Platelets are well recognized as a key cell component of the hemostatic system. Recently, several additional functions have been discovered for these blood cells but most importantly in the process ...of inflammation. Numerous research groups have demonstrated crucial roles for platelets in the pathogenesis of varied clinical conditions where inflammation is important. Alterations in both platelet number and function have been observed with these different conditions. The relevance of these findings is their therapeutic implications through simple antiplatelet therapy to more complex, as yet clinically untrialed options, like interfering with platelet-leukocyte or platelet-endothelial interaction. This review focuses on how platelets are relevant in inflammatory conditions with an impetus on the clinical aspects.
Platelets play a very important role in physiological haemostasis and thrombus formation. Platelet aggregation is the key pathophysiological factor in the development of arterial ischaemic events, ...including coronary artery disease, cerebrovascular accidents and peripheral arterial disease. As such, antiplatelet therapy plays a very important role in preventing recurrent events in the individuals who are affected by one of these conditions. Until recently, the repertoire of antiplatelet therapy was limited to aspirin and clopidogrel. However, this landscape has changed dramatically with the advent of newer and more potent agents, prasugrel and ticagrelor and also the glycoprotein IIb/IIIa antagonists. This armamentarium is likely to expand further with the advent of protease-activated receptor-1 antagonists and the intravenous cangrelor. This review summarises the different agents available and some practical considerations for their use from a general physician’s perspective.
OBJECTIVES:Recent studies have reported a high prevalence of thrombotic events in coronavirus disease 2019. However, the significance of thromboembolic complications has not been widely appreciated. ...The purpose of this review is to provide current knowledge of this serious problem.
DESIGN:Narrative review.
DATA SOURCES:Online search of published medical literature through PubMed using the term “COVID-19,” “SARS,” “acute respiratory distress syndrome,” “coronavirus,” “coagulopathy,” “thrombus,” and “anticoagulants.”
STUDY SELECTION AND DATA EXTRACTION:Articles were chosen for inclusion based on their relevance to coagulopathy and thrombosis in coronavirus disease 2019, and anticoagulant therapy. Reference lists were reviewed to identify additional relevant articles.
DATA SYNTHESIS:Coronavirus disease 2019 is associated with a strikingly high prevalence of coagulopathy and venous thromboembolism that may contribute to respiratory deterioration. Monitoring coagulation variables is important, as abnormal coagulation tests are related to adverse outcomes and may necessitate adjuvant antithrombotic interventions. In the initial phase of the infection, D-dimer and fibrinogen levels are increased, while activated partial prothrombin time, prothrombin time, and platelet counts are often relatively normal. Increased D-dimer levels three times the upper limit of normal may trigger screening for venous thromboembolism. In all hospitalized patients, thromboprophylaxis using low-molecular-weight heparin is currently recommended. The etiology of the procoagulant responses is complex and thought to be a result of specific interactions between host defense mechanisms and the coagulation system. Although the coagulopathy is reminiscent of disseminated intravascular coagulation and thrombotic microangiopathy, it has features that are markedly distinct from these entities.
CONCLUSIONS:Severe acute respiratory syndrome coronavirus 2/coronavirus disease 2019 frequently induces hypercoagulability with both microangiopathy and local thrombus formation, and a systemic coagulation defect that leads to large vessel thrombosis and major thromboembolic complications, including pulmonary embolism in critically ill hospitalized patients. D-dimers and fibrinogen levels should be monitored, and all hospitalized patients should undergo thromboembolism prophylaxis with an increase in therapeutic anticoagulation in certain clinical situations.
The coronavirus disease 2019 (COVID‐19) pandemic has already left an indelible mark in human lives. Despite the havoc it created, this pandemic also saw significant advances in the management of an ...infectious disease wherein worldwide collaborative efforts from health care professionals have been unprecedented. One of the commonest complications recognised early in the pandemic is the development of coagulopathy. In this review, the lessons learnt from COVID‐19 coagulopathy are summarised with some perspectives on future clinical and research strategies. These include how local versus systemic coagulopathy can matter, how we can put D‐dimers to effective use, exhort more input into identifying a simple platelet activation marker, rethink the role of fibrinogen, look differently at lupus anticoagulant and heparin‐induced thrombocytopenia, bring back disseminated intravascular coagulation into our differential diagnosis slate and most importantly channel more funding into haemostasis and thrombosis research.
Disseminated intravascular coagulation (DIC) is an intermediary mechanism of disease which develops secondary to many causes including sepsis, trauma and malignancies. This review attempts to ...summarise the new pathophysiological developments and the impact they have on the current and future management of DIC.
Several publications detailing the pathophysiology of DIC and the clinical management were identified using a pubmed search. Expert commentary: In recent years, on the initiatives of the international society of thrombosis and haemostasis, important advances have been made on the diagnostic aspect of DIC. In addition, several researchers have focused on the pathophysiology of the condition which is likely to provide better diagnostic markers and targeted therapy. However, some confusion still exists in the definition and management of DIC since various specialists understands the mechanisms involved in DIC from different perspectives.
Thrombotic complications and coagulopathy frequently occur in COVID-19. However, the characteristics of COVID-19-associated coagulopathy (CAC) are distinct from those seen with bacterial ...sepsis-induced coagulopathy (SIC) and disseminated intravascular coagulation (DIC), with CAC usually showing increased D-dimer and fibrinogen levels but initially minimal abnormalities in prothrombin time and platelet count. Venous thromboembolism and arterial thrombosis are more frequent in CAC compared to SIC/DIC. Clinical and laboratory features of CAC overlap somewhat with a hemophagocytic syndrome, antiphospholipid syndrome, and thrombotic microangiopathy. We summarize the key characteristics of representative coagulopathies, discussing similarities and differences so as to define the unique character of CAC.
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