Journal Club – Diagnostic Accuracy of ECG for Acute Coronary Occlusion resulting in MI

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Presenter: Dr. Nick Byers (iFMEM R2)

Host: Dr. Colin Rouse

Article:

Research question/PICOD

  • Question:
    • Does shifting from a STEMI/NSTEMI paradigm to a new approach (ACO-MI/ non-ACO-MI) result in better identification of the patients who need acute reperfusion therapy?
  • Population:
    • Adult ED patients with ACS Symptoms
  • Intervention/Comparison:
    • STEMI/NSTEMI vs ACOMI/NACOMI
  • Outcome:
    • Composite ACO defined as one of:
      • A) Total occlusion or presence of culprit lesion on angiography with a peak troponin I level equal to or greater than 1.0 ng/mL plus an at least 20% rise within 24 h
      • B) A highly elevated peak troponin (greater than 5.0 ng/mL), which was shown to be correlated with ACO
      • C) Cardiac arrest before any troponin rise has been documented with supporting clinical evidence of possible ACO
    • All cause in hospital mortality
    • All cause long term mortality
  • Secondary Outcomes: 
    • Time from ECG to coronary angioplasty or CABG
    • The sensitivity and specificity of current criteria in diagnosing ACO
    • The sensitivity and specificity of ECG without ST-segment elevation to diagnose ACO (accuracy of ECG interpretation of acute coronary occlusion without STEMI criteria)
    • The specificity of ECG with STEMI criteria (correct ECG interpretation of false positive STEMI criteria)
    • The sensitivity of ECG with STEMI criteria (correct ECG interpretation of false negative STEMI criteria)
    • The outcome according to ECG subclassifications (outcomes of the patients who are labeled as STEMI and the patients who are labeled as having NSTEMI but have acute coronary occlusion)
  • Design:
    • Single center, retrospective case-control study in Turkey

Results

Authors conclusions

“We believe that it is time for a new paradigm shift from the STEMI/non-STEMI to the ACOMI/non-ACOMI in the acute management of MI”

 

Discussion at Journal Club

Strengths

  • 3000 patients included, 1000 per arm
  • Reviewers were blinded, disagreements were resolved by a 3rd independent reviewer
  • EKGs were reviewed again 3 months later to decrease inter-observer variability
  • Consecutive patients with an initial diagnosis of MI (i.e. not a convenience sample)
  • All patients received guideline-recommended medical treatment
  • There were documented criteria of ECG findings to classify the ECGs

Weakness

  • This was a retrospective study and at a single centre.
  • When troponins were taken was not controlled for/accounted for in any way
  • Control group age, medical comorbidities, and cardiac risk factors were much less
  • Their results suggest 17% of patients in N-ACOMI (N-STEMI Subgroup B) with angiographic ACO were missed (slide 16 results)
  • Study wasn’t powered enough to indicate modest benefit of early intervention over late
  • Extrapolating results to the real world may be difficult because ecg interpretation

 

Bottom line/suggested change to practice/actions

  • This single center retrospective chart review suggests that considering coronary occlusion vs. just ST elevation on ekg decreases long-term mortality, and has a better sensitivity, specificity, PPV, and NPV.
  • This could be a great way of getting patients better access to PCI for occlusive lesions, though inter-operator variability and time constraints are likely to be difficult to implement

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