Abstract 19692: Pressure-Flow Derived Hemodynamic Predictors of Reduced Kidney Function With Age in a Community Dwelling Population
Background: Significant hemodynamic changes with age have been implicated in age-associated kidney function decline. Pulse pressure, augmentation index, and pulse wave velocity have been found to be associated with reduced kidney function. However, relative to these measures, pressure-volume derived parameters provide more physiologic assessment of the pulsatility and are likely to better correlate with kidney function.
Hypothesis: Pressure-flow loading parameters are more strongly associated with kidney function than pulse pressure, augmentation index, and pulse wave velocity.
Methods: We studied 382 participants (185 men, age range 26-95) from the Baltimore Longitudinal Study of Aging who had urine, carotid tonometry, and left-ventricular outflow Doppler analyses performed. Pressure and flow waveform analysis was performed using custom-designed Matlab software to calculate reflected wave transit time (RWTT), reflection coefficient (RC), and characteristic impedance (Zc). Other hemodynamic assessment included measurements of mean arterial pressure (MAP), central pulse pressure (PP), augmentation index (AI), and pulse wave velocity (PWV). Kidney function was assessed by creatinine clearance (CC).
Results: Adjusting for gender, race, weight, hypertension, and diabetes, CC declined with advancing age (β=-1.3, P<0.0001). While not associated with PP, AI, and PWV, CC was inversely associated with Zc and RC and positively associated with RWTT and MAP. In standardized multivariate analysis, RWTT had the highest standardized coefficient (β=112.4, P=0.0037) followed by Zc (β=-56.1, P=0.0387), RC (β=-25.3, P=0.0113), and MAP (β=0.5, P<0.0001). The hemodynamic variables explained 4% of the decline in kidney function with age.
Conclusions: The decline in kidney function with age is more strongly associated with pressure-flow pulsatility parameters than those determined exclusively via measurement of pressure. The identified pressure-flow pulsatility parameters are indicative of increases in late arterial loading with decreased kidney function. Additional analyses involving a larger population with longitudinal data are needed to confirm these findings.
Author Disclosures: M. Oberdier: None. S. Studenski: None. E. Lakatta: None. M. AlGhatrif: None.
- © 2016 by American Heart Association, Inc.