Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt following pneumonectomy.

A 62-year-old man presents with breathlessness 6 months following right pneumonectomy for lung adenocarcinoma. Previous investigations had not yielded a diagnosis and his symptoms were progressing. The patient described worsened symptoms when stood up (platypnoea), with profound hypoxia until laid supine (orthodeoxia). Platypnoea-orthodeoxia syndrome due to a right-to-left interatrial shunt was diagnosed on contrast-enhanced transoesophageal echocardiography with the patient undergoing successful percutaneous patent foramen ovale closure. Patent foramen ovale is often asymptomatic with a population prevalence of around 20%-30%. Anatomical shifts postpneumonectomy can open, or worsen a previously closed interatrial communication leading to right-to-left shunting of blood. Platypnoea-orthodeoxia is under-recognised, impairing quality of life and patient outcome. Investigations can be falsely reassuring, or poorly sensitive for the causative pathology. Percutaneous closure is safe with high success rates and this case highlights the need for a high index of suspicion for shunts, particularly in postpneumonectomy patients.