TOMAHAWK

In Review

Desch S, et al. "Angiography after out-of-hospital cardiac arrest without ST-segment elevation". The New England Journal of Medicine. 2021. 385(27):2544-2553.
PubMed • Full text • PDF • ClinicalTrials.gov

Clinical Question

In adult patients (30+ years old) with out of hospital cardiac arrest who have been successfully resuscitated but have no ST elevations post-resuscitation, does immediate PCI improve survival?

Bottom Line

There is no survival benefit for performing immediate PCI for resuscitated out of hospital cardiac arrest (OHCA) who have no post-resuscitation ST elevations

Major Points

The role of angiography among those with out of hospital cardiac arrest (OHCA) was unclear. The TOMAHAWK trial randomized 554 adults with OHCA, regardless of shockable rhythm who didn't have primary indication for angiography (e.g., STEMI/LBBB) or clear non-cardiac reason for OHCA to immediate or delayed angiography. There was a non-significant trend towards higher rate of 30 day mortality among those brought for immediate angiography (54% vs. 46%; HR 1.28; 95% CI 1.00-1.63).

Guidelines

ESC 2020 An immediate invasive strategy (<2 hours) is recommended (I/C) in patients with at least one of:

• Hemodynamic instability or cardiogenic shock
• Life-threatening arrhythmias

ESC 2020 II A/B

• Delayed as opposed to immediate angiography should be considered among hemodynamically stable patients without
• ST-elevation successfully resuscitated after out-of-hospital cardiac arrest.

SCAI 2020 Consensus

• Deferring transport to cardiac catheterization lab at initial encounter is recommended in OHCA patients with an initial non-shockable rhythm Consensus
• Deferring invasive strategy at initial encounter is recommended in hemodynamically stable, comatose OHCA patients without STEMI on post-ROSC ECG

Design

• Multicenter, open-label, 1:1 randomized, controlled trial
  • Investigator initiated
• N=554
  • Immediate Angiography (n=281)
  • Delayed Angiography (n=273)
• Setting: 31 centers in Germany and Denmark
• Enrollment: 2016-2019
• Mean follow-up: 30 days
• Analysis: Intention-to-treat
• Primary outcome: 30 day all cause mortality

Population

Inclusion Criteria

• Aged ≥30 years
• Out of hospital cardiac arrest (OHCA) of possible cardiac origin with ROSC
• Shockable and unshockable rhythms included

Exclusion Criteria

• ST elevation or LBBB
• No ROSC
• Severe hemodynamic or electrical instability that would indicate urgent coronary angiography and likely intervention
• Non-cardiac origin of OHCA (e.g., TBI, metabolic disorder, electrolyte disorder, intoxication, hemorrhage, lung disease leading to respiratory failure, suffocation, drowning)
• In-hospital
• Pregnancy

Baseline Characteristics

From the immediate angiography group

• Demographics: Age 69 years, 30% female
• Anthropometrics: BMI 26.5
• Comorbidities: DM 29%, HTN 67%, smoker 30%, dyslipidemia 35%, CAD 34%, prior MI 19%, prior PCI 18%, prior CABG 80%
• Arrest details: Witnessed 91%, shockable rhythm 52%, bystander CPR 58%, duration from arrest to BLS 2 min, duration from arrest to ROSC 15 min, prehospital ECMO 1%
• Admission details: GCS 3, SBP 110, LVEF 45%
  • Labs (since this was a European study, the authors reported in SI units): Blood pH (presumably arterial) 7.22, lactate 5 mmol/L, creatinine 118 umol/L, troponin T 0.09 ug/L, troponin I 0.40 uG/L, blood glucose 11.5 mmol/L

Interventions

• Randomized to a group:
  • Immediate angiography - Brought to cath lab ASAP after admission
  • Delayed angiography - Initial ICU care to stratify OHCA etiology, with later coronary angiography if indicated.
    • Coronary angiography was allowed in first 24 hours if ≥1 of the following:
      • Troponin 70x ULN or CK-MB 10x ULN
      • Electrical instability
      • Cardiogenic shock
      • New ST elevations
• Both groups revascularized by PCI if at least one culprit lesion; CABG allowed if thought to be more appropriate

Outcomes

Comparisons are immediate angiography vs. delayed angiography.

