Key result
Single-beat Chen method systematically underpredicts left ventricular elastance and responds paradoxically to volume changes.
Why the study?
The reliability and applicability of the single-beat Chen method for estimating left ventricular end-systolic elastance in clinical scenarios needed evaluation through sensitivity analysis.
Sensitivity of Chen Ees(sb) to inputs warrants modeling caution; leaves open clinical reliability without prospective validation.
INTRODUCTION: Left ventricular (LV) end-systolic elastance (Ees) can be estimated using single-beat (Ees(sb)) Chen method, employing systolic and diastolic arm-cuff pressures, stroke volume (SV), ejection fraction and estimated normalized ventricular elastance at arterial end-diastole. This work aims to conduct a sensitivity analysis of Chen formula to verify its reliability and applicability in clinical scenario. METHODS: Starting from a baseline condition, we evaluated the sensitivity of Ees(sb) to the parameters contained in the formula. Moreover, a mathematical model of the cardiovascular system was used to evaluate the sensitivity of Ees(sb) to end-diastolic LV elastance (Eed), Ees, arterial systemic resistance (Ras) and heart rate (HR). CONCLUSION: Unexpectedly Ees(sb) increases for higher LV end-systolic volume and decreases for higher SV. These results contrast with Ees definition, which is the ratio between the LV end-systolic pressure and the LV end-systolic volume. Moreover, Ees(sb) is influenced by cardiocirculatory parameters such as LV Eed, HR, Ras, ejection time, and pre-ejection time. Finally, Ees(sb) computed with the model output often underestimates model Ees.
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A 2022 study studied Left ventricular elastance estimation. Single-beat Chen method vs. Mathematical model of the cardiovascular system was evaluated on Sensitivity of estimated normalized ventricular elastance to cardiocirculatory parameters. The single-beat Chen method for estimating left ventricular elastance incorrectly increases for higher end-systolic volume and decreases for higher stroke volume, often underestimating true elastance.
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