Congenital Sinus of Valsalva Aneurysm

Congenital sinus of Valsalva aneurysm was first described by Hope in 1839. This first published account describes rupture of a sinus of Valsalva, which is the most feared complication. Soon afterwards, clinicians described other cases of unruptured aneurysms and applied anatomic descriptions. The condition may have been clinically described for the first time in 1883.

The 3 sinuses of Valsalva are located in the most proximal portion of the aorta, just above the cusps of the aortic valve. The sinuses correspond to the individual cusps of the aortic valve. These structures contained within the pericardium are easily revealed using aortography and echocardiography as distinct but subtle out-pouchings of the aortic wall just above the valve. The sinuses end in the area of the sinotubular junction, and the tubular portion of the aorta begins here.

Aneurysm of a sinus of Valsalva is a rare congenital cardiac defect that can rupture, causing heart failure or other catastrophic cardiac events. If the aneurysm remains unruptured, it occasionally causes obstruction of cardiac flow resulting from compression of normal structures. Dissection of the aneurysm into the cardiac tissues may occur, causing obstruction or destruction of local structures.

Acquired aneurysmal dilatation of the sinuses of Valsalva may occur because of Marfan syndrome, syphilitic aortitis, or as a function of aging. These entities are not discussed in this article.

Pathophysiology

Aneurysmal dilatation of the sinuses of Valsalva occurs when the aortic media is defective, allowing separation of the media from the aortic annulus fibrosus. The defect is inherited, but frank aneurysmal dilatation is rarely seen at birth. Sinus of Valsalva aneurysm is associated with a ventricular septal defect in approximately 40% of patients.

Aneurysms typically develop as a discrete flaw in the aortic media within one of the sinuses of Valsalva. Aneurysms most often involve the right aortic sinus (67-85% of patients, often associated with a supracristal ventricular septal defect), followed by the noncoronary sinus, whereas an aneurysm of the left sinus is rare. Under the strain of aortic pressure, the sinus gradually weakens and dilates, causing the formation of an aneurysm. Lack of supporting tissue (eg, ventricular septal defect) may contribute to instability and progressive distortion of the aortic sinus, often with associated aortic insufficiency. Deficiency of the aortic media where it attaches to the aortic annulus produces dilation of the aortic sinuses, usually over many years.

Distortion and prolapse of the sinus and aortic valve tissue can lead to progressive aortic valve insufficiency. Unruptured aneurysm may cause distortion and obstruction in the right ventricular outflow tract. Distortion and compression may also cause myocardial ischemia (by coronary artery compression) and, possibly, heart block (by compressing the conduction system). Rupture may occur into any chamber, although rupture most commonly occurs into the aortic right ventricular communication. Rupture into the right atrium is the second most common, in association with a noncoronary cusp aneurysm. Rupture may occur less commonly into the left-sided chambers, the pulmonary artery, and rarely extends into the pericardium.

Frequency

United States – Sinus of Valsalva aneurysm comprises approximately 0.1-3.5% of all congenital cardiac anomalies. Discovery in the pediatric age group is unusual.

International – Incidence in the Western Hemisphere (outside of the United States) is approximately the same as in the United States. An increase in prevalence is observed in Asians because of the higher incidence of supracristal (subpulmonic) ventricular septal defects.

Mortality/Morbidity

Morbidity and mortality are most often associated with acute severe aortic valve insufficiency resulting from aneurysm rupture. The mortality rate in patients with a sinus of Valsalva aneurysm in whom surgery is not performed is high within the first year after rupture.

Causes of sudden death from sinus of Valsalva aneurysm most commonly involve rupture of the aneurysm with the acute onset of overwhelming congestive heart failure, cardiac tamponade, dysrhythmia, or coronary ischemia, depending on the location of the aneurysm and the subsequent flow disturbance. Size and location of the shunt are the major determinants of presentation and prognosis. Late death usually occurs within 1 year after rupture if the shunt is substantial; longer survival may occur if the shunt is small.
Major cardiac morbidity and late mortality in this condition also depend on the magnitude and location of shunts. In some instances, an unruptured aneurysm also causes major symptoms and hemodynamic alterations because of obstruction of valves or impingement upon cardiac structures (eg, coronary arteries, conduction system).
The surgical mortality rate is estimated to be 5% or less.

Race

Increased incidence in the Asian population has been described, which is the result of increased incidence of supracristal ventricular septal defect in Asian persons. These ventricular defects may contribute to instability of the aortic sinuses, particularly the right aortic sinus.

Sex

Male-to-female ratio is 4:1.

Age

Average age of patients with rupture of a sinus of Valsalva aneurysm is approximately 30 years, with a range of 11-67 years in one series. Problems in infancy and childhood are uncommon.

Clinical

History

Children with sinus of Valsalva aneurysm are most often asymptomatic. Symptoms typically present in young adulthood (usually in patients

Sudden massive rupture may occur after strenuous exertion and may be signaled by acute chest or epigastric pain with dyspnea. Symptoms may be confused with those of acute myocardial infarction.
Patients with a smaller insidious rupture may be asymptomatic, but small ruptures also may be associated with progressive symptoms of exertional dyspnea and/or chest discomfort from advancing heart failure.
Patients with unruptured aneurysms may be asymptomatic. Angina may occur secondary to coronary compression resulting from an unruptured aneurysm. Syncope or dizziness may be caused by aneurysm compression of the conduction system, with associated heart block (Adams-Stokes syndrome).