Primary Outcomes

30 day all cause mortality

54.0% vs. 46.0% (HR 1.28; 95% CI 1.00-1.63)

Secondary Outcomes

95% CIs not adjusted for multiplicity. HLE is Hodges-Lehmann estimator.

Myocardial infarction

0% vs. <1% (RR 0; 95% CI 0-1.93)

Severe neurological deficit

Defined as Cerebral Performance Category scale of 3 (severe neurologic disability), 4 (persistent vegetative state), or 5 (brain death)

18.8% vs. 12.7% (RR 1.48; 95% CI 0.82-2.67)

All-cause mortality or severe neurological deficit

64.3% vs. 55.6% (RR 1.16; 95% CI 1.00-1.34)

Median length of ICU stay

7 vs. 8 days (HLE -1; 95% CI -2 to 0)

Median Peak SAPS II

70 vs. 69 (HLE 0; 95% CI -4 to 4)

Rehospitalization for heart failure

0.4% vs. 0.4% (RR 1.00; 95% CI 0.19-1.85)

Median peak Troponin T (µg/L)

0.39 vs. 0.34 (HLE 0.04; 95% CI -0.03 to 0.11)

Median peak Troponin I (µg/L)

1.46 vs. 1.10 (HLE 0.06; 95% CI -0.37 to 0.49)

Median peak creatinine (µmol/L)

133 vs. 133 (HLE 2.08; 95% CI -8.6 to 12.22)

Moderate Bleeding

4.6% vs. 3.4% (RR 1.34; 95% CI 0.57-3.14)

Stroke

1.6% vs. 2.1% (RR 1.13; 95% CI 0.33-3.84)

Acute renal failure requiring renal replacement therapy

18.9% vs. 15.8% (RR 1.14; 95% CI 0.78-1.68)

Subgroup Analysis

The primary outcome was similar by age of 65 years, diabetes, type of first rhythm, use of TTM. While the authors did not note any large differences in the primary outcome by these subgroups, the WJC editors note that the point estimate for the primary estimate was closer to "null" than "harm" with immediate angiography among those with confirmed MI as OHCA (with very wide CIs given small numbers in this group), among men, and ROSC ≥15 min from arrest. The WJC authors do not think there were obvious signals of potential benefit from immediate angiography in these groups.

Out of hospital cardiac arrest confirmed as MI

No: 50% vs 40% (HR 1.34, 95% CI 0.95-1.89)

Yes: 38% vs 42% (HR 0.97, 95% CI 0.50-1.90)

Sex

Females: 62% vs 46% (HR 1.64, 95% CI 1.06-2.54)

Males: 51% vs 47% (HR 1.14, 95% CI 0.84-1.53)

Duration of time until ROSC

≥15 min: 58% vs 57% (HR 1.02, 95% CI 0.76-1.36)

<15 min: 34% vs 30% (HR 1.52, 95% CI 0.78-2.93)

Additional Measures

Coronary angiography performed

96% vs. 62%

PCI: 37% vs. 43%

Median (IQR) duration from arrest to angiography

2.9 (2.2-3.9) vs. 47 (26-117) hours

Disease

None: 39% vs. 28%

1 Vessel: 15% vs. 13%

2 Vessel: 13% vs. 16%

3 Vessel: 33% vs. 44%

Culprit lesion identified

38% vs. 43%

Adverse Events

Not reported.

Criticisms

• Open label design
• Exclusion of hemodynamically and electrically unstable patients
• Study not designed to assess physiological benefits of PCI

Funding

• German Center For Cardiovascular Research