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Ryan Hospital Philadelphia, PA

The Stars Align for Skye

By: Ashley Berke

She was the first dog Hans Stedman saw when he entered the Montgomery County SPCA. The six-month-old German Shepherd was surrounded by potential adopters. Realizing the puppy was in high demand, Stedman immediately filled out an adoption application and enjoyed some one-on-one playtime with Skye.

Stedman didn’t make it out of the parking lot before receiving a phone call from the SPCA manager. He had been selected to adopt Skye. “I was probably seen as a desirable adopter since my mom is a vet,” Stedman surmised.

Dr. Lisa Evans with the family dog and Skye before surgery.

During the car ride home, Skye regurgitated. “I chalked it up to car sickness,” Stedman said. But before the end of the weekend, the young pup regurgitated several more times. “That’s when my mom said she needed to be examined.”


Stedman’s mother, Dr. Lisa Evans, is a Penn Vet alumna and owner of Skippack Animal Hospital. After hearing Skye’s symptoms, she instructed Stedman to be careful when feeding her.

“We blended her food so that she wouldn’t regurgitate it,” Stedman said. He also brought Skye to Evans’ practice for a barium swallow, a test that can be used to evaluate difficulty swallowing and potential problems with the esophagus. 

Radiograph of the lateral side of Skye's abdomen

That’s when Evans discovered that Skye had megaesophagus, or an enlarged esophagus, caused by a persistent right aortic arch. She immediately called her friend, Dr. David Holt, Professor of Surgery at Penn Vet. Two days later, Skye was scheduled for surgery at Ryan Hospital.

Abnormal Arches

What is a persistent right aortic arch, and how does it occur? In short, a persistent right aortic arch is an abnormal development of the major blood vessels in the chest.

In the embryo, there are six pairs of vessels, or aortic arches, that initially serve a function, but eventually shrink away or become other vessels as the embryo grows. During normal development, the left aortic arch remains as the main artery. When the right aortic arch fails to disappear, or “persists,” the esophagus becomes trapped between the arch, the pulmonary artery, and the ligamentum arteriosum (arterial ligament), restricting the passage of food to the stomach. 

During surgery, Dr. Holt planned to cut the ligamentum arteriosum to free up the esophagus. But Skye’s case was unusual. She didn’t have a ligamentum arteriosum.

“What I believe happened is that, instead of having a full ligamentum arteriosum, Skye had a remnant of the left aortic arch and part of the ligamentum arteriosum,” Holt said. “I have never seen a case quite like it.” 

But Dr. Holt was well prepared for this type of surgery, having been trained at Penn Vet by one of the “fathers of cardiac surgery,” Dr. James Buchanan. “He was very kind, patient, and understanding,” Holt said of Buchanan. “He taught me how to do these surgeries.” 

Dr. David Holt (center) with the team post-surgery. 

Holt proceeded with precision during the procedure, taking extra care due to the location and complexity of the stricture. He cut the remnants that were causing the esophageal constriction and dilation. He then passed a stomach tube through the esophagus to ensure there was no obstruction. After several tense hours, he knew Skye was in the clear.

Following surgery, Skye spent the night in Ryan Hospital’s Intensive Care Unit for observation and pain management. She recovered well and was able to return home the next day.

“I was so relieved,” Stedman said. “I was extremely happy to hear that the surgery had gone well.” 

“This whole situation was life-saving for Skye,” Evans added. “How did she find us? What are the odds that Hans would visit the SPCA on her first day there? It’s just remarkable!”

Helping Future Generations

Also present in the operating room during Skye’s surgery was Stedman’s father, Dr. Hansell Stedman, a surgeon at the Hospital of the University of Pennsylvania. Stedman had previously worked on a cardiac gene therapy project with Holt, and Skye’s case presented a new opportunity for collaboration.

“This was an atypical case, and a shining example of what Penn Vet does best,” Stedman said. “Not only do we plan to write a case report,” he added, “but we also have the opportunity to look at this case at the genetic level.”

Skye spends the night in the ICU after surgery.

What is the signaling that causes a right persistent aortic arch? Is there a way to prevent this from happening in specific breeds going forward? Can the findings lead to advances in human medicine, as well? These are all questions that Holt, Evans, Stedman, and geneticists at Penn Vet and Penn Medicine can continue to explore.

It’s this kind of collaboration that sets Penn Vet apart. Integrated with world-class biomedical research facilities at Penn, the school takes an interdisciplinary approach to research and clinical care, enabling experts at Ryan Hospital to employ the latest in breakthrough science when caring for pets.

The Sky’s the Limit

As for Skye, now that she’s healthy, she will move to Penn this fall. Stedman, a rising sophomore studying mechanical engineering, will bring her to the Phi Gamma Delta fraternity on Locust Walk next month, where she will surely become a popular presence on campus. 

“I’m looking forward to going to High Rise Field and Clark Park with her,” Stedman said.

Skye is currently in puppy training classes, and Stedman plans to enroll her in the Penn Vet Working Dog Center’s classes in the fall. “She’s super smart,” he said. “She learned everything on her first try.”

And should Skye need specialty veterinary care again in the future, she will only be two blocks away from Ryan Hospital.

“I’m so glad to have Penn Vet there,” Evans said. “We can all work together. It’s a win-win-win.”

Hans with Skye at Skippack Animal Hospital