Pont, Adriaan D.Bester, Elizabeth G.Kitshoff, Adriaan Mynhardt2026-03-312026-03-312026-05Pont, A.D., Bester, E.G. & Kitshoff, A.M. Postoperative chylothorax following surgical transection of a left ligamentum arteriosum in a cat with a persistent right aortic arch. Veterinary Record Case Reports 2026; 14: e70412: 1-5. https://doi.org/10.1002/vrc2.70412.2052-6121 (online)10.1002/vrc2.70412http://hdl.handle.net/2263/109372A 6-month-old intact female domestic shorthair cat was presented for surgical correction of a vascular ring anomaly. The main clinical sign on presentation was persistent regurgitation after ingestion of solid food. Computed tomography of the thorax confirmed the diagnosis of a persistent right aortic arch (PRAA) with a left ligamentum arteriosum. The left ligamentum arteriosum was identified, ligated and transected via a left fifth intercostal thoracotomy to relieve the oesophageal constriction associated with the persistent right aortic arch. Within 24 h postoperatively, the patient developed dyspnoea and tachypnoea. A pleural effusion was noted on drainage of the left thoracic drain, which had been placed intraoperatively. The pleural effusion analysis was consistent with a chylothorax. A right-sided thoracostomy tube was placed in addition to the left, and a continuous drainage system was utilised. The chylous effusion resolved on Day 6 postoperatively. This case report highlights the occurrence and management of iatrogenic chylothorax following surgical correction of a PRAA with a left ligamentum arteriosum in a cat.en© 2026 The Author(s). Veterinary Record Case Reports published by John Wiley & Sons Ltd on behalf of British Veterinary Association. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License.Persistent right aortic arch (PRAA)Vascular ring anomalyLeft ligamentum arteriosumCatSurgical correctionCase reportArticle