Thrombotic Complications in COVID-19 Patients

Coronavirus disease 2019 (COVID-19) is associated with a pronounced prothrombotic state that encompasses both macrovascular and microvascular events. Endothelial injury driven by viral invasion, coupled with an exaggerated inflammatory response, promotes platelet activation, complement deposition and a cytokine-mediated coagulopathy. Clinically, this manifests as deep vein thrombosis, pulmonary embolism, arterial thromboses and immunothrombosis within the pulmonary microcirculation. Biomarkers such as elevated D-dimer and fibrinogen levels correlate with disease severity and poorer outcomes. Critically ill patients—particularly those receiving invasive ventilation or extracorporeal support—demonstrate the highest incidence of thrombotic events despite standard prophylaxis. Management strategies therefore hinge on early risk stratification, intensified thromboprophylaxis and vigilant haemostatic monitoring. Global data highlight regional variations in incidence but universally underscore the necessity of tailored anticoagulation protocols to mitigate morbidity and mortality. Emerging evidence informs optimal dosing regimens, duration of prophylaxis after hospital discharge and potential adjunctive benefits of heparins beyond their anticoagulant action.

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Thrombotic Complications in COVID-19 Patients publication trend

The graph below shows the total number of articles in thrombotic complications in covid-19 patients across all publications each year (not limited to Nature Index journals).

Technical terms

Deep vein thrombosis (DVT): formation of a blood clot within a deep vein, most often in the legs, which may lead to venous obstruction and embolisation.

Pulmonary embolism (PE): blockage of a pulmonary artery by a thrombus, often originating from a peripheral vein, causing ventilation–perfusion mismatch and haemodynamic compromise.

D-dimer: a fibrin degradation fragment produced during clot breakdown, used as a biomarker to assess active thrombosis and guide diagnostic pathways.

Coagulopathy: a pathological condition characterised by an imbalance in the coagulation cascade, leading to either excessive bleeding or thrombosis.

Anticoagulation: therapeutic use of agents such as heparins to inhibit clot formation and prevent progression of thrombosis.

References

1. Risk of pulmonary embolism and deep vein thrombosis following COVID‐19: a nationwide cohort study. MedComm (2024).
2. Predictors and outcomes of acute pulmonary embolism in COVID-19; insights from US National COVID cohort collaborative. Respiratory Research (2023).
3. COVID-19: Coagulopathy, Risk of Thrombosis, and the Rationale for Anticoagulation. Clinical and Applied Thrombosis/Hemostasis (2020).
4. Venous Thrombosis Among Critically Ill Patients With Coronavirus Disease 2019 (COVID-19). JAMA Network Open (2020).
5. Prevention of thrombotic risk in hospitalized patients with COVID-19 and hemostasis monitoring. Critical Care (2020).
6. Venous Thromboembolism among Hospitalized Patients with COVID-19 Undergoing Thromboprophylaxis: A Systematic Review and Meta-Analysis. Journal of Clinical Medicine (2020).