Serum deoxyribonuclease I activity can be a useful diagnostic marker for the early diagnosis of unstable angina pectoris or non–ST-segment elevation myocardial infarction

Summary Background and purpose: Recently, serum deoxyribonuclease I (DNase I) activity has been highlighted as a potential diagnostic marker for transient myocardial ischemia. To evaluate whether serum DNase I activity can be a useful biomarker for diagnosing unstable angina pectoris (UAP) or non—ST-segment elevation myocardial infarction (NSTEMI), we investigated serial changes in DNase I levels after chest pain in UAP and NSTEMI (UAP/NSTEMI) patients. Methods and results: Thirty-three and ten patients classified into the UAP/NSTEMI and the chest pain syndrome (CPS) group, respectively, were enrolled. The serum DNase I activity levels within 3 h after chest pain and the absolute median value of percentage differences in serum DNase I activity levels from admission to 3 h after hospitalization in the UAP/NSTEMI patients was significantly higher than those in the CPS patients. We evaluated the patients to show positive results for DNase I activity if the serum levels or percentage differences exceeded the corresponding cut-off values. The sensitivity and specificity of DNase I within 6 h after chest pain in the UAP/NSTEMI patients without elevated levels of cardiac troponin T and the MB isoenzyme of creatine kinase were 89% and 88%, respectively.