Ischemic time was the only predictor of coronary thrombus composition in STEMI patients, associated with a 2-fold increase in fibrin content per ischemic hour (adjusted OR 2; 95% CI 1.03-3.7; p=0.01).
Observational (n=288)
How does ischemic time affect the composition of coronary thrombus in STEMI patients?
In STEMI patients, coronary thrombus composition is highly dependent on ischemic time, with fibrin content increasing and platelet content decreasing over time, which may impact the efficacy of reperfusion therapies.
Effect estimate: adjusted OR 2 (95% CI 1.03-3.7)
p-value: p=0.01
Objective To analyse composition of coronary thrombus in vivo, in ST-elevation Myocardial Infarction (STEMI) patients. Background The dynamic process of intracoronary thrombus formation in STEMI patients is poorly understood. Methods Intracoronary thrombi (n=45) were obtained by thromboaspiration in 288 consecutive STEMI patients presenting for primary percutaneous intervention and analyzed using high definition pictures taken with a scanning electron microscope. Plasma biomarkers (TnI, CRPus, IL-6, PAI-1, sCD40 ligand and TNF-α) and plasma fibrin clots viscoelastic properties were measured simultaneously on peripheral blood. Results Thrombi were mainly composed of fibrin (55.9±18%) with platelets (16.8±18%), erythrocytes (11.5±9%), cholesterol crystal (5.2±8.4%) and leukocytes (1.3±2.0%). The median ischemic time was 175 min IQR 140-297. Ischemic time impacted thrombi composition, resulting in a positive correlation with intracoronary thrombus fibrin content, r=0.38, p=0.01 and a negative correlation with platelet content r=-0.34, p=0.02. Thus, fibrin content increased with ischemic time, ranging from 48.4±21% (6 hours) (p=0.02), while platelet content decreased from 24.9±23% (6 hours) (p=0.07). Soluble CD40 ligand was positively correlated to platelet content in the thrombus (r=0.40, p=0.02) and negatively correlated with fibrin content (r=-0.36; p=0.04). Multivariate analysis indicated that ischemic time was the only predictor of thrombus composition with a 2-fold increase of fibrin-content per ischemic hour (adjusted OR2 1.03-3.7 p=0.01). Conclusions In acute STEMI, platelet and fibrin contents of the occlusive thrombus are highly dependent of ischemic time, which may have a direct impact on the efficacy of drugs or devices used for coronary reperfusion.
“Following a plaque rupture, platelets are activated and rapidly aggregated, leading to the formation of an arterial platelet-rich thrombus within a few minutes that is sensitive to rapid and potent platelet inhibition, anticoagulation, or rapid administration of fibrinolytics as the fibrin fibers are less dense and not yet stabilized. Beyond 3 h, a fibrin fiber-rich thrombus less responsive to antithrombotic therapy is formed and requires an adjunctive mechanical treatment by percutaneous coronary intervention.”
Silvain et al. (2011) conducted an observational in ST-elevation Myocardial Infarction (STEMI) (n=288). Ischemic time was evaluated on Fibrin content increase per ischemic hour (adjusted OR 2, 95% CI 1.03-3.7, p=0.01). Ischemic time was the only predictor of coronary thrombus composition in STEMI patients, associated with a 2-fold increase in fibrin content per ischemic hour (adjusted OR 2; 95% CI 1.03-3.7; p=0.01).