Necropsy finds no definitive cause of Kentucky Derby winner Medina Spirit's death

Medina Spirit’s death remains an unsolved mystery. But though the Kentucky Derby winner’s post-mortem was not definitive, neither was it incriminating.

Still subject to disqualification from the 2021 Derby for a post-race drug test that detected the corticosteroid betamethasone, Medina Spirit’s necropsy revealed the presence of no drugs or toxicants other than those reported to the California Horse Racing Board (CHRB): the anti-ulcer medication Omeprazole and the diuretic Lasix.

Though pathologists suspect the cause of death was acute heart failure, they stopped short of a conclusive diagnosis.

“It’s absolutely frustrating,” said Dr. Francisco Uzal, branch chief of the California Animal Health and Food Safety Lab. “The rule of thumb in most racing jurisdictions, pathologists agree, is that probably 50% of the cases go unresolved.”

More: In death as in life, Kentucky Derby winner Medina Spirit still matters

Trainer Bob Baffert’s seventh Kentucky Derby winner dropped dead on Dec. 6 at Santa Anita following a five-furlong workout, seven months after he crossed the finish line first in Derby 147 and a month after his second-place finish in the Breeders’ Cup Classic. Friday’s release of Medina Spirit’s necropsy report is unlikely to influence Monday’s scheduled stewards hearing on the 2021 Derby, but it could work to Baffert’s benefit in terms of possible penalties imposed on the trainer and/or eventual appeals through the court system.

Though Baffert’s attorneys continue to claim Kentucky regulations do not apply to an ointment containing betamethasone as they do to the injectable version, the presence of any amount of the substance in a horse’s race-day sample is considered grounds for disqualification, regardless of its source.

No betamethasone was detected in Medina Spirit’s samples tested during the necropsy. Nor was there any trace of erythropoietin (EPO), the subject of a speculative story that appeared in the New York Post. Conditions consistent with a cardiac-caused death included swollen lungs, foam in the trachea (windpipe), an enlarged spleen and congestion and “mild” hemorrhages in other tissues.

More: Medina Spirit, disputed winner of 2021 Kentucky Derby, dies after workout

Extensive testing was performed after the horse’s body was transported from Santa Anita to the California Animal Health and Food Safety laboratory in San Bernardino. Tissue samples were collected from the horse’s heart, lungs, liver, spleen, kidney, stomach, intestines, muscle, brain, spinal cord, testicles, and other glands. Samples of blood, urine, and aqueous humor (the liquid that nourishes the cornea) were screened for the presence of hundreds of substances, both legal medications and prohibited drugs. Dr. Benjamin Moeller said the necropsy revealed no unidentified compounds for which no tests exist.

Uzal said Medina Spirit’s necropsy was similar to those performed on other horses, except that the findings were subjected to peer review by the University of Kentucky’s Dr. Laura Kennedy and Dr. Grant Maxie of Canada’s University of Guelph. Both concurred cardiac issues were the probable cause of death, but not the only possibility.

“In my experience, the minimal degree of myocardial inflammation in this case can be found both in thoroughbred horses in active race training that die for reasons other than sudden death, and in cases of sudden death,” Kennedy wrote. “. . .There was significant pulmonary edema and congestion, with a mild degree of hemorrhage. These findings are common in cases of sudden death, and do not rule in nor rule out a particular cause.”

In short, too close to call.

“We were hopeful that the necropsy would have revealed more information about the pathophysiology that led to Medina Spirit’s sudden cardiac arrest," said Clark Brewster, one of Baffert's attorneys, "but it appears that his tragic death was an act of God and was not preventable."

Tim Sullivan: 502-582-4650, tsullivan@courier-journal.com; Twitter: @TimSullivan714

This article originally appeared on Louisville Courier Journal: No unreported drugs found in Kentucky Derby winner Medina Spirit