Leading trainer Nicky Henderson has revealed Altior returned an unsatisfactory scope after his shock defeat at Kempton on Sunday.
The 10-year-old returned to the track for the first time in 323 days for the Desert Orchid Chase and looked rusty as he struggled to keep pace with Nube Negra.
Altior was pushed along for large parts of the race before finishing second on his seasonal bow.
Henderson was forced to allay talk of retiring the dual Champion Chase-winner and has now revealed there may be medical reasons for his flat run.
He told Nick Luck's Daily Podcast: “There was evidence (of a dirty scope). I spoke to (vet) Simon Knapp last night – he confirmed there was, and we need to do a tracheal wash, which then goes to the laboratory. I wouldn't be surprised if we find there is something amiss.
“It's definitely not normal, because he was scoped on Christmas Eve and we know it was 100 per cent clean, but 48 hours is a long time in a horse's life.
“It would be enough (to affect his performance) – it would in Simon Knapp's opinion anyway.”
