Congenital portosystemic shunt concurrent with an atrial septal defect in a Maltese dog

Background: Portosystemic shunt and atrial septal defect (ASD) are generally congenital diseases in dogs. Rarely, dogs with congenital vascular anomalies could be related to other vascular anomalies. Case Description: A 1-year-old male Maltese dog, neutered and weighing 1.7 kg, was brought in for additional assessment of a congenital portosystemic shunt (CPSS). CPSS was diagnosed as porto-caval shunt by computed tomography. Surgical attenuation was performed. Although prognosis after CPSS attenuation was good, the dog was presented with exercise intolerance one year after the operation. Thoracic radiographs observed generalized cardiomegaly. Echocardiography revealed pulmonary hypertension and right-to-left shunting ASD. Conclusion: The present study reports a rare case of CPSS concurrent with ASD in a dog. As dogs with CPSS might have been associated with other vascular anomalies; therefore, echocardiography is recommended for early diagnosis of other cardiovascular anomalies.