Radiography, CT‐angiography and post‐mortem findings in a foal with a congenital type 3 vascular ring anomaly.

Summary: Congenital vascular ring anomalies (VRA) have been occasionally described in horses. To the authors' knowledge, this is the first case report providing radiographic and computed tomography (CT) findings of a congenital type 3 persistent right aortic arch (PRAA) in a foal. A 1.5 months old Franches‐Montagnes colt was presented for growth retardation with a history of mild intermittent bilateral nasal discharge occasionally containing milk and coughing since birth. Thoracic radiographs and ultrasound, oesophagoscopy, positive contrast oesophagography and CT angiography were performed. A final diagnosis of persistent right fourth aortic arch, with left ligamentum arteriosum and aberrant left subclavian artery (type 3 VRA) and subsequent aspiration pneumonia was achieved. Due to the poor physical condition, the presence of severe aspiration pneumonia and most importantly the lack of a surgical option for a type 3 VRA, the colt was euthanised and the post‐mortem examination confirmed the oesophagography and CT angiography findings. [ABSTRACT FROM AUTHOR]