Diagnosing aortic stenosis: from echocardiography to clinical decision-making

From auscultation to echocardiography: initial diagnostic tests

Aortic stenosis is often suspected during a routine heart auscultation. The cardiologist hears a systolic ejection murmur, which is a sound produced by blood struggling to pass through the narrowed valve. While this murmur alone is not enough to confirm a diagnosis or assess severity, it serves as the trigger for further testing.

• Transthoracic Doppler echocardiography (TTE) : A painless procedure performed using a probe placed on the chest, it allows for visualization of the aortic valve and measurement of severity parameters. It is the gold standard for diagnosing and monitoring aortic stenosis. ‍
• Electrocardiogram (ECG) : This can reveal left ventricular hypertrophy, a consequence of the heart working harder over time to overcome the valvular obstruction. ‍
• Chest X-ray : This may show dilation of the ascending aorta or left ventricular overload, providing useful context for the cardiologist.

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Valve area, gradient, velocity: understanding your echocardiogram results

Echocardiography provides several measurements used to classify the severity of the stenosis:

• Moderate aortic stenosis : valve area between 1 and 1.5 cm², mean gradient between 20 and 40 mmHg. At this stage, regular monitoring is generally implemented. ‍
• Severe aortic stenosis : area less than 1 cm², mean gradient greater than 40 mmHg, peak velocity greater than 4 m/s. This stage requires a specialist evaluation to determine if an intervention is indicated. ‍
• Critical aortic stenosis : the most advanced form, with a very reduced area and high pressures, often associated with marked symptoms.

The presence or absence of symptoms changes the clinical interpretation: asymptomatic severe stenosis does not necessarily imply immediate intervention, but it does warrant close monitoring and a specialist consultation.

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Coronary angiography, CT scan, Heart Team: the steps before a treatment decision

When the initial assessment points to severe aortic stenosis and an intervention is being considered, additional tests are prescribed to prepare for the decision:

• Coronary angiography or coronary CT scan : these examine the condition of the coronary arteries. Associated coronary artery disease, which is common in the population affected by degenerative aortic stenosis, can be treated during the same surgical procedure. ‍
• Cardiac CT scan : Essential for pre-TAVI assessment, it defines the anatomy of the aortic annulus, vascular access routes, and adjacent structures to select the appropriate prosthesis and plan the procedure. ‍
• Exercise stress test : Prescribed for asymptomatic patients with severe stenosis, it allows for an objective evaluation of exercise tolerance and the detection of clinical or electrical signs not apparent at rest. ‍
• Multidisciplinary team meeting (MDT) : Once the full assessment is complete, it is discussed in a meeting involving cardiologists, cardiac surgeons, and anesthesiologists. This team formulates the treatment recommendation, taking into account all clinical parameters and patient preferences.

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