Copeptin levels in patients with vasovagal syncope

Background and purpose: Vasovagal syncope (VVS) is linked to more than one pathophysiologic mechanisms. Copeptin, an emerging cardiovascularmarker, is a surrogate for arginine-vasopressin, which increases following VVS. We aimed to assess the dynamic pattern of copeptin levels in typical VVS, categorized by the degree of vasoconstriction during orthostasis, and healthy controls. Methods: The following groups were studied: Group A (n=21), with adequate limb vasoconstriction during the first min. of tilt, assessed by limb plethysmography (at least 30% flow reduction); Group B (n = 15), showing impaired vasoconstriction during orthostasis (b10% reduction); Group C (n=18), history of VVS and negative tilt test result; Group D (n = 18), healthy controls. Copeptin plasma levels were assessed before and 5 min following tilt test positivity or termination. Results: Baseline copeptin valueswere similar in all groups (8.3 +/- 6.4 in Group A, 5.7 +/- 2.3 pmol/l in B, 6.0 +/- 1.9 in C, and 6.9 +/- 2.6 in D, p: 0.41). Significant increases in copeptin during tilt were observed in all Groups of VVS patients (A, B, C), including those with negative tilt (Group C: from 6.0 +/- 1.9 to 27.7 +/- 12.6 pmol/l, p: 0.001), but not in controls. Following tilt termination, a greater increase was observed in copeptin values in Group B vs all other Groups A, C, and D (111.6 +/- 63.5 vs 29.5 +/- 51.3, 27.7 +/- 12.6, and 8.3 +/- 2.9, respectively). Conclusions: Copeptin increases following tilt not only in VVS with a positive response, but also in typical history patients with a negative test. Increased copeptin levels following orthostasis may be useful for diagnosing VVS. (C) 2016 Published by Elsevier Ireland Ltd.