Carotid energy pulsatility index provides complementary hemodynamic information to renal function in a community-based cohort

Conventional hemodynamic, including Carotid-femoral pulse wave velocity (cfPWV), characteristic impedance (Zc), and brachial pulse pressure, do not directly quantify pulsatile energy transmission through the arterial system. Carotid energy pulsatility index (PI), derived from synchronized carotid pressure-flow waveforms, may capture this complementary aspect of arterial hemodynamics. We examined whether carotid energy PI was independently associated with renal function after accounting for conventional vascular hemodynamic measures. Participants from the community-based Cardiovascular Disease Risk Factors Two-Township Study (CVDFACTS) underwent synchronized carotid pressure-flow waveform assessment. Associations of carotid energy PI with eGFR were evaluated using multivariable, restricted cubic spline, and segmented regression analyses. Among 1424 participants (46.8% men; mean age 59.7 ± 11.9 years), higher carotid energy PI was independently associated with lower eGFR after adjustment for covariates (standardized β = -0.088, 95% CI -0.136 to -0.039; P < 0.001). Restricted cubic spline and segmented regression analyses identified turning points at 11.395 m/s for cfPWV and 0.043 for carotid energy PI. Compared with participants with low cfPWV and low carotid energy PI, those with concurrent elevations in both parameters had lower eGFR (β = -3.58, 95% CI -6.03 to -1.12; P = 0.004). Carotid energy PI was independently associated with renal function, with the greatest renal burden observed when pulsatile energy and arterial stiffness were jointly elevated. These findings suggest that carotid energy PI provides information complementary to conventional vascular measures.