A recent study was published in the Equine Veterinary Journal titled, "Serial evaluation of resting and exercising overground endoscopic examination results in young Thoroughbreds with no treatment intervention." The study was authored by McGivney, C.L.; Sweeney, S.,; Gough, K.F.; Hill, E.W.; and Katz, L.M.
This retrospective cohort study aimed to determine whether the severity of upper respiratory tract disorders in Thoroughbred racehorses identified using overground endoscopy varied over serial examinations.
Video recordings from overground endoscopic examinations (OGE) of Thoroughbreds in flat‐race training from one training yard between September 2012 and April 2016 were analyzed. Horses were included in the study if they underwent ≥2 OGE during a sprint training session over an identical distance on the same track, were wearing the same tack for all examinations and had not undergone any surgical intervention between examinations. Endoscopic recordings were blindly evaluated by a single observer and standard grading schemes applied.
A total of 72 horses had both pre‐exercise and ≥2 exercising OGE recordings available. At exercise, 94% of horses had at least one upper respiratory tract (URT) abnormality, whereas 79% had ≥2 concurrent abnormalities. There was poor agreement between examinations for the severity of palatial instability, epiglottic grade, medial deviation of the aryepiglottic fold, pharyngeal lymphoid hyperplasia and intermittent dorsal displacement of the soft palate (iDDSP) at all stages of exercise. Only 3/14 horses with iDDSP at exercise consistently displaced at each OGE.
Bottom line: There can be significant variation in URT disorder grade/appearance between multiple OGE examinations.
The study concluded that: "Variability for most URT abnormalities identified with OGE should be considered when making therapeutic decisions based on a single examination and may partially explain development of additional URT conditions after surgical intervention."
For more from this study visit Wiley's online library.