In our cohort, intracranial haemorrhage was not detected in patients presenting with OHCA and STEMI, even in the presence of a visible external head injury. According to current guidelines, a primary PCI strategy is recommended in patients resuscitated from cardiac arrest and ECG findings consistent with STEMI. This is followed by CT of the head and/or CT pulmonary angiography if coronary angiography fails to identify causative lesions [3, 4].

The added value of and indications for a head CT scan before emergency angiography in OHCA patients have not been established. A meta-analysis by Petek and colleagues studied the diagnostic yield of CT scanning in non-traumatic OHCA patients in general, not specifically for cardiac causes. Between 0.3% and 24% of head CT scans led to a diagnosis such as subarachnoid or meningeal haemorrhage that was not necessarily the cause of the OHCA [5]. One study performed in a single centre in San Francisco prospectively investigated the value of head CT in all OHCA patients arriving at their ED with return of spontaneous circulation (ROSC), including patients presenting with STEMI [6]. Their goal was to identify the incidence of intracranial haemorrhage as a cause of OHCA. A total of 85 CT scans were performed in 95 patients who had sustained ROSC after OHCA. In 3 patients intracranial haemorrhage was detected, 2 of whom presented with OHCA based on a non-shockable rhythm. No information was available about the type and cause of intracranial haemorrhage and whether collapse or trauma was present. In 10 patients CT of the head was deferred, in 6 of these because of an emergency PCI.

In the majority (73%) of patients in our cohort that underwent CT, antithrombotic treatment was delayed until after the scan had been performed. When an emergency CT scan was performed, PCI was delayed on average by 26 min. In this small retrospective study the delay of 26 min did not lead to demonstrable cardiac damage (measured by peak CK and CK-MB) or increased mortality. However, it is known that infarct size and mortality rates increase as door-to-balloon time increases [2, 7]. Shortening door-to-balloon time reduces 1‑year mortality and every reduction of door-to-balloon time by 30 min resulted in a reduction of 1‑year mortality [8, 9]. Therefore efforts to shorten door-to-balloon time should apply for all patients. The risk of missing a possible haemorrhage should be taken into account. Based on our retrospective study we cannot conclude that prior CT scanning in this clinical scenario should not be performed, but our findings suggest that even in the case of serious traumatic injury after OHCA, the risk of intracranial haemorrhage is low. Therefore, we believe that in the majority of cases deferring head CT and immediately proceeding to emergency PCI might be reasonable.

Our study has several limitations. Follow-up data were not available for all patients due to transfers to other hospitals. Even though we detected no intracranial haemorrhage, the patient numbers of the current cohort are low and therefore our conclusions are hypothesis generating. The possible consequences of missing an intracranial haemorrhage prior to emergency PCI may be clinically relevant as treatment with dual antiplatelet therapy and heparin could have detrimental effects.

Finally, in every hospital logistics and the amount of time required to perform a CT scan can differ. A CT scanner located nearby/at the ED will probably reduce the delay in performing a CT scan, thereby facilitating rapid proceeding to PCI.

In conclusion, in this retrospective study CT of the head did not result in a diagnosis of intracranial haemorrhage or deferral of PCI but did delay PCI treatment for STEMI in patients presenting with OHCA.