Sinus of Valsalva Aneurysm

What is Sinus of Valsalva Aneurysm (SVA)?

Sinus of Valsalva aneurysm (SVA) is a saccular protrusion of the aortic sinus wall, which is often accompanied by a rupture of SVA into the adjacent heart cavities and fistulas formation.

Embryology

The main cause of SVA development is deficiency of normal elastic tissue between the aortic media and the annulus fibrosus. Over time, the walls of the aneurysm become thinner, which leads to its rupture and to a Valsalva sinus fistula.

Anatomy

Sinuses of Valsalva or aortic sinuses are widenings between the wall of the aorta and each of the three cusps of the aortic valve. Sinuses are called according to the coronary arteries extending from them: right, left and noncoronary. In most cases, the right coronary sinus is affected, less often - non-coronary and left coronary sinuses. 

Right - and noncoronary sinus of Valsalva fistulas fall into the right atrium or right ventricle; left coronary sinus fistulas – into the pulmonary artery and left ventricle. Sinus of Valsalva fistulas are often combined with other abnormalities: VSD, aortic valve insufficiency, bicuspid aortic valve, etc.

Classification

1. Fistulas from the right coronary sinus;
2. Fistulas from the left coronary sinus;
3. Fistulas from the noncoronary sinus.

Hemodynamics

There are no hemodynamic disturbances until rupture. The severity of hemodynamic disturbance depends on the size of the fistula. Blood is shunting from high-pressure chambers (e.g. Aorta) into low-pressure chambers (e.g. right atrium) The constant left-to-right shunt leads to volume overload, and this defect is also characterized by the development of aortic valve insufficiency.

Workup

• ECG. There are no specific signs of SVA. Changes appear in case of SVA rupture - an overload of the right or left heart. 
• Chest radiography. Not specific. Slightly increased heart shadow is shown in case of large and long-lasting fistula.
• Echocardiography. Echocardiography is the technique of choice for identifying a SVA .This method provides conclusive information regarding SVA and allows precise identification of structural anomalies and fistula location. Doppler echocardiography can detect the blood shunt and its direction in case of fistula as well as evaluate aortic valve regurgitation.
• Angiography, MRI. Rarely used.

Clinical Presentation

Nonruptured sinus of Valsalva aneurysms are most often asymptomatic. The appearance of chest pain, arrhythmias, loss of consciousness is the result of compression of certain neighboring structures and it needs further workup.

Chest pain, dyspnea and palpitations accompany SVA rupture. It is associated with acute pulmonary hypervolemia, with a decrease in coronary blood flow and cardiac output due to outflow of blood from the aorta. At the same time appears continuous murmur. Arterial diastolic pressure decreases, pulse pressure increases. Symptoms of congestive heart failure develop rapidly. Auscultatory finding in the preclinical period is the murmur on the left sternal border. The clinical presentation depends on the location and size of the fistula. Physical signs often resemble the patent ductus arteriosus - a very loud constant murmur that is heard on the left sternal border. 

Treatment

SVA ruptures always require surgical correction. Surgical treatment consists of closing the fistula by suturing or patch closure. Some authors recommend additionally strengthening annulus fibrosus of the aortic valve. In rare cases, reconstructive surgery (aortic root reconstruction) is used.