Circulating cell-free DNA levels correlate with postresuscitation survival rates in out-of-hospital cardiac arrest patients.

Early prediction of prognosis is helpful in cardiac arrest patients. Plasma cell-free DNA, which increases rapidly after cell death, is a novel biomarker for the prognosis of critical ill patients. Changes in the plasma cell-free DNA level and its role for the early prognosis of cardiac arrest patients remain unclear. We prospectively enrolled adult out-of-hospital cardiac arrest (OHCA) patients with sustained return of spontaneous circulation. The resuscitation variables were recorded following the Utstein recommendation. The plasma cell-free DNA concentration was determined by quantitative real-time polymerase chain reaction assay of β-globin gene. A total of 42 patients were enrolled for the study. The plasma cell-free DNA level within 2h after cardiac arrest was higher in the non-survival group than the survival-to-discharge group (median level 1659.9 g.e./mL vs. 1121.6g.e./mL, p=0.003 by non-parametric test). The plasma cell-free DNA level at 72 h became no difference between these two groups. The optimal cutoff value of plasma cell-free DNA for predicting survival-to-discharge was 1,170 g.e./mL by ROC curve analysis (area under curve 0.752, p=0.010). A plasma cell-free DNA level higher than 1,170 g.e./mL and was an independent predictor for in-hospital mortality by multiple logistic regression analysis (adjusted odds ratio of 12.35, p=0.023) and was also associated with higher 90 day mortality (p=0.021 by log-rank test). In conclusion, the plasma cell-free DNA level increases during the early post-cardiac arrest phase and can be an early prognostic factor for OHCA patients.