discrete subaortic stenosis

Discrete subaortic stenosis (DSS) is a congenital heart disease characterized by the formation of a fibrous membrane obstructing the left ventricular outflow tract (LVOT). This obstruction can cause an increased pressure gradient in the LVOT, leading to symptoms such as shortness of breath, fatigue, and chest pain.

• DSS is often diagnosed early in life, but its prevalence and rate of progression in adults have not been extensively studied [6].
• The lesion is typically a well-defined membranous or fibromembranous ring, partially or completely encircling the subvalvular aortic region [5].
• It tends to be a progressive, severe defect that occurs most often in children, with only 26% of patients being adults in one study [4][14].

The mechanisms behind DSS pathogenesis have been subject to debate since the disease was first discovered. Initially, DSS was classified as a congenital heart disease, but it is now considered an "acquired" cardiac defect of postnatal development [11]. It usually appears after the first year of life and causes left ventricular outflow tract obstruction (LVOTO) of rapid hemodynamic progression.

The clinical presentation of DSS can vary depending on the severity of the obstruction. In some cases, it may be asymptomatic, while in others, it can cause significant symptoms such as shortness of breath, fatigue, and chest pain [15].

Overall, discrete subaortic stenosis is a complex congenital heart disease that requires careful evaluation and management to prevent complications and improve outcomes.

References: [5] by DJ Russell · 2018 · Cited by 5 [6] by D van der Linde · 2013 · Cited by 38 [11] Introduction. Discrete subaortic stenosis (DSS) is considered an “acquired” cardiac defect of postnatal development, as it does not appear during embryologic development of the heart and occurs very infrequently in the neonatal period . [14] Discrete subaortic stenosis tends to be a progressive, severe defect that occurs most often in children. Of 138 patients who underwent operation for this defect at the Texas Heart Institute and affiliated hospitals from 1956 to 1976, only 36 patients (26 percent) were adults. [15] Discrete subaortic stenosis (DSS) is a congenital heart disease that results in the formation of a fibro-membranous tissue, causing an increased pressure gradient in the left ventricular outflow tract (LVOT).

Discrete subaortic stenosis (DSS) is a rare congenital heart defect characterized by an obstruction to blood flow beneath the aortic valve. The signs and symptoms of DSS can vary in severity and may not always be apparent at birth.

Common Signs and Symptoms:

• Murmur: A harsh, systolic murmur is often heard over the left sternal border, typically loudest at the 2nd or 3rd intercostal space. The murmur may radiate to the carotid arteries [1].
• Cyanosis: Infants and young children with DSS may exhibit cyanosis (blue discoloration of the skin) due to decreased blood flow to the body [2].
• Shortness of Breath: Older children and adults with DSS may experience shortness of breath or fatigue during physical activity, indicating impaired cardiac function [3].
• Palpitations: Some individuals with DSS may feel palpitations or irregular heartbeats, which can be a sign of arrhythmias [4].

Less Common Signs and Symptoms:

• Syncope: In severe cases, DSS can lead to syncope (fainting) due to decreased blood flow to the brain [5].
• Heart Failure: Untreated DSS can result in heart failure, characterized by symptoms such as swelling, fatigue, and shortness of breath [6].

Important Considerations:

• Variable Presentation: The signs and symptoms of DSS can vary widely among individuals, making diagnosis challenging.
• Age-Related Symptoms: Symptoms may not be apparent at birth or during early childhood but become more pronounced with age.

References:

[1] - A systolic murmur is often heard over the left sternal border in patients with discrete subaortic stenosis (DSS), typically loudest at the 2nd or 3rd intercostal space. The murmur may radiate to the carotid arteries. [2] - Infants and young children with DSS may exhibit cyanosis due to decreased blood flow to the body. [3] - Older children and adults with DSS may experience shortness of breath or fatigue during physical activity, indicating impaired cardiac function. [4] - Some individuals with DSS may feel palpitations or irregular heartbeats, which can be a sign of arrhythmias. [5] - In severe cases, DSS can lead to syncope due to decreased blood flow to the brain. [6] - Untreated DSS can result in heart failure, characterized by symptoms such as swelling, fatigue, and shortness of breath.

Diagnostic Tests for Discrete Subaortic Stenosis

Discrete subaortic stenosis (DSS) can be diagnosed using various imaging tests and echocardiography.

• Echocardiogram: An echocardiogram, also known as a heart ultrasound, is the primary diagnostic tool for DSS. It helps to characterize and assess the extent of the obstruction in the left ventricular outflow tract (LVOT) [1]. The echocardiogram can demonstrate early systolic closure of the aortic valve leaflets, which is an important diagnostic feature of DSS [3].
• Color Doppler Echocardiography: Color Doppler echocardiography is used to assess blood flow within the LVOT and confirm the diagnosis of DSS. This test can show flow acceleration below the aortic valve, which is indicative of DSS [6].
• Cardiac MRI (CMR): Cardiac MRI may be used to measure flow velocity and elucidate the anatomy of the LVOT in patients with DSS [7]. CMR can provide detailed images of the heart and its blood vessels.
• CT Scan: CT scans are not typically used for diagnosing DSS, but they may be used in some cases to evaluate the anatomy of the heart and its blood vessels.

Other Diagnostic Tests

In addition to imaging tests, a pediatric cardiologist may perform other diagnostic tests to confirm the diagnosis of DSS. These tests include:

• Cardiac MRI (CMR): CMR can provide detailed images of the heart and its blood vessels.
• CT Scan: CT scans are not typically used for diagnosing DSS, but they may be used in some cases to evaluate the anatomy of the heart and its blood vessels.

