Blood pressure waveform (BPW) can be used to characterize changes in the cardiovascular system due to diseases and aging. The BPW morphology is largely determined by both the total mechanical impedance of the vasculature and the flow waveform produced by the left ventricle. The BPW can be further decomposed into its two primary components: the forward and reflected waveforms. It is known that under several conditions, such as aging, arterial wall stiffening, and increased cardiovascular risk, the magnitudes and phases of these waves change and therefore distort the aggregate BPW. Previous studies of the BPW has yielded mixed results, largely due to the insensitivities of the primary wave morphology index, augmentation index (AI). To this end, a new method of morphology characterization was developed which takes into account the overall harmonic content of the BPW.
Harmonic distortion (HD), derived from Fourier-transformed BPW, was first used to characterize changes in the aortic wall. Utilizing mice subjected to normal and high fat, high-sucrose diets, the results demonstrate that HD exhibits a linear relationship with both systolic blood pressure (SBP) and arterial stiffness. Next, a transmission line model of arterial impedance was developed to study physiologically realistic BPWs under various arterial tree sizes and stiffness. Comparison of HD and other indexes reveals that HD correlates strongly with arterial stiffness, surpassing AI in accuracy for higher stiffness values. Finally, HD analysis was applied to BPWs collected clinically on a diverse group of participants. HD emerges as a more sensitive indicator than AI, notably correlating with diabetes and demonstrating stability across heart rate variations. The superior statistical performance of HD over AI in hemodynamic variables underscores its potential as a robust measure for cardiovascular risk assessment. This research offers a comprehensive framework for assessing arterial health, highlighting the potential of HD as a stable, sensitive, and noninvasive measure. This integrated approach contributes to a nuanced understanding of the intricate factors influencing BPW morphology and its implications for cardiovascular health in the context of aging and disease.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/47949 |
| Date | 18 January 2024 |
| Creators | Milkovich, Nicholas |
| Contributors | Zhang, Katherine Yanhang, Suki, Béla |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
| Rights | Attribution-NonCommercial-NoDerivatives 4.0 International, http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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