Disentangling the complexities of thrombosis and anticoagulant therapy: Optimizing management and clinical outcomes

This thesis explores key aspects of thrombosis, prothrombotic conditions, and anticoagulant therapy, with the aim of improving treatment strategies and long-term outcomes across diverse patient groups.

The first part focuses on COVID-19-associated thrombosis. In intensive care unit patients, intensified thromboprophylaxis did not reduce the incidence of pulmonary embolism, though a potential reduction in mortality was observed. Structural changes in the fibrin network and elevated fibrinogen variants were found in severely ill patients but appeared related to disease severity rather than the SARS-CoV-2 virus itself. Additionally, patients who developed pulmonary embolism during COVID-19 hospitalization had lower quality of life after discharge, although persistent complications were uncommon.

The second and third parts address the safety of anticoagulation and its use in vulnerable populations. COVID-19 vaccination was generally safe, though a subset of immune thrombocytopenia patients experienced transient exacerbations, and users of vitamin K antagonists (VKA) had brief periods of reduced anticoagulation stability post-vaccination without increased bleeding risk. In patients nearing the end of life, anticoagulants were often continued until shortly before death, despite a decline in treatment quality. In those with cancer, stopping anticoagulation was linked to a high risk of recurrence. Finally, lowering INR targets in patients with mechanical heart valves did not raise thrombotic risk and may reduce bleeding, particularly in women. These findings support more tailored, evidence-based approaches to anticoagulant therapy.