Outflow Obstruction

Coarctation of Aorta

This refers to a narrowing of the aorta, which is divided into infantile and adult forms.

– It occurs due to arterial duct tissue encircling the aorta at the point of insertion of the ductus arteriosus

– When the duct closes, the aorta also constricts, causing a severe obstruction to left ventricle outflow

– Coarctation of the aorta exists in both infantile and adult forms: 

Diagnosis:

Echocardiogram

Management:

– Prostaglandin E1 to stop closure of the ductus arteriosus

– Surgery is the definitive cure 

Adult coarctation of the aorta

This is narrowing of the aorta that gradually becomes more severe over many years

– Blood bypasses the obstruction via collateral vessels in the chest wall

– This not associated with a PDA and the coarctation lies just after origin of left subclavian artery

Symptoms:

– Over time gives hypertension in upper parts and hypotension in lower extremities

– Radio-femoral delay

– Systolic murmur which radiates to the back

– Weak femoral pulse and cold feet.

– Collateral circulation develops across intercostal arteries to reach lower bodies, causing these blood vessels to dilate

Tests:

CXR shows “notching” of ribs due to engorged arteries (“3” sign)

Management:

May require stenting or surgery depending on severity

Aortic stenosis

This is narrowing of the aortic valve orifice as the aortic valve leaflets become partly fused together, which restricts blood exit from the left ventricle

– This defect often occurs in association with mitral stenosis and coarctation of the aorta

Symptoms:

Many are asymptomatic with a murmur

– Gives ejection systolic murmur which radiates to the carotids and a carotid thrill

– If severe –> reduced exercise tolerance, chest pain on exertion, syncope

– If critical –> severe heart failure leading to shock

– Narrow pulse pressure with slowly rising pulse

Diagnosis:

Echocardiogram

Management:

Children need regular clinical and echocardiogram to determine whether they need intervention

– Balloon valvotomy –> if symptoms on exercise or high resting pressure gradient (>64mmHg)

– Children with significant aortic valve stenosis will eventually require aortic valve replacement

Pulmonary Stenosis

This is a condition where the opening of the pulmonary artery is constricted due to the pulmonary valve leaflets being partly fused together.

– This restricts exit of blood from the right ventricle into the pulmonary artery

Symptoms:

– Mostly asymptomatic

– Ejection systolic murmur and ejection click loudest over the pulmonary area

– If severe, this can lead to right ventricular failure and signs of right sided heart failure e.g., hepatomegaly

Diagnosis:

Echocardiogram

Management:

Transcatheter balloon dilation (if pressure gradient across the valve is >64mmHg)

 Interruption of Aortic arch

This is a heart condition in which there is no connection between the proximal ascending and the descending aorta

– This means that blood from the left ventricle is impeded from entering the systemic circulation

– The interruption occurs before the origin of the left subclavian artery, meaning oxygenated blood can still go to the right side of the body and head and neck, but not the left arm and legs

– Flow of blood into the systemic circulation distal to the interruption is dependent on right-to-left shunting via the ductus arteriosus from pulmonary artery into the descending aorta

– A ventricular septal defect is also usually present allowing oxygenated blood into the descending aorta