Aortic Stenosis: Essential Diagnostic Tests You Should Know

If you or a loved one has been diagnosed with aortic stenosis, it's important to understand the diagnostic process. Aortic stenosis is a condition in which the aortic valve becomes narrowed, restricting blood flow from the heart to the rest of the body. To accurately assess the severity of the condition and determine the best treatment plan, a variety of diagnostic tests are commonly used by cardiologists.

1. Physical Examination

During a physical exam, your doctor will look for signs of aortic stenosis through visual observation, touch, and listening to your heart sounds.

Visual Inspection

One of the first steps in the physical examination is visual inspection. Doctors may observe increased apical impulse, which can be slightly displaced to the left and downward due to the heart's compensatory mechanisms.

P palpation

During palpation, the physician may detect a sustained or hyperdynamic impulse at the apex of the heart. In more severe cases, a noticeable delay between the apical and carotid artery pulses can be felt, known as pulsus parvus et tardus.

Percussion

Heart dullness on percussion may appear normal in early stages. However, if heart failure develops, the cardiac silhouette may expand to the left.

Auscultation

Heart auscultation is crucial for identifying abnormal heart sounds and murmurs. A systolic ejection murmur is typically heard at the right upper sternal border and may radiate to the carotid arteries. This finding is often a key indicator of aortic stenosis.

Blood Pressure Measurement

Blood pressure readings may show a reduced systolic and diastolic pressure with a narrow pulse pressure. In elderly patients, coexisting aortic stiffness may mask a significant drop in systolic pressure.

2. Laboratory Tests

Blood tests are also an essential part of the diagnostic process. Measuring brain natriuretic peptide (BNP) levels can help determine if heart failure is present. Elevated BNP levels are often associated with increased pressure in the heart chambers and reduced cardiac function.

3. Imaging Studies

Chest X-Ray

A chest X-ray can reveal signs of heart enlargement and calcification of the aortic valve. In mild cases, the heart size may appear normal. However, in moderate to severe stenosis, left ventricular enlargement and mild left atrial enlargement may be evident. Post-stenotic dilation of the ascending aorta can also be seen, especially in later stages. Pulmonary congestion may appear if heart failure is present.

Echocardiography

Echocardiography is the gold standard for diagnosing and assessing the severity of aortic stenosis. It allows for detailed visualization of the aortic valve structure and function.

M-Mode Echocardiography can reveal thickened and calcified valve leaflets with restricted movement. The systolic separation between valve cusps is typically reduced.

2D Echocardiography provides a comprehensive view of the valve anatomy, left ventricular size, and ejection fraction, helping to assess the degree of left ventricular dysfunction.

Doppler Echocardiography is particularly useful in measuring the pressure gradient across the aortic valve. The mean transvalvular pressure gradient helps classify the severity of stenosis as mild, moderate, or severe.

Computed Tomography (CT)

While not routinely required, CT scans are often used to evaluate calcification of the aortic valve and assess for associated conditions such as aortic root dilation or aneurysm. These findings are especially common in patients over the age of 60.

Cardiac Catheterization

In some cases, invasive testing may be necessary. Cardiac catheterization allows for direct measurement of the pressure gradient between the left ventricle and the aorta. It also provides information on cardiac output and helps assess the presence of coronary artery disease, which is important when considering surgical options.

4. Additional Diagnostic Tools

Electrocardiogram (ECG)

Most patients with aortic stenosis show signs of left ventricular hypertrophy on ECG. This is often characterized by T-wave inversions and ST-segment depressions in the left precordial leads. A depression of more than 0.3 mV may indicate significant left ventricular thickening and strain.

Exercise Stress Test

This test evaluates how well the heart responds to physical activity. It can help uncover symptoms that may not be present at rest and is useful in determining the functional impact of aortic stenosis. It also helps identify other potential cardiac abnormalities.

Accurate diagnosis is crucial in managing aortic stenosis effectively. By combining physical exams, lab tests, imaging studies, and specialized cardiac assessments, doctors can develop a comprehensive treatment plan tailored to each patient's needs.