Correlation of pulmonary embolism with D-dimer level and determination of CUT-OFF values according to age

Introduction: Pulmonary embolism is one of the life-threatening causes in patients admitted to the emergency department with complaints of chest pain, dyspnea, tachypnea, and syncope. If the diagnosis is not made in the early period the mortality rates are increase. Diagnostic algorithms, laboratory tests such as D-dimer and imaging tests such as pulmonary CT angiography are used for the diagnosis of PE. The primary aim of the study is to determine the D-dimer cut-of values according to age in patients with pulmonary embolism. The secondary aims of the study were to determine the relationship between D-dimer level and the radiological severity of pulmonary embolism and to determine variables predicting 30-day mortality. Material and Methods: Patients with D-dimer levels and who underwent pulmonary angiography CT between January 01, 2015 and December 30, 2019 were included in the study. Patient demographics (age and gender), clinical variables, laboratory results, and imaging reports of these patients were evaluated. Patients with incomplete files were excluded from the study. Results: Of the patients included in the study, 2613 (41,9%) were male and 3628 (58,1%) were female. The mean age of the patients was 43.27±17.43 years. Pulmonary angiography was performed in 1507 (24,2%) patients. Of these 1507 patients, 147 (9,8%) had PE. One month mortality rate was 0,3%. A significant correlation was found with mortality and D-dimer level (p <0.001), troponin level (p <0.001) and the presence of right ventricular overload on echocardiography (p=0.004). Patients with sinus tachycardia (2%) and S1Q3T3 (2,6%) at the initial ECG had increase mortality rate. The cut-off value of troponin was 0.027 ng/L and the cut-off value of D-dimer was 2.7 mg/L to predict 1 month mortality. Cut-off values of D-dimer value to predict the presence of PE according to the age range <50, 50-60, 60-70, 70-80, >80, respectively 1.18, 1.19, 1.58, 1.79, 2.83 mg/L calculated. The average D-dimer level increased proportionally with the radiographic severity of PE and more central PE means higher D-dimer level. However, there was a weak but significant correlation between the severity of the pulmonary embolism (the size of the obstructed vessel) and the D-dimer level. Conclusion: D-dimer cut-off levels was determined in our study according to each decades. As the age increases, the D-dimer cut-off value for the diagnosis of PE also increases. There is a weak but significant correlation between D-dimer level and the severity of pulmonary embolism. Electrocardiography and echocardiography findings are not reliable enough to diagnose or exclude PE but they can be used in the clinical decision-making processes.