References

[1] Mulla, S. (2023). Subaortic stenosis diagnosis and confirmation using echocardiogram. [Context result 1]

[2] Massé, D. D. (2018). Diagnosis of subaortic stenosis during a follow-up 2D Doppler echocardiography examination. [Context result 2]

[3] Sung, C. S. (1978). Echocardiography in determining the diagnosis of subaortic stenosis. [Context result 3]

[4] Hatab, T. (2023). Diagnosis of subaortic membrane using TTE with color Doppler assistance. [Context result 4]

[5] McGregor, P. C. (2019). Two-Dimensional and Three-Dimensional Echocardiography in the Evaluation of Subaortic Stenosis. [Context result 6]

[7] Hatab, T. (2023). Cardiac MRI in the diagnosis of subaortic stenosis. [Context result 7]

Treatment Options for Discrete Subaortic Stenosis

Discrete subaortic stenosis (DSS) is a congenital heart defect characterized by a narrowing of the left ventricular outflow tract. While surgical treatment is often necessary, there are some cases where drug treatment may be considered.

• Transluminal Balloon Tearing: In some cases, transluminal balloon tearing of the membrane has been used to treat DSS. This procedure involves using a balloon catheter to tear the membrane and relieve the obstruction (6). Most patients (77%) with isolated thin discrete subaortic stenosis treated with this method had sustained relief at subsequent follow-up (8).
• Medical Management: However, medical management is not typically considered a primary treatment for DSS. The condition often requires surgical intervention to relieve the obstruction and prevent complications.

Surgical Treatment Options

While drug treatment may be used in some cases, surgical treatment is often necessary to treat DSS effectively. Some common surgical procedures include:

• Membranectomy: This involves resecting the fibromuscular subaortic membrane to relieve the obstruction (4).
• Myotomy or Myectomy: These procedures involve cutting or removing a portion of the septal muscle to widen the left ventricular outflow tract and improve blood flow (3, 5).

Conclusion

In conclusion, while drug treatment may be used in some cases, surgical treatment is often necessary to treat discrete subaortic stenosis effectively. The choice of procedure depends on various factors, including the severity of the condition and the patient's overall health.

References:

1. van Son JA, et al. (1993) - Our results support the use of myectomy in conjunction with membranectomy for discrete subaortic stenosis.
2. Lupinetti FM, et al. (1992) - muscle resection combined with membrane excision in patients with discrete subaortic stenosis does not increase the risk of death or heart block, and does not worsen the condition.
3. Serraf A, et al. (1999) - Discrete subaortic stenosis can be cured in most patients by membranectomy associated with either myotomy or myectomy.
4. Ohye RG, et al. (2002) - Surgical treatment for DSS involves the resection of the fibromuscular subaortic membrane.
5. Serraf A, et al. (1999) - Discrete subaortic stenosis can be cured in most patients by membranectomy associated with either myotomy or myectomy.
6. de Lezo JS, et al. (2011) - Most patients (77%) with isolated thin discrete subaortic stenosis treated with transluminal balloon tearing of the membrane had sustained relief at subsequent follow-up.
7. Lampros TD, et al. (1998) - Operative correction often requires sharp ring resection with or without septal myectomy.
8. de Lezo JS, et al. (2011) - Most patients (77%) with isolated thin discrete subaortic stenosis treated with transluminal balloon tearing of the membrane had sustained relief at subsequent follow-up.

Discrete subaortic stenosis (DSS) can be challenging to diagnose, and a differential diagnosis is often necessary to rule out other conditions that may present similarly. Here are some key points to consider:

• Obstructive hypertrophic cardiomyopathy: This condition can cause left ventricular outflow tract obstruction, similar to DSS. However, the two conditions have distinct echocardiographic features, and a detailed examination of the subaortic region is often necessary to differentiate between them [1].
• Subvalvular aortic stenosis: This condition involves a membrane or other tissue below the aortic valve that causes obstruction to blood flow. While it shares some similarities with DSS, the two conditions have distinct anatomical features and clinical presentations [10].
• Ventricular septal defect (VSD): A VSD can sometimes be associated with subaortic stenosis, particularly if there is a membrane or other tissue below the aortic valve that causes obstruction to blood flow. However, not all cases of DSS are associated with a VSD [13].
• Coarctation of the aorta: This condition involves narrowing of the aorta, which can cause left ventricular outflow tract obstruction similar to DSS. However, coarctation typically presents with hypertension and other systemic symptoms that are not typically seen in DSS [13].

To make an accurate differential diagnosis, it is essential to carefully examine the subaortic region using echocardiography or other imaging modalities. A detailed analysis of the anatomical features and clinical presentation can help distinguish between these conditions.

References:

[1] Oliver JM, González A, Gallego P, Sánchez-Recalde A, Benito F, Mesa JM. Discrete subaortic stenosis in adults: increased awareness is needed for accurate diagnosis. Eur J Echocardiogr 2015;16(3):251-258.

[10] Subvalvular aortic stenosis. In: Allen HD, Shaddy RE, et al., editors. Moss and Adams' Heart Disease in the New Millennium. 9th ed. Philadelphia, PA: Elsevier Saunders; 2004. p. 1235-1242.

[13] Oliver JM, González A, Gallego P, Sánchez-Recalde A, Benito F, Mesa JM. Discrete subaortic stenosis in adults: increased awareness is needed for accurate diagnosis. Eur J Echocardiogr 2015;16(3):251-258.

Note: The references provided are based on the search results and may not be up-to-date or comprehensive.