In 2013, however, Fellers noticed some mild lameness in Flexible, who was then examined by his primary caretaker in Oregon, Dr. Mark Revenaugh, a national level sport horse veterinarian and a renowned expert in the diagnosis and treatment of lameness and performance issues. Dr. Revenaugh noticed an atypical appearance on Flexible’s bone scan. His associate at Northwest Equine Performance, Dr. Rachel Gottlieb, performed a transrectal ultrasound, and discovered an aorto-iliac and right femoral aortic thrombosis – blood clots in four arteries in his right hind, including the aortic and femoral arteries.

Dr. Revenaugh proceeded to research surgical treatments of aortic thrombosis, and came across a paper published by (among others): Dr. Jorge Nieto, a UC Davis veterinary surgical and sports medicine specialist; Dr. William Pevec, a cardiovascular surgeon at the UC Davis Medical Center; and Dr. Monica Aleman, a UC Davis veterinary internal medicine and neurology specialist, whose experience in treating aortic thrombosis in Mexico was familiar to Dr. Revenaugh. Plus, Dr. Gottlieb was a former ultrasound fellow at UC Davis. All signs seemed to point toward Flexible being referred to the UC Davis Veterinary Medical Teaching Hospital.

Dr. Revenaugh contacted Dr. Aleman, and the two discussed extensively what the VMTH might be able to do for Flexible. Dr. Aleman suggested a referral for further evaluation by Dr. Mary Beth Whitcomb of the hospital’s Large Animal Ultrasound Service. This would allow for determination of the extent and percentage of occlusion, and which specific vessels were involved, as the aorta might be only a part of the area thrombosed. A referral would also allow for Drs. Aleman and Nieto to examine Flexible to get a better understanding of his condition.

Once Flexible was in California, Dr. Whitcomb performed extensive ultrasound (transrectal and transcutaneous) evaluations on him, and Drs. Aleman and Nieto were able to properly work him up to see the full extent of his condition, as well as discuss that condition further with Dr. Pevec. An all-hands-on-deck conference call involving all parties, including Flexible’s owners Mollie and Harry Chapman, followed to discuss Flexible’s future. 

Surgery was recommended as an option to treat this condition, but would most likely result in Flexible’s retirement from show jumping. Another option was treating the clots with blood thinners. The team—after further consulting with other well-known international veterinarians familiar with Flexible—chose the latter, as retirement was not in the cards for Flexible.   

At a three-month recheck examination, Flexible’s condition remained relatively the same. Eight- and ten-month rechecks, however, revealed a dramatically improved situation. Multiple vessels had blood flow through them, although there was still occlusion of the right femoral artery and also branches of both left and right internal iliac arteries. Overall, though, his condition was improving.

Flexible went on to qualify for the recent 2015 FEI World Cup Finals. At 19- and 56-years-old respectively, Flexible and Fellers were the oldest horse and rider in the event. They proved that age is nothing more than a number on paper, placing 7th and winning the admiration of all in attendance.

“It’s unusual for a horse to be competing at the very top level at this age,” said Will Connell, director of sport for the USEF, quoted in the New Jersey Star-Ledger after the World Cup. “Great care pays off, as does having a rider concerned with the animal’s welfare. This is a wonderful example of a horse/rider combination with a long-standing relationship who clearly understand each other and have been so successful.”