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For most resuscitated out-of-hospital cardiac arrest (OHCA) patients, rushing to angiography was no help for subsequent survival and in fact produced numerically worse outcomes, the TOMAHAWK trial showed.

Routine early coronary angiography provided no improvement over a more selective strategy in rates of all-cause mortality at 30 days (54.0% vs 46.0%, HR 1.28, 95% CI 1.00-1.63) among people with OHCA of potential cardiac origin who lacked ST-segment elevation on the post-resuscitation ECG, reported Steffen Desch, MD, of University of Leipzig Heart Center in Germany.

Desch presented study results during a Hot Line session at the European Society of Cardiology (ESC) virtual meeting. TOMAHAWK results were simultaneously published in the .

TOMAHAWK therefore supports the COACT study that showed no benefit to rushing resuscitated patients to the cath lab instead of waiting until after neurologic recovery. The new study broadens the relevant patient population by enrolling OHCA survivors with both shockable and nonshockable rhythms.

"You can take your time and first evaluate the clinical course in the ICU and, if still indicated, coronary angiography might be performed at a later time point, in the following days or not at all," Desch concluded during an ESC press conference.

However, "you should always move quickly when there's ST elevation on the ECG," he said, adding that there should be a low threshold for immediate angiography in cases where the resuscitated patient is awake and reports a history of angina or coronary disease.

"It's just for the majority of patients, this is probably not very useful," he explained.

Session discussant Susanna Price, MBBS, PhD, of Royal Brompton Hospital in London, emphasized that OHCA remains a major public health challenge associated with poor survival and huge variations in practice across the world.

It is helpful to have another study favoring a selective approach to invasive angiography since this allows for less urgent patient transfer and more appropriate clinician focus -- both important especially during the COVID-19 pandemic, she suggested.

The rationale for immediate angiography was that acute MI is the most common trigger of OHCA, and that such a strategy would help eligible patients get to coronary revascularization faster under the dogma that time is heart and brain.

Yet the study's secondary endpoint of death or severe neurologic deficit at 30 days trended higher with immediate coronary catheterization (64.3% vs 55.6%, RR 1.16, 95% CI 1.00-1.34) -- a potential signal of harm from neglecting brain injury or risks from invasive angiography.

"[N]eurologic rather than cardiac injury may have the most substantial effect on overall prognosis in many patients with cardiac arrest, thereby attenuating a possible beneficial effect of coronary revascularization. Of note, brain injury was by far the most frequent cause of death among the patients in our trial," study authors wrote.

Given the large number of patients dying from neurological causes in the study, it's worth waiting for a patient to regain consciousness before angiography, commented ESC session chair Franz Weidinger, MD, of Rudolfstiftung Hospital in Vienna.

Desch placed less importance on the risk from procedural complications from angiography, arguing that safety endpoints such as bleeding or stroke were not significantly different between groups. Troponin levels were also similar.

The investigators had 554 OHCA survivors randomized upon admission to emergency departments at 31 centers across Germany and Denmark. Most participants had been intubated at hospital arrival and were comatose at study entry.

Study protocol had the immediate angiography group transferred to the catheterization laboratory as soon as possible after hospital admission without spending time on a CT scan to assess neurological status. Those randomly assigned selective angiography went to the ICU to first have the cause of OHCA probed and to receive initial treatment.

People in both study arms were to undergo revascularization if operators found a culprit lesion on imaging.

Coronary angiography was performed in 95.5% and 62.2% of the immediate and selective angiography groups, respectively. Median time from arrest to coronary angiography was 2.9 versus 46.9 hours.

A culprit lesion was identified more often in the delayed angiography arm (43.0% vs 38.1%) and therefore led to more percutaneous coronary intervention in this group (43.2% vs 37.2%).

The trial doesn't answer the question of how long it is best to wait to get resuscitated patients into the cath lab, Desch acknowledged.

Whether CT angiography might play a role in managing these patients is also unclear, according to ESC panelist Stephan Windecker, MD, of Bern University Hospital, Switzerland.

Desch noted that follow-up for TOMAHAWK is planned out to 3 and 6 months.

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