Neonatal obstructive left‑heart lesions - recognition and emergency management
Introduction
Obstructive left‑heart lesions (for example, coarctation of the aorta, interrupted aortic arch, critical aortic stenosis, hypoplastic left heart syndrome) restrict systemic outflow from the left ventricle. Many are duct‑dependent: systemic perfusion is maintained by a patent ductus arteriosus (PDA) in the immediate newborn period.
Physiological constriction or closure of the ductus after birth may precipitate abrupt cardiovascular collapse. The emergency department (ED) role is rapid recognition, physiological stabilisation using newborn resuscitation principles, and urgent specialist escalation and transfer.
Key lesions that are commonly duct‑dependent
- Critical coarctation of the aorta
- Interrupted aortic arch
- Critical aortic stenosis / severe aortic valve disease
- Hypoplastic left heart syndrome (HLHS)
Pathophysiology - why ductal patency matters
In utero the PDA diverts blood from the pulmonary artery to the descending aorta. After birth the ductus normally constricts; in left‑sided obstructive lesions the PDA may provide the only adequate systemic blood flow.
Closure of the ductus removes that alternative pathway, causing marked reduction in systemic output, hypotension, metabolic acidosis and end‑organ hypoperfusion.
Stabilisation aims to support airway/ventilation and circulation, maintain or reopen ductal flow where indicated, and arrange rapid transfer for definitive care at a paediatric cardiac centre.