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

• Published in: Thrombosis journal 2017-06, Vol.15 (1), p.16-16, Article 16
• Main Authors: Hamrefors, Viktor, Fedorowski, Artur, Strandberg, Karin, Sutton, Richard, Isma, Nazim
• Format: Article
• Language: English
• Subjects: Anticoagulants; Antigens; Biological markers; Blood; Blood platelets; Cardiac and Cardiovascular Systems; Cardiology; Cardiovascular disease; Clinical Medicine; Coagulation factors; Diagnosis; Fainting; Fibrinogen; Health risk assessment; Heart attacks; Hypercoagulability; Independent sample; Kardiologi; Klinisk medicin; Laboratories; Medical and Health Sciences; Medicin och hälsovetenskap; Observational studies; Orthostatic stress; Partial thromboplastin time; Physiological aspects; Proteins; Risk factors; Thromboembolism; Von Willebrand factor
• ISSN: 1477-9560; 1477-9560
• DOI: 10.1186/s12959-017-0139-z

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. 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. After 3 min in the upright position, VWF:Ag (1.28 ± 0.55 vs. 1.22 ± 0.54;