Tissue factor-containing circulating microparticles tied to thrombotic load in acute myocardial infarction
The thrombotic burden in patients with acute myocardial infarction may be examined through tissue factor-, monocyte- and platelet-microparticles, a new study reports.
The platelets and monocytes of acute myocardial infarction patients remain activated and secrete circulating microparticles that may be used to gauge the severity of the condition.
The study involved 200 patients between the ages of 70 and 82. Patients were diagnosed to have acute myocardial infarction and were recruited 2 to 8 weeks after the event. Fasting venous blood samples were collected from the participants.
Flow cytometry was performed to measure circulating microparticles isolated from the blood and vascular cells which tested positive to Annexin V. A chromogenic assay was performed to measure tissue factor, a good indicator of plasma procoagulant activity.
Patients with ST-elevation myocardial infarction were found to have significantly higher levels of circulating microparticles derived from platelets compared to those without the condition.
Furthermore, those who experienced heart failure during their acute myocardial infarction showed significantly higher levels monocyte- and platelet-derived circulating microparticles containing tissue factor (p<0.004 and p<0.0001, respectively).
Patients that were in the New York Heart Association (NYHA) Functional Classification class III showed significantly higher levels of three circulating microparticles compared to those in classes I and II: f CD142+ /AV+ , CD14+/AV+ and CD14+/CD142+/AV+ (p=0.001, p=0.015 and p=0.014, respectively). It was also shown that the levels of these circulating microparticles associated positively with plasma procoagulant activity (p≤0.027 for all).
The findings imply that circulating microparticles derived from platelets and monocytes and which contain tissue factor may be associated with thrombotic burden in patients with acute myocardial infarction.