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.
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.
Authors: Michele Brignole; Paolo Alboni; David G Benditt; Lennart Bergfeldt; Jean-Jacques Blanc; Poul Erik Bloch Thomsen; J Gert van Dijk; Adam Fitzpatrick; Stefan Hohnloser; Jan Janousek; Wishwa Kapoor; Rose Anne Kenny; Piotr Kulakowski; Giulio Masotti; Angel Moya; Antonio Raviele; Richard Sutton; George Theodorakis; Andrea Ungar; Wouter Wieling; Silvia G Priori; Maria Angeles Alonso Garcia; Andrzej Budaj; Martin Cowie; Jaap Deckers; Enrique Fernandez Burgos; John Lekakis; Bertil Lindhal; Gianfranco Mazzotta; João Morais; Ali Oto; Otto Smiseth; Carlo Menozzi; Hugo Ector; Panos Vardas Journal: Eur Heart J Date: 2004-11 Impact factor: 29.983
Authors: C Loesberg; M D Gonsalves; J Zandbergen; C Willems; W G van Aken; H V Stel; J A Van Mourik; P G De Groot Journal: Biochim Biophys Acta Date: 1983-09-22
Authors: N Colman; K Nahm; K S Ganzeboom; W K Shen; J Reitsma; M Linzer; W Wieling; H Kaufmann Journal: Clin Auton Res Date: 2004-10 Impact factor: 4.435
Authors: P G de Groot; M D Gonsalves; C Loesberg; M F van Buul-Wortelboer; W G van Aken; J A van Mourik Journal: J Biol Chem Date: 1984-11-10 Impact factor: 5.157