A study of association between platelet volume indices and ST elevation myocardial infarction

INTRODUCTION AND OBJECTIVE: ST elevation myocardial infarction (STEMI) is caused by formation of a thrombus at a ruptured atheromatous plaque. Larger platelets are enzymatically and metabolically more active and play a crucial role in thrombus formation. Our objective was to study the association between platelet volume indices (mean platelet volume (MPV) and platelet distribution width (PDW)) and STEMI. METHODS: A hospital-based case control study to compare the platelet indices of 52 STEMI patients before commencing antiplatelet therapy and age and gender matched 52 controls who had no history of ischemic heart disease or antiplatelet therapy. Blood samples were collected to EDTA bottles and analyzed using Mindray BC 6800 automated analyzer. RESULTS: STEMI patients had significantly increased mean MPV and PDW compared to the control group ((8.22 ± 0.99 fL vs 7.74 ± 0.69 fL, p = 0.005) and (15.81 ± 0.41 fL vs 15.62 ± 0.33 fL, p = 0.007) respectively). Significant positive correlation existed between MPV and PDW (R = 0.556, p = 0.000) and weak negative correlation in platelet count with MPV (R = −0.323, p = 0.019) and PDW (R = −0.309, p = 0.026) of STEMI patients. Receiver Operating Characteristic (ROC) curves showed that MPV and PDW with cutoff values of 7.55 fL, 15.55 fL and with Area under the curve (AUC) of 0.640, 0.620 respectively. The sensitivities and specificities were found to be 73.1%, 69.2% and 61.5%, 55.8% for MPV and PDW respectively. CONCLUSION: Increased MPV and PDW were found to have a significant association with STEMI and this test has the potential to be used as a preliminary test to identify high-risk patient for myocardial infarction.