Cardiac Stress Testing

• Up until recently, we used the Diamond and Forrester Score for Pre-test probability for CAD
  • Problem: developed in the 70s; diff pt pop than what we see these days
  • Alternatives:
    • ESC: Age, sex, angina typicality
    • CAD Consortium: Age, sex, angina typicality, diabetes mellitus, smoking status, hypertension, and dyslipidemia
• ACC ASCVD Risk Calculator is the recommended one
• Factors to consider in Patients with Known CAD
  • Complexity of CAD
  • LV function - very powerful prognosticator
    • prefer more accurate test in folks with ↓ EF
  • Co-morbidities
    • Diabetes mellitus
    • Chronic kidney disease
  • Results of previous testing
• Radiation Exposure: Age and Sex
  • Risk from radiation greatest in younger patients
  • Latency period 10-20 years following exposure
  • Risk higher for women
  • Lifetime risk 400% for 20-year-old woman vs. 50-year-old man
  • Estimated additional risk of 10 mSv dose is 1:2,000 for age distribution of US population
  • Mean age of patients undergoing MPI imaging ~65 yrs
• Testing based on patient characteristics
  • Intermediate-risk ASx patient → Exercise ECG
    • Stress imaging, e.g. Stress Echocardiography, PET, etc. are Class III (no benefit) for low or intermediate-risk patients, but can be considered if:
      • DM
      • Strong family history of CHD
      • Previous risk assessment testing suggests high risk of CHD, (eg, CAC score ≥ 400)

Which test to order?

Patients with **acute and stable chest pain**

	Exercise ECG	Stress Echo	SPECT	PET	Stress CMR
Patient can exercise	X	X	X
Pharmacologic stress indicated		X	X	X	X
Quantitative flow				X	X
LV dysfunction/scar		X	X	X	X

Warranty Period for Stress Testing

Test Modality	Result	Warranty Period
Anatomic	Normal coronary angiogram CCTA with no stenosis or plaque	2 y
Stress testing	Normal stress test (given adequate stress)	1 y

Contraindications by Stress Modality

• STEMI or NSTEMI acute coronary syndrome or unstable angina
• Recent ACS (STEMI or NSTEMI), less than 2 days after, with ongoing/active symptoms of ischemia or heart tailure
• ↑ Troponin of possible ischemic etiology, ↑ in value or with ongoing/active symptoms of ischemia or ischemic ECG ∆
• Decompensated heart failure
• Significant Hypertension: resting SBP ≥200 mmHg or resting DBP ≥ 110 mmHg
• Significant Hypotension: symptomatic hypotension or asymptomatic hypotension with SBP at rest ≤85 mmHg
• Uncontrolled cardiac arrhythmias (causing Sx or hemodynamic compromise)
• Symptomatic severe aortic stenosis
• Acute pulmonary embolism
• Acute aortic syndromes, including acute Type A aortic dissection or acute Type B aortic dissection with symptoms
• Third-degree AV block without a functioning pacemaker
• Acute symptomatic significant medical illness
• Inability to participate or cooperate with testing, or inability remain still and flat for imaging

Source: Table 5 of ¹

Exercise ECG	Nuclear (PET, SPECT)	Stress Echocardiography	Stress Cardiac MRI	CCTA
- Abnormal ST changes on resting ECG, digoxin, LBBB, WPWpattern, ventricular paced rhythm (unless test is performed to establish exercise capacity and not for diagnosis of ischemia) - Unable to achieve ≥5 METs or unsafe to exercise - High-risk unstable angina or AMI (<2 d) i.e., active ACS - Uncontrolled HF - Significant cardiac arrhythmias (e.g., VT, complete atrioventricular block) or high risk for arrhythmias caused by QT prolongation - Severe symptomatic aortic stenosis - Severe systemic arterial hypertension (e.g., ≥200/110 mm Hg) - Acute illness (e.g., acute PE, acute myocarditis/pericarditis, acute aortic dissection)	- High-risk unstable angina, complicated ACS or AMI (<2 d) -Contraindications to vasodilator administration - Severe systemic arterial hypertension (e.g., ≥200/110 mm Hg)	- Poor windows - Unable to reach target HR - Uncontrolled HF - High-risk unstable angina, active ACS or AMI (<2 d) - Serious ventricular arrhythmia or high risk for arrhythmias attributable to QT prolongation - Respiratory failure - Severe COPD, acute PE, severe pulmonary hypertension - Contraindications to dobutamine (if pharmacologic stress test needed) - Severe systemic arterial hypertension (e.g., ≥200/110 mm Hg)	- Reduced GFR (<30 mL/min/1.73 m2) - Contraindications to vasodilator administration - Implanted devices that are not MRI-safe or that will produce artifact - Significant claustrophobia - Caffeine ☕ use within past	- Allergy to iodinated contrast - Inability to cooperate with scan acquisition and/or breath-hold instructions - Clinically unstable - Renal impairment - Unable to achieve target HR - Heart rate variability and arrhythmia - Contraindication to nitroglycerin (if indicated)

Exercise ECG

See Exercise ECG

Pharmacologic Stressors

See Pharmacologic Stressors

Stress Echocardiography

See Stress Echocardiography

Stress SPECT

See SPECT

• Widely available
• Intermediate expense
• Radiation exposure
  • Range of radiation exposure 6-8 mSv
• Time consuming if both stress and rest imaging needed
• Intermediate diagnostic accuracy (sensitivity ~80% & specificity ~70%

Stress PET

See PET

• High quality images with high diagnostic accuracy
• Ability to quantitate blood flow
• Assessment of LV function at rest and peak stress
  • 30 minute rest/stress test
• Short acquisition times (rest and stress ‹35 minutes)
• Low radiation exposure (2.0 - 2.4 mSv)
• Best test for very large patients
• Importance of Myocardial Flow Reserve
  • 📄 Patel KK, Spertus JA, Chan PS, et al. Myocardial blood flow reserve assessed by positron emission tomography myocardial perfusion imaging identifies patients with a survival benefit from early revascularization. European Heart Journal. 2019;41(6):759-768. doi:10.1093/eurheartj/ehz389

Coronary Computed Tomography Angiography (CCTA)

• Tool which McGhie thinks we don’t use often enough
  • Likes in patients with low-to-intermediate risk
• Strength is its Negative Predictive Value
  • Very high -ve predictive value (almost 100%)
• Rapid acquisition
• No requirement for stress
• Inexpensive
• Readily available
• SCOT HEART Study - 📄 Coronary CT Angiography and 5-Year Risk of Myocardial Infarction. New England Journal of Medicine. 2018;379(10):924-933. doi:10.1056/nejmoa1805971
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Footnotes

1. Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain. Journal of the American College of Cardiology. 2021;78(22):e187-e285. doi:10.1016/j.jacc.2021.07.053 ↩