Intensive Care : Heart Surgeon Leads Pioneering Operation on Endangered Orangutan


In the first open-heart surgery performed on an ape, a medical team led by an internationally known heart surgeon worked for seven hours Saturday to repair a life-threatening hole in the heart of a young orangutan at the San Diego Zoo.

A team of surgeons, nurses, anesthesiologists and medical technicians from the UC San Diego Medical Center, assisted by veterinarians and animal keepers from the zoo, worked to patch a gaping hole in the heart of a 2-year-old Sumatran orangutan named Karen, a member of an endangered species.

“If Karen were human, I’d tell her parents that everything went fine, and her prognosis is excellent,” lead surgeon Dr. Stuart Jamieson said after emerging from the operating room at the zoo hospital.


The surgery is virtually identical to the procedure commonly performed on humans with the same heart defect. Even if successful, the veterinary surgery is unlikely to be repeated soon because heart problems are rarely detected among zoo animals.

Without surgery to correct the congenital defect, the 22-pound orangutan faced the risk of a fatal heart attack as her heart arteries hardened and her blood became depleted of oxygen. The longer doctors waited, the greater the chance that irreparable damage had already occurred.

“It was either now or never for Karen,” said Dr. Kurt Benirschke, professor of pathology at UCSD and founder of the zoo’s Center for the Reproduction of Endangered Species. “It was only going to get worse.”

On Saturday night, Karen was put on a breathing machine because of a buildup of fluid in her lungs, a common postoperative reaction. Veterinarians planned to stay with her around the clock until she is out of danger.

If Karen recovers completely, she could grow to 80 pounds and live to the age of 30 or more. Keepers hope to have her back with other orangutans within a few months.

Jamieson said that although the team encountered differences between humans and apes in the skin and chest, “once we were in the heart, it was like what we do every day.”


The hole was a particularly large one, destroying nearly the entire wall between two chambers of the heart, preventing blood from getting enough oxygen. Jamieson and fellow surgeon Dr. Jolene Kriett stretched a section of the heart sac across the hole and stitched it shut.

Physicians from UCSD and other medical groups in San Diego have a long history of working pro bono with veterinarians at the zoo on tricky and challenging cases.

Among those cases have been an albino koala with cancer in the roof of its mouth, jaguars and elephants who needed root canal work, a gorilla with an ear infection, a giraffe that needed X-rays, a Komodo dragon with a broken leg and a rare owl with failing eyesight.

Although medical-veterinary cooperation is common, zoo officials said this was the first open-heart surgery ever done on a San Diego zoo animal. “This is cutting edge,” said Douglas Myers, the zoo’s executive director, one of a dozen people who watched nervously from an upstairs observation room.

“I can’t think of a better way to spend a Saturday than helping an endangered species survive,” Jamieson said.

Jamieson has performed more than 550 heart transplants and headed the heart-lung transplant programs at Stanford and the University of Minnesota before coming to UCSD. When he and key members of his team came to UCSD from Minnesota five years ago, it was considered a major medical coup.

For the surgery on Karen, the same equipment used on human patients was brought to the zoo hospital: a heart-lung machine, a machine for cleansing blood, and a pacemaker in case doctors had trouble restarting the heart.


During surgery, the orangutan’s heart was stopped and she was attached to the heart-lung machine.

If there was a strangeness to treating an ape with the same procedures and technology used on humans, it disappeared when Karen was draped in a sterile surgical sheet with only a portion of her gray-brown chest exposed, with all its reddish hair shaved away.

“Once the patient was under the cover, she looked just like a normal baby,” said scrub nurse Maria Camilon.

When Jamieson and Kriett began, the operating room fell silent. Jamieson wore a head-mounted camera to provide a close-up view to observers via closed-circuit TV.

Even before her surgery, Karen, one of seven orangutans at the San Diego Zoo, had her share of travails. For openers, she was an unplanned and unwanted offspring.

Her mother, Karta, became pregnant despite being on birth control pills. For genetic reasons, it was not thought wise for Karta to reproduce with the dominant male, Otis, her father.


Keepers deduced that Karta was pretending to swallow her daily pill and spitting it out when no one was watching. Karta refused to nurse Karen, forcing keepers to take Karen from her mother and feed her from a bottle.

In her first year she suffered unusual bouts of diarrhea and lethargy. Her growth seemed stunted.

After veterinarians heard a heart murmur, a cardiac catheterization performed by Dr. Abraham Rothman, a pediatric cardiologist from UCSD, confirmed that Karen had been born with an atrial septal defect, a 3/4-inch hole between the two chambers of the heart.

The condition accounts for 10% of heart problems in children, and the surgery to repair it has become commonplace. In adults the human heart and the ape heart are nearly identical, and zoo veterinarians decided that Karen would be a good candidate for surgery.

There were still risks. For one thing, the hole was near the heart’s center for electrical activity and a slip of the scalpel could be deadly. Also, doctors were not sure if Karen’s vascular system was the same as that of an adult orangutan.

Hunting, poaching and destruction of the hardwood forests in their native Borneo and Sumatra have led the orangutans to be listed as endangered. The American Assn. of Zoological Parks and Aquariums has begun a breeding program for orangutans, and also is trying to raise awareness of their plight.