From the Guidelines
A stress test is typically needed before aortic valve repair in patients with aortic stenosis who have equivocal symptoms, are asymptomatic with severe stenosis planning exercise, or have discrepancies between symptoms and stenosis severity. For symptomatic patients with severe aortic stenosis, a stress test is generally unnecessary and potentially dangerous, as it can increase the risk of complications such as syncope, ventricular tachycardia, and death 1. However, in asymptomatic patients with severe aortic stenosis, exercise testing can help identify those who might benefit from earlier intervention by revealing exercise-induced symptoms, abnormal blood pressure responses, or significant ST-segment changes.
Key Considerations
- Exercise testing should be performed under the direct supervision of an experienced clinician, with close monitoring of blood pressure and electrocardiogram (ECG) 1.
- Low-dose dobutamine stress echocardiography is particularly valuable for patients with low-flow, low-gradient aortic stenosis and reduced left ventricular function to distinguish true severe stenosis from pseudo-severe stenosis 1.
- The test should be performed in a controlled environment with appropriate monitoring and immediate access to resuscitation equipment, as patients with severe aortic stenosis have increased risk of complications during stress testing.
Indications for Stress Testing
- Asymptomatic patients with severe aortic stenosis planning to exercise or engage in strenuous activities.
- Patients with equivocal symptoms or discrepancies between symptoms and stenosis severity.
- Patients with low-flow, low-gradient aortic stenosis and reduced left ventricular function.
Contraindications for Stress Testing
- Symptomatic patients with severe aortic stenosis, due to the high risk of complications.
- Patients with certain comorbidities or conditions that may increase the risk of complications during stress testing.
According to the most recent and highest quality study, a stress test is recommended for asymptomatic patients with severe aortic stenosis who are planning to exercise or have equivocal symptoms 1. This recommendation is based on the potential benefits of exercise testing in identifying patients who may benefit from earlier intervention and improving outcomes.
From the Research
Indications for Stress Test Before Aortic Valve Repair
- A stress test is recommended for asymptomatic patients with severe aortic stenosis to identify those at higher risk of cardiac events and to guide the optimal timing of aortic valve replacement 2, 3, 4, 5.
- The test can help detect patients who are falsely asymptomatic due to subconscious self-limitation of daily physical activity, and who may benefit from early aortic valve replacement 3, 5.
- Exercise stress testing with or without imaging is contraindicated in symptomatic patients with severe aortic stenosis, but is recommended in asymptomatic patients to provide incremental prognostic value 2, 5.
Abnormal Stress Test Results
- Abnormal stress test results, such as the development of symptoms, abnormal blood pressure response, or exercise-induced increase in mean pressure gradient, are associated with poor outcome and should be considered as an indication for surgery 2, 5.
- Exercise echocardiography can further unmask a subset of asymptomatic patients who are at high risk of reduced cardiac event-free survival, and who may benefit from early elective aortic valve surgery 2, 5.
Safety and Prognostic Value of Stress Testing
- Stress testing in asymptomatic patients with severe aortic stenosis is safe, with no reported complications during or after testing 6.
- The test has prognostic value in identifying patients at risk for adverse cardiac events and sudden cardiac death, with a significantly lower risk of adverse events in patients with normal stress test results compared to those with abnormal results 6.