Platelets
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Coronavirus disease 2019 (COVID-19) is a global public health emergency with many clinical facets, and new knowledge about its pathogenetic mechanisms is deemed necessary; among these, there are certainly coagulation disorders. In the history of medicine, autopsies and tissue sampling have played a fundamental role in order to understand the pathogenesis of emerging diseases, including infectious ones; compared to the past, histopathology can be now expanded by innovative techniques and modern technologies. For the first time in worldwide literature, we provide a detailed postmortem and biopsy report on the marked increase, up to 1 order of magnitude, of naked megakaryocyte nuclei in the bone marrow and lungs from serious COVID-19 patients. Most likely related to high interleukin-6 serum levels stimulating megakaryocytopoiesis, this phenomenon concurs to explain well the pulmonary abnormal immunothrombosis in these critically ill patients, all without molecular or electron microscopy signs of megakaryocyte infection.
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Knowledge of platelet count and function is key to ensuring appropriate hemostatic management. We hypothesized that the novel, portable TEG®6s coagulation assessment system could evaluate the contribution of both platelet count and function to clot formation. Whole-blood samples with variable platelet counts were prepared from healthy volunteers. ⋯ MA showed significant negative relationships with abciximab concentration (p < .001). Platelet function inhibition was detected by all three assays at >68% measured by LTA and quantified in the range 68.4-82% (CK), 69.4-88% (CKH), and 69.7-76% (CRT). This demonstrates the TEG®6s analyzer can accurately evaluate platelet count and function at the site-of-care.
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The pathogenesis of thrombocytopenia can be divided into increased destruction (ID) of platelets in the peripheral blood and decreased production (DP) of platelets in the bone marrow. This study aimed to analyze the efficacy of immature platelet fraction (IPF) related parameters, including the IPF count (IPF#), IPF percentage (IPF%) and highly fluorescence IPF percentage (H-IPF%), measured by XN-9000, in the differential diagnosis of thrombocytopenia. One hundred and twenty healthy volunteers were enrolled in the healthy control (HC) group, and 180 thrombocytopenia patients were grouped into either the increased destruction (ID) group or the decreased production (DP) group according to their final diagnosis. ⋯ IPF related parameters showed high efficacy in the differential diagnosis of thrombocytopenia. However, due to the small numerical values of the IPF related parameters in some thrombocytopenia patients, the fluctuations of IPF% and H-IPF% should also be taken into consideration. Though H-IPF% is a new parameter, its effectiveness in the differential diagnosis of thrombocytopenia is not better than IPF%'s.
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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease in 2019 (COVID-19) which rapidly evolved from an outbreak in Wuhan, China into a pandemic that has resulted in over millions of infections and over hundreds of thousands of mortalities worldwide. Various coagulopathies have been reported in association with COVID-19, including disseminated intravascular coagulation (DIC), sepsis-induced coagulopathy (SIC), local microthrombi, venous thromboembolism (VTE), arterial thrombotic complications, and thrombo-inflammation. There is a plethora of publications and conflicting data on hematological and hemostatic derangements in COVID-19 with some data suggesting the link to disease progress, severity and/or mortality. ⋯ Of those, a link between thrombocytopenia and COVID-19 severity or mortality was suggested. In this opinion report, we examine the published evidence of hematological and hemostatic laboratory derangements in COVID-19 and the interrelated SARS-CoV-2 induced inflammation, with a focussed discussion on platelet count alterations. We explore whether thrombocytopenia could be a potential disease biomarker and we provide recommendations for future studies in this regard.
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Dual antiplatelet therapy (DAPT) is the basis of preventing stent thrombosis and ischemic events after percutaneous coronary intervention (PCI), but prolonging the duration of DAPT will increase the risk of bleeding. The optimal duration of DAPT after PCI remains controversial at present. The purpose of this meta-analysis was to investigate the efficacy and safety of short-term DAPT in patients undergoing PCI. ⋯ No difference was observed in the risk of all-cause death (RR 0.92, 95% CI 0.80-1.06, P = 0.25), cardiovascular death (RR 0.88, 0.69-1.12, P = 0.29), myocardial infarction (RR 1.05, 0.94-1.19, P = 0.38), definite or probable stent thrombosis (RR 1.05, 0.80-1.36, P = 0.73), and stroke (RR 1.02, 0.80-1.30, P = 0.89) between short term and standard DAPT. The short-term DAPT could reduce the risk of major bleeding (RR 0.67, 0.48-0.94, P = 0.02) and any bleeding (RR 0.63, 0.48-0.82, P = 0.0005) compared with 12 months of DAPT. In conclusion, the short-term DAPT can reduce the risk of bleeding compared with standard DAPT, without increasing the risk of death or ischemia (Registered by PROSPERO, CRD42020153881).