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Updated: Jun 21, 2026

Integrated Compensatory Responses in a Human Model of Hemorrhage
Published on: November 20, 2016
The influence of vasovagal response on the coagulation system
Markus Kraemer1, Markus Kuepper, Andrea Nebe-vom Stein
1Autonomic Laboratory, Department of Neurology, Alfried Krupp von Bohlen und Halbach Hospital, Alfried-Krupp-Strasse 21, 45117, Essen, Germany. markus.kraemer1977@gmx.de
Background:
Vasovagal response (VVR) is provoked by a reduced venous blood return to the heart as a reaction to orthostatic stress and to haemorrhage. Recently, two cases were reported showing elevated plasma concentration of von-Willebrand-factor (VWF) and factor VIII (FVIII) after VVR due to venapuncture. Although the effect of epinephrine as trigger for VWF liberation is known, a connection between VVR and activation of the coagulation system has not been studied systematically.
Methods:
We examined 21 subjects with lower body negative pressure. We measured the plasma concentration of von-Willebrand-factor-antigen (VWF:Ag), the activity of von-Willebrand-factor-Ristocetin-Cofactor (VWF:RiCo) and FVIII at several stress-levels and consecutively split up the different VWF-multimers.
Results:
In 16 of 21 subjects VVR could be induced. These subjects showed a significant increase of VWF:Ag concentration in plasma and an increase of FVIII and VWF:RiCo activity. The five individuals who experienced all stress-levels without VVR did not show any changes in their clotting factor levels.
Conclusion:
VVR leads to measurable changes in the coagulation system. This might be a further diagnostic tool in treating patients with syncope.
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