TOMAHAWK: no benefit in immediate angiography after out of hospital cardiac arrest without ST segment elevation

Key Points:

• In patients with resuscitated out-of-hospital cardiac arrest (OHCA) of potential cardiac etiology with either shockable or non-shockable arrest rhythm, performing immediate nonselective coronary angiography did not reduce 30-day all-cause mortality compared with delayed, selective angiography.
• Of those undergoing immediate angiography, a culprit lesion was identified in 38.1% of patients, compared with 43% of patients undergoing delayed selective angiography.

While the role of early coronary angiography in patients with cardiac arrest secondary to ST-elevation MI (STEMI) is clear, there has been considerable ambiguity in the treatment of patients with cardiac arrest with strong suspicion of underlying cardiac cause without an apparent STEMI. Several clinical trials have attempted to address this important clinical question. The COACT trial examined the use of immediate coronary angiography versus delayed nonselective coronary angiography in patients who suffered an OHCA without a STEMI and were successfully resuscitated; there was no difference found in overall survival at 90 days. Similarly, the PEARL study (although terminated prematurely) found no difference in survival to discharge or adverse events in patients who received early coronary angiography vs no early angiography. The aim of the Immediate Unselected Coronary Angiography Versus Delayed Triage in Survivors of Out-of-hospital Cardiac Arrest Without ST-segment Elevation (TOMAHAWK) clinical trial (NCT02750462) was to evaluate the effect of immediate, nonselective coronary angiography vs delayed, selectively chosen angiography on patients with OHCA without STEMI on 30-day mortality. In a Hot Line presentation at the 2021 European Society of Cardiology Conference today, Dr. Steffen Desch (Heart Center Leipzig, University Center Lübeck) and his team presented the results of the TOMAHAWK trial.

The TOMAHAWK trial was a multicenter, randomized, international clinical trial involving 31 sites in Germany and Denmark. Patients > 18 years old with documented resuscitated OHCA of possible cardiac origin but without overt STEMI were included. Relevant exclusion criteria were as follows: a) ST-elevation or LBBB, b) lack of ROSC upon hospital admission, c) severe hemodynamic or electrical instability precluding a delay for angiography, d) clear non-cardiac etiology of arrest, e) pregnancy, and f) participation in other conflicting research trials.

A total of 554 patients were randomized; 281 were selected to receive immediate nonselective coronary angiography, of whom 253 actually received the procedure. 273 patients were randomized to receive delayed, selective angiography, of whom 165 ultimately received angiography. The primary endpoint was 30-day all-cause mortality. Secondary endpoints at 30 days included a) myocardial infarction, b) severe neurological deficit, c) composite all-cause mortality and severe neurologic deficit, d) length of ICU stay, e) moderate to severe bleeding, f) serial simplified acute physiology score (SAPS) II, g) CHF rehospitalization, h) peak myocardial enzyme release, i) stroke, and j) acute renal failure requiring renal replacement therapy.

In the immediate angiography group, the median time from arrest to angiography was 2.9 hours, vs 46.9 hours in the delayed/selective group. A culprit lesion was identified in 38.1% vs 43% respectively, and PCI was performed in 37.2% vs 43.2%. There was no difference in the primary endpoint of 30-day all-cause mortality (HR 1.28 [95% CI 1.00-1.63], p=0.058). There were no significant differences in the secondary endpoints, other than a small statistically significant increase in the composite of all-cause mortality and severe neurologic deficit in the immediate angiography group (RR 1.16 [1.002-1.34]). The authors performed multiple subgroup analyses, stratifying the primary endpoint by several factors including age, initial rhythm, confirmed myocardial infarction, and time from arrest to ROSC; there was no significant differences observed in any subgroup.

When discussing the implications of the study at the ESC Congress, Dr.Desch stated: “I think the results of the study are clear. We should not rush to immediate angiography [in OHCA patients]…we should take a delayed, selective approach. As to the optimal timing of delayed angiography…that is not clear.”

The associated manuscript has been published in the New England Journal of Medicine