Congenital Heart Disease: outflow obstruction Flashcards
Outline 3 examples of outflow obstruction
Aortic stenosis
Pulmonary stenosis
Adult-type coarctation of the aorta
Define aortic stenosis
The aortic valve leaflets are partly fused together, thus restricting the exit from the left ventricle
There could be 1-3 aortic leaflets
Aortic stenosis is often associated with mitral valve stenosis and coarctation of the aorta
Presentation of aortic stenosis
Symptoms
- Reduced exercise tolerance (SOBOE)
- Chest pain on exertion
- Syncope
NOTE: these only occur when the stenosis is severe, otherwise often ASYMPTOMATIC
IMPORTANT: neonates with critical aortic stenosis and duct-dependent circulation may present with severe heart failure leading to SHOCK
Signs
- Small volume, slow rising pulse
- Carotid thrill (ALWAYS)
- Ejection systolic murmur- maximal at the upper RIGHT sternal edge and radiating to the carotids
- Delayed and soft aortic second sound
- Apical ejection click
Investigations of aortic stenosis
CXR
Normal or prominent left ventricle with post-stenotic dilation of the ascending aorta
ECG
May be left ventricular hypertrophy
Management of aortic stenosis
Regular clinical and echocardiographic monitoring
Balloon valvulotomy in those:
* Symptomatic on exercise
* High resting pressure gradient (>64mmHg) across the aortic valve
Most children with significant stenosis will eventually need aortic valve replacement
Early treatment is palliative and directed towards delaying this for as long as possible
Define pulmonary stenosis
The pulmonary valve leaflets are partly fused together, restricting right ventricular outflow
Presentation of pulmonary stenosis
Symptoms
- Usually asymptomatic
- Some may present with cyanosis
Signs
- Ejection systolic murmur- best heard at the upper LEFT sternal edge (thrill may be present)
- Ejection click- best heard at the upper left sternal edge
- Prominent right ventricular impulse (heave) – only if SEVERE
Investigations of pulmonary stenosis
CXR
* Normal or post-stenotic dilation of the pulmonary artery
ECG
* Evidence of right ventricular hypertrophy (upright T wave in V1)
Echo
* Confirms diagnosis
* Assess severity
* Exc cardiac lesions
Management of pulmonary stenosis
Most children are asymptomatic
Prostaglandin E1 infusion- for critical stenoses (+ supplemental oxygen if respiratory distress)
When the pressure gradient across the pulmonary valve becomes markedly increased (> 64mmHg), intervention is needed
Percutaneous balloon dilation (pulmonary valvuloplasty) – treatment of choice
Surgical valvuloplasty – may be required if valvuloplasty ineffective/ contraindicated
Endocarditis prophylaxis
Complications of pulmonic stenosis
Depends on severity and damage to RV or RA
Define Adult-type coarctation of the aorta
Uncommon
NOT duct-dependent
Gradually becomes more severe over many years
Presentation of Adult-type coarctation of the aorta
Asymptomatic
Systemic hypertension in the right arm
Ejection systolic murmur- upper sternal edge
Collaterals heard with continuous murmur at the back
Radio-femoral delay
* This is due to blood bypassing the obstruction via collateral vessels in the chest wall and thus the pulse in the legs is delayed
Investigation of Adult-type coarctation of the aorta
CXR
* Rib notching- due to the development of large collateral intercostal arteries running under the ribs posteriorly to bypass the obstruction
* ‘3’ sign – visible notch in the descending aorta at the site of the coarctation
ECG
* Left ventricular hypertrophy
* Echocardiography- assess anatomical abnormality
Management of Adult-type coarctation of the aorta
Sick infant à follow ABC and prostaglandin infusion guidelines
Surgical repair/ techniques
* A stent may be inserted via cardiac catheter (balloon or metal tube)
* Removal of coarctation and reconnection of the ends
* Graft from elsewhere