On Thursday an international team determined the animal was suffering from some sort of gastrointestinal illness.
As Hana's condition deteriorated Thursday evening, the experts decided to try surgery using general anesthesia, which the aquarium says has never been done before on a dolphin or whale.
Aquarium veterinarian Dr. Martin Haulena described the surgery as a breakthrough in veterinary care and says such a procedure would have been considered impossible only a few years ago.
While the surgery was considered a success on Friday by Haulena, Hana died on Sunday night.
Haulena is scheduled to provide more information at a media briefing around 9:30 Monday morning.
Hana had been at the Vancouver Aquarium since 2005. The dolphin arrived from Enoshima Aquarium in Japan, where it was treated for injuries from a fixed-location fishing net off the country's east coast in 2003.