Obstructive Cardiac Lesions

This section deals primarily with ventricular outflow tract obstructive lesions. Congenital mitral and tricuspid valve stenosis are relatively rare in children, thus will be not discussed here.

Outflow tract obstruction leads to an increase in the pressure proximal to the lesion and secondary myocardial hypertrophy. Turbulent flow across the obstruction produces an ejection systolic murmur. Myocardial hypertrophy leads to increased oxygen consumption with decreased exercise tolerance and possible myocardial ischemia and fibrosis. Ventricular dilatation is not a usual response to obstruction, and if present suggests ventricular failure.

Children with mild or moderate obstructive lesions usually have few symptoms. Children with severe obstruction may have low cardiac output symptoms. Newborns with severe obstruction are often PDA dependent to bypass the obstruction.

Arterial switch (PS)


Pulmonary stenosis can be valvular, sub-valvular (infundibular), or supra-valvular.  

Clinical presentations

Patients with mild or moderate PS are usually asymptomatic. Severe PS may present with decreased cardiac output symptoms such as exertional dyspnea and subsequently symptoms of congestive cardiac failure.

Making the diagnosis


Balloon valvuloplasty may be done to relieve the valvular obstruction in moderate or severe cases. Surgery is indicated in supra-valvular and sub-valvular PS or if valvuloplasty is unsuccessful. Infants with critical PS need PGE1 to maintain the ductal patency before intervention.

Aortic Stenosis (AS)


Aortic stenosis may be valvular, supra-valvular or sub-valvular.

Clinical presentation

Aortic stenosis is more common in males. Children with mild or moderate AS are usually asymptomatic. Severe AS may be accompanied by exertional chest pain, decreased exercise tolerance or episodes of syncope. Infants with critical AS may present with CHF early in life.

Making the diagnosis


Mild or moderate AS requires only supportive care. Severe valvular AS can be treated by balloon valvuloplasty. Subvalvular and supravalvular aortic stenosis are not amenable to balloon valvuloplasty and may need surgical intervention.

PGE1 infusion is essential to maintain the ductal patency in neonates with critical AS.

Surgery may involve simple valvotomy or valve replacement with a prosthesis or homograft. Another alternative is the Ross autograft procedure in which the patient's normal pulmonary valve is excised and placed in the aortic position and a homograft replaces the pulmonary valve.

Coarctation of the Aorta

Coarctation of the aorta is usually congenital, but may be acquired as in Takayasu arteritis. It may also be associated with Turner or William's syndromes, and with other CHD such as bicuspid aortic valve, VSD, or double outlet right ventricle.


Congenital coarctation is almost always juxta-ductal (opposite to the ductus arteriosus), and may be either discrete or tubular


Coaractation of aorta

Figure showing Coarctation of the Aorta


Coarctation of the aorta causes mechanical obstruction of blood flow from the left ventricle. The pressure proximal to the coarctation is usually elevated. Collateral vessels may develop to bypass the obstruction; the most common collaterals are the internal mammary and the intercostal arteries. LVH develops in response to the elevated pressure proximal to the coarctation.

Clinical presentation

Most patients with coarctation are asymptomatic. Some patients may present with symptoms of either upper extremity hypertension (headaches, blurred vision or frequent nose bleeds) or symptoms of reduced blood flow to the lower extremities (exercise induced claudication). In infancy, severe coarctation may present with CHF as the ductus arteriosus closes. If it is not diagnosed and treated promptly, acidosis, shock and death may occur.

Making the diagnosis


In asymptomatic patients without hypertension, elective surgery or angioplasty is recommended at 18 to 24 months of age. The presence of significant hypertension or CHF in infancy indicates the need for early repair. Neonates with CHF may also need medical management including PGE1 to keep the ductus arteriosus open.

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