Objective: This study aimed to investigate whether out-of-hospital cardiac arrest (OHCA) may induce severe DNA damage measured using comet assay in successfully resuscitated humans and to evaluate a short-term prognostic role. Methods: In this prospective, controlled, blinded study (1/2013-1/2014), 41 patients (age, 63 +/- 14 years) successfully resuscitated from non-traumatic OHCA and 10 healthy controls (age, 53 +/- 17 years) were enrolled.
DNA damage [double-strand breaks (DSBs) and single-strand breaks (SSBs)] was measured using comet assay in peripheral lymphocytes sampled at admission. Clinical data were recorded (according to Utstein style).
A good short-term prognosis was defined as survival for 30 days. Results: Among the patients, there were 71% (29/41) short-term survivors.
After OHCA, DNA damage (DSBs and SSBs) was higher (11.0 +/- 7.6% and 0.79 +/- 2.41% in tail) among patients than among controls (1.96 +/- 1.63% and 0.02 +/- 0.03% in tail), and it was more apparent for DSBs (p< 0.001 and p=0.085). There was no difference in the DNA damage between patients with cardiac and non-cardiac etiology, or between survivors and nonsurvivors.
Among Utstein style parameters, ventricular fibrillation, asystole, and early electrical defibrillation influenced DSBs; none of the factors influenced SSBs. Factors influencing survival were SSBs, ventricular fibrillation, length of cardiopulmonary resuscitation by professionals =15 min, cardiogenic shock, and postanoxic encephalopathy.
In contrast to DSBs [area under the curve (AUC)=0.520], SSBs seem to have a potential in prognostication (AUC=0.639). Conclusion: This study for the first time demonstrates revelation of DNA damage using comet assay in patients successfully resuscitated from OHCA.
Whether DNA damage measured using comet assay may be a prognostic marker remains unknown, although our data may encourage some suggestions.