Diagnostic Accuracy of D-Dimers in Patients with Non-ST-Segment Elevation Myocardial Infarction Using Troponin-I as the Gold Standard.

Abstract

Background: Non-ST segment elevation myocardial infarction (NSTEMI) is defined as a clinical syndrome characterized by symptoms of myocardial ischemia and the release of biomarkers of myocardial necrosis in the absence of electrocardiographic ST-segment elevation. Biomarkers play a pivotal role in both the early diagnosis and prognosis of myocardial infarction. Among them, D-dimer has been proposed as a potential diagnostic marker. This study aimed to determine the diagnostic accuracy of D-dimer in patients with NSTEMI, using Troponin-I as the gold standard.

Methodology: Following approval from the College of Physicians and Surgeons Pakistan (CPSP), a cross-sectional validation study was conducted in the Department of Cardiology, Hayatabad Medical Complex, Peshawar, from March 7 to September 7, 2019. Patients aged 18 to 80 years presenting with suspected NSTEMI were enrolled after providing written informed consent. Each participant underwent a detailed history, physical examination, and 12-lead electrocardiography (ECG). Troponin-I was measured prior to administration of anticoagulant therapy in the emergency department, while D-dimer was tested concurrently. Diagnostic accuracy was assessed using Troponin-I as the reference standard.

Results: A total of 275 patients were included, of whom 69.81% were male. The mean age was 62 ± 10.79 years. The majority of patients were non-smokers (81.45%), non-diabetic (86.55%), and normotensive (86.55%). When compared with Troponin-I, D-dimer showed a sensitivity of 38.68%, specificity of 47.38%, positive predictive value (PPV) of 14.91%, negative predictive value (NPV) of 76.36%, and an overall diagnostic accuracy of 45.64%.

Conclusion: Although D-dimer alone demonstrated limited sensitivity and specificity, its relatively high negative predictive value suggests potential utility as a supportive biomarker in ruling out NSTEMI. Incorporating D-dimer testing into the routine chest pain unit protocol, alongside established biomarkers such as Troponin-I, may aid in early risk stratification and clinical decision-making.