Vasoactive Agents and Blood Pressure Regulation in Sequential Ultrafiltration and Hemodialysis

Abstract

Hypotension is a common and sometimes dangerous side effect of hemodialysis. Its etiology is multifactorial and largely unknown. Earlier studies on the role of endogenous blood pressure regulating agents such as catecholamines and renin have rendered conflicting results. We studied the influence of ultrafiltration and isovolemic hemodialysis separately on the plasma concentrations of the following blood pressure regulating agents: adrenaline, noradrenaline, dopamine, neuropeptide Y, calcitonin gene-related peptide (CGRP), renin (PRA), angiotensin II, vasopressin, aldosterone and cortisol. During isolated ultrafiltration, plasma levels of two strong vasoconstrictors (noradrenaline and angiotensin II) and one strong vasodilator (calcitonin gene-related peptide, CGRP) increased significantly (noradrenaline 3.24 +/- 0.60 nM to 4.31 +/- 0.55 nM; p = 0.032, angiotensin II 19.74 +/- 3.46 pmol/l to 28.49 +/- 7.24 pmol/l; p = 0.047) No symptomatic hypotension occurred. At the end of isovolemic hemodialysis, plasma levels of all the vasoconstricting agents had decreased to pretreatment values, but those of CGRP had continued to rise (from 85.3 +/- 17.6 pmol/l to 114.5 +/- 25.3 pmol/l, p = 0.031). During isovolemic hemodialysis, blood pressure fell to symptomatic levels, but was restored at the end of treatment. The study shows that hemodialysis patients respond to fluid removal by ultrafiltration with an increase in plasma levels of CGRP, noradrenaline and angiotensin II. The net effect is an appropriate vasoconstriction and adequate blood pressure is maintained during isolated ultrafiltration.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of a Hemodialysis Session on Plasma Levels of Endothelin-1 in Hypertensive and Normotensive Subjects with End-Stage Renal Failure

“…The sympathetic activation and consequently increased local levels of catecholamines might also stimulate generation of ET-1 [1]. Odar-Cederloef et al [17]observed falls of neck vein pressure by about 1.2 mm Hg and rises in circulating norepinephrine by 30% during isolated ultrafiltration with fluid removal of about 2.1 liters. Kinet et al [18]reported reduction of mean pulmonary capillary wedge pressure by 9.4 mm Hg after hemodialysis, whereas tilting-induced reductions of central venous pressure of about 3.4 mm Hg produced significant elevations of circulating ET-1 [19].…”

Dialysis Hypotension: A Role for Inadequate Increase in Arginine Vasopressin Levels? A Systematic Literature Review and Meta-Analysis

“…Studies in which UF-only was preceded or followed by isovolumic HD showed divergent results regarding the course of AVP [2,39,40,48,59]. It is beyond the scope of this article to discuss these studies in detail.…”

“…Plasma AVP levels in patients varied widely, with some studies reporting pre-HD plasma AVP levels above the concentration regarded as the upper level of normal of 4 pg/ml [2,16,24,25,35,37,38,39,40,41,45,46,47,48,49,50,51,52,53,54], while others found pretreatment plasma AVP levels around or below 4 pg/ml [32,33,34,43,44,55,56,57] (fig. 3a).The variation in pretreatment plasma AVP levels might be due to analytical variation resulting from the use of different assays.…”

“…These studies showed mixed results, but it is important to note that plasma AVP levels were generally measured after intradialytic hypotension instead of during intradialytic hypotension. In addition, in these eight studies a total of five different definitions of intradialytic hypotension were used [21,29,34,47,60], whereas in three studies no definition was provided at all [2,45,48]. In some of these studies it was found that plasma AVP levels were higher after intradialytic hypotension had occurred [45,48,60], whereas others found no difference in plasma AVP levels between patients with and without intradialytic hypotension [47], or only observed higher AVP levels when intradialytic hypotension was accompanied by nausea [29].…”

“…Intradialytic hypotension is a serious complication of hemodialysis (HD) and is estimated to occur in about 20-30% of HD treatments [1,2]. Symptoms of intradialytic hypotension vary from mild, transient symptoms, such as muscle cramps, nausea and dizziness, to serious complications like cardiac ischemia and arrhythmias, and cerebrovascular events [1,3].…”