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Procoagulatory changes induced by head-up tilt test in patients with syncope : Observational study

Hamrefors, Viktor LU ; Fedorowski, Artur LU ; Strandberg, Karin LU ; Sutton, Richard and Isma, Nazim LU (2017) In Thrombosis Journal 15(1).
Abstract

Background: Orthostatic hypercoagulability is proposed as a mechanism promoting cardiovascular and thromboembolic events after awakening and during prolonged orthostasis. We evaluated early changes in coagulation biomarkers induced by tilt testing among patients investigated for suspected syncope, aiming to test the hypothesis that orthostatic challenge evokes procoagulatory changes to a different degree according to diagnosis. Methods: One-hundred-and-seventy-eight consecutive patients (age, 51±21years; 46% men) were analysed. Blood samples were collected during supine rest and after 3min of 70° head-up tilt test (HUT) for determination of fibrinogen, von Willebrand factor antigen (VWF:Ag) and activity (VWF:GP1bA), factor VIII... (More)

Background: Orthostatic hypercoagulability is proposed as a mechanism promoting cardiovascular and thromboembolic events after awakening and during prolonged orthostasis. We evaluated early changes in coagulation biomarkers induced by tilt testing among patients investigated for suspected syncope, aiming to test the hypothesis that orthostatic challenge evokes procoagulatory changes to a different degree according to diagnosis. Methods: One-hundred-and-seventy-eight consecutive patients (age, 51±21years; 46% men) were analysed. Blood samples were collected during supine rest and after 3min of 70° head-up tilt test (HUT) for determination of fibrinogen, von Willebrand factor antigen (VWF:Ag) and activity (VWF:GP1bA), factor VIII (FVIII:C), lupus anticoagulant (LA1), functional APC-resistance, and activated prothrombin time (APTT) with and without activated protein C (C+/-). Analyses were stratified according to age, sex and diagnosis. Results: After 3min in the upright position, VWF:Ag (1.28±0.55 vs. 1.22±0.54; p<0.001) and fibrinogen (2.84±0.60 vs. 2.75±0.60, p<0.001) increased, whereas APTT/C+/- (75.1±18.8 vs. 84.3±19.6s; p<0.001, and 30.8±3.7 vs. 32.1±3.8s; p<0.001, respectively) and APC-resistance (2.42±0.43 vs. 2.60±0.41, p<0.001) decreased compared with supine values. Significant changes in fibrinogen were restricted to women (p<0.001) who also had lower LA1 during HUT (p=0.007), indicating increased coagulability. Diagnosis vasovagal syncope was associated with less increase in VWF:Ag during HUT compared to other diagnoses (0.01±0.16 vs. 0.09±0.17; p=0.004). Conclusions: Procoagulatory changes in haemostatic plasma components are observed early during orthostasis in patients with history of syncope, irrespective of syncope aetiology. These findings may contribute to the understanding of orthostatic hypercoagulability and chronobiology of cardiovascular disease.

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publication status
published
subject
keywords
Coagulation factors, Fibrinogen, Hypercoagulability, Orthostatic stress, Partial thromboplastin time, Von Willebrand factor
in
Thrombosis Journal
volume
15
issue
1
publisher
BioMed Central
external identifiers
  • scopus:85021120414
  • wos:000403969400001
ISSN
1477-9560
DOI
10.1186/s12959-017-0139-z
language
English
LU publication?
yes
id
703463e2-e265-4f90-b598-96201d0c9dca
date added to LUP
2017-08-11 10:38:38
date last changed
2017-09-18 11:41:25
@article{703463e2-e265-4f90-b598-96201d0c9dca,
  abstract     = {<p>Background: Orthostatic hypercoagulability is proposed as a mechanism promoting cardiovascular and thromboembolic events after awakening and during prolonged orthostasis. We evaluated early changes in coagulation biomarkers induced by tilt testing among patients investigated for suspected syncope, aiming to test the hypothesis that orthostatic challenge evokes procoagulatory changes to a different degree according to diagnosis. Methods: One-hundred-and-seventy-eight consecutive patients (age, 51±21years; 46% men) were analysed. Blood samples were collected during supine rest and after 3min of 70° head-up tilt test (HUT) for determination of fibrinogen, von Willebrand factor antigen (VWF:Ag) and activity (VWF:GP1bA), factor VIII (FVIII:C), lupus anticoagulant (LA1), functional APC-resistance, and activated prothrombin time (APTT) with and without activated protein C (C+/-). Analyses were stratified according to age, sex and diagnosis. Results: After 3min in the upright position, VWF:Ag (1.28±0.55 vs. 1.22±0.54; p&lt;0.001) and fibrinogen (2.84±0.60 vs. 2.75±0.60, p&lt;0.001) increased, whereas APTT/C+/- (75.1±18.8 vs. 84.3±19.6s; p&lt;0.001, and 30.8±3.7 vs. 32.1±3.8s; p&lt;0.001, respectively) and APC-resistance (2.42±0.43 vs. 2.60±0.41, p&lt;0.001) decreased compared with supine values. Significant changes in fibrinogen were restricted to women (p&lt;0.001) who also had lower LA1 during HUT (p=0.007), indicating increased coagulability. Diagnosis vasovagal syncope was associated with less increase in VWF:Ag during HUT compared to other diagnoses (0.01±0.16 vs. 0.09±0.17; p=0.004). Conclusions: Procoagulatory changes in haemostatic plasma components are observed early during orthostasis in patients with history of syncope, irrespective of syncope aetiology. These findings may contribute to the understanding of orthostatic hypercoagulability and chronobiology of cardiovascular disease.</p>},
  articleno    = {16},
  author       = {Hamrefors, Viktor and Fedorowski, Artur and Strandberg, Karin and Sutton, Richard and Isma, Nazim},
  issn         = {1477-9560},
  keyword      = {Coagulation factors,Fibrinogen,Hypercoagulability,Orthostatic stress,Partial thromboplastin time,Von Willebrand factor},
  language     = {eng},
  month        = {06},
  number       = {1},
  publisher    = {BioMed Central},
  series       = {Thrombosis Journal},
  title        = {Procoagulatory changes induced by head-up tilt test in patients with syncope : Observational study},
  url          = {http://dx.doi.org/10.1186/s12959-017-0139-z},
  volume       = {15},
  year         = {2017},
}