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Equine veterinary journal2021; 54(2); 283-289; doi: 10.1111/evj.13448

Training related risk factors for exercise induced pulmonary haemorrhage in British National Hunt racehorses.

Abstract: Exercise induced pulmonary haemorrhage (EIPH) is an important condition of horses performing high intensity exercise, with reported prevalence among racehorses of up to 95%, based on the detection of blood on tracheobronchoscopy. Previously identified risk factors include age, sex, season, race type, years spent in racing and lower airway inflammation. Objective: To estimate the prevalence of EIPH in British National Hunt racehorses as indicated by two outcome measures: presence of tracheal blood on tracheobronchoscopy, and presence of moderate-large (significant) proportions of haemosiderophages in tracheal wash (TW) fluid; and to identify training-related risk factors for these indicators of EIPH. Methods: Prospective longitudinal study. Methods: Data from tracheobronchoscopy and TW cytology were analysed using univariable and multivariable mixed-effects logistic regression. Results: 1184 observations, from 177 horses, were analysed. The prevalence of tracheal blood was 7.2% (95%CI: 5.8, 8.8) and significant haemosiderophages in TW fluid was 36% (95%CI: 33.3, 38.8). Increased time in training was significantly associated with increased odds of EIPH. For each additional year spent in training the odds of tracheal blood and presence of significant proportions haemosiderophages increased approximately 1.5-fold (OR = 1.5; 95%CI: 1.1-2.0; P = .005; and OR = 1.5; 95%CI: 1.3, 1.8; P < .001, respectively). Current inflammation was associated with previous haemorrhage, but not current haemorrhage. Conclusions: There are no standardised measures for quantification of TW cytological parameters for EIPH diagnosis. Few horses were examined following jumping. Recent racing dates were not included in analysis. Conclusions: Increasing time in training was a risk factor for both indicators of EIPH. Current inflammation was associated with previous haemorrhage, but not current or future haemorrhage, suggesting that haemorrhage leads to inflammation but not that inflammation leads to haemorrhage. Overall, our findings are consistent with the capillary stress failure theory of EIPH. The development of standardised measures for TW cytological diagnosis of EIPH is warranted.
Publication Date: 2021-05-09 PubMed ID: 33843093DOI: 10.1111/evj.13448Google Scholar: Lookup
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  • Journal Article

Summary

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The research investigates the prevalence of Exercise Induced Pulmonary Haemorrhage (EIPH) in British National Hunt racehorses and identifies training-related risk factors impacting the likelihood of EIPH. It finds that longer training duration intensifies the risk of EIPH.

Objective and Methodology

The study aims to evaluate the occurrence of EIPH in British National Hunt racehorses utilizing two principal outcome measurements. These are the presence of tracheal blood visible on tracheobronchoscopy, and the presence of large amounts of haemosiderophages (a type of white blood cell) in the horse’s tracheal wash (TW) fluid. The research also indentifies training-related risk factors for these indicators of EIPH.

A prospective longitudinal study was conducted to facilitate the objectives. The study utilized data derived from tracheobronchoscopy and TW cytology, which was in turn studied using univariable and multivariable mixed-effects logistic regression.

Results

  • The research analysed 1184 observations, obtained from 177 horses. The resulting evaluation reported a gross prevalence of tracheal blood at 7.2% and significant presence of haemosiderophages in TW fluid at 36%.
  • An increased time spent in training was significantly correlated with the increased odds of EIPH. For every additional year spent training, the odds for tracheal blood and the presence of significant haemosiderophages approximately increased 1.5-fold.
  • Current inflammation was linked with previous instances of haemorrhage but did not seem to correlate with current or future haemorrhage.

Conclusions and Recommendations

  • The study expressed a need for standardized measurements for the evaluation of the cytological parameters used in the TW diagnosis of EIPH since none currently exist. It was also observed that few horses were examined following jumping, and recent racing dates were not included in the analysis.
  • An increased duration of training was pinpointed to be a risk factor for indicators of EIPH. Furthermore, while current inflammation was associated with previous haemorrhage, the research suggests that haemorrhage leads to inflammation but does not seem to trigger future haemorrhage. This supports the prevailing capillary stress failure theory of EIPH.
  • Finally, the research suggests the development of standardised measures for TW cytological diagnosis of EIPH would be extremely beneficial.

Cite This Article

APA
McGilvray TA, Cardwell JM. (2021). Training related risk factors for exercise induced pulmonary haemorrhage in British National Hunt racehorses. Equine Vet J, 54(2), 283-289. https://doi.org/10.1111/evj.13448

Publication

ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English
Volume: 54
Issue: 2
Pages: 283-289

Researcher Affiliations

McGilvray, Tegan A
  • The Royal Veterinary College, Hawkshead Lane, North Mymms, UK.
Cardwell, Jacqueline M
  • The Royal Veterinary College, Hawkshead Lane, North Mymms, UK.

MeSH Terms

  • Animals
  • Hemorrhage / etiology
  • Hemorrhage / veterinary
  • Horse Diseases / etiology
  • Horses
  • Longitudinal Studies
  • Lung Diseases / etiology
  • Lung Diseases / veterinary
  • Physical Conditioning, Animal / adverse effects
  • Prospective Studies
  • Risk Factors

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Citations

This article has been cited 3 times.
  1. Lo Feudo CM, Stucchi L, Conturba B, Stancari G, Zucca E, Ferrucci F. Medical causes of poor performance and their associations with fitness in Standardbred racehorses.. J Vet Intern Med 2023 Jul-Aug;37(4):1514-1527.
    doi: 10.1111/jvim.16734pubmed: 37148147google scholar: lookup
  2. Sugiyama F, Takahashi Y, Nomura M, Ebisuda Y, Mukai K, Yoshida T. Risk Factors for Epistaxis in Thoroughbred Flat Races in Japan (2001-2020).. Animals (Basel) 2023 Apr 14;13(8).
    doi: 10.3390/ani13081348pubmed: 37106911google scholar: lookup
  3. Lo Feudo CM, Stucchi L, Stancari G, Alberti E, Conturba B, Zucca E, Ferrucci F. Associations between Exercise-Induced Pulmonary Hemorrhage (EIPH) and Fitness Parameters Measured by Incremental Treadmill Test in Standardbred Racehorses.. Animals (Basel) 2022 Feb 12;12(4).
    doi: 10.3390/ani12040449pubmed: 35203157google scholar: lookup