TOMAHAWK RCT – Immediate vs Delayed Angiography for Out-of-Hospital Cardiac Arrest

October 28, 2021

Written by Laura Murphy

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There was no significant difference in 30-day mortality between immediate vs delayed cardiac catheterization strategies for hemodynamically stable patients who were post-arrest without STEMI on post-ROSC ECG.

Why does this matter?
The prognosis for patients who have out-of-hospital cardiac arrest (OHCA) is poor, even for those who are successfully resuscitated. Acute myocardial infarction is a common cause of OHCA, but there has not been a demonstrated benefit for immediate cardiac catheterization in patients without STEMI. The TOMAHAWK trial was the second and largest randomized trial addressing the timing of coronary angiography in hemodynamically stable patients without ST-segment elevation following OHCA.

Rest well, interventionalists…
The TOMAHAWK trial expanded on the findings of the COACT trial (prior JF here) to include patients with shockable or non-shockable initial rhythm. Patients with STEMI, obvious extra-cardiac etiology of arrest, hemodynamic or electrical instability, or cardiogenic shock were excluded.

Patients in the immediate group had coronary angiography performed as soon as possible (median 2.9 hours post-arrest), and patients in the delayed group underwent angiography >24 hours post-arrest at the discretion of the treating clinician (62.2% of patients had cardiac catheterization). For the primary outcome of 30-day mortality (all-cause), there was no statistically significant difference between immediate and delayed group (54.0% in vs 46.0%; hazard ratio 1.28; 95% CI, 1.0 to 1.63, p=0.06). The composite secondary endpoint of death or severe neurologic deficit occurred more frequently in the immediate group [64.3% vs 55.6%, RR 1.16; 95% CI 1.00 to 1.34]. This raised an interesting hypothesis, but the results were not adjusted for multiple outcomes, so there wasn’t enough evidence to say that early angiography is harmful. There was not a significant difference in safety outcomes (bleeding, stroke, need for renal replacement therapy). Finally, brain injury was the most common cause of death, so poor neurologic prognosis may attenuate any potential mortality benefit for patients undergoing revascularization.

For post-OHCA patients with hemodynamic or electrical instability, or clinical evidence of evolving ischemia, I will continue to discuss potential benefits of cardiac catheterization with cardiology. However, ICU admission with delayed catheterization for hemodynamically stable patients without STEMI continues to be a reasonable strategy. The authors also report that culprit lesions were identified in only 40% of all patients undergoing angiography, so be sure to consider and treat other causes of cardiac arrest.

Source
Angiography after Out-of-Hospital Cardiac Arrest without ST-Segment Elevation. N Engl J Med. 2021 Aug 29. doi: 10.1056/NEJMoa2101909. [Epub ahead of print].