Risk stratification of emergency department patients with chest pain using d-dimer and high-sensivity C-reactive protein

Abstract

Study objectives: Several recent reports in the literature have shown positive association between HS-CRP and d-dimer levels with diagnosis of acute coronary syndrome. Our study aims to find out whether these 2 markers would be useful in the risk stratification of patients presenting to the emergency department (ED) with undifferentiated chest pain. Methods: One hundred twenty-three patients, aged 25 years or older, were recruited when they presented to the ED with nontraumatic chest pain. They were evaluated and treated at the discretion of the treating physician but had additional d-dimer and HS-CRP done. Treating physicians were blinded to the results of these tests. Patients who had no history of ischemic heart disease and were diagnosed to have noncardiac chest pain underwent cardiac stress testing or other appropriate investigations to exclude cardiac ischemia and confirm their diagnoses. Final diagnoses were determined by cardiologists. These patients were followed up for mortality, ischemic events, and related hospital admissions at 1 week and 6 months after ED visit. Results: There was a nonsignificant difference in the mean HS-CRP levels of patients with acute coronary syndrome and noncardiac chest pain. However, HS-CRP level for patients with related admission within 1 week of presentation was 41.5 mg/dL compared with 3.4 mg/dL for patients who did not have related admission ( P =.01). There was no significant difference for mortality rate or related admission at 6 months. d-dimer levels of patients with angina were significantly higher than those of patients with noncardiac chest pain. They were 143.9 μg/L and 99.7 μg/L, respectively ( P =.016). Thirteen patients had acute myocardial infarction within 1 week of the presenting episode, and they had a mean d-dimer level of 154.9 μg/L compared with mean d-dimer level of 95.8 μg/L for patients who did not have acute myocardial infarction within 1 week of the presenting episode ( P =.013). Twenty-three patients had a related admission within 6 months. Their mean d-dimer level of 150.7 μg/L was significantly higher than the 91.7 μg/L for patients who did not have a related admission within 6 months ( P =.001). Conclusion: Our findings suggest that high HS-CRP level predicted a related admission within 1 week of the presenting episode, which is potentially useful in risk stratification. A patient with risk factors and atypical-sounding pain but high HS-CRP level will probably need more urgent further cardiac evaluation after acute myocardial infarction had been ruled out than a patient who had normal HS-CRP levels. A higher d-dimer level was associated with an increased risk of coronary artery disease. Patients with higher levels of d-dimer were also more likely to have acute myocardial infarction within 1 week of presentation with chest pain and have a related admission within 6 months. These patients should be evaluated as soon as possible by a cardiologist for definitive treatment. Our study numbers are too small for us to recommend a cutoff value for HS-CRP and d-dimer levels at which the clinician should be alarmed. Further studies with larger patient recruitment would help elucidate this issue.