Exercise-induced pulmonary perfusion redistribution in heaves.

The study is about comparing the differences in blood flow distribution in the lungs of healthy horses versus horses with “heaves” during exercise, using a minimally invasive technique called scintigraphy.

Research Methodology

• The study involved a comparison between six healthy horses (Group A) and five horses with heaves, which is a chronic airway condition similar to asthma in humans, both when the disease was dormant (B(I)) and active (B(II)).
• The researchers used scintigraphy, a diagnostic imaging technique that uses radioactive substances to visualize and examine the functioning of body organs. This approach is considered minimally invasive.
• They examined the exercise-induced pulmonary perfusion (QE), which refers to the blood flow in the lungs during exercise, and it was expressed as a percentage of the resting perfusion (QR), which is the blood flow in the lungs when the horse is at rest.
• After that, they calculated the ratio of QE to QR, which helped in defining the region in the lungs that is more perfused during exercise than at rest (R1).

Findings

• All groups showed a major increase in the QE image during exercise; this signifies that exercise leads to increased blood flow in the lungs. However, a larger increase was observed in the lung height of ‘heavey’ horses.
• In comparison to group A, horses with heaves showcased a larger R1 region with a significantly higher QE/QR ratio. This implies that horses with heaves have more blood flow redistribution in their lungs during exercise.
• The region of R1, the area more perfused during exercise, was found to be mainly in the dorsal lung region for all groups, suggesting that this region is the primary area for pulmonary perfusion redistribution during exercise.

Conclusions

• The research proves the effectiveness of scintigraphy in studying exercise-induced pulmonary perfusion redistribution.
• It shows that exercise leads to the redistribution of blood flow to the dorsal lung region.
• The study also highlights an intensified redistribution of pulmonary perfusion in horses with heaves, whether they are clinically affected or not.