Acute coronary syndrome: ECG and CK-MB help diagnose it and stress testing helps rule it out

Clinical bottom line (level 2a)

  1. The following tests make acute cardiac ischaemia more likely
    • abnormal prehospital ECG
    • abnormal continuous serial ECG
    • abnormal exercise stress ECG
    • rest echocardiography
    • abnormal CK-MB
  2. Acute cardiac ischaemia is less likely with
    • normal exercise stress ECG
    • normal technetium-99m sestamibi scanning
    • low ACP-TIPI score
Lau et al: AHRQ Publication No. 01-E006, Rockville, MD 2201; : -
Lau et al: Ann Emerg Med 2001; 37 : 453-460
Balk et al: Ann Emerg Med 2001; 37 : 478-494
Expires March 2004

The study

Systematic review of all diagnostic studies of
  • Patients: suspected acute coronary ischaemia
  • Intervention: ECG, blood tests, stress testing
  • Outcome: acute coronary ischaemia

    Articles found in English using Medlnie, 1966 to January 1999 (search terms: Detailed in text, but included "chest pain," "myocardial ischemia" or "infarction," "emergency," and "emergency service." ) and and retrieved studies used in a previous report, searched references of published meta-analyses and selected review articles, and consulted technical experts

    Selection criteria: see above and below
    Appraisal criteria: Prospective or retrospective cohorts, blinding and reference standard used. . Data were abstracted either independently by two members or by one member and then verified by a second member.
    Articles excluded if:
    • no clear reference to emergency department settings
    • populations with special comorbidities (e.g., patients with renal disease)
    • aged < 18


    407 articles:
    • 5 on ECGs involving 4311 patients
    • 2 on rest echocardiography involving 228 patients
    • 3 on techetium-99m sestamibi imaging involving 702 patients mostly with normal/non-diagnostic ECGs and normal serial cardiac markers
    • 2 on exercise stress ECG involving 312 patients
    • 1 on CK-MB at presentation involving 1042 patients
    • 1 on serial CK-MB involving 1042 patients
    • 4 on ACI-TIPI involving 5496 patients

    Where possible data was combined using a random-effects model. Significant heterogeneity was noted for the sensitivity of prehospital ECG for myocardial infarction, and for sensitivity and specificity of prehospital ECG for acute cardiac ischaemia .

    The evidence


    diagnostic test number of patients sensitivity for
    acute cardiac ischemia ischaemia
    (95% CI)    		 specificity for
    acute cardiac ischemia ischaemia
    (95% CI)    		 LR+ LR-
    continuous serial ECG 21-25%
    (% to %)     		92-99%
    (% to %)     		2.6-25 0.76-0.86
    prehospital ECG 68%
    (59% to 76%)     		97%
    (98% to 92%)     		23 0.33
    exercise stress ECG 70-100%
    (% to %)     		82-93%
    (% to %)     		3.9-14 0.0-0.37
    rest echocardiography 70%
    (43% to 88%)     		87%
    (72% to 94%)     		5.4 0.34
    technetium-99m sestamibi imaging 89%
    (73% to 96%)     		77%
    (63% to 87%)     		3.9 0.14
    CK-MB (presentation) 23%
    (% to %)     		96%
    (% to %)     		5.8 0.80
    CK-MB (serial) 31%
    (% to %)     		95%
    (% to %)     		6.2 0.73
    ACI-TIPI 86-95%
    (% to %)     		78-92%
    (% to %)     		3.9-12 0.054-0.18
    total

    Comments

    1. By limiting the search strategy to English and Medline, important articles may have been missed.
    2. Studies varied in quality leading to ranges rather than confidence intervals in some cases.
    3. ACI-TIPI: Acute Cardiac Ischemia Time-Insensitive Predictive Instrument calculates a patient's probability of acute cardiac ischaemia using an logistic regression equation.

    Citation

    1. Lau J, Ioannidis J, Balk E, et al: Evaluation of Technologies for Identifying Acute Cardiac Ischemia in Emergency Departments. Evidence Report/Technology Assessment Number 26 (Prepared by The New England Medical Center Evidence-based Practice Center under Contract No. 290-97-0019). AHRQ Publication No. 01-E006, Rockville, MD 2201; : -
    2. Lau J, Ioannidis JP, Balk EM, et al: diagnosing acute cardiac ischemia in the emergency department: a systematic review of the accuracy and clinical effect of current technologies. Ann Emerg Med 2001; 37 : 453-460
    3. Balk EM, Ioannidis JP, Selem D, et al: accuracy of biomarkers to diagnose acute cardiac ischemia in the emergency department: a meta-analysis. Ann Emerg Med 2001; 37 : 478-494
    Search Terms: from AHRQ website
    Contributor: Chris Ball, March 2002
    Reviewer:

    Clinical Question.
    Patient suspected acute cardiac ischaemia
    Intervention or Exposure ECG, techetium sestamibi scanning
    Outcome acute cardiac ischaemia
    		•