Antithrombotic and prohemorrhagic actions of different concentrations of apixaban in patients exposed to single and dual antiplatelet regimens.

We evaluated modifications in the hemostatic balance of different concentrations of apixaban (APIX) in 25 healthy donors and 53 patients treated with aspirin (ASA, n = 21), ASA and clopidogrel (ASA + CLOPI, n = 11), or ASA and ticagrelor (ASA + TICA, n = 21). Blood samples from participants were spiked ex vivo with apixaban 0 (APIX0), 40 (APIX40), and 160 ng/mL (APIX160). We assessed the effects of APIX on (1) clot formation, by ROTEM thromboelastometry; (2) thrombin generation primed by platelets; and (3) platelet and fibrin interactions with a thrombogenic surface, in a microfluidic model with circulating blood. APIX caused dose-related prolongations of clotting time with minimal impact on other ROTEM parameters. Thrombin generation was significantly inhibited by APIX160, with ASA + TICA actions showing the strongest inhibition (p < 0.01 vs APIX0). Microfluidic studies showed that APIX160 was more potent at suppressing platelet and fibrin interactions (p < 0.001 vs. APIX0). APIX40 demonstrated a consistent antithrombotic action but with a favorable protective effect on the structural quality of fibrin. APIX potentiated the antithrombotic effects of current antiplatelet regimens. APIX at 40 ng/mL, enhanced the antithrombotic action of single or dual antiplatelet regimens but was more conservative for hemostasis than the 160 ng/mL concentration.

Myocardial Injury in COVID-19 Patients: Association with Inflammation, Coagulopathy and In-Hospital Prognosis.

The exact mechanisms leading to myocardial injury in the coronavirus disease 2019 (COVID-19) are still unknown. In this retrospective observational study, we include all consecutive COVID-19 patients admitted to our center. They were divided into two groups according to the presence of myocardial injury. Clinical variables, Charlson Comorbidity Index (CCI), C-reactive protein (CRP), CAC (COVID-19-associated coagulopathy), defined according to the ISTH score, treatment and in-hospital events were collected. Between March and April 2020, 331 COVID-19 patients were enrolled, 72 of them (21.8%) with myocardial injury. Patients with myocardial injury showed a higher CCI score (median (interquartile range), 5 (4-7) vs. 2 (1-4), p = 0.001), higher CRP values (18.3 (9.6-25.9) mg/dL vs. 12.0 (5.4-19.4) mg/dL, p ˂ 0.001) and CAC score (1 (0-2) vs. 0 (0-1), p = 0.001), and had lower use of any anticoagulant (57 patients (82.6%) vs. 229 patients (90.9%), p = 0.078), than those without. In the adjusted logistic regression, CRP, myocardial injury, CCI and CAC score were positive independent predictors of mortality, whereas anticoagulants resulted as a protective factor. Myocardial injury in COVID-19 patients is associated with inflammation and coagulopathy, resulting in a worse in-hospital prognosis. Treatment with anticoagulant agents may help to improve in-hospital outcomes.