Related Experiment Video
Updated: May 30, 2025

Measurement of Factor V Activity in Human Plasma Using a Microplate Coagulation Assay
Published on: September 9, 2012
Changes in Coagulation Factor XI Activity Levels in Patients with ST-Segment Elevation Myocardial Infarction
Marco Spagnolo1, Nicola Ammirabile1, Luigi Cutore1
1Division of Cardiology, A.O.U. Policlinico "G. Rodolico - San Marco" - University of Catania, Catania, Italy.
Background:
Although factor XI (FXI) inhibitors are currently tested for the prevention of thrombotic events, their early treatment could prevent thrombus consolidation in ST-segment elevation myocardial infarction (STEMI). This study aims to characterize coagulation FXI levels and their variations in patients with STEMI undergoing primary percutaneous coronary intervention (PCI).
Methods:
Patients with STEMI were prospectively enrolled between December 2023 and May 2024. FXI activity (FXIa) levels were measured at admission and after PCI (i.e., before discharge). Variations in FXIa levels were evaluated. Differences in indicators of thrombotic risk between groups with high and low FXIa variability were analyzed, and predictors of high FXIa variability were identified.
Results:
After screening, 54 patients with STEMI were included. The median FXIa level was 0.865 IU/mL (interquartile range [IQR] 0.554-0.978) at admission and 1.161 IU/mL (IQR 0.982-1.317) before discharge, with a median difference of +34.2% (p-value < 0.001). No significant differences were found in indicators of thrombotic risk between groups at high and low FXIa variability, except for the days intercurred between the assays (p-value = 0.016). Neither this nor other variables emerged as independent predictors of high FXIa variability.
Conclusion:
This study first reported an increase in FXIa levels from admission to discharge in STEMI patients undergoing PCI. Common indicators of thrombotic risk were not associated with FXIa levels or their variability. These findings aim to stimulate further research into anticoagulant therapies tailored to the patient's coagulative state and disease.
Related Concept Videos
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
Clot Retraction and Fibrinolysis
Coagulation
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
Blood Studies for Cardiovascular System I: Cardiac Biomarkers
The essential diagnostic tools for detecting myocardial necrosis and monitoring individuals suspected of having acute coronary syndrome (ACS) include:
Troponins
Troponins, particularly cardiac troponins I and T, are the most precise and sensitive markers of myocardial injury. They are detectable within 4-6 hours of myocardial injury and remain...

