Acquired aortopulmonary fistula – a case report highlighting diagnostic and surgical challenges

Background: Aorto-pulmonary fistula (APF) is a rare but potentially life-threatening condition, most often secondary to aortic surgery or dissection. This case report describes a non-iatrogenic APF caused by a chronic aortic arch aneurysm, an uncommon aetiology not widely described in the literature. Case Summary: A 68-year-old woman was admitted for severe right heart failure (RHF) secondary to pulmonary hypertension refractory to high-dose diuretics. Three months prior, aortic arch aneurysm was documented, but the cause of PH remained unclear. Targeted transthoracic echocardiography (TTE) using off-axis views revealed abnormal aorto-pulmonary flow, confirmed by dedicated CT angiography. She underwent staged open surgery, resulting in complete fistula closure and full haemodynamic recovery. Postoperative recovery was uneventful, with marked improvement in RHF, right ventricular function, and pulmonary pressures at 3 months. Conclusion: Prompt diagnosis, guided by high clinical suspicion and targeted, multimodal imaging, is essential for identifying rare and potentially life-threatening causes of pulmonary hypertension. Early diagnosis facilitates timely intervention and significantly improves patient outcomes.