Case Report: Focusing on the unexpected: decision-making and embolisation of an unexpected intercostal artery guided by intraoperative transoesophageal echocardiography in persistent thoracic aortic false lumen perfusion and growth.

Persistent false lumen perfusion of the remaining dissected aorta after open or endovascular aortic repair remains a major determinant of late aneurysmal growth and reintervention, often driven by complex and sometimes unexpected haemodynamic mechanisms. This case involves a 77-year-old man with progressive false lumen enlargement following staged hybrid repair of a chronic type A aortic dissection. Despite apparently successful gutter embolisation around a Candy Plug, intraoperative transoesophageal echocardiography (TEE) revealed persistent false lumen flow. Careful TEE assessment identified an unexpected proximal intercostal artery as the source of reperfusion. Selective catheterisation and coil embolisation of this artery were successfully performed under combined TEE and fusion imaging guidance, achieving immediate and durable exclusion. This case highlights the unique value of intraoperative TEE as a real-time haemodynamic imaging tool that can detect endoleaks missed by angiography and directly guide therapeutic decision-making in complex aortic dissections.