Race performance following epiglottic entrapment surgery in Thoroughbred yearlings

Abstract

Summary Background Epiglottic entrapment can occur in yearling Thoroughbreds (TB); however, race performance following surgical correction is unknown. Objectives To determine the race performance of horses treated surgically for epiglottic entrapment as yearlings as compared to an untreated cohort. A second objective was to identify risk factors for treated horses not racing post‐operatively. Study design Retrospective cohort and case–control studies. Methods Medical (1989–2014) and race records of 66 treated TB racehorses were reviewed. Observed abnormalities on pre‐ and post‐operative endoscopic images and surgical method were recorded. Race records (EquineLine) were recorded. Racing performance of treated yearling TBs and two of their maternal half‐siblings, which were used as the untreated cohort, was evaluated in a cohort study. A case–control study was used to investigate risk factors for not racing post‐operatively among treated horses. Quarterly starts and earnings were compared to an untreated cohort. Survival analysis was used to assess career longevity. Rates of racing and earnings were compared between groups using Poisson and negative binomial regression respectively. Associations between clinical variables and not racing post‐surgery were evaluated using logistic regression. Results Sixty‐six treated horses were identified, 65 of which had at least one half‐sibling. Proportions of horses that raced were similar for treated and maternal cohorts (70.0 vs. 70.8%, P = 0.9). Treated horses performed similarly to untreated horses. In treated horses, epiglottic entrapment with abnormal right arytenoid movement was associated with never racing (OR 15.40, 95% CI 1.64–144.23, P = 0.02). More females were affected by epiglottic entrapment than males (47/66 vs. 19/66 respectively, P<0.001). Main limitations The retrospective design over a prolonged period of time with cases obtained from a single hospital population. Low case numbers likely influenced the outcome of the multivariable analysis. Conclusions Thoroughbred racehorses treated in their yearling year for epiglottic entrapment had no differences in performance variables compared to their untreated cohort. Epiglottic entrapment with abnormal right arytenoid movement might decrease odds of racing post‐operatively.

Highlights of recent clinically relevant papers

“…This retrospective study by Alexandra Curtiss and colleagues in the USA aimed to evaluate the racing performance of horses treated surgically for epiglottic entrapment as yearlings compared to their maternal half‐siblings .…”

Clinical insights: Upper respiratory tract obstruction

“…A retrospective study of epiglottic entrapment identified and treated in 66 Thoroughbred yearlings supports early diagnosis and treatment of URT disorders . Investigating whether yearlings diagnosed and surgically treated for epiglottic entrapment were less likely to race as compared to maternal half‐siblings with no identified URT abnormalities, medical and racing records were reviewed, with pre‐ and post‐surgical endoscopic images available for most horses.…”