LVET Preload Response for Aortic Valve Replacement Timing
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Solution Overview
Problem
Current methods for determining the optimal timing of aortic valve replacement are inadequate, particularly in detecting early myocardial dysfunction and irreversible damage in aortic stenosis, as conventional echocardiography is limited by resolution, operator dependence, and high-cost advanced imaging is not widely accessible, leading to delayed interventions.
Innovation Solution
A non-invasive system using LVET measurements in response to changes in preload, combined with PPG or SPG pulse waves, to assess Frank-Starling reserve and determine the appropriate time for valve replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional echocardiography is used to assess aortic stenosis, then valve morphology and hemodynamics can be evaluated, but early myocardial dysfunction and subtle myocardial changes cannot be detected
Solution Approach 1:
The patent replaces conventional echocardiographic imaging with a mechanical/physiological measurement approach using LVET (left ventricular ejection time) and Frank-Starling reserve assessment. This substitution allows detection of early myocardial dysfunction through functional response to preload changes rather than relying on structural imaging resolution, thereby solving the contradiction between imaging precision and detection capability for early changes.
Solution Approach 2:
The patent utilizes changes in LVET and Frank-Starling reserve parameters in response to preload modifications to detect early myocardial dysfunction. By monitoring dynamic parameter changes rather than static structural features, the system achieves higher sensitivity for early myocardial changes without requiring advanced imaging modalities.
2Measurement precision
If advanced imaging modalities like cardiac MRI and CT are used to detect early myocardial changes, then detection accuracy is improved, but cost and accessibility are reduced
Solution Approach 1:
The patent employs a cost-effective, easily deployable measurement system based on LVET and Frank-Starling reserve assessment that can be performed with standard equipment. This approach replaces expensive advanced imaging modalities (MRI, CT) with a simpler, more accessible physiological measurement method, thereby maintaining high detection accuracy while significantly improving cost-effectiveness and accessibility.
Solution Approach 2:
The patent substitutes complex advanced imaging systems with a simpler physiological measurement system that uses LVET and preload response assessment. This substitution achieves comparable or superior detection of early myocardial changes while being much more cost-effective and accessible, directly addressing the contradiction between precision and ease of manufacture.
3Productivity
If conventional echocardiography is used for monitoring, then routine use is maintained, but detection of diminished Frank-Starling reserve is delayed
Solution Approach 1:
The patent enables preliminary detection of myocardial dysfunction by assessing Frank-Starling reserve and LVET response to preload changes before significant irreversible damage occurs. This preliminary assessment allows early intervention timing to be determined, preventing the delay in detection that occurs with conventional echocardiography monitoring.
Solution Approach 2:
The patent establishes a feedback mechanism through repeated measurement of LVET and Frank-Starling reserve to monitor disease progression and detect early changes in myocardial function. This continuous feedback allows for timely detection of diminished reserve capacity, enabling earlier intervention compared to conventional monitoring approaches.
4Ease of operation
If echocardiography is used to assess diastolic function, then evaluation can be performed, but accuracy is reduced in patients with comorbid conditions
Solution Approach 1:
The patent replaces echocardiographic assessment of diastolic function with a physiological measurement approach using LVET and Frank-Starling reserve response to preload changes. This substitution provides more accurate detection of diastolic dysfunction in patients with comorbid conditions, as the measurement relies on functional response rather than image quality that is compromised by obesity, hypertension, and other factors.
Data Source
AI summary
A non-invasive diagnostic system assesses the optimal timing for aortic valve replacement (AVR) by quantifying left-ventricular Frank-Starling reserve before irreversible myocardial damage occurs. The system (i) acquires left-ventricular ejection time (LVET) and other systolic-time intervals from optical or vibrational sensors positioned on the patient, (ii) induces a reversible preload change—e.g., passive leg raise or posture transition—to create a controlled venous-return increment, (iii) processes the paired baseline and post-maneuver waveforms to extract systolic time interval metrics, and (iv) analyzes the ΔLVET/Δpreload relationship against historical or population references. A diminished LVET response signals loss of contractile reserve, enabling timely AVR while myocardial changes remain reversible. The platform integrates measurement hardware, a data-processing engine, a data-analysis module, and a reporting interface, and may be configured as a wrist, ring, chest, or ear sensor. The method can be implemented at point-of-care without operator-dependent imaging or invasive monitoring.