Physical

Positive physical findings may be absent in a patient with an unruptured sinus of Valsalva aneurysm. Physical signs of a ruptured aneurysm vary, depending on the location of the shunt, and may mimic signs observed in a patient with a sizable coronary arteriovenous (AV) fistula. Physical signs may include the following:

A loud continuous murmur, accentuated in the diastole, occurs with aneurysm rupture into the right ventricle or right atrium. The systolic component of the continuous murmur is usually heard best higher in the chest, whereas the diastolic component may be best heard lower along the sternal border.
A parasternal thrill is heard from associated ventricular septal defect with large volume of runoff or, possibly, outflow obstruction.
Bounding pulses occur as a result of aortic runoff into lower-pressure chambers.
Shunt from the aortic root to the left ventricle may produce a diastolic murmur similar to that of aortic insufficiency.
Pulmonary rales may be present from progressive left heart failure.
With an unruptured aneurysm partially obstructing the right ventricular outflow tract, an ejection murmur may be heard at the left base radiating into the back.

Causes

Sinus of Valsalva aneurysm is presumed to be caused by a spontaneous genetic mutation. Although the defect is inherited, no distinct pattern of inheritance has been noted. Frank aneurysmal dilatation is rarely seen at birth.

Subpulmonic ventricular septal defect may be an important contributing factor in the progression of sinus of Valsalva aneurysms.
Tertiary syphilis is of historical significance as a cause for aortic aneurysms.
Traumatic injury to the aortic root (usually from direct chest compression) may rarely cause rupture of the aortic root.
A number of generalized disorders may be associated with dilatation and/or distortion of the aortic root, including Marfan syndrome, Ehlers-Danlos syndrome, Turner syndrome, Williams syndrome, bicuspid aortic valve, and osteogenesis imperfecta.

Medical Care

Direct the medical care of the patient with a ruptured sinus of Valsalva aneurysm toward hemodynamic stabilization, prevention or treatment of endocarditis, and management of arrhythmias, cardiac ischemia, or both using the following indications and medications:

Heart failure: Administer diuretics, digitalis, and ACE inhibitors, and perform stabilization of cardiac rhythm (as indicated).
Cardiac ischemia: Administer nitrates and beta-blockers.
Endocarditis: Standard prophylaxis is no longer routinely recommended. Standard prophylaxis should be used after an episode of bacterial endocarditis has occurred to prevent reoccurrence.

Surgical Care

Prompt surgical therapy is recommended when a ruptured sinus of Valsalva aneurysm is diagnosed. A combined approach from the affected chamber and from inside the aorta is most helpful to allow inspection of the aortic valve and to avoid injury to the coronary vessels. The procedure is described as follows:

The fistula tract from the ruptured aneurysm is closed, and an associated ventricular septal defect can be repaired.
The aorta is reunited with the valve annulus either by direct anastomosis or by the interposition of a graft, if required.
Competency of the aortic valve is tested using transesophageal Doppler ultrasound, and valve repair can be undertaken, if necessary.
Preservation of the aortic valve, particularly in children, is of paramount importance; therefore, early surgical intervention may be warranted.
No consensus as to when to perform surgery on a fortuitously discovered unruptured sinus of Valsalva aneurysm has been reached.
Regular follow-up of these patients using echocardiography or MRI to document the size of the aneurysm is indicated.
Undertake elective repair of a known sinus of Valsalva aneurysm at the same time as surgical repair of any other intracardiac shunt or defect.
Percutaneous, transcatheter closure of a ruptured sinus of Valsalva aneurysm was first described in 1994. Numerous occluder devices have been used, especially the Amplatzer device. Guidance for transcatheter closure is provided by 2-dimensional or 3-dimensional transesophageal echocardiographic guidance.

Activity

Patients with a sinus of Valsalva aneurysm should avoid participation in contact sports or activities involving vigorous exertion or sustained heavy lifting. Chest trauma may precipitate rupture of a sinus aneurysm.

Patients with ruptured aneurysms who are awaiting surgical repair can be allowed activity to tolerance levels. Activity may be limited because of symptoms of congestive heart failure.

Medication

No specific medical therapy is indicated for sinus of Valsalva aneurysm. Treatment of congestive heart failure may be required if rupture of the aneurysm occurs into the right heart chambers; standard therapy for heart failure is recommended, although surgery is the treatment of choice.

Further Outpatient Care

Regularly follow-up with patients with sinus of Valsalva aneurysm who have not undergone surgical repair using echocardiography or MRI to document the size of an unruptured sinus of Valsalva aneurysm.

Early rupture can be detected using color Doppler echocardiography or real-time MRI.

Deterrence/Prevention

Because the genetic mutation that causes the sinus of Valsalva aneurysm is presumed to be spontaneous, no preventive measures are available. With careful follow-up monitoring of an unruptured sinus of Valsalva aneurysm, complications of rupture and infective endocarditis can be avoided.

Complications

Congestive heart failure with acute or progressive rupture or with aortic valve insufficiency
Infective endocarditis (possibly associated with smaller ruptured aneurysms in 5-10% of patients)
Angina and myocardial ischemia
Heart block resulting from compression of the conduction system
Aortobronchial fistula or aortopulmonary artery fistula (possible rare complications)
Abnormal flow (spontaneous contrast) in a dilated unruptured sinus of Valsalva aneurysm (postulated to be a source for systemic embolization)

Prognosis

Prognosis after surgical repair in patients with sinus of Valsalva aneurysm is excellent, particularly if the aortic valve has not been damaged.

Prognosis in patients with a ruptured aneurysm who have not undergone surgical repair may be poor, with survival beyond 1 year uncommon.

Prognosis in patients with an unruptured sinus of Valsalva aneurysm is unknown because patients may be entirely asymptomatic.

Source: Emedicine