High altitude: A hypercoagulable state: Results of a prospective cohort study

Kotwal, Jyoti; Apte, CV; Kotwal, Atul; Mukherjee, Bhasker; Jayaram, J

doi:10.1016/j.thromres.2006.09.013

Cited by 54 publications

(49 citation statements)

References 24 publications

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“…The effect of altitude on the coagulation system is subject to debate (33,34). Although plausible, there is no direct evidence that antiplatelet aggregation and/or anticoagulant therapy are risk factors for high-altitude retinal hemorrhage (HARH) or hemorrhagic stroke.…”

Section: Cerebrovascular Effectsmentioning

confidence: 99%

Physical Activity at Altitude: Challenges for People With Diabetes

Mol

Vries²,

Koning

et al. 2014

Diabetes Care

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A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Furthermore, cold temperatures and altitude can complicate accurate reading of glucose monitoring equipment and storage of insulin. These factors potentially lead to dangerous hyperglycemia or hypoglycemia. Over the last years, more information has become available on this subject. PURPOSETo provide an up-to-date overview of the pathophysiological changes during physical activity at altitude and the potential problems related to diabetes, including the use of (continuous) blood glucose monitors and insulin pumps. To propose practical recommendations for preparations and travel to altitude for subjects with diabetes. DATA SOURCES AND SYNTHESISWe researched PubMed, medical textbooks, and related Internet sites, and extracted human studies and data based on relevance for diabetes, exercise, and altitude. LIMITATIONSGiven the paucity of controlled trials regarding diabetes and altitude, we composed a narrative review and filled in areas lacking diabetes-specific studies with data obtained from nondiabetic subjects. CONCLUSIONSSubjects with diabetes can take part in activities at high, and even extreme, altitude. However, careful assessment of diabetes-related complications, optimal preparation, and adequate knowledge of glycemic regulation at altitude and altitude-related complications is needed.An increasing number of subjects with diabetes reside at high altitude for short periods of time, partly for work, but mainly for recreational purposes such as skiing, trekking, and climbing. Exercise under conditions of hypobaric hypoxia poses some unique challenges for subjects with diabetes and could potentially lead to dangerous situations such as unexpected hypoglycemia and hyperglycemia, inaccurate

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Section: Cerebrovascular Effectsmentioning

confidence: 99%

Physical Activity at Altitude: Challenges for People With Diabetes

Mol

Vries²,

Koning

et al. 2014

Diabetes Care

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“…[10][11][12][13] Although platelets play an indispensable role in thrombogenesis, the involvement of platelets in hypoxia-induced thrombotic events has not been adequately explored. Most of the studies were focused on changes in platelet numbers; only a few reports focused on platelet reactivity at high altitude.…”

Section: Introductionmentioning

confidence: 99%

Altered expression of platelet proteins and calpain activity mediate hypoxia-induced prothrombotic phenotype

Tyagi

Ahmad

Gupta

et al. 2014

Blood

121

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Key Points• Hypoxia induces altered platelet proteome/reactivity, which correlates with a prothrombotic phenotype.• CAPNS1-dependent calpain activity in platelet activation cascade is associated with hypoxia-induced thrombogenesis.Oxygen-compromised environments, such as high altitude, air travel, and sports, and pathological conditions, such as solid tumors, have been suggested to be prothrombotic. Despite the indispensable role of platelets in thrombus formation, the studies linking hypoxia, platelet reactivity, and thrombus formation are limited. In the present study, platelet proteome/reactivity was analyzed to elucidate the acute hypoxia-induced prothrombotic phenotype. Rats exposed to acute simulated hypoxia (282 torr/8% oxygen) demonstrated a decreased bleeding propensity and increased platelet reactivity. Proteomic analysis of hypoxic platelets revealed 27 differentially expressed proteins, including those involved in coagulation. Among these proteins, calpain small subunit 1, a 28-kDa regulatory component for calpain function, was significantly upregulated under hypoxic conditions. Moreover, intraplatelet Ca 21 level and platelet calpain activity were also found to be in accordance with calpain small subunit 1 expression. The inhibition of calpain activity demonstrated reversal of hypoxia-induced platelet hyperreactivity. The prothrombotic role for calpain was further confirmed by an in vivo model of hypoxia-induced thrombosis. Interestingly, patients who developed thrombosis while at extreme altitude had elevated plasma calpain activities and increased soluble P-selectin level. In summary, this study suggests that augmented calpain activity is associated with increased incidence of thrombosis under hypoxic environments. (Blood. 2014;123(8):1250-1260

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“…The main reason was speculated to be polycythemia, but some patients also had concurrent protein C or S deficiency 12 . Kotwal et al showed that there was a significant rise from baseline in hemoglobin, platelet count and fibrinogen levels in soldiers spending eight months at 3500 meters producing a presumed hypercoagulable state 16 . Based on current evidence, recommendations for routine testing of familial thrombophilia cannot be made, but mountaineers are advised to maintain adequate hydration, and avoid smoking.…”

Section: Discussionmentioning

confidence: 99%