Effect of Beta-Blocker Cardioselectivity on Vascular Refilling in Hemodialysis Patients

Abstract

<b><i>Background:</i></b> β-Blockers are the most frequently prescribed cardioprotective drugs in hemodialysis (HD) patients, despite their weak evidence. We sought to evaluate the effects of β-blockers on vascular refilling during HD treatments and examine whether carvedilol, for being noncardioselective and poorly dialyzable, associates more impact than others. <b><i>Methods:</i></b> The study was performed in a cohort of maintenance HD patients from a tertiary center. All patients had previous β-blocker prescription. We conducted a prospective crossover study and measured vascular refilling volume (<i>V</i><sub>ref</sub>) and vascular refilling fraction (<i>F</i><sub>ref</sub>) in 2 circumstances: under β-blocker treatment (βb profile) and without β-blocker effect (non-βb profile). <b><i>Results:</i></b> Twenty patients were included, 10 of whom were treated with carvedilol. Predialysis values were comparable between the 2 profiles. Although the βb profile showed lower <i>V</i><sub>ref</sub> and higher ABV drop, these differences did not reach statistical significance. Data showed an increase in <i>F</i><sub>ref</sub> in the non-βb profile (70.01 ± 6.80% vs. 63.14 ± 11.65%; <i>p</i> = 0.015). The βb profile associated a significantly higher risk of intradialytic hypotension (IDH) (risk ratio 2.40; 95% CI: 1.04–5.55). When analyzing separately the carvedilol group, patients dialyzed under drug effect experienced a significant impairment in <i>V</i><sub>ref</sub>, <i>F</i><sub>ref</sub>, and refilling rate. <b><i>Conclusions:</i></b> Administering β-blockers before HD associated a higher risk of IDH and a decrease in <i>F</i><sub>ref</sub>. Patients dialyzed under carvedilol effect showed an impaired refilling, probably related to its noncardioselectivity and lower dializability.

Dynamics of vascular refilling in extended nocturnal hemodialysis

“…A refilling fraction of 70%-75% also implies that for each liter of UF volume the blood volume is depleted by 250-300 ml. In patients under beta-blocker treatment, 13,22 and especially under carvedilol, this gap may reach 400 ml or more, and leads to a significantly higher risk of intradialytic hypotension. 22 This must be taken into account in volume management to avoid intradialytic complications.…”

Vascular refilling depends on the ratio of blood volume to extracellular volume in hemodialysis patients

“…In previous clinical studies on vascular refilling, the refilling fractions reached a mean level of about 70-75% with relatively large individual variability (SD about ± 10%, or even individually minimum 40 and maximum 98%). 4,6,10,11,[13][14][15][16][17][18][19] In theory, the sum of refilling fraction and BV/ECV ratio should be 1. 11 However, we could not confirm this hypothesis in this study (sum 1.07).…”

“…In previous clinical studies on vascular refilling, the refilling fractions reached a mean level of about 70–75% with relatively large individual variability (SD about ± 10%, or even individually minimum 40 and maximum 98%). 4,6,10,11,13–19…”

Individually adjusted absolute blood volume feedback control: A promising solution for intradialytic hypotension

“…Based on our previous experience, despite several clinical and hemodynamic factors that modify vascular refilling, there is a considerable interindividual discrepancy in patients’ refilling 23–26 . Subsequently, a uniform ABV threshold might be inaccurate in predicting IDH, and we suggest individualizing critical ABV.…”