Open Access
CC BY 4.0 · Thromb Haemost 2018; 118(01): 063-071
DOI: 10.1160/TH17-02-0138
Coagulation and Fibrinolysis
Schattauer GmbH Stuttgart

Thromboelastometry and Platelet Function during Acclimatization to High Altitude

Alistair S. Rocke
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
,
Gordon G. Paterson
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
2   Edinburgh Medical School, University of Edinburgh, Edinburgh, United Kingdom
,
Matthew T. Barber
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
,
Alexander I. R. Jackson
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
3   Clinical and Experimental Sciences Academic Unit, University of Southampton, Southampton, United Kingdom
,
Shona Main
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
,
Calum Stannett
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
,
Martin F. Schnopp
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
,
J. Kenneth Baillie
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
4   Division of Genetics and Genomics, The Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
,
Elizabeth H. Horne
5   Department of Clinical Haematology, St James's University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
,
Carl Moores
6   Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, NHS Lothian, Edinburgh, United Kingdom
,
Paul Harrison
7   Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
,
Alastair F. Nimmo
6   Department of Anaesthesia, Critical Care and Pain Medicine, Royal Infirmary of Edinburgh, NHS Lothian, Edinburgh, United Kingdom
,
A. A. Roger Thompson
1   Apex (Altitude Physiology Expeditions), Edinburgh, United Kingdom
8   Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, United Kingdom
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Publikationsverlauf

26. Februar 2017

23. September 2017

Publikationsdatum:
05. Januar 2018 (online)

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Abstract

Interaction between hypoxia and coagulation is important given the increased risk of thrombotic diseases in chronically hypoxic patients who reside at sea level and in residents at high altitude. Hypoxia alters the proteome of platelets favouring a prothrombotic phenotype, but studies of activation and consumption of specific coagulation factors in hypoxic humans have yielded conflicting results. We tested blood from 63 healthy lowland volunteers acclimatizing to high altitude (5,200 m) using thromboelastometry and assays of platelet function to examine the effects of hypoxia on haemostasis. Using data from two separate cohorts of patients following identical ascent profiles, we detected a significant delay in clot formation, but increased clot strength by day 7 at 5,200 m. The latter finding may be accounted for by the significant rise in platelet count and fibrinogen concentration that occurred during acclimatization. Platelet function assays revealed evidence of platelet hyper-reactivity, with shortened PFA-100 closure times and increased platelet aggregation in response to adenosine diphosphate. Post-expedition results were consistent with the normalization of coagulation following descent to sea level. These robust findings indicate that hypoxia increases platelet reactivity and, with the exception of the paradoxical delay in thromboelastometry clotting time, suggest a prothrombotic phenotype at altitude. Further work to elucidate the mechanism of platelet activation in hypoxia will be important and could impact upon the management of patients with acute or chronic hypoxic respiratory diseases who are at risk of thrombotic events.

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