Hemostasis Biomarkers and Long-Term Risk of Recurrent Cardiovascular Events and Bleeding Complications in Young Patients with an Ischemic Stroke

Background: Patients with ischemic stroke at a young age (18-50 years) have a persistent increased risk of recurrent ischemic cardiovascular events, despite antithrombotic treatment. Additionally, antithrombotic agents result in a higher risk of bleeding complications. Balancing hemostasis to prevent thrombotic events and minimizing the risk of hemorrhagic events is challenging. Previous research observed a hypercoagulable state and a significant degree of inflammation years after an acute ischemic stroke in young adults. It is known that an increased clotting tendency is a risk factor for a first ischemic stroke, especially in young adults. However, the risk profile of a recurrent event in these individuals can be different. To this end, our study aims to investigate the role of plasma pro- and anticoagulation biomarkers, platelet activation markers and thrombin generation parameters in the risk of recurrent ischemic arterial events and bleeding complications after a first ischemic stroke or transient ischemic attack (TIA) at a young age.

Method: Patients from a single-center cohort study (the FUTURE cohort) with a first-ever TIA or ischemic stroke event between 1980 and 2010 were included. Blood was collected in 2010 and patients were followed on recurrent ischemic events or bleeding complications between 2010 and 2023. The following coagulation parameters were measured: blood cell count, Von Willebrand factor, active Von Willebrand factor, factor VIII, prothrombin, fragment 1.2, d-dimer, fibrinogen, fibrin degradation products, antithrombin, alpha-2-macroglobulin, serum CXCL-4 and CXCL-7. In addition, thrombin generation (TG) was determined using 1pM and 5pM tissue factor, and thrombomodulin in platelet-poor plasma to assess the functional capacity of plasma to form thrombin. The primary outcome was a composite of recurrent ischemic stroke, TIA, acute coronary syndrome or peripheral artery disease. The secondary outcome was the occurrence of a bleeding complication using the Bleeding Academic Research Consortium (BARC) criteria. We applied Cox proportional hazard models to estimate hazard ratios (HR) with 95% confidence intervals (CI).

Results: Among 378 patients (median age 42.1 years, 56% women), 74 experienced a recurrent ischemic event during a mean follow-up of 6.5 years. An increased platelet and leukocyte count, along with elevated levels of fragment 1.2, fibrinogen and D-dimer were associated with a higher risk of ischemic events (table 1). Patients with low plasma antithrombin activity had a higher risk of recurrent ischemic events, especially in women (HR 0.67 [0.47-0.96]). After adjustment for age, sex and traditional risk factors, the association between leukocytes numbers, fragment 1.2 and fibrinogen levels and antithrombin activity and the risk of recurrent ischemic events remained: HR 1.14 [1.05-1.25], 1.07 [1.01-1.14], 0.80 [0.65-0.98], and 1.09 [1.00-1.17], respectively. In patients without vitamin K antagonist treatment, the association between antithrombin activity (HR 0.78 [0.62-0.98]) and leukocytes numbers (HR 1.15 [1.05-1.25]) with recurrent ischemic events were stronger. Thrombin generation parameters were not related to recurrence. Bleeding complications were observed in 16% of patients, mainly among women and predominantly attributable to gynecological bleedings. Hemoglobin, platelets, CXCL-4 and -7, prothrombin, fragment 1.2 and alpha-2-macroglobulin were associated with a bleeding complication (table 2). The association for platelets (HR 0.93 [0.89-0.97]), CXCL-4 (HR 0.90 [0.82-0.99]) and alpha-2-macroglobulin (HR 1.15 [1.03-1.29]) remained after adjustment.

Conclusion: Lower antithrombin activity and, higher fragment 1.2, fibrinogen levels, and leukocytes counts were linked to an increased risk of recurrent ischemic events. Bleeding was associated with platelets, CXCL4, and alpha-2-macroglobulin. Overall, especially platelets appear to be significantly involved in the risk of both recurrent arterial thrombosis and bleeding, whereas the observed association with risk of recurrent ischemic events implies a more dominant role of the coagulation system.