Cardiac Stress Test Evaluation

Primary Evaluations

The American College of Cardiology recommends that cardiac stress tests be used to evaluate for the presence, extent, and severity of coronary artery disease by assessing myocardial perfusion, ventricular function, and hemodynamic responses under conditions of increased cardiac workload, with a focus on identifying areas of reduced coronary blood flow and perfusion defects 1, 2
Coronary artery disease detection is achieved through stress tests that reveal perfusion defects or wall motion abnormalities when blood supply cannot meet increased myocardial oxygen demand during stress, with a diagnostic accuracy that is higher when using stress imaging (echocardiography or nuclear) compared to exercise ECG alone 1
Myocardial perfusion is assessed using radionuclide tracers that are taken up by the myocardium in proportion to coronary blood flow, allowing visualization of hypoperfused or ischemic areas, and providing information on coronary flow reserve 1, 2, 6
Regional and global ventricular function is evaluated through assessment of wall motion abnormalities and changes in ejection fraction during stress, which can indicate ischemia or viability, with low-dose dobutamine being used to identify viable but dysfunctional myocardium 1, 3

The European Heart Society recommends exercise as the preferred method of stress testing when feasible, as it provides physiological cardiovascular responses and functional capacity assessment, with treadmill or bicycle ergometer protocols being commonly used 2, 5
Pharmacological stress using vasodilators (dipyridamole, adenosine, regadenoson) causes maximal coronary arteriolar vasodilation, creating a "steal phenomenon" that directs blood away from territories supplied by obstructed arteries, and is used to evaluate coronary flow reserve 2, 3, 6
Adrenergic agents (dobutamine) increase heart rate and contractility, and are used to evaluate contractile reserve and viability, particularly in patients who are unable to exercise 2, 3

Diastolic function is assessed through exercise stress echocardiography, which can detect impaired LV diastolic function reserve and increased filling pressures, providing prognostic information on future cardiac events 4
Valvular function is evaluated through changes in transvalvular gradients and regurgitation during stress, with the European Heart Society recommending that valvular function be assessed in patients with known or suspected valvular disease 2, 3
Pulmonary artery pressure is assessed through elevation during exercise, which may indicate pulmonary hypertension, and is an important consideration in patients with cardiovascular disease 2

The diagnostic value of cardiac stress testing lies in its ability to identify ischemia in patients with intermediate probability of coronary artery disease, with the European Heart Society recommending that stress testing be used to guide treatment decisions 5, 1
Treatment guidance is provided through the use of cardiac stress testing to determine the need for cardiac catheterization, revascularization, or medical therapy, with the American College of Cardiology recommending that stress testing be used to guide treatment decisions 1, 5
Post-intervention assessment is evaluated through the use of cardiac stress testing to assess the efficacy of medical treatment or revascularization, with the European Heart Society recommending that stress testing be used to monitor patient outcomes 5

Absolute contraindications for cardiac stress testing include acute coronary syndrome, high-risk unstable angina, decompensated heart failure, severe aortic stenosis, uncontrolled arrhythmias, severe hypertension (≥200/110 mmHg), acute aortic dissection, and acute pericarditis/myocarditis, as recommended by the European Heart Society 7
Relative contraindications exist for different stress modalities (dobutamine, vasodilators) based on patient characteristics, and should be considered on a case-by-case basis 7

The ischemic cascade during stress testing includes sequential abnormalities: perfusion defects, myocardial stiffening, wall motion abnormalities, ECG changes, and chest pain, as described by the Journal of the American College of Radiology 8
The choice of stress modality should be based on patient characteristics, local expertise, and specific diagnostic questions, with the European Heart Society recommending that the choice of stress modality be individualized to each patient 2