Cardiac Stress Imaging

See Also

Preparation
Stress Testing

Hold all Beta Blockers 24 hours before test
Hold nitrates (Nitroglycerin) on day of the test

Efficacy

Exercise Stress Test
1. Test Sensitivity: 55-68%
2. Test Specificity: 70-77%
Stress Echocardiogram
1. Test Sensitivity: 64-90%
2. Test Specificity: 80-87%
Stress Myocardial Perfusion Scan (Thallium Scan, SPECT)
1. Test Sensitivity: 85-90%
2. Test Specificity: 80-90%
Stress MRI
1. Test Sensitivity: 87 to 90%
2. Test Specificity: 80 to 88%
Cardiac CT
1. Test Sensitivity: 93-97%
2. Test Specificity: 80-90%
Cardiac Catheterization
1. Test Sensitivity: 98%
2. Test Specificity: 82%
References

Tests
Screening

Indications
1. Intermediate CAD risk asymptomatic patients
Tests
1. CT Coronary Calcium
2. Consider other markers of subclinical disease
  1. Ankle-Brachial Index
  2. Carotid intimal-medial thickness
  3. Retinography

Tests
Stress Test

Indications
1. Symptomatic patients with intermediate CAD risk
2. Asymptomatic patients with high CAD risk
Tests:
1. Exercise Stress Test (no imaging)
  1. Indicated as cost effective first-line test
  2. See Cardiac Stress Imaging Indications
  3. Consider imaging if nondiagnostic EKG is likely (uninterpretable EKG)
    1. Resting ST depression >1mm
    2. Left Bundle Branch Block
    3. Paced rhythm
    4. Digoxin
    5. WPW Syndrome
  4. Avoid non-imaging stress test if prior coronary revascularization (low sensitivity)
2. Stress Tests with Imaging and Exercise as stressor
  1. Indications
    1. See Cardiac Stress Imaging Indications
  2. Stress Echocardiogram
    1. Most cost-effective, versatile Cardiac Imaging
    2. Pre- and Immediate Post-Exercise Imaging (within 1-2 minutes)
      1. Evaluates ventricular wall motion and wall thickness changes with Exercise
    3. Large body habitus interferes with echo windows
      1. Consider Optison contrast to increase accuracy
    4. May be better study post-revascularization
      1. Lower sensitivity than Myocardial Perfusion Imaging, but much better Specificity
      2. Stress Echo is less likely to result in False Positive tests post-revascularization
  3. Stress Myocardial Perfusion Imaging
    1. Diaphragm and Breast interferes with images
  4. Stress Testing with Cardiac MRI (CMR)
    1. Limited availability
3. Stress Imaging with Pharmacologic Provocation
  1. Indicated if patient unable to Exercise 5 mets (~5 minutes on bruce protocol)
  2. Dobutamine Echocardiogram
    1. No Beta Blockers for 24 hours before test
  3. Myocardial Perfusion Imaging with Adenosine
    1. Avoid in severe COPD, Asthma, Carotid Stenosis
    2. No nitrates on day of test
    3. No Methylxanthines (e.g. Caffeine) for 24 hours
  4. Myocardial Perfusion Imaging with Dipyridamole
    1. Uses Dipyridamole (Persantine) instead of Adenosine
    2. Determine Cardiac Risk pre-major non-cardiac surgery
    3. May also help with prognosis after major surgery

Tests
Angiography

Indications
1. Significantly abnormal stress test (see above)
2. Symptomatic patient and high Cardiac Risk
Tests
1. See Coronary Angiography
2. CT Coronary Angiography
3. MR Coronary Angiography

Tests
Adjunctive

Transthoracic Echocardiogram
1. See Echocardiogram in Myocardial Infarction
Transesophageal Echocardiogram
1. Evaluates for non-ischemic intracardiac lesions
2. Aortic Dissection
3. Valvular dysfunction (including vegetations)
4. Intracardiac thrombi
5. Intracardiac shunts

References