Cell-Free Double-Stranded DNA to DNase Ratio Predicts Outcome after Primary Survived Cardiac Arrest

Abstract

(1) Double-stranded DNA (dsDNA) and deoxyribonuclease (DNase) as surrogate parameters for accumulating inflammatory hazards are insufficiently studied in resuscitation research. (2) Blood samples of 76 individuals after CA were analyzed 24 and 96 h after ICU admission. Plasma levels of dsDNA, interleukin-8, and monocyte chemoattractant protein-1 and activity of DNase were assessed along with baseline characteristics, intensive care measures, and outcome data. DsDNA/DNase ratio was used as main prognostication parameter. After calculating an optimal empirical cut-off for outcome prediction (death or Cerebral Performance Category ≥3 at 6 months), multivariable logistic regression was applied. (3) Using receiver operating characteristic (ROC) analysis, an area under the curve (AUC) of 0.65 (95% CI 0.50-0.79) was found for dsDNA/DNase after 24 h versus 0.83 (95% CI 0.73-0.92) after 96 h (p = 0.03). The empirical cut-off for dsDNA/DNase ratio after 96 h was 149.97 (Youden). DsDNA/DNase ratio was associated with unfavorable outcome at six months (aOR 1.006, 95% CI 1.0017-1.0094, p = 0.005). In multivariable analysis, the association of dsDNA/DNase ratio independently predicted outcome as a continuous variable (aOR 1.004, 95% CI 1.0004-1.0079, p = 0.029) after adjusting for potential confounders. (4) DsDNA/DNase ratio at 96 h demonstrates good predictive performance for estimating outcome after CA.

Keywords: cardiopulmonary resuscitation; critical care outcomes; deoxyribonuclease; double-stranded DNA; post-cardiac arrest syndrome.

Figure A1

Single radial enzyme diffusion (SRED) assays were analyzed using ImageJ. Per sample, a degradation index was calculated based on circumference (big red circle) and background-corrected intensity of the digested area, excluding the well (filled small circle). Representative SRED assays of three different samples with low, intermediate, and high DNase activity [mU/mL] are shown.

Figure A2

Sex distribution. Abbreviations: CA: cardiac arrest.

Figure A3

Age distribution. Abbreviations: CA: cardiac arrest.

Figure 1

Schematic representation of the potential pathophysiological role of neutrophil extracellular traps (NETs) in post-cardiac arrest syndrome (PCAS). Abbreviations: DNase: deoxyribonuclease; dsDNA double-stranded DNA; NET: neutrophil extracellular traps; PCAS: post cardiac arrest syndrome; ROS: reactive oxygen species.

Figure 2

Boxplots comparing (a) dsDNA [ng/mL] after 24 and 96 h, (b) DNase [mU/mL] after 24 and 96 h, (c) dsDNA/DNase ratio after 24 and 96 h. Abbreviations: 24 h (+): value after 24 h in patients alive/CPC < 3 after six months; 24 h (−): value after 24 h in patients deceased/CPC > 2 after six months; 96 h (+): value after 96 h in patients alive/CPC < 3 after six months; 24 h (−): value after 96 h in patients deceased/CPC > 2 after six months; Whiskers represent minimum and maximum values. Asterisks indicate statistical significance (*: p < 0.05; ***: p < 0.001). For the y-axis of Figure 2c, a log10 scale was used for a more comprehensive visualization. Abbreviations: DNase: deoxyribonuclease; dsDNA: double-stranded DNA; n.s.: not specified.

Figure 3

Receiver-operating-characteristics (ROC) curves for dsDNA/DNase ratio after 24 and 96 h.

Figure 4

Kaplan–Meier plot for patients with dsDNA/DNase Ratio ≤ 149.97 versus dsDNA/DNase Ratio > 149.97. 96 h after ICU admission. Abbreviations: CI: confidence interval; ICU: intensive care unit.