Extracellular Volume Overload and Increased Vasoconstriction in Patients With Recurrent Intradialytic Hypertension

Abstract

Background/Aims: Intradialytic hypertension (IH) occurs frequently in some hemodialysis patients and increases mortality risk. We simultaneously compared pre-dialysis, post-dialysis and changes in extracellular volume and hemodynamics in recurrent IH patients and controls. Methods: We performed a case-control study among prevalent hemodialysis patients with recurrent IH and hypertensive hemodialysis controls. We used bioimpedance spectroscopy and impedance cardiography to compare pre-dialysis, post-dialysis, and intradialytic change in total body water (TBW) and extracellular water (ECW), as well as cardiac index (CI) and total peripheral resistance index (TPRI). Results: The ECW/TBW was 0.453 (0.05) pre-dialysis and 0.427 (0.04) post-dialysis in controls vs. 0.478 (0.03) and 0.461 (0.03) in IH patients (p=0.01 post-dialysis). The ECW/TBW change was -0.027 (0.03) in controls and -0.013 (0.02) in IH patients (p=0.1). In controls, pre- and post-dialysis TPRI were 3254 (994) and 2469 (529) dynes/sec/cm²/m² vs. 2983 (747) and 3408 (980) dynes/sec/cm²/m² in IH patients (p=0.002 post-dialysis). There were between-group differences in TPRI change (0=0.0001), but not CI (p=0.09). Conclusions: Recurrent intradialytic hypertension is associated with higher post-dialysis extracellular volume and TPRI. Intradialytic TPRI surges account for the vasoconstrictive state post-dialysis, but intradialytic fluid shifts may contribute to post-hemodialysis volume expansion.

Intradialytic Hypertension Frequency and Short-Term Clinical Outcomes Among Individuals Receiving Maintenance Hemodialysis

“…6,7,10,11 While the exact pathophysiology is unclear, mechanistic studies suggest that volume overload contributes to a substantial proportion of intradialytic hypertension episodes. 12,13 Intradialytic Hypertension Frequency and Short-Term Clinical Outcomes Among Individuals Receiving Maintenance Hemodialysis Magdalene M. Assimon, 1,2 Lily Wang, 3 and Jennifer E. Flythe 1,3 BACKGROUND Intradialytic hypertension occurs in 5-20% of hemodialysis treatments. Observational data support an association between intradialytic hypertension and long-term mortality.…”

Assessing Extracellular Volume in Hemodialysis Patients Using Intradialytic Blood Pressure Slopes

“…Of 262 subjects screened, 36 enrolled in the original case-control study (18 subjects per group) [8]. An additional 35 subjects were subsequently enrolled for this analysis.…”

“…The original case-control study compared measurements of BIS and noninvasive cardiac output monitoring in patients with intradialytic hypertension and other hypertensive hemodialysis controls [8]. Inclusion criteria were age >18 years, hemodialysis vintage >1 month, and hypertension defined by Kidney Disease Outcomes Quality Initiative (KDOQI) guidelines (systolic BP >140 mm Hg pre-dialysis or >130 mm Hg post-dialysis) [11].…”

“…Intradialytic blood pressure (BP) patterns have recently been linked to the degree of ECV overload [7, 8] with patients exhibiting intradialytic hypertension having higher ratios of ECV/TBW compared to patients with BP decreases. These findings require deeper investigation because (1) only 15% of hemodialysis patients regularly experience intradialytic hypertension [9, 10] and (2) it is uncertain if this relationship extends across a continuous spectrum of intradialytic BP changes.…”

N-Terminal Prohormone of Brain Natriuretic Peptide but not C-Terminal Pre-Pro Vasopressin (Copeptin) Level is Associated with the Response to Antihypertensive Therapy in Haemodialysis Patients

“…It should be acknowledged that the definition of resistant hypertension in the population of HD patients is not applicable due to the lack of diuretics efficacy in oliguric/anuric patients. Hypertension in HD patients often reflects inadequate volume control [6], and preservation of fluid in the extracellular space [7]. It should be stressed that the clinical assessment of volaemia could raise significant difficulties as up to now, there is the lack of simple reliable, validated, clinically applicable method for volume assessment in HD patients.…”