Background: Coronary artery disease is mainly caused by atherosclerosis and its complications. Platelets and their activity have an important role in initiation of atherosclerotic lesions and coronary thrombus formation. Larger platelets are enzymatically and metabolically more active and have a higher potential thrombotic ability as compared with smaller platelets. Aims: To study the changes in platelet volume indices and platelet count in acute myocardial infarction, stable coronary artery disease and compare them with controls to assess their usefulness in predicting coronary events. Materials and Methods: This was a comparative study of 128 subjects; 39 patients with acute myocardial infarction (AMI), 24 patients with stable coronary artery disease (SCAD) and 65 controls. Venous sample were drawn from AMI subjects on admission (within 4 hours of chest pain) and collected in standardized EDTA sample tubes. Platelet count and volume indices were assayed within 30 minutes of blood collection, using Sysmex KX21-N autoanalyzer. Venous samples were also drawn from SCAD on who were admitted for angiography and subject attending routine checkups. Results: The mean platelet volume was significantly higher in patients with AMI (9.65 ± 0.96) as compared to SCAD (9.37 ± 0.88) and controls (9.21 ± 0.58). The best cut-off values for MPV when predicting AMI and SCAD in patients were 9.25 fl (sensitivity 56.4%; specificity 45.9%) and 9.15 fl (sensitivity 54.2%; specificity 42.23%), respectively. Conclusions: Measurements of MPV may be of some benefit in detecting those patients at higher risk for an AMI and CAD.
Key words: Acute myocardial infarction, coronary artery disease, mean platelet volume