pressure without requiring direct intravascular placement. This resolves the contradiction by achieving accurate pressure measurement while avoiding the complexity and risks of intravascular device implantation.
Solution Approach 2:
The patent replaces the traditional mechanical intravascular pressure transducer with an optical sensing system. Instead of using a mechanical transducer directly in the blood vessel, the invention uses an optical sensor to detect wall motion and converts this mechanical motion into optical signals, which are then processed to determine pressure. This substitution reduces device complexity and eliminates the need for intravascular implantation while maintaining measurement accuracy.
2Object-affected harmful factors
If Finapres technique with PPG sensor and inflatable cuff is used, then non-invasive measurement is achieved, but ease of operation deteriorates due to continuous cuff pressure requirement
Solution Approach 1:
The patent extracts the essential measurement function from the Finapres system by removing the inflatable cuff component. Instead of using continuous cuff pressure to maintain zero transmural pressure, the invention directly measures arterial wall motion using an implanted sensor, eliminating the need for continuous cuff inflation and deflation cycles. This extraction resolves the contradiction by maintaining non-invasive measurement while removing the operational complexity of continuous cuff pressure management.
3Device complexity
If traditional auscultatory method with stethoscope and occlusive cuff is used, then measurement simplicity is maintained, but productivity deteriorates due to slow measurement speed
Solution Approach 1:
The patent implements continuous measurement by having the sensor continuously monitor arterial wall motion throughout the cardiac cycle. Instead of taking discrete measurements with a stethoscope and cuff, the system continuously captures pressure waveform data, enabling real-time monitoring without interrupting the measurement process. This continuity resolves the contradiction by maintaining measurement simplicity while dramatically improving productivity through automated, continuous data acquisition.
4Measurement precision
If intravascular lead implantation is performed, then measurement accuracy is improved, but ease of operation worsens due to requirement for highly skilled physician
Solution Approach 1:
The patent uses the arterial wall as an intermediary structure to achieve measurement accuracy without direct intravascular implantation. By placing the sensor on the external surface of the arterial wall, the system leverages the wall's mechanical response to pressure changes as a mediator that transmits pressure information without requiring the sensor to be inside the vessel. This intermediary approach resolves the contradiction by maintaining measurement accuracy while significantly reducing implantation difficulty.
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 chronic, accurate monitoring of arterial blood pressure, improving hemodynamic assessment and enabling timely interventions, while being less invasive and more comfortable for patients.
Implementation Method 1
Photoplethysmography (PPG) uses optical techniques to perform volume measurements
Implementation Method 2
Implanted electrodes are used to obtain a first signal indicative of electrical activity of the patient's heart
Data Source
AI summary
Implantable systems, and methods for use therewith, for monitoring arterial blood pressure on a chronic basis are provided herein. A first signal indicative of electrical activity of a patient's heart, and a second signal indicative of mechanical activity of the patient's heart, are obtained using implanted electrodes and an implanted sensor. By measuring the times between various features of the first signal relative to features of the second signal, values indicative of systolic pressure and diastolic pressure can be determined. In specific embodiments, such features are used to determine a peak pulse arrival time (PPAT), which is used to determine the value indicative of systolic pressure. Additionally, a peak-to-peak amplitude at the maximum peak of the second signal, and the value indicative of systolic pressure, can be used to determine the value indicative of diastolic pressure.