Diagnostic Value of D-Dimer in Patients Visiting the Emergency Department with Symptoms of Acute Coronary Syndrome: A Retrospective Observational Study

Background: D-dimer is a fibrin degradation product formed during fibrinolysis and reflects the activation of coagulation and fibrinolytic pathways. The role of D-dimer in acute coronary syndrome (ACS) remains uncertain. This study was designed to analyse differences in D-dimer levels in patients with different forms of ACS and the diagnostic efficiency and possible complementary role of the D-dimer biomarker. Methods: This study applied a retrospective observational design and included adult patients presenting to the emergency department with chest pain. Differences in D-dimer levels across diagnostic categories were analysed. To evaluate the diagnostic performance of D-dimer, receiver operating characteristic (ROC) analysis was conducted, which involved calculations of area under the curve (AUC), sensitivity, specificity, and likelihood ratios. Also, the incremental value of D-dimer over clinical data and cardiac troponin was determined through a multivariate logistic regression model. Results: The study found that the level of D-dimer was significantly higher in patients with ST elevation myocardial infarction (STEMI) and Non-ST elevation myocardial infarction (NSTEMI) compared to patients with unstable angina (UA) and non-specific chest pain (p < 0.001). As per ROC analysis, the level of D-dimer demonstrated modest discrimination between STEMI/NSTEMI and unstable angina (AUC 0.618; 95% CI 0.538-0.697), and a fair discrimination between STEMI/NSTEMI and non-specific chest pain (AUC 0.668; 95% CI 0.601-0.736). At a cutoff of 0.50 mg/L, sensitivity and specificity were limited. In multivariable models, D-dimer did not provide incremental diagnostic value beyond clinical variables and cardiac troponin (ΔAUC not significant). Conclusion: Despite higher D-dimer concentrations in myocardial infarction, the marker exhibited modest diagnostic performance and did not provide additional diagnostic value over cardiac troponin. Therefore, D-dimer is suggested to be used as an adjunct rather than primary diagnostic instrument in patients presenting with suspected acute coronary syndrome.