Background
In some patients with post-COVID-19, evidence has been found for persistent changes in the coagulation system for months after acute SARS-CoV-2 infection [1,3]. Observational studies show that the risk of venous thromboembolic complications may remain elevated in the post-acute phase, particularly in the first three to six months after infection [3]. At the same time, there is considerable heterogeneity between patients and a lack of robust interventional research supporting routine anticoagulation in post-COVID-19 [1,2].
Pathophysiological considerations
Jing et al. describe that some post-COVID patients experience persistent endothelial inflammation and impaired blood clotting, which may contribute to a long-term increased risk of thrombosis [2]. In addition, elevated D-dimer levels are described in a subgroup for up to four to twelve months after infection, possibly related to persistent inflammation and immunothrombosis [2]. Crook et al. place these findings in a broader context of long-term vascular and inflammatory dysregulation after COVID-19, in which endothelial damage, inflammation, and coagulation activation mutually reinforce each other [1].
Therapeutic implications
Jing notes that based on these findings, anticoagulation seems an obvious treatment option, but clinical trials are needed to develop concrete recommendations [2]. Currently, there are no randomized controlled trials supporting routine prophylactic anticoagulation in post-COVID [1,2]. Results from studies in acute COVID-19 or post-hospital discharge cannot simply be extrapolated to patients with post-COVID in the primary care or chronic phase [2].
Clinical policy
Based on current knowledge, routine anticoagulation in post-COVID patients without additional risk factors is not recommended [1,2]. Anticoagulation can be considered in individual patients with a clear indication, such as a previous venous thromboembolism, active malignancy, severe immobility, or a combination of significantly elevated coagulation markers and clinical risk factors [2,3]. Antiplatelet therapy, such as acetylsalicylic acid, is not recommended without an existing cardiovascular indication [1,2]. In clinical practice, vigilance and easily accessible diagnostics in suspected thrombosis are preferred over prophylactic treatment [1]. Additionally, it is advisable to identify and, where possible, treat other thrombotic risk factors.
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Post-COVID-19 can be associated with long-term prothrombotic changes, but it remains unclear whether anticoagulation is a meaningful intervention [1–3]. Decision-making should be individualized and risk-driven.
Sources
[1] Crook H. et al. Long COVID: mechanisms, risk factors and management. Journal of Medical Virology, 2021.
[2] Jing Z. et al. Long COVID: pathophysiological mechanisms and therapeutic strategies. Signal Transduction and Targeted Therapy, 2022.
[3] Katsoularis I. et al. Risk of venous thromboembolism following COVID-19. BMJ, 2022.
