Carotid pulsatile energy fraction surpasses traditional hemodynamic markers in explaining cognitive impairment among hemodialysis patients

Cognitive impairment is a frequent yet poorly understood complication of maintenance hemodialysis. We studied 162 thrice-weekly hemodialysis patients and 1858 community adults characterized previously with identical pressure-flow protocols. Group comparisons were conducted following propensity score matching and utilizing ANCOVA, adjusted for age, sex, educational attainment, body mass index, diabetes, and hypertension. On a mid-week non-dialysis day, synchronous applanation tonometry and Doppler ultrasound recorded ascending-aortic and common-carotid waveforms; mean hydraulic energy, pulsatile energy and the pulsatile energy fraction (PEF) were computed for each heartbeat. Global cognition was assessed with the Montreal Cognitive Assessment (MoCA), with scores < 26 indicating impairment. Cognitive dysfunction was present in 39% of 152 hemodialysis patients versus 33% of community adults (Standardized Mean Difference = 0.134). Compared with the Community group, hemodialysis group exhibited a 45% increase in aortic PEF (0.16 ± 0.07 vs 0.11 ± 0.03), and a 74% increase in carotid PEF (0.080 ± 0.04 vs 0.046 ± 0.02). In multivariable models adjusted for age, sex, education level, and body-mass index, carotid PEF displayed the strongest inverse association with MoCA (standardized β = -0.287, p < 0.001). Introducing carotid PEF increased the model's explained variance and rendered pulse pressure and carotid-femoral pulse-wave velocity non-significant. Conversely, higher steady mean carotid energy correlated positively with MoCA (β = +0.158, p = 0.030). These findings indicate that cognitive performance in hemodialysis patients is governed less by conventional pressure or stiffness metrics than by the pulsatile energy transmitted to the carotids, positioning carotid PEF as a mechanistic marker and promising therapeutic target for preserving cognition in this vulnerable population.