New interest in fibrinogen as an ischemic risk factor.

Platelet-fibrin clot formation is a key process in acute arterial thrombosis. The relationship between thrombin-induced platelet-fibrin clot strength (P-FCS) and fibrinogen levels in patients with cardiovascular disease (CVD) and COVID-19 has not been studied. In thhe current study, the contribution of fibrinogen to P-FCS has been explored in healthy subjects (n=157), patients hospitalized with COVID-19 (n=116), and patients with CVD (n=93) using thrombelastography (TEG 6s) with citrate cartridge. We found that thrombin-induced P-FCS, fibrin clot strength (F-CS) and fibrinogen levels (FLEV) were higher among patients with CVD and COVID-19 compared to HS (p<0,05 for all) and highest among patients with COVID-19. P-FCS, an established risk factor for post-PCI ischemic event occurrences, was associated with both F-CS and FLEV (R2=0.67, p<0.001 for both comparisons. These data indicate that fibrinogen levels strongly influence the viscoelastic strength of the platelet-fibrin clot, fibrinogen may be an important driving factor for arterial thrombosis in the presence of potent platelet inhibition and may be as equally important a risk factor as high platelet reactivity. Since P-FCS is significantly associated with fibrinogen levels, the role of fibrinogen as a risk factor for arterial ischemic event occurrences should be further studied to improve antithrombotic therapy personalization.