Non invasive tests of CAD

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NONINVASIVE EVALUATION OF CAD
POCKET medicine NOTES ANWER GHANI
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Stress testing

• Indications dx obstructive CAD, evaluate ? in
  clinical status in Pt w/ known CAD, risk
• stratify after ACS, evaluate exercise tolerance,
  localize ischemia (imaging required)
• Contraindications 
• Absolute AMI w/in 48 h, high-risk UA, acute PE,
  severe AS, uncontrolled HF,
• uncontrolled arrhythmias, myopericarditis, acute
  aortic dissection
• Relative left main CAD, mod symptomatic
  valvular stenosis, severe HTN, HCMP, high-degree
  AVB, severe electrolyte abnl.

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Exercise tolerance test

• Generally preferred if Pt can meaningfully
  exercise ECG ?s w/ Se 65, Sp 80
• Typically via treadmill w/ Bruce protocol
  (modified Bruce or submax if decond. or recent
• MI)
• Hold anti-isch. meds (eg, nitrates, ßB) if dxing
  CAD but give to assess adequacy of meds

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Pharmacologic stress test

• Use if unable to exercise, or recent MI. Se Sp
  exercise.
• Coronary vasodilator diffuse vasodilation
  Regadenoson (?side effects), dipyridamole,
  adenosine. Side effects flushing, ? HR, AVB,
  SOB, bronchospasm.
• Dobuta. longer test may precip arrhythmia

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Imaging for stress test

• Use if uninterpretable ECG 
• Use when need to localize ischemia
• Radionuclide myocardial perfusion imaging w/
  images obtained at rest w/ stress
• Echo (exercise or dobuta) Se 85, Sp 85 no
  radiation operator dependent
• Cardiac MRI (w/ pharmacologic stress) another
  option with excellent Se Sp

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Test results

• HR (must achieve 85 of max pred HR 220-age
  for exer. test to be dx)
•  BP response,
• peak double product (HR BP nl gt20k)
• HR recovery (HR peak HR1 min later nl gt12)

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TEST RESULTS

• ECG ?s downsloping or horizontal ST ? (1 mm)
  6080 ms after QRS predictive of CAD (but does
  not localize ischemic territory) however, STE
  highly predictive
• localizes
• Imaging radionuclide defects or
  echocardiographic regional wall motion
  abnormalities
• reversible defect ischemia fixed defect
  infarct transient isch dilation ? Severe 3VD

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High-risk test results. consider coronary angio)

• ECG ST ? 2 mm or 1 mm in stage 1 or in 5
  leads or 5 min in recovery ST ? VT
• Physiologic ? or fail to ? BP, angina during
  exercise, Duke score 11?EF
• Radionuclide reversible defects, transient LV
  cavity dilation, ? lung uptake

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Myocardial viability 

• Goal identify hibernating myocardium that could
  regain fxn after revascularization
• MRI (Se 85, Sp 75), 
• PET (Se 90, Sp 65)
• Dobutamine stress echo (Se 80, Sp 80)

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Coronary CT/MR angio

•  CCTA 100 Se, 54 Sp for ACS, 
•  ? cath/PCI, radiation vs. fxnal study
•  CCTA vs. fxnal testing ? ? radiation, cath/PCI
  early by 5 y, ? CHD death/MI
• Unlike CCTA, MR does not require iodinated
  contrast or radiation, and can assess LV fxn

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Coronary artery calcium score

• Quantifies extent of calcium thus, estimates
  plaque burden (but not coronary stenosis)
• CAC sensitive (91) but not specific (49) for
  presence of CAD
• ACC/AHA guidelines note CAC assessment is
  reasonable in asx Pts w/ intermed risk and
  selected borderline risk.

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THANKS

• ANWER GHANI