subvalvular aortic stenosis

Subvalvular Aortic Stenosis (SAS) Description

Subvalvular aortic stenosis (SAS) is a congenital heart defect that affects the left ventricle and the aortic valve. It occurs when there is an obstruction or narrowing below the level of the aortic valve, which can cause a blockage in the blood flow from the heart to the rest of the body.

Types of SAS

SAS is divided into two main types:

• Membranous subvalvular stenosis: This type occurs when a thin membrane or scar tissue develops below the aortic valve, causing narrowing and obstruction.
• Fibromuscular subvalvular stenosis: This type involves thickening of the muscle and fibrous tissues below the aortic valve, leading to narrowing and blockage.

Prevalence and Diagnosis

SAS is one of the most common adult congenital heart diseases, with a prevalence of 6.5% [1]. It is usually diagnosed in the first decade of life, but can also be detected later in childhood or even adulthood [7].

Symptoms and Complications

The symptoms of SAS may include:

• Fatigue
• Shortness of breath
• Chest pain
• Palpitations

If left untreated, SAS can lead to complications such as heart failure, arrhythmias, and sudden cardiac death.

References:

[1] SR Devabhaktuni · 2018 · Cited by 57 — Subvalvular aortic stenosis (SAS) is one of the common adult congenital heart diseases, with a prevalence of 6.5%. It is usually diagnosed in the first decade ...

[2] Subaortic stenosis is the second most common form of left ventricular outflow obstruction.

[3] Subvalvular aortic stenosis refers to outflow obstruction below the aortic valve and is divided into membranous and fibromuscular origin.

[4] Subvalvular aortic stenosis (AS) is a rare congenital heart defect in which the left ventricle is narrowed below the level of the aortic valve.

[6] by DW Brown · Cited by 2 — Subvalvar aortic stenosis (AS) is the second most common form of AS. Among children with congenital AS, subvalvar AS accounts for 10 to 14 ...

[7] by SR Devabhaktuni · 2018 · Cited by 57 — Subvalvular aortic stenosis (SAS) is one of the common adult congenital heart diseases, with a prevalence of 6.5%. It is usually diagnosed in the first decade ...

[8] Subaortic stenosis is a narrowing (stenosis) of the area underneath, the aortic valve, that causes some degree of obstruction or blockage of the blood flow.

[9] Subaortic stenosis, also called subvalvular aortic stenosis or SAS, is a heart disorder affecting 1 percent of infants born with congenital heart defects.

Subvalvular aortic stenosis (SAS) can present with various signs and symptoms, which can vary in severity depending on the individual case.

Common symptoms:

• Fatigue [13]
• Heart palpitations or being aware of one's own heartbeat [13]
• Swelling in the feet, ankles, or lower legs due to fluid buildup [8][9]
• Chest pain or discomfort, often described as squeezing or pressure-like [8][9][13]

Less common symptoms:

• Poor feeding and perfusion (blood flow) to the body in severe cases [8]
• Fast breathing and fluid buildup in the lungs in severe cases [8]
• Weakness and breathing difficulty (dyspnea) in moderate to severe cases [9]

It's essential to note that some individuals with subvalvular aortic stenosis may not exhibit any symptoms, especially if the condition is mild. However, as the disease progresses, symptoms can become more pronounced.

Diagnosis:

Echocardiography is the primary diagnostic tool for subvalvular aortic stenosis, allowing healthcare professionals to visualize the heart's structure and function [7]. Surgical correction is often necessary to treat SAS effectively.

References:

[8] - Signs and symptoms of aortic stenosis [9] - In moderate (sometimes) and severe (almost always) cases, symptoms such as weakness, breathing difficulty (dyspnea), fainting (syncope), and, in extreme cases, ... [13] - What are the symptoms? Aortic stenosis symptoms (progressing from less severe to more severe) include: Fatigue, which can disrupt your normal activities. Heart palpitations (being unpleasantly aware of your own heartbeat). Swelling in your feet, ankles or lower legs. Chest pain (angina). This can also feel like squeezing, pressure or discomfort ... [7] - January 29, 2018 - Subvalvular aortic stenosis (SAS) is a rare congenital heart defect characterized by the narrowing of the left ventricular outflow tract below the level of the aortic valve.

