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Dynamic Hemostasis and Fibrinolysis Assays in Intensive Care COVID-19 Patients and Association with Thrombosis and Bleeding-A Systematic Review and a Cohort Study
Hvas CL, Larsen JB, Adelborg K, Christensen S, Hvas AM
Seminars in thrombosis and hemostasis. 2021
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Abstract
Patients admitted to the intensive care unit (ICU) with coronavirus disease 2019 (COVID-19), the infectious pathology caused by severe acute respiratory syndrome coronavirus 2, have a high risk of thrombosis, though the precise mechanisms behind this remain unclarified. A systematic literature search in PubMed and EMBASE identified 18 prospective studies applying dynamic coagulation assays in ICU COVID-19 patients. Overall, these studies revealed normal or slightly reduced primary hemostasis, prolonged clot initiation, but increased clot firmness. Thrombin generation assay parameters generally were equivalent to the control groups or within reference range. Fibrinolysis assays showed increased clot resistance. Only six studies related their findings to clinical outcome. We also prospectively included 51 COVID-19 patients admitted to the ICU. Blood samples were examined on day 1, 3-4, and 7-8 with platelet function tests, rotational thromboelastometry (ROTEM), in vivo and ex vivo thrombin generation, and clot lysis assay. Data on thrombosis, bleeding, and mortality were recorded during 30 days. Primary hemostasis was comparable to healthy controls, but COVID-19 patients had longer ROTEM-clotting times and higher maximum clot firmness than healthy controls. Ex vivo thrombin generation was similar to that of healthy controls while in vivo thrombin generation markers, thrombin-antithrombin (TAT) complex, and prothrombin fragment 1 + 2 (F1 + 2) were higher in ICU COVID-19 patients than in healthy controls. Impaired fibrinolysis was present at all time points. TAT complex and F1 + 2 levels were significantly higher in patients developing thrombosis (n = 16) than in those without. In conclusion, only few previous studies employed dynamic hemostasis assays in COVID-19 ICU-patients and failed to reveal a clear association with development of thrombosis. In ICU COVID-19 patients, we confirmed normal platelet aggregation, while in vivo thrombin generation was increased and fibrinolysis decreased. Thrombosis may be driven by increased thrombin formation in vivo.
PICO Summary
Population
Patients admitted to intensive care unit with COVID-19 (18 studies).
Intervention
Systematic review examining the haemostasis with a wide range of dynamic haemostasis assays including platelet aggregation, global whole blood coagulation, thrombin generation assays, and fibrinolysis assays.
Comparison
Outcome
The included studies revealed normal or slightly reduced primary haemostasis, prolonged clot initiation, but increased clot firmness. Thrombin generation assay parameters generally were equivalent to the control groups or within reference range. Fibrinolysis assays showed increased clot resistance. Only six studies related their findings to clinical outcome.
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Efficacy and Safety of Antifibrinolytic Drugs in Pediatric Surgery: A Systematic Review
Hovgesen NT, Larsen JB, Fenger-Eriksen C, Hansen AK, Hvas AM
Seminars in thrombosis and hemostasis. 2021;47(5):538-568
Abstract
Antifibrinolytic drugs are used to reduce blood loss and subsequent transfusions during surgery and following trauma, but the optimal dosing regimen in the pediatric population is still unresolved. The aim of this systematic review was to evaluate efficacy and safety of antifibrinolytic drugs in pediatric surgery and trauma to determine the optimal dosing regimen. A literature search was performed in PubMed, Embase, Cochrane, and Web of Science on May 3, 2020. We included randomized controlled studies investigating the effect of tranexamic acid (TXA), aprotinin, and epsilon-aminocaproic acid, in terms of reducing blood loss, blood transfusions, reoperations, and rebleeds in pediatric patients aged 0 to 18 years undergoing cardiac surgery, noncardiac surgery, or trauma. Fifty randomized controlled trials (RCTs) were included; 28 RCTs investigated cardiac surgery and 22 investigated noncardiac surgery. No RCTs regarding trauma met the inclusion criteria. All antifibrinolytic drugs reduced postoperative blood loss and transfusions when used in pediatric surgery. The dosing regimen varied between studies, but similar effect sizes were found in terms of reduced blood loss regardless of the cumulative dose used. Few studies found adverse events, and no difference in incidence or type of adverse events was seen between the antifibrinolytic and the placebo group. In conclusion, use of antifibrinolytics is efficient and safe in children undergoing surgery. We propose TXA as the drug of choice based on its level of evidence and safety profile; we recommend a dosing regimen composed of a loading dose of 10 to 15 mg/kg prior to surgery followed by 1 to 5 mg/kg/h as continuous infusion throughout surgery.