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. 2024 Mar 1;19(3):329-335.
doi: 10.2215/CJN.0000000000000356. Epub 2023 Nov 16.

Association of Bioimpedance Parameters with Increases in Blood Pressure during Hemodialysis

Enass Elsayed  1   2 , Youssef M K Farag  3   4 , Katherine Scovner Ravi  1   2 , Glenn M Chertow  5 , Finnian R Mc Causland  1   2
Affiliations

Association of Bioimpedance Parameters with Increases in Blood Pressure during Hemodialysis

Enass Elsayed et al. Clin J Am Soc Nephrol. .

Abstract

Background: Intradialytic hypertension, defined as an increase in BP from pre- to post-hemodialysis (HD), affects 5%-15% of patients receiving maintenance HD and is associated with cardiovascular and all-cause mortality. Hypervolemia is believed to be a major etiological factor, yet the association of more objective biomarkers of volume status with intradialytic hypertension is not well described.

Methods: In a post hoc analysis of the Frequent Hemodialysis Network Daily Trial ( n =234), using data from baseline, 1-, 4-, and 12-month visits ( n =800), we used random-effects regression to assess the association of bioimpedance estimates of volume (vector length) with post-HD systolic BP (continuous) and any increase in systolic BP (categorical) from pre- to post-HD. We adjusted models for randomized group; age; sex; self-reported race; Quételet (body mass) index; vascular access; HD vintage; hypertension; history of heart failure; diabetes; residual kidney function (urea clearance); pre-HD systolic BP; ultrafiltration rate; serum-dialysate sodium gradient; and baseline values of hemoglobin, phosphate, and equilibrated Kt/V urea.

Results: The mean age of participants was 50±14 years, 39% were female, and 43% were Black. In adjusted models, shorter vector length (per 50 Ω/m) was associated with higher post-HD systolic BP (2.9 mm Hg; 95% confidence interval [CI], 1.6 to 4.3) and higher odds of intradialytic hypertension (odds ratio 1.66; 95% CI, 1.07 to 2.55). Similar patterns of association were noted with a more stringent definition of intradialytic hypertension (>10 mm Hg increase from pre- to post-HD systolic BP), where shorter vector length (per 50 Ω/m) was associated with a higher odds of intradialytic hypertension (odds ratio 2.17; 95% CI, 0.88 to 5.36).

Conclusions: Shorter vector length, a bioimpedance-derived proxy of hypervolemia, was independently associated with higher post-HD systolic BP and risk of intradialytic hypertension.

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Conflict of interest statement

G.M. Chertow reports consultancy for Akebia, Ardelyx, AstraZeneca, Calico, Gilead, Miromatrix, Reata, Sanifit, Unicycive, and Vertex; ownership interest in Ardelyx, CloudCath, Durect, DxNow, Eliaz Therapeutics, Outset, Physiowave, PuraCath, Renibus, and Unicycive; research funding from CSL Behring, NIAID, and NIDDK; advisory or leadership roles for Satellite Healthcare Board of Directors and as a Co-Editor of Brenner & Rector's The Kidney (Elsevier); and other interests or relationships with DSMB service: Bayer, Gilead, Mineralys, NIDDK, and ReCor. G.M. Chertow served as Chair or Co-Chair of Trial Steering Committees with Akebia, AstraZeneca, CSL Behring, Sanifit, and Vertex. He has served as an advisor to CloudCath, Durect, Eliaz Therapeutics, Miromatrix, Outset, Physiowave, Renibus, and Unicycive. He has served on Data Safety Monitoring Boards with Bayer, Mineralys, and ReCor. Y.M.K. Farag reports employment with Bayer US, LLC. F.R. Mc Causland reports consultancy for GlaxoSmithKline and Zydus Therapeutics Inc.; research funding paid to institution from Advanced Medical, Fifth Eye, Lexicon, NIH, Novartis, and Satellite Healthcare; and expert witness fees from Rubin Anders Scientific. K.S. Ravi reports research funding from the NIH (K23 DK127248). K.S. Ravi's spouse reports ownership interest in Halo LLC. The remaining author has nothing to disclose.

Figures

None
Graphical abstract
Figure 1
Figure 1
CONSORT diagram. FHN, Frequent Hemodialysis Network.
Figure 2
Figure 2
Association of mean vector length with mean post-dialysis systolic BP. The solid black line represents the association of mean vector length with mean post-dialysis systolic BP; the dashed lines are the 95% confidence intervals; the histogram in the background represents the frequency of patients with various mean vector lengths. HD, hemodialysis.
See this image and copyright information in PMC

Comment in

References

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