Serum Vasopressin Response in Patients With Intradialytic Hypotension

Abstract

Background and Objectives: Arginine vasopressin (AVP), an endogenous hormone with vasopressor properties, may be inadequately secreted during episodes of intradialytic hypotension (IDH).Design, Setting, Participants, and Measurements: To evaluate this, we performed a prospective, observational pilot study of 20 chronic hemodialysis patients assessing the baseline AVP level and trend of AVP with ultrafiltration in patients with a diagnosis of IDH compared with patients without IDH. Ten symptomatic IDH patients and 10 controls were enrolled and matched for age, gender, and dialysis vintage. AVP levels were obtained hourly throughout the dialysis session and during hypotensive episodes.Results: We observed that IDH patients experienced greater decreases in both systolic and diastolic blood pressure during the dialysis session despite equivalent ultrafiltration in both groups. AVP concentration did not increase in the IDH patients (5.0 ؎ 1.8) compared with controls (6.4 ؎ 6.0) (P ‫؍‬ 0.5) despite hypotensive events.Conclusions: This study suggests that symptomatic IDH patients are unable to mount an appropriate increase in AVP secretion in the setting of hypotension. These findings support the possibility of AVP as a mechanism driven therapy for patients with symptomatic IDH.

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

“…The normal plasma AVP concentration in a fasted and hydrated person is below 4 pg/ml [18,19,20,21]. The plasma half-life of AVP is about 5-35 min and it is rapidly metabolized by liver and kidney vasopressinases [19,20,22].…”

“…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].…”

“…In only two studies was blood sampling performed at the moment that intradialytic hypotension actually occurred [21,29]. In one of these studies, Rho et al [21] showed that plasma AVP levels did not differ between patients who did and those who did not experience intradialytic hypotension.…”

“…In one of these studies, Rho et al [21] showed that plasma AVP levels did not differ between patients who did and those who did not experience intradialytic hypotension. All in all, at present no clear conclusion can be made about whether an inadequate rise in AVP levels has a role in the pathophysiology of intradialytic hypotension.…”

“…First, since AVP secretion is under control of the baroreflex arc, autonomic dysfunction could impair the release of AVP, as has been suggested by several groups [21,24,33]. Dysfunction of the autonomic nervous system is common in patients on HD [47,63,64].…”