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2.
JAMA ; 327(3): 227-236, 2022 01 18.
Article in English | MEDLINE | ID: covidwho-1669289

ABSTRACT

Importance: Platelets represent a potential therapeutic target for improved clinical outcomes in patients with COVID-19. Objective: To evaluate the benefits and risks of adding a P2Y12 inhibitor to anticoagulant therapy among non-critically ill patients hospitalized for COVID-19. Design, Setting, and Participants: An open-label, bayesian, adaptive randomized clinical trial including 562 non-critically ill patients hospitalized for COVID-19 was conducted between February 2021 and June 2021 at 60 hospitals in Brazil, Italy, Spain, and the US. The date of final 90-day follow-up was September 15, 2021. Interventions: Patients were randomized to a therapeutic dose of heparin plus a P2Y12 inhibitor (n = 293) or a therapeutic dose of heparin only (usual care) (n = 269) in a 1:1 ratio for 14 days or until hospital discharge, whichever was sooner. Ticagrelor was the preferred P2Y12 inhibitor. Main Outcomes and Measures: The composite primary outcome was organ support-free days evaluated on an ordinal scale that combined in-hospital death (assigned a value of -1) and, for those who survived to hospital discharge, the number of days free of respiratory or cardiovascular organ support up to day 21 of the index hospitalization (range, -1 to 21 days; higher scores indicate less organ support and better outcomes). The primary safety outcome was major bleeding by 28 days as defined by the International Society on Thrombosis and Hemostasis. Results: Enrollment of non-critically ill patients was discontinued when the prespecified criterion for futility was met. All 562 patients who were randomized (mean age, 52.7 [SD, 13.5] years; 41.5% women) completed the trial and 87% received a therapeutic dose of heparin by the end of study day 1. In the P2Y12 inhibitor group, ticagrelor was used in 63% of patients and clopidogrel in 37%. The median number of organ support-free days was 21 days (IQR, 20-21 days) among patients in the P2Y12 inhibitor group and was 21 days (IQR, 21-21 days) in the usual care group (adjusted odds ratio, 0.83 [95% credible interval, 0.55-1.25]; posterior probability of futility [defined as an odds ratio <1.2], 96%). Major bleeding occurred in 6 patients (2.0%) in the P2Y12 inhibitor group and in 2 patients (0.7%) in the usual care group (adjusted odds ratio, 3.31 [95% CI, 0.64-17.2]; P = .15). Conclusions and Relevance: Among non-critically ill patients hospitalized for COVID-19, the use of a P2Y12 inhibitor in addition to a therapeutic dose of heparin, compared with a therapeutic dose of heparin only, did not result in an increased odds of improvement in organ support-free days within 21 days during hospitalization. Trial Registration: ClinicalTrials.gov Identifier: NCT04505774.


Subject(s)
Anticoagulants/administration & dosage , COVID-19/drug therapy , Heparin/administration & dosage , Inpatients , Purinergic P2Y Receptor Antagonists/administration & dosage , Aged , Aged, 80 and over , Anticoagulants/adverse effects , COVID-19/blood , COVID-19/mortality , Clopidogrel/administration & dosage , Clopidogrel/adverse effects , Comorbidity , Extracorporeal Membrane Oxygenation/statistics & numerical data , Female , Hemorrhage/chemically induced , Heparin/adverse effects , Hospital Mortality , Humans , Male , Medical Futility , Middle Aged , Outcome Assessment, Health Care , Oxygen Inhalation Therapy/statistics & numerical data , Platelet Activation/drug effects , Platelet Aggregation Inhibitors/administration & dosage , Platelet Aggregation Inhibitors/adverse effects , Purinergic P2Y Receptor Antagonists/adverse effects , Receptors, Purinergic P2Y12 , Respiration, Artificial/statistics & numerical data , Thrombosis/epidemiology , Ticagrelor/administration & dosage , Ticagrelor/adverse effects , Time Factors , Treatment Outcome
4.
Platelets ; 33(1): 48-53, 2022 Jan 02.
Article in English | MEDLINE | ID: covidwho-1541393

ABSTRACT

Coagulopathy is an evident complication of COVID-19 with predominance of a prothrombotic state. Platelet activation plays a key role. The terms "hyper-reactivity" and "hyperactivity" used in recent literature may not be clear or sufficient to explain the pathological events involved in COVID-related thrombosis (CRT). Inflammation may play a bigger role compared to thrombosis in COVID-related mortality because a smaller percentage of patients with COVID-19 die due to direct effects of thrombosis. Not all COVID-19 patients have thrombocytopenia and a few show thrombocytosis. We believe the platelet pathology is more complex than just activation or hyper-activation, particularly due to the platelets' role in inflammation. Understanding the pathology and consequences of platelets' role may help optimize management strategies and diminish CRT-associated morbidity and mortality. In this viewpoint report, we examine the published evidence of platelet hyper-reactivity in COVID-19 with a focused analysis of the key pathologies, diverse alterations, disease outcomes, and therapeutic targets. We believe that COVID-19 is a disease of inflammation and pathologic platelets, and based on the complexity and diverse pathologies, we propose the term "thrombocytopathy" as a more reflective term of the platelets' involvement in COVID-19. In our opinion, thrombocytopathy is the unpredictable pathologic alterations of platelets in function, morphology and number, caused by different factors with a variety of presentations.


