Fluid overload modifies ambulatory blood pressure and pulse wave characteristics in hemodialysis patients undergoing targeted fluid management

Figures

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  Figure 1:. Overview of parameters and interactions of the trended cosinor model. Each panel shows one of the trended cosinor model’s terms and interactions of interest across the 44-h interdialytic interval, drawn at three levels of post-dialysis FO (−1.1, 0, and +1.1 L). From left to right: the mean level, comprising the intercept and the FO main effect, indicating BP or PWC values right after dialysis; the interdialytic trend over the interval, whose slope is progressively flattened by the FO × time interaction; the circadian rhythm, a 24-h cosine/sine oscillation whose amplitude (and, depending on the coefficients, phase) is altered by the FO × cosine and FO × sine interactions; and their sum, the fitted interdialytic curve. Abbreviation: FO, fluid overload.

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  Figure 2:. Interdialytic patterns of peripheral systolic blood pressure (pSBP) and pulse wave velocity (PWV). Panels A and B show interdialytic patterns of pSBP and PWV overall and stratified by post-dialysis fluid overload (FO, hypovolemia: <−1.1 L; euvolemia: −1.1 to +1.1 L; and hypervolemia: >1.1 L). The respective top row depicts values individually and with smooth curves (method “gam”). The respective bottom row depicts measurements as the visit-level average difference from the respective first measurement timepoint. Steepness indicates by how much pSBP/PWV changed from the first interdialytic measurement day. Circles (red) indicate measurements taken during the day (07:01–23:00) while triangles (blue) indicate measurements taken during the night (23:01–07:00). “Day 1” and “Day 3” indicate the days of the two dialysis treatments framing the interdialytic interval. Abbreviations: FO, fluid overload; pSBP, peripheral systolic blood pressure; PWV, pulse wave velocity.

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  Figure 3:. Predicted blood pressure (BP) and pulse wave characteristics (PWCs) at different levels of fluid overload (FO). Curves show predicted BPs and PWCs at three post-dialysis FO levels (−1.1, 0, and +1.1 L) derived from trended cosinor linear mixed-effects models. These curves visualize how different post-dialysis FO levels affect interdialytic intercepts, slopes, and circadian rhythms within a subject who is held otherwise constant for all other model confounders. Predictions were adjusted for confounders at sample means or medians. FO levels affected the start of the curve and interacted with the trend, circadian phase, and amplitude. Shaded areas show 95% CIs from parametric bootstrap. Shaded gray areas show nighttime hours (23:01–07:00). “Day 1” and “Day 3” indicate the days of the two dialysis treatments framing the interdialytic interval. Abbreviations: BP, blood pressure; cDBP and pDBP, central and peripheral diastolic blood pressure; cSBP and pSBP, central and peripheral systolic blood pressure; FO, fluid overload; PR, peripheral resistance; PWC, pulse wave characteristic; and SV, stroke volume.

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  Figure 4:. Predicted pulse wave characteristics (PWCs) at different levels of fluid overload (FO). Curves show predicted PWCs at three post-dialysis FO levels (−1.1, 0, and +1.1 L) derived from trended cosinor linear mixed-effects models. These curves visualize how different post-dialysis FO levels affect interdialytic intercepts, slopes, and circadian rhythms within a subject who is held otherwise constant for all other model confounders. Predictions were adjusted for confounders at sample means or medians. FO levels affected the start of the curve and interacted with the trend, circadian phase, and amplitude. Shaded areas show 95% CIs from parametric bootstrap. Shaded gray areas show nighttime hours (23:01–07:00). “Day 1” and “Day 3” indicate the days of the two dialysis treatments framing the interdialytic interval. Abbreviations: AIx, augmentation index; FO, fluid overload; pb, backward wave amplitude; Pex Peak, excess pressure peak; pf, forward wave amplitude; Pr Peak, reservoir pressure peak; PWC, pulse wave characteristic; and PWV, pulse wave velocity.