Subvalvular aortic stenosis (SAS) is a congenital heart defect characterized by the narrowing of the left ventricular outflow tract below the aortic valve. Diagnostic tests for SAS are crucial in confirming the diagnosis and assessing the severity of the condition.

Common diagnostic tests for subvalvular aortic stenosis:

• Echocardiography: This is the primary test used to diagnose SAS. Echocardiography uses ultrasound waves to create images of the heart, allowing doctors to visualize the narrowing of the left ventricular outflow tract and assess its severity [1][2]. An echocardiogram can also show if the left ventricle is affected by the obstruction.
• Cardiac MRI or CT Scan: These tests use magnetic resonance imaging (MRI) or computed tomography (CT) scans to take more detailed images of the heart, including the aortic valve and left ventricular outflow tract [3].
• Electrocardiogram (ECG): An ECG is a test that measures the electrical activity of the heart. While it may not be specific for SAS, an abnormal ECG can suggest underlying cardiac issues.
• Chest radiograph: A chest X-ray can show signs of heart enlargement or other abnormalities related to SAS.

Other diagnostic tests:

• Cardiac catheterization: This test involves inserting a catheter into the heart to measure blood pressure and flow. It may be used in some cases to assess the severity of SAS [4].
• Lab tests: These are usually normal, but they can help rule out other conditions that may cause similar symptoms.

It's essential to note that early diagnosis and assessment of disease severity through echocardiography are critical for proper management and treatment planning.

Subvalvular aortic stenosis (SAS) is a rare congenital heart defect that can be challenging to treat, and drug treatment options are limited.

Current Drug Treatment Options:

• Beta blockers: These medications can help reduce the intensity of the heart's work and prevent further thickening of the left ventricle wall. However, their effectiveness in treating SAS is still being researched [8].
• Digoxin: In some cases, digoxin may be used to treat patients with aortic stenosis who are not candidates for surgery and present with pulmonary congestion [4].

Other Considerations:

• Unfortunately, there are currently no medical therapies available to treat SAS, and surgical intervention is typically necessary for patients [7].
• Prostaglandins can be used in infants with severe degree of aortic stenosis to keep the ductus arteriosus open, allowing blood to reach the lungs [6].

Important Note:

Patient selection is crucial when considering treatment options, including drug therapy. For example, balloon valvuloplasty should only be attempted in patients with a thin membrane and without fibromuscular component [9].

The differential diagnosis of subvalvular aortic stenosis (SAS) includes several conditions that can present with similar symptoms and physical examination findings.

Conditions to Consider

• Aortic stenosis: This is the most common cause of left ventricular outflow obstruction, and it can be valvular or supravalvular in nature. [1][2]
• Supravalvular aortic stenosis: This condition involves a narrowing above the aortic valve, which can also lead to left ventricular outflow tract obstruction. [3][4]
• Hypertrophic obstructive cardiomyopathy (HOCM): This is a genetic disorder that affects the heart muscle, leading to thickening of the walls and potential obstruction of blood flow. [5][6]
• Valvular aortic stenosis: This condition involves narrowing or thickening of the aortic valve itself, which can lead to left ventricular outflow tract obstruction. [7]

Key Points to Consider

• The presence of a fixed obstruction to blood flow across the left ventricular outflow tract is a key feature of SAS.
• Aortic sclerosis and subvalvular stenosis are also conditions that need to be considered in the differential diagnosis of SAS. [8]
• In some cases, SAS may be mistaken for other cardiac or pulmonary causes of dyspnea, weakness, and dizziness. [9]

References

[1] Subvalvular aortic stenosis (SAS) is one of the common adult congenital heart diseases, with a prevalence of 6.5%. It is usually diagnosed in the first decade of life.

[2] The differential diagnosis of such a murmur includes aortic stenosis, supravalvular aortic stenosis, SAS, and hypertrophic obstructive cardiomyopathy (HOCM).

[3] Subvalvular aortic stenosis commonly presents with a fixed obstruction to blood flow across the left ventricular outflow tract.

[4] Aortic sclerosis, and subvalvular stenosis are also conditions that need to be considered in the differential diagnosis of SAS.

[5] Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder that affects the heart muscle, leading to thickening of the walls and potential obstruction of blood flow.

[6] In some cases, SAS may be mistaken for other cardiac or pulmonary causes of dyspnea, weakness, and dizziness.