Subject(s)
Blood Platelets/pathology , COVID-19/complications , Cytokine Release Syndrome/complications , Disseminated Intravascular Coagulation/complications , Pulmonary Embolism/complications , SARS-CoV-2/pathogenicity , Abciximab/therapeutic use , Acute Disease , Anticoagulants/therapeutic use , Aspirin/therapeutic use , Blood Platelets/drug effects , Blood Platelets/virology , COVID-19/diagnosis , COVID-19/drug therapy , COVID-19/virology , Clopidogrel/therapeutic use , Cytokine Release Syndrome/diagnosis , Cytokine Release Syndrome/drug therapy , Cytokine Release Syndrome/virology , Disseminated Intravascular Coagulation/diagnosis , Disseminated Intravascular Coagulation/drug therapy , Disseminated Intravascular Coagulation/virology , Fibrinolytic Agents/therapeutic use , Humans , Lung/blood supply , Lung/drug effects , Lung/pathology , Lung/virology , Platelet Activation/drug effects , Pulmonary Embolism/diagnosis , Pulmonary Embolism/drug therapy , Pulmonary Embolism/virology , Treatment Outcome
5.
Int J Lab Hematol ; 43(4): 547-558, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1231132

ABSTRACT

COVID-19 (coronavirus disease 2019) represents a prothrombotic disorder, and there have been several reports of platelet factor 4/heparin antibodies being present in COVID-19-infected patients. This has thus been identified in some publications as representing a high incidence of heparin-induced thrombocytopenia (HIT), whereas in others, findings have been tempered by general lack of functional reactivity using confirmation assays of serotonin release assay (SRA) or heparin-induced platelet aggregation (HIPA). Moreover, in at least two publications, data are provided suggesting that antibodies can arise in heparin naïve patients or that platelet activation may not be heparin-dependent. From this literature, we would conclude that platelet factor 4/heparin antibodies can be observed in COVID-19-infected patients, and they may occur at higher incidence than in historical non-COVID-19-infected cohorts. However, the situation is complex, since not all platelet factor 4/heparin antibodies may lead to platelet activation, and not all identified antibodies are heparin-dependent, such that they do not necessarily reflect "true" HIT. Most recently, a "HIT-like" syndrome has reported in patients who have been vaccinated against COVID-19. Accordingly, much more is yet to be learnt about the insidious disease that COVID-19 represents, including autoimmune outcomes in affected patients.


Subject(s)
Antibodies/immunology , Anticoagulants/adverse effects , COVID-19/complications , Heparin/adverse effects , Platelet Factor 4/immunology , Thrombocytopenia/chemically induced , Thrombocytopenia/complications , Animals , Anticoagulants/immunology , COVID-19/immunology , Heparin/immunology , Humans , Platelet Activation/drug effects , SARS-CoV-2/immunology , Thrombocytopenia/immunology
6.
Thromb Haemost ; 121(11): 1395-1399, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1182893

ABSTRACT

A series of cases with rare thromboembolic incidents including cerebral sinus vein thrombosis (some of them fatal) and concomitant thrombocytopenia occurring shortly after vaccination with the coronavirus disease 2019 (COVID-19) vaccine AZD1222 (Vaxzevria) have caused significant concern and led to its temporary suspension in many countries. Immediate laboratory efforts in four of these patients have identified a tentative pathomechanism underlying this syndrome termed initially vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) and renamed recently vaccine-induced immune thrombotic thrombocytopenia (VITT). It encompasses the presence of platelet-activating antibodies to platelet factor-4/heparin complexes, possibly emulated by polyanionic constituents of AZD1222, and thus resembles heparin-induced thrombocytopenia (HIT). Because these immune complexes bind and activate platelets via Fcγ receptor IIA (FcγRIIA), high-dose intravenous immunoglobulin G has been suggested for treatment of VITT in addition to non-heparin anticoagulants. Here we propose inhibitors of Bruton tyrosine kinase (Btk) approved for B cell malignancies (e.g., ibrutinib) as another therapeutic option in VITT, as they are expected to pleiotropically target multiple pathways downstream of FcγRIIA-mediated Btk activation, for example, as demonstrated for the effective inhibition of platelet aggregation, dense granule secretion, P-selectin expression and platelet-neutrophil aggregate formation stimulated by FcγRIIA cross-linking. Moreover, C-type lectin-like receptor CLEC-2- and GPIb-mediated platelet activation, the interactions and activation of monocytes and the release of neutrophil extracellular traps, as encountered in HIT, could be attenuated by Btk inhibitors. As a paradigm for emergency repurposing of approved drugs in COVID-19, off-label use of Btk inhibitors in a low-dose range not affecting haemostatic functions could thus be considered a sufficiently safe option to treat VITT.


Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Blood Platelets/drug effects , COVID-19 Vaccines/adverse effects , Platelet Activation/drug effects , Protein Kinase Inhibitors/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Vaccination/adverse effects , Agammaglobulinaemia Tyrosine Kinase/metabolism , Animals , Autoantibodies/blood , Blood Platelets/enzymology , Blood Platelets/immunology , COVID-19 Vaccines/administration & dosage , Humans , Molecular Targeted Therapy , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/enzymology , Purpura, Thrombocytopenic, Idiopathic/immunology , Receptors, IgG/metabolism , Signal Transduction
7.
J Hematol Oncol ; 13(1): 161, 2020 12 01.
Article in English | MEDLINE | ID: covidwho-953805

ABSTRACT

As our understanding on coronavirus disease 2019 (COVID-19) deepens, it is increasingly recognized that COVID-19 is more than a respiratory condition. Thrombocytopenia and thromboembolic complications are a composite factor associated with critical COVID-19 and increased mortality. Immune-inflammation-mediated destruction, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection per se and increased consumption are proposed to be responsible for thrombocytopenia. Multiple concomitant conditions or results caused by SARS-CoV-2 infection are high risk factors for thrombosis. Recently, platelet activation and platelet-mediated immune inflammation induced by SARS-CoV-2 infection were also found to be the contributors to the thrombosis in COVID-19 patients. In addition to thrombus scoring system, D-dimer is an excellent indicator for monitoring thrombosis. COVID-19 patients with high risk for thrombosis should be subjected to early thromboprophylaxis, and prolonged activated partial-thromboplastin time should not be a barrier to the use of anticoagulation therapies in the control of thrombosis in COVID-19 patients.


Subject(s)
COVID-19/complications , Thrombocytopenia/etiology , Thrombosis/etiology , Anticoagulants/therapeutic use , COVID-19/blood , COVID-19/drug therapy , Fibrin Fibrinogen Degradation Products/analysis , Hospitalization , Humans , Platelet Activation/drug effects , SARS-CoV-2/physiology , Thrombocytopenia/blood , Thrombocytopenia/drug therapy , Thrombosis/blood , Thrombosis/drug therapy
8.
Nitric Oxide ; 107: 11-18, 2021 02 01.
Article in English | MEDLINE | ID: covidwho-949808

ABSTRACT

Nitric oxide, NO, has been explored as a therapeutic agent to treat thrombosis. In particular, NO has potential in treating mechanical device-associated thrombosis due to its ability to reduce platelet activation and due to the central role of platelet activation and adhesion in device thrombosis. Nitrite is a unique NO donor that reduces platelet activation in that it's activity requires the presence of red blood cells whereas NO activity of other NO donors is blunted by red blood cells. Interestingly, we have previously shown that red blood cell mediated inhibition of platelet activation by adenosine diphosophate (ADP) is dramatically enhanced by illumination with far-red light that is likely due to photolysis of red cell surface bound NO congeners. We now report the effects of nitrite, far-red light, and their combination on several measure of blood coagulation using a variety of agonists. We employed turbidity assays in platelet rich plasma, platelet activation using flow cytometry analysis of a fluorescently labeled antibody to the activated platelet fibrinogen binding site, multiplate impedance-based platelet aggregometry, and assessment of platelet adhesion to collagen coated flow-through microslides. In all cases, the combination of far-red light and nitrite treatment decreased measures of coagulation, but in some cases mono-treatment with nitrite or light alone had no effect. Perhaps most relevant to device thrombosis, we observed that platelet adhesions was inhibited by the combination of nitrite and light treatment while nitrite alone and far-red light alone trended to decrease adhesion, but the results were mixed. These results support the potential of combined far-red light and nitrite treatment for preventing thrombosis in extra-corporeal or shallow-tissue depth devices where the far-red light can penetrate. Such a combined treatment could be advantageous due to the localized treatment afforded by far-red light illumination with minimal systemic effects. Given the role of thrombosis in COVID 19, application to treatment of patients infected with SARS Cov-2 might also be considered.


Subject(s)
Blood Coagulation/drug effects , Blood Coagulation/radiation effects , Nitric Oxide Donors/pharmacology , Nitrites/pharmacology , Blood Platelets/drug effects , Blood Platelets/radiation effects , COVID-19/drug therapy , COVID-19/radiotherapy , Humans , Light , Nitric Oxide/metabolism , Platelet Activation/drug effects , Platelet Activation/radiation effects , Platelet Adhesiveness/drug effects , Platelet Adhesiveness/radiation effects , Platelet Aggregation/drug effects , Platelet Aggregation/radiation effects , SARS-CoV-2/drug effects
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