Systems Biochemistry of Haemostasis Dysregulation in COVID-19 Survivors with Post-Acute Sequelae in South West Nigeria

Persistent haemostatic dysregulation is a defining feature of post-acute COVID-19 sequelae, characterised by microthrombus formation, platelet activation, and endotheliopathy that outlast the acute infectious phase. This study applies a systems biochemistry approach to characterise haemostatic dysregulation in COVID-19 survivors with post-acute sequelae in Ogun and Lagos States, South West Nigeria. A prospective cohort design was employed, recruiting 120 confirmed COVID-19 survivors with post-acute sequelae persisting beyond 12 weeks and 80 COVID-19 survivors without sequelae. A comprehensive haemostatic panel including thrombin-antithrombin complex, plasminogen activator inhibitor-1, von Willebrand factor multimers, platelet factor 4, fibrin D-dimer, and soluble P-selectin was measured. Thromboelastography was performed to evaluate global viscoelastic haemostatic profiles. Endothelial biomarkers including angiopoietin-2, soluble thrombomodulin, and ICAM-1 were simultaneously determined. Systems-level analysis integrating haemostatic, endothelial, and inflammatory data by hierarchical clustering identified patient haemostatic phenotypes associated with specific post-acute sequelae symptom domains. This study makes an original theoretical contribution to post-COVID haemostasis science in an African population and proposes a novel biochemical phenotyping framework applicable to clinical management. Keywords: post-acute COVID-19 sequelae, haemostasis, thromboelastography, endotheliopathy, South West Nigeria.