Congenital Heart Disease: outflow obstruction Flashcards

1
Q

Outline 3 examples of outflow obstruction

A

Aortic stenosis

Pulmonary stenosis

Adult-type coarctation of the aorta

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2
Q

Define aortic stenosis

A

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

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3
Q

Presentation of aortic stenosis

A

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
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4
Q

Investigations of aortic stenosis

A

CXR

Normal or prominent left ventricle with post-stenotic dilation of the ascending aorta

ECG

May be left ventricular hypertrophy

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5
Q

Management of aortic stenosis

A

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

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6
Q

Define pulmonary stenosis

A

The pulmonary valve leaflets are partly fused together, restricting right ventricular outflow

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7
Q

Presentation of pulmonary stenosis

A

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
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8
Q

Investigations of pulmonary stenosis

A

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

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9
Q

Management of pulmonary stenosis

A

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

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10
Q

Complications of pulmonic stenosis

A

Depends on severity and damage to RV or RA 

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11
Q

Define Adult-type coarctation of the aorta

A

Uncommon

NOT duct-dependent

Gradually becomes more severe over many years

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12
Q

Presentation of Adult-type coarctation of the aorta

A

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

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13
Q

Investigation of Adult-type coarctation of the aorta

A

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

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14
Q

Management of Adult-type coarctation of the aorta

A

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

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