Clearance of vasopressin and copeptin during hemodialysis

A recent study in 29 hemodialysis patients has provided insight in the course
of the vasoconstrictor arginine vasopressin and its pro-hormone copeptin.
Vasopressin could, at least in part, play a role in hemodynamic stability
during hemodialysis. Analysis of vasopressin is difficult considering its
(pre-)analytical variability and there has been suggested that copeptin is a
good marker for vasopressin.
Little is known about the effect of hemodialysis on levels of vasopressin and
copeptin and to what extent both hormones are removed with hemodialysis. In
order to also study the effect of renal function on vasopressin and copeptin,
data of the 29 hemodialysis patients were combined with data from patients with
renal failure in different stages. Nowadays, more and more studies are
conducted in which copeptin is measured and it is of importance to delineate
whether there is an effect of kidney function on copeptin for correct
interpretation of the results. Comparison of the data from the two study
populations revealed that the ratio copeptin/vasopressin is different in
dialysis patients in comparison with patients with renal failure. We did not
find any errors in the sample handling, storage and thawing of the samples and
in the assay itsself and it could be that the copeptin/vasopressin ratio
differs between patients on dialysis and patients with chronic kidney disease.
It is important to replicate the results of vasopressin and copeptin from the
previous study to know with more certainty if the ratio is indeed different in
dialysis patients.

To study the ratio of copeptin and vasopressin in hemodialysis patients at the
start of the dialysis session and if the ratio is affected by the hemodialysis
procedure itsself by calculation of the clearance of both molecules with
hemodialysis. The objective of this study is to replicate the results of
vasopressin and copeptin from the previous study.

Blood will be drawn three times in total: once the start of dialysis and twice
after 30 minutes of dialysis (once before the artificial kidney and once after
the artificial kidney). Also, 10 ml of dialysate shall be collected after 30
minutes of dialysis.

The study will be conducted during a routine hemodialysis treatment and in
total 30 ml of blood will be drawn from the dialysis line. Patients do not have
to undergo an extra venipuncture. There are no risks associated with
participation in this study.