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Updated: May 4, 2026
Author Spotlight: High-Sensitivity Tissue Factor Activity Assay for Plasma Diagnosis
Published on: December 29, 2023
Detection of tissue factor antigen and coagulation activity in coronary artery thrombi isolated from patients with
Tullio Palmerini1, Luciana Tomasi1, Chiara Barozzi1
1Dipartimento Cardiovascolare, Policlinico S. Orsola, Bologna, Italy.
Insights
Active tissue factor was found in coronary artery thrombi of patients with ST-segment elevation myocardial infarction (STEMI). This suggests tissue factor plays a role in activating the coagulation cascade, leading to coronary thrombosis.
Area of Science:
- Cardiovascular Medicine
- Hematology
- Pathology
Background:
- Ruptured atherosclerotic plaques are well-studied, but thrombi composition in ST-elevation myocardial infarction (STEMI) is less understood.
- Investigating the presence of coagulant active tissue factor in STEMI thrombi is crucial.
Purpose of the Study:
- To determine if coagulant active tissue factor is present in coronary artery thrombi from patients with STEMI undergoing primary percutaneous coronary intervention.
Main Methods:
- Nineteen STEMI patients undergoing primary PCI had coronary thrombi aspirated.
- Thrombi were analyzed via histology (4 patients) or assessed for tissue factor activity using a modified aPTT test (15 patients).
- Immunoprecipitation and immunoblotting were performed in 12 patients.
Main Results:
- Tissue factor staining was observed in platelet aggregates and inflammatory cells within thrombi.
- Monocytes showed strong tissue factor staining; neutrophils had variable staining; red blood cells did not stain.
- Plasma clotting time was significantly prolonged when thrombi were incubated with a tissue factor-inhibiting antibody (mAb 5G9).
- Tissue factor was confirmed by immunoprecipitation in 10 patients.
Conclusions:
- Active tissue factor is present in coronary artery thrombi of STEMI patients.
- This finding suggests tissue factor contributes to the activation of the coagulation cascade.
- Tissue factor likely plays a role in the pathogenesis of coronary thrombosis in STEMI.
Introduction:
Although ruptured atherosclerotic plaques have been extensively analyzed, the composition of thrombi causing arterial occlusion in patients with ST-segment elevation acute myocardial infarction has been less thoroughly investigated. We sought to investigate whether coagulant active tissue factor can be retrieved in thrombi of patients with STEMI undergoing primary percutaneous coronary intervention.
Methods:
Nineteen patients with ST-segment elevation acute myocardial infarction referred for primary percutaneous coronary intervention were enrolled in this study. Coronary thrombi aspirated from coronary arteries were routinely processed for paraffin embedding and histological evaluation (4 patients) or immediately snap frozen for evaluation of tissue factor activity using a modified aPTT test (15 patients). Immunoprecipitation followed by immunoblotting was also performed in 12 patients.
Results:
Thrombi aspirated from coronary arteries showed large and irregular areas of tissue factor staining within platelet aggregates, and in close contact with inflammatory cells. Some platelet aggregates stained positive for tissue factor, whereas others did not. Monocytes consistently stained strongly for tissue factor, neutrophils had a more variable and irregular tissue factor staining, and red blood cells did not demonstrate staining for tissue factor. Median clotting time of plasma samples containing homogenized thrombi incubated with a monoclonal antibody that specifically inhibits tissue factor-mediated coagulation activity (mAb 5G9) were significantly longer than their respective controls (88.9 seconds versus 76.5 seconds, respectively; p<0.001). Tissue factor was also identified by immunoprecipitation in 10 patients, with significant variability among band intensities.
Conclusions:
Active tissue factor is present in coronary artery thrombi of patients with ST-segment elevation acute myocardial infarction, suggesting that it contributes to activate the coagulation cascade ensuing in coronary thrombosis.
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