Abstract
<title>Abstract</title> <p> <bold>Introduction:</bold> Increased blood pressure variability (BPV) is independently associated with cardiovascular mortality in hemodialysis (HD). Fluid overload (FO) is a major modifiable driver of blood pressure (BP), yet the relationship between BPV and FO is unknown. We assessed whether FO correlates with BPV, whether bioimpedance spectroscopy (BIS)-guided fluid management alters BPV, and whether pulse wave characteristics (PWC) correlate with BPV within individual HD patients. <bold>Methods</bold> We analysed 76 HD patients in a quality improvement project which consisted of targeted fluid management. Short-term BPV, primarily average real variability (ARV), was calculated from 44-hour interdialytic ambulatory recordings. FO strata (hypovolemia: <-1.1 L; euvolemia: -1.1 to + 1.1 L; hypervolemia: >1.1 L) were defined by post-HD BIS. Within-patient repeated-measures correlations (rmcorr) assessed correlations of FO and PWC with BP ARV. <bold>Results</bold> Peripheral systolic ARV was 12.3 ± 3.2 mmHg overall (baseline 12.5 ± 3.1; follow-up 11.8 ± 3.3). Among 37 patients with paired data, FO fell significantly from baseline to follow-up (ΔFO -0.59 ± 1.72 L, p = 0.043). ARV did not change (ΔARV − 0.25 ± 2.59 mmHg, p = 0.56), even in the 14 hypervolemic patients with more pronounced decrease in FO (ΔFO -2.06 ± 1.1 L; ΔARV − 0.04 mmHg, 95% CI [-1.37 to + 1.30]). FO did not correlate with ARV within-patient (r=-0.078, p > 0.99). In contrast, PWCs correlated strongly with ARV on an intra-patient basis, especially pulse wave velocity (r = + 0.631, p < 0.001). <bold>Conclusions</bold> FO did not correlate with BPV, whereas PWCs, particularly pulse wave velocity, were the dominant within-individual correlates. In HD, short-term BPV appears dissociated from volume status. BIS-guided fluid management addresses mean BP but should not be expected to reduce short-term BPV. </p>