A baby cougar named “Tasha” from Cougar Mountain Zoo recently underwent a delicate surgery to correct a congenital defect that was preventing her from eating solid foods.

Her surgery was performed at Seattle Veterinary Specialists (SVS) by Michael Mison, DVM, DACVS. SVS is a multispecialty and 24-hour emergency/critical care facility in Kirkland.

“There were no complications during surgery, and I’m happy to report that Tasha is recovering nicely. We expect her to have a long and healthy life,” said Dr. Mison.

Three-month-old Tasha was diagnosed with the vascular ring defect at SVS on Aug. 10. The term “vascular” relates to blood vessels. Vascular ring anomalies occur in the fetus when embryonic blood vessels don’t develop normally.

In some cases, such as Tasha’s, these embryonic blood vessels persist after birth as a tough band of tissue, instead of disappearing as they normally should. They entrap important structures, often near the base of the heart in a ring of immoveable tissues.

Dr. Mison explained, “One structure commonly affected by vascular ring defects is the esophagus, which is soft and collapsible. This means that when Tasha started to eat solid foods, the food was not able to pass normally into the stomach due to the encircling band of tissue. She started to regurgitate constantly and lose weight, and Tasha was smaller than other animals her age.”

The surgery to correct this condition involves opening the chest, and then identifying and removing the restrictive band of tissue. The surgery requires delicate dissection around the base of the heart and vital nerves.

In a group effort by members of the SVS medical team, an inflatable balloon was inserted into Tasha’s esophagus via her mouth and inflated, which helped Dr. Mison to identify the band of tissue that was causing all of Tasha’s trouble.

Dr. Mison then gently elevated the band of tissue from the esophagus and heart and tied it off with surgical silk before cutting it away carefully. The team continued to balloon-dilate the esophagus to help stretch out the area that had been entrapped since Tasha’s birth.

Tasha was returned to Cougar Mountain Zoo in Issaquah and is recovering.