ACS - Stress Testing

Revision as of 00:41, 20 September 2013 by Ostermayer (talk | contribs)

Background

  • Stress testing is recommended for pts w/ low-moderate pretest probability of CAD
    • Not helpful in pts w/ very low risk or high risk

ECG-Based Exercise Treadmill Testing

  • 68% sn, 77% sp
  • Contraindications to Exercise Testing
    • Absolute
      • MI (within 2 days)
      • High-risk unstable angina
      • Uncontrolled cardiac dysrhythmias
      • Symptomaticaortic stenosis
      • Uncontrolled symptomatic heart failure
      • Acute pulmonary embolus or pulmonary infarction
      • Acute myocarditis or pericarditis
      • Acute aortic dissection
    • Relative
      • Baseline ST segment abnormalities
      • Left main coronary stenosis
      • Moderate stenotic valvular heart disease
      • Electrolyte abnormalities
      • Severe HTN (>200 sys, >110 dia)
      • Tachydysrhythmias or bradydysrhythmias
      • HOCM
      • Mental or physical impairment
      • High-degree atrioventricular block


    • The Bottom Line:
      • ETT has low sensitivity and specificity overall (especially for women) and as such is not a good test for patients in whom suspicion for ACS is high
      • ETT is safe in low-risk and select intermediate-risk patients as a way of determining who is at low risk for short term adverse events (and therefore can go home)
      • ETT does not have prognostic value for patients who return to the ED with concerning symptoms or EKG changes

Echocardiography

  • Sn 80% sp 84%
    • When used in low-risk pts, NPV 97-100%
  • Who should be tested (ACC/AHA Class IIa)
    • patients with abnormal baseline EKG
    • patients unable to exercise
    • women with low- to intermediate-risk
  • Who shouldn’t be tested with stress echo
    • patients in whom a sub-optimal study is likely (very obese, COPD with expanded AP chest diameter, etc)
    • patients with grossly abnormal baseline LV or valvular function (e.g. severe AS)


  • The Bottom Line
    • Stress echocardiography (chemical or exercise induced) has greater sensitivity and specificity than ETT for ACS (especially for women)
    • Patients with normal stress echos are at very low risk for mortality within 1 year
    • A normal stress echo does not preclude subsequent ACS, nor should it lower suspicion for ACS when a patient presents with new symptoms!


Nuclear Medicine aka PMIBI

  • Who Should be Tested
    • patients with intermediate risk ACS who have uninterpretable EKGs or are unable to exercise
    • patients in whom stress echocardiography is unlikely to yield a technically adequate study
  • Who Shouldn’t be
    • Low risk patients


  • The Bottom Line
    • P-MIBI has greater sensitivity than stress echo in the diagnosis of CAD (not what we’re interested in) at much higher cost and technical difficulty
    • Both studies have good sensitivity and specificity for the diagnosis of ACS and good NPV for short-term events (what we’re interested in)

See Also

Acute Coronary Syndrome (Main)

Source

Tintinalli Rosens