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

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, a...

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Autores principales: Hamrefors, Viktor, Fedorowski, Artur, Strandberg, Karin, Sutton, Richard, Isma, Nazim
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477734/
https://www.ncbi.nlm.nih.gov/pubmed/28649180
http://dx.doi.org/10.1186/s12959-017-0139-z
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author Hamrefors, Viktor
Fedorowski, Artur
Strandberg, Karin
Sutton, Richard
Isma, Nazim
author_facet Hamrefors, Viktor
Fedorowski, Artur
Strandberg, Karin
Sutton, Richard
Isma, Nazim
author_sort Hamrefors, Viktor
collection PubMed
description 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 ± 21 years; 46% men) were analysed. Blood samples were collected during supine rest and after 3 min 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 3 min 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 ± 19.6 s; p < 0.001, and 30.8 ± 3.7 vs. 32.1 ± 3.8 s; 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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spelling pubmed-54777342017-06-23 Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study Hamrefors, Viktor Fedorowski, Artur Strandberg, Karin Sutton, Richard Isma, Nazim Thromb J Research 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 ± 21 years; 46% men) were analysed. Blood samples were collected during supine rest and after 3 min 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 3 min 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 ± 19.6 s; p < 0.001, and 30.8 ± 3.7 vs. 32.1 ± 3.8 s; 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. BioMed Central 2017-06-20 /pmc/articles/PMC5477734/ /pubmed/28649180 http://dx.doi.org/10.1186/s12959-017-0139-z Text en © The Author(s). 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Hamrefors, Viktor
Fedorowski, Artur
Strandberg, Karin
Sutton, Richard
Isma, Nazim
Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title_full Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title_fullStr Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title_full_unstemmed Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title_short Procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
title_sort procoagulatory changes induced by head-up tilt test in patients with syncope: observational study
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477734/
https://www.ncbi.nlm.nih.gov/pubmed/28649180
http://dx.doi.org/10.1186/s12959-017-0139-z
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