What are the indications for stress echocardiography (echo)?

Indications for Stress Echocardiography

Stress echocardiography is primarily indicated for diagnosis of coronary artery disease, assessment of prognosis in patients with known coronary disease, and evaluation of valvular heart disease. 1

Primary Indications

Diagnosis of Coronary Artery Disease

• Patients with intermediate pre-test probability of CAD with uninterpretable ECG or inability to exercise 1
• Patients with intermediate pre-test probability of CAD with interpretable ECG who are able to exercise 1
• Patients with high pre-test probability of CAD, regardless of ECG interpretability and ability to exercise 1
• Patients with prior stress ECG that was uninterpretable or equivocal 1
• Patients with baseline ECG abnormalities including left bundle-branch block, electronically paced rhythm, and left ventricular hypertrophy 1, 2
• Patients taking digoxin (which can affect ECG interpretation) 1
• Patients with chest pain and intermediate probability of CAD who have non-diagnostic resting or exercise ECG 3

Evaluation of Known Coronary Artery Disease

• Assessment of prognosis in patients with established coronary artery disease 1, 4
• Functional assessment of coronary artery stenosis in patients being considered for revascularization 3
• Risk stratification after myocardial infarction 5
• Assessment of myocardial viability before potential revascularization using low-dose dobutamine protocol 3, 5

Valvular Heart Disease Assessment

• Evaluation of patients with known or suspected valvular heart disease 1
• Assessment of left ventricular function during exercise in patients with valvular heart disease 2
• Evaluation of changes in transvalvular gradient during exercise 2
• Assessment of patients whose symptoms are out of proportion to the severity of valve disease at rest 2

Preoperative Risk Assessment

• Risk stratification before noncardiac surgical procedures, including organ transplantation 1, 5

Choice of Stress Modality

Exercise Stress Echocardiography

• Preferred method for patients who can exercise adequately 1, 3
• Can be performed with treadmill or bicycle exercise 1
• Provides additional prognostic data from physiologic exercise variables 6

Pharmacologic Stress Echocardiography

• Dobutamine stress is indicated for patients unable to exercise due to physical limitations 1, 5
• Vasodilator stress (adenosine, dipyridamole) can be used to assess coronary flow reserve 3
• Atrial pacing stress can be used for patients with pacemakers 3

Contraindications

General Contraindications

• Acute coronary syndrome or high-risk unstable angina 7
• Decompensated heart failure 7
• Severe or symptomatic aortic stenosis 7
• Uncontrolled cardiac arrhythmias 7
• Severe systemic arterial hypertension (≥200/110 mmHg) 7
• Acute aortic dissection, pericarditis, or myocarditis 7
• Acute pulmonary embolism 7
• Severe pulmonary hypertension 7

Specific Contraindications for Dobutamine Stress

• Critical aortic stenosis 7
• Hemodynamically significant left ventricular outflow tract obstruction 7
• Hypokalemia 7
• Uncontrolled congestive heart failure 7
• Uncontrolled dysrhythmias 7

Specific Contraindications for Vasodilator Stress

• Second or third-degree atrioventricular block without permanent pacemaker 7
• Significant hypotension (SBP <90 mmHg) 7
• Bronchoconstrictive or bronchospastic disease 7
• Recent use of dipyridamole or methylxanthines 7

Clinical Value and Outcomes

• Stress echocardiography provides information on both resting ventricular function and stress-induced ischemia, two important determinants of cardiac events 6
• Normal results on stress echocardiography indicate a low cardiovascular event rate (<1% per year) 2, 4
• Peak wall motion score index effectively stratifies patients into low, intermediate, and high-risk groups for future cardiac events 4
• Patients with markedly abnormal stress echocardiographic results benefit most from coronary revascularization 4
• Stress echocardiography serves as an effective gatekeeper for coronary angiography and revascularization 4

Important Clinical Considerations

• Stress echocardiography is not indicated for cardiovascular risk assessment in low or intermediate-risk asymptomatic adults 1
• The diagnostic performance is highly dependent on the availability of skilled acquisition and interpretation of images 1
• Two operators should perform the test: an experienced physician and a trained nurse or another doctor 3
• The laboratory should be equipped with a defibrillator and resuscitation kit 3
• In very obese patients or those with chronic obstructive pulmonary disease, nuclear perfusion imaging may be preferable due to potentially reduced echocardiographic image quality 8