ARCADIA, Calif. (AP) — A necropsy on 2021 Kentucky Derby winner Medina Spirit showed no definitive cause of death.

The California Horse Racing Board on Friday released the results of the examination done after the colt collapsed and died after a workout on Dec. 6 at Santa Anita.

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Trainer Bob Baffert said the colt suffered a heart attack. Medina Spirit had just completed five furlongs in his second workout since finishing second in the Breeders’ Cup Classic in November.

The necropsy report said Medina Spirit’s swollen lungs and foam in his windpipe, as well as enlarged spleen and congestions and mild hemorrhages in other tissues “are common in horses dying suddenly, and are compatible with, but not specific for a cardiac cause of death.”

Medina Spirit’s Kentucky Derby victory last May came under scrutiny after he tested positive for betamethasone, a legal medication that is not allowed on race day in Kentucky.

As a result, Baffert was suspended by Churchill Downs and barred from entering horses in the 2022 and 2023 Kentucky Derbies. He also was banned by the New York Racing Association from entering horses at its Belmont, Saratoga and Aqueduct tracks.

Prior to the 2021 Preakness Stakes, Baffert and the Maryland Jockey Club agreed to blood sample testing of the horse. Medina Spirit passed all three of his drug tests before running in the second jewel of horse racing’s Triple Crown, Maryland racing officials said. The samples were taken on May 6, May 10 and May 11.

At 11-1, Rombauer pulled off the upset in the race, passing Medina Spirit, who went on to finish third.

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The necropsy on Medina Spirit found the anti-ulcer medication omeprazole and the diuretic Lasix in blood and urine samples consistent with the medication report filed with CHRB by the attending veterinarian.

The report said no other drugs, heavy metals or toxicants were detected.

The necropsy included gross examination of the body and internal organs, and specimen collection for microscopic examination, toxicology, drug testing, and genetic testing, with specimens also stored for possible future testing.

After the examination was completed, Medina Spirit was cremated, the CHRB said.

During the necropsy, the horse was examined for obvious causes of death and visually apparent abnormalities. Tissue samples were collected from the heart, lungs, liver, spleen, kidney, stomach, intestines, muscle, brain, spinal cord, testicles, and other glands, and were examined under the microscope for evidence of abnormalities.

Liver tissue was tested for heavy metals, anticoagulants, pesticides, environmental contaminants, drugs, and other products. Blood and urine samples were screened for the presence of hundreds of substances, both legal medications and prohibited drugs, including erythropoietin (EPO), clenbuterol, and betamethasone.

Next comes a required review of the necropsy report, which will be done by Dr. Alina Vale. A safety steward and a member of the board of stewards will also participate in the review.

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Any potential rule violations uncovered in the review process will be investigated by the CHRB and would result in a complaint and possible disciplinary action.