Exercise-induced pulmonary haemorrhage in the horses: results of a detailed clinical, post mortem and imaging study. VII. Ventilation/perfusion scintigraphy in horses with EIPH.

The research article investigates the correlation between observed symptoms in living horses with exercise-induced pulmonary haemorrhage (EIPH) and the findings from post mortem examinations. By using thoracic radiography and ventilation/perfusion scintigraphy, the study found that ventilation and perfusion deficiencies in the lungs and arterial issues within the affected horses align closely with evidence uncovered during post mortem examinations.

Methods and Participants

• The study involved a detailed clinical, post mortem and imaging examination on five live racing Thoroughbred horses with recent histories of EIPH.
• Both thoracic radiography and ventilation/perfusion scintigraphy (V/Q) were utilized as the primary methods for live scans and imaging.
• Using these techniques, images of Ventilation/Perfusion ratios for both the left and right lungfields were generated and used for further analysis.

Key Findings

• In all assessed horses, clear ventilatory and perfusion deficits were discovered specifically in the dorsocaudal areas of the lung. These findings had a strong correlation to previously observed radiographic lesions from post mortem assessments.
• In the affected lung areas, pulmonary arterial perfusion was more severely impaired. This finding is consistent with post mortem evidence of reduced pulmonary arterial perfusion and bronchial arterial dominance in these same areas.
• Ventilation deficits in these same regions also suggested a high probability of partial airway obstruction, which is in line with the small airway disease noted during previous post mortem observations.

Implications and Conclusions

• The study suggests that the vascular and airway lesions revealed during detailed post mortem examinations of horses with EIPH also have functional implications even when the horses are at rest.
• The long-term impact of EIPH appears to be severe due to the chronic, insidious, and progressive nature of lung and airway lesions associated with the condition. This affects the management of EIPH in horses, suggesting a need for strategic interventions to mitigate the issue.