Percutaneous transcatheter right atrial stent placement for recurrent cor triatriatum dexter following initial surgical excision of right intra-atrial membrane in a dog.

A four-year-old spayed female Shiba Inu dog weighing 6.1 kg presented with ascites. Cor triatriatum dexter (CTD) without any other concurrent cardiovascular anomalies was diagnosed using echocardiography. The ostium of the abnormal membrane dividing the right atrium into two abnormal chambers was surgically excised under cardiopulmonary bypass. All clinical abnormalities were resolved after surgery. However, seven months later, ascites and CTD recurred. A balloon-expandable stent was placed at the site of recurrence, which improved caudal venous return to the right ventricle. After the second procedure, ascites were resolved, and the dog remained asymptomatic for 18 months without complications. There are previous reports of successful surgical resection of the CTD and of stenting in recurrent CTD following balloon dilation in dogs. However, to the authors' knowledge, no previous reports have described recurrent CTD in dogs after surgical resection of the CTD. In this case, as with recurrent CTD following balloon dilation, stent placement at the site of the CTD can be a viable treatment option when the abnormal membrane recurs.