Coarctation

Question 1

Coarctation - background

Answer 1

1. Definition: stricture in distal part of aortic arch
2. May occur at any point; in the majority of cases (98%), it is usually distal to the origin of the left subclavian artery at the level of the ductus arteriosus
3. Infants present at 48h old when the duct closes
4. In older children, the BP is elevated in blood vessels proximal to the obstruction, and an extensive collateral circulation develops
5. Seen more often in boys than girls (2:1), although it is common in Turner syndrome. Often associated with other cardiac defects, including AS, VSD and mitral valve abnormalities

Question 2

Coarctation - clinical features

Answer 2

1. In severe defects a PDA is required to maintain the systemic circulation (blood supply to the descending aorta is via the PDA)
2. Severe HF and collapse may occur in the neonatal period. May also have oliguria and acidosis. Often in the first two weeks of life when the ductus closes
3. Results in a disparity in pulse volume with weak or absent femoral pulses. May have radio-femoral delay (obvious in older children but difficult to detect in young children)
4. Mild defects may present later with HTN (right arm)
5. May have continuous murmurs over back due to development of collateral vessels

Question 3

Coarctation - prognosis + mx

Answer 3

Prognosis

1. Outside the neonatal period, mortality from untreated HTN is high and usually occurs when aged 20-40y
2. Complications (4) = premature CAD, CHF, hypertensive encephalopathy and intracranial haemorrhage

Mx

3. Neonates - reopen PDA by IV infusion of prostaglandin E1
4. Neonates need resuscitation and early surgery
5. Older children/adolescents require stent insertion at cardiac catheter or surgical resection