Plasma fibrinogen independently predicts hypofibrinolysis in severe COVID-19

ABSTRACT

High rates of thrombosis are present in patients with SARS-CoV-2 infection. Deeper insight into the prothrombotic state is essential to provide the best thromboprophylaxis care. We aimed to explore associations among platelet indices, conventional hemostasis parameters, and viscoelastometry data. 21 patients with severe COVID-19 and 21 age-matched controls were enrolled. Each patient received 100 mg aspirin therapy at the time of blood sampling. To monitor the aspirin therapy, a platelet function test from hirudin anticoagulated whole blood was performed using the ASPI test by Multiplate analyser. High on-aspirin platelet reactivity (n=8) was defined with an AUC>40 cut-off value by ASPI tests. Furthermore, vitro viscoelastometric tests were carried out using a ClotPro analyser in COVID-associated thromboembolic events nor the survival rate showed significant associations with high on-aspirin platelet reactivity status. Patients presented with higher levels of inflammatory markers, along with evidence of hypercoagulability by ClotPro. H-IPF (%) was significantly higher among non-survivors (n=18) compared to survivors (P=0.011), and a negative correlation (P=0.002) was found between H-IPF and plasminogen level in the total population. The platelet count was significantly higher among patients with high on-aspirin platelet reactivity (P= 0.03). ECA-A10 (P=0.008), and ECA-MCF (P=0.016) were significantly higher, while the tPA-CFT (P<0.001) was significantly lower among patients with high on-aspirin platelet reactivity. However, only fibrinogen proved to be an independent predictor of hypofibrinolysis in severe COVID-19 patients. Surprisingly, a faster developing, more solid clot formation was observed in aspirin taking COVID-19 patients. In conclusion, an individually tailored thromboprophylaxis is needed to prevent thrombotic complications, particularly in the hypofibrinolytic cluster.