Differential Diagnostic Value Of Cardiac Troponin I And D-dimer Levels In Patients With Acute Chest Pain

Objective To evaluate the value of combined D-dimer and cardiac troponin I levels by point-of-care testing for differential diagnosis of etiology in patients with acute chest pain.Methods Patients attending our chest pain clinic were divided into five groups according to their final clinical diagnosis: non-cardiac chest pain(NCCP),unstable angina(UA),acute ST segment elevation myocardial infarction(STEMI),acute non-ST segment elevation myocardial infarction(NSTEMI),and acute aortic dissection(AAD),among which UA,STEMI,NSTEMI and AAD all belong to the cardiac chest pain(CCP).All patients presented with chest pain symptoms within 24 hours of admission to the hospital.In five groups,blood D-dimer and cardiac troponin I(cTnI)were detected by point-of-care testing(POCT)immediately after the outpatient visit for chest pain,and Med Calc software was used to draw the receiver operating characteristic curve(ROC curve)to evaluate the diagnostic value of D-dimer level and cTnI in predicting AAD。The ROC curve was applied to evaluate the optimal cutoff value at D-dimer level and cTnI for predicting the diagnosis of AAD.Results 1.A total of 549 patients with chest pain who were eligible for enrollment were finally included,including 101 with NCCP,261 with UA,52 with NSTEMI,91 with STEMI,and 44 with AAD.The five groups NCCP,UA,NSTEMI,STEMI,and AAD had significant differences in age,medical history(hypertension,diabetes,smoking,and drinking),blood pressure at the emergency department visit,and white blood cell(WBC)count(P < 0.05),whereas no statistical difference was observed in the comparison of gender composition ratio between groups(P=0.102).The proportions of patients with hypertension,diabetes,smoking and drinking were higher in the CCP group than in the NCCP group,and the differences were statistically significant(P < 0.001).Patients with AAD had a history of hypertension,smoking,drinking,and blood pressure level at emergency department visit was significantly higher than that of the other groups,whereas those with a history of diabetes were significantly lower than those with ACS(P< 0.001).Approximately 96%(95.9%)of the patients in the AAD group had a history of hypertension,whereas this proportion was only 7.9% in the NCCP.A higher proportion of patients in the ACS group had a history of diabetes compared to the AAD or NCCP groups.2.In point-of-care testing of admitted patients,significantly higher D-dimer levels were found in the CCP group compared with the NCCP group(0.21 vs.0.30;P<0.001).D-dimer levels were also relatively higher in the AAD group compared to the UA,AMI,or NCCP groups(5.05 vs.0.23,0.33,and 0.21;P<0.001).3.In the ROC curve analysis to identify AAD and AMI,it was shown that D-dimer level >1.40 mg/L was a valid predictor for the diagnosis of AAD but not AMI,with the area under the ROC curve(AUC)of0.937 and a cut-off value of 1.40 mg/L with a sensitivity and specificity of 84.09%,respectively.90.21%.The AUC of cTnI used to identify AMI and AAD was 0.898,and the sensitivity and specificity at a cut-off value of 0.09 ng/m L were 92.31% and 84.09%,respectively;after combining D-dimer and cTnI,the sensitivity,specificity,and AUC of identifying AAD and AMI were improved compared with those of the application alone,and the AUC was 0.980.The sensitivity and specificity were 93.18% and 95.10%.Conclusions D-dimer combined with cTnI is a better combined test that can be used as a preliminary identification of the cause of acute chest pain in emergency medicine,especially in distinguishing AAD from AMI,showing a high sensitivity and specificity.