Coronary thrombus composition: Links with inflammation, platelet and endothelial markers

- Patients with ST-segment elevation myocardial infarction (STEMI) were analyzed.
- Coronary thrombus composition evolves over time during the acute phase of STEMI.
- Markers of platelet, neutrophil and endothelial activation are altered in STEMI.
- Fibrin content within thrombi is linked to markers of cellular activation.
- Cellular and plasmatic components affect thrombus formation on coronary plaque.

Objectives: We investigated whether markers of platelet, neutrophil and endothelial activation, plasma fibrin clot properties and patient clinical profile may characterize coronary thrombus composition in ST-segment elevation myocardial infarction (STEMI) patients. Methods: A total of 40 intracoronary thrombi obtained 4.0-16.5 h since chest pain onset by manual aspiration during primary coronary intervention (PCI) were assessed using scanning electron microscopy. Plasma fibrin clot permeation coefficient (Ks) and clot lysis time (CLT), together with platelet and endothelial activation, fibrinolysis, and inflammation markers, were measured ex vivo in 16 patients on admission (pre-PCI group) and on the next morning in 24 patients (post-PCI group). Results: Fibrin, erythrocyte, platelet and white blood cell content in the thrombi were estimated at 49.1%, 24.2%, 11.6% and 3.7% respectively. In the pre-PCI group, in addition to fibrinogen, P-selectin and plasminogen activator inhibitor-1 were positively correlated with thrombus fibrin content. In the post-PCI group, in addition to von Willebrand factor antigen (vWF:Ag), soluble CD40 ligand and myeloperoxidase (MPO) were positively correlated with thrombus fibrin content. After adjustment for fibrinogen and onset-to-thrombectomy time circulating vWF:Ag in both groups, and MPO and P-selectin in the pre-PCI group were the independent predictors of fibrin-rich intracoronary thrombus presence. Other predictors were renal impairment, arterial hypertension and time from symptom onset to thrombus aspiration in all patients. Conclusions: In STEMI patients coronary thrombus composition is partly characterized by plasma markers of platelet, neutrophil and endothelial activation, with a varying contribution of these factors over time.