Associations of Reservoir-Excess Pressure Parameters Derived From Central and Peripheral Arteries With Kidney Function

Abstract

Background: Central artery reservoir-excess pressure parameters are clinically important but impractical to record directly. However, diastolic waveform morphology is consistent across central and peripheral arteries. Therefore, peripheral artery reservoir-excess pressure parameters related to diastolic waveform morphology may be representative of central parameters and share clinically important associations with end-organ damage. This has never been determined and was the aim of this study.

Methods: Intra-arterial blood pressure (BP) waveforms were measured sequentially at the aorta, brachial, and radial arteries among 220 individuals (aged 61 ± 10 years, 68% male). Customized software was used to derive reservoir-excess pressure parameters at each arterial site (reservoir and excess pressure, systolic and diastolic rate constants) and clinical relevance was determined by association with estimated glomerular filtration rate (eGFR).

Results: Between the aorta and brachial artery, the mean difference in the diastolic rate constant and reservoir pressure integral was -0.162 S-1 (P = 0.08) and -0.772 mm Hg s (P = 0.23), respectively. The diastolic rate constant had the strongest and most consistent associations with eGFR across aortic and brachial sites (β = -0.20, P = 0.02; β = -0.20, P = 0.03, respectively; adjusted for traditional cardiovascular risk factors). Aortic, but not brachial peak reservoir pressure was associated with eGFR in adjusted models (aortic β = -0.48, P = 0.02).

Conclusions: The diastolic rate constant is the most consistent reservoir-excess pressure parameter, in both its absolute values and associations with kidney dysfunction, when derived from the aorta and brachial artery. Thus, the diastolic rate constant could be utilized in the clinical setting to improve BP risk stratification.

Keywords: blood pressure; hemodynamics; hypertension; physiology; vascular stiffness.