Role of hemogram parameters in diagnosis and assessing severity of pulmonary embolism

Abstract

Introduction To investigate the changes in platelets indices in patients with pulmonary embolism (PE) and to examine the correlation of these parameters with the extent of vascular occlusion. Patients and methods The present study was conducted on 70 patients who were admitted because of clinical suspicion of PE. For all patients, complete history taking and examination, routine laboratory investigations, chest radiography, ECG, and transthoracic echocardiography were done. For patients with low and intermediate clinical probability, assessment of d-dimer level was done. For patients with high clinical probability and those with positive d-dimer finding, pulmonary computed tomography angiography was performed with measurement of pulmonary artery obstructive index (PAOI) and right ventricle to left ventricle (RV/LV) ratio. Results Fifty patients were confirmed to have PE and the remaining 20 patients were negative for PE. The group of patients without PE served as a control group. The differences in platelet count, mean platelet volume (MPV), platelet distribution width (PDW), red cell distribution width, and other parameters were compared between both the groups. MPV and PDW were significantly higher in patients with acute PE than in other patients (P=0.0002 and 0.0001). A significant correlation was found between MPV and both PAOI (P=0.049) and RV/LV ratio (P=0.0004). Moreover, significant correlation between PDW and PAOI (P=0.001) and between PDW and RV/LV (P=0.044) was found. The best cutoff value for MPV for the prediction of RV dysfunction was more than 9.4 fl (sensitivity 46.7%; specificity 94.7%). The best cutoff value for PDW for the prediction of RV dysfunction was more than 15.85 fl (sensitivity 75%; specificity 65.9%; P=0.006).

Keywords

• platelet indices
• pulmonary artery obstructive index
• pulmonary embolism
• right ventricle/left ventricle ratio