BOSTON -- Okpara, a western lowland gorilla, will be put under anesthesia Monday so Zoo New England’s veterinary staff can examine him.

The examination will include a general physical, bloodwork and a cardiac exam.

“Okie is 15 years old and he is at the age where we start to get concerned about cardiac disease. We’re never done an echocardiogram on him before and this is preventative care,” said Dr. Hayley Weston Murphy, Zoo New England director of veterinary services.

Cardiac disease is the leading cause of death in male captive gorillas, according to Murphy, who is leading a national study, the Gorilla Health Project, which aims to find ways to prevent the disease.

“Nobody has ever tried to look at the risk factors for developing cardiac disease in gorillas,” said Murphy.

Laboratory results, which will include information on Okie’s cholesterol levels and cardiac biomarkers, are expected within a week. Cardiac biomarkers are protein molecules released into the bloodstream from heart muscle damaged by a blocked artery, according to the zoo.

While Okie’s examination is considered routine, anesthesia always presents some danger to the gorillas.

“Any animal immobilization involving general anesthesia always carries some risk,” said Murphy.

Kubandu, a western lowland gorilla, died of complications from anesthesia during an annual physical exam at the zoo in 1997.

Earlier this month, zoo veterinarians anesthetized another gorilla, Gigi, in order to perform a colonoscopy. The gorilla had been suffering from digestive problems. The colonoscopy results were normal.