Elevated factor XI is associated with recurrent left ventricular thrombus of unknown origin

Area of Science:

• Cardiology
• Hematology
• Thrombosis Research

Background:

• Elevated factor XI (FXI) is a known risk factor for thromboembolism.
• The association between FXI levels and left ventricular thrombus (LVT) formation, recurrence, and subsequent thromboembolic events requires further investigation.

Purpose of the Study:

• To investigate the association between FXI levels and the presence of LVT.
• To determine if FXI levels correlate with LVT recurrence and subsequent thromboembolic events in patients with LVT of unknown origin.

Main Methods:

• A case-control study involving 54 patients with prior LVT and 54 controls.
• Measurement of FXI levels, plasma clot permeability (K_s), fibrinolysis time (CLT), endogenous thrombin potential (ETP), von Willebrand factor (vWF), and fibrinolysis proteins.
• Follow-up assessment for LVT recurrence, ischemic stroke, or systemic embolism.

Main Results:

• Elevated FXI levels (>120%) were more prevalent in LVT patients (25.9%) compared to controls (11.1%), particularly with active FXI.
• FXI levels correlated with age, K_s, and CLT, but not ETP, vWF, or fibrinolysis proteins.
• The primary endpoint occurred in 31.5% of LVT patients versus 7.4% of controls during follow-up, with elevated FXI independently associated with the primary endpoint (OR 1.18).

Conclusions:

• Elevated FXI, in conjunction with a prothrombotic state, characterizes patients with prior LVT of unknown origin.
• High FXI levels predispose to LVT recurrence and/or ischemic stroke.
• FXI measurement may aid in identifying patients who could benefit from extended anticoagulation or FXI inhibitors.