Association of Platelet Parameters in Acute Coronary Syndrome before and after Anti-platelet Therapy

Abstract

Identification of risk factors for acute coronary syndrome (ACS) is important for both diagnostic and prognostic purposes. Among the platelet parameters- mean platelet volume (MPV) and platelet distribution width (PDW) are thought to be risk factors of ACS. This quasi- experimental study was conducted from September 2011 to August 2012 in the Department of Clinical Pathology, in collaboration with Departments of Cardiology, Bangbandhu Sheikh Mujib Medical University (BSMMU), Dhaka and Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic Disorders (BIRDEM) . It was enrolled 79 patients with ACS, diagnosed based on clinical history, electrocardiographic changes and increased cardiac markers especially troponin I, and 63 subjects were enrolled as control. For determination of platelet parameters, the blood samples were obtained from all patients of ACS before anti-platelet therapy when patient attended in the cardiac emergency and after 5th day of ongoing anti-platelet therapy; and from control group on the 1^st day and 5^th day at outpatient department. The blood samples were taken properly and processed in haematology autoanalyser. In this study, the baseline characteristics of study patients were measured. Platelet counts were 273.1±50.15 x 109/L in patients with ACS and 290.78±74.86 x 109/L in control subjects in 1^st sample and 284.56±41.93 x 109/L in patients with ACS in 2^nd sample. In 1^st samples, platelet counts were slightly low in patients with ACS compared to controls and 2^nd samples. There were no statistical significant differences between the groups and the samples. MPV was 12.48±1.17 fl and 10.45±0.66 fl in patients with ACS and controls and 11.55±1.08 fl in 2^nd sample in ACS cases. PDW was 16.23±2.56 fl, 11.89±1.42 fl and 14.29±2.11 fl in patients with ACS, controls and 2^nd sample of ACS cases respectively. Both MPV and PDW were statistically significant between the groups and the samples (p<0.001). The sensitivity, specificity, positive and negative predictive value of platelet parameters of ACS cases were obtained from ROC curve and compared with controls. The best cut off value of platelet count, MPV and PDW were >225 x 109/L, > 10.7 fl and >12.7 fl respectively. The sensitivity, specificity, accuracy, positive and negative predictive value of platelet counts, MPV and PDW were 83%, 28.1%, 42.3%, 37.6%, 64%; 90.6%, 49.4%, 64.8%, 51.6%, 89.8%; and 94.3%,52.8%, 69%,54.9%, 94.1% respectively. The study showed that PDW had higher sensitivity and specificity in contrast to MPV. Platelet parameters were increased in patients with ACS before anti-platelet therapy and gradually decreased after anti-platelet therapy. These two markers may used as predictor for early detection of ACS and risk stratification, when other cardiac biomarkers are negative.