The refractory out-of-hospital cardiac arrest (OHCA) is a global public health challenge with poor survival and neurological outcomes.1,2 A hyperinvasive resuscitation approach including early transport to hospital under extracorporeal cardiopulmonary resuscitation (ECPR), and immediate invasive evaluation upon hospital arrival may lead to better outcomes in this patient population – shows the Prague OHCA study, which was presented online in a Late-Breaking Clinical Trials session at the American College of Cardiology (ACC) 2021.

The Prague OHCAs is the largest clinical trial to compare the efficacy of a bundle of hyperinvasive interventions (mentioned above) with standard of care (usual post-cardiac arrest care) among patients with refractory OHCA. “There is no larger trial as we have randomised 256 patients during almost 8 years of study [2013-2020]” said Jan Bělohlávek, MD, PhD, professor of medicine at Charles University in Prague, Czech Republic, and lead author of the study. And “we have chosen a very hard endpoint for our study, which was 180-day survival with favourable neurological outcomes - this means cerebral performance category 1 and 2” elaborated Dr Bělohlávek.

Despite the numerically obvious difference in 6-month mortality between the hyperinvasive approach and standard care, the statistical significance was not reached (32% vs 22%, P = 0.09). Still, the trial was terminated early based on significant improvement in the secondary outcome of 30-day neurological function (31% vs 18%, P = 0.02) and the benefits observed in a subgroup of patients who were resuscitated for 45 minutes or longer, particularly those in the hyperinvasive arm (20 vs 6 survived, P= 0.018). Importantly, of the 6 survivors in the standard group, 4 were crossovers to the hyperinvasive group, but were analysed in the group to which they were randomised. These findings may suggest that “we cannot recommend so-called one-[size]-fits-all recommendation” noted Dr Bělohlávek, emphasising that “there is stronger evidence right now for doing this in very selected subgroup of patients.”

In summary, the Prague OHCA trial demonstrated that a hyperinvasive approach is feasible and effective in refractory OHCA, but a timely procedure in patient selection and intra-arrest transport remains an extremely important point to consider for favourable results. Moreover, for a successful resuscitation, efforts should be made to provide necessary prerequisites such as an optimal prehospital care, high percentage of bystander CPR, dispatch centre directed CPR, and close cooperation with dedicated cardiac arrest centres.

Reference:

1. Yan, S., Gan, Y., Jiang, N. et al. The global survival rate among adult out-of-hospital cardiac arrest patients who received cardiopulmonary resuscitation: a systematic review and meta-analysis. Crit Care.2020; 24, 61. doi:10.1186/s13054-020-2773-2
2. Shanmugasundaram, M., Lotun, K. Refractory Out of Hospital Cardiac Arrest. Curr Cardiol Rev. 2018;14(2):109-114. doi:10.2174/1573403X14666180507155622.