Splenectomy alters blood pressure response to incremental treadmill exercise in horses.

This research investigated how the removal of the spleen (splenectomy) affects the blood pressure response in horses during incremental exercise. The results showed that, while the heart rates increased in both intact and splenectomized horses, the increase was significantly higher in the splenectomized horses during the initial exercise stages. However, the right atrial pressure did not change in splenectomized horses but increased in intact horses.

Methodology

• The study involved six horses with intact spleens (IN) and five horses that had undergone splenectomy (SP).
• These horses were subjected to an incremental exercise test, during which they ran uphill on a treadmill with a 6-degree incline.
• The initial speed was set at 4 m/s, with the speed increasing by 1 m/s every minute until the horse’s heart rate plateaued.
• Various data were collected and analyzed for the last 18 seconds of each exercise stage (at 4, 5, 6, and 7 m/s).

Findings

• The average resting points of all parameters studied showed no significant differences between the two groups.
• However, during exercise, the heart rates of both groups increased, with a significantly greater increase seen in the splenectomized horses during the initial stages of the test.
• Despite this, there were no significant differences in the maximum heart rate between the two groups.
• The right atrial pressure (RAP) in the splenectomized horses saw no change during exercise, while the intact horses experienced a significant increase.
• Meanwhile, the right ventricular pressure (RVP) increased for both groups during exercise, with no notable differences between them.
• The mean arterial pressure (MAP) increased by 30% (or 29 mmHg) in the splenectomized horses, with the increase plateauing by the 5 m/s exercise stage.

Conclusion

• This research shows that splenectomy can alter the blood pressure response during incremental treadmill exercise in horses.
• This has potential implications for how exercise is managed and monitored in horses that have undergone splenectomy, and further research may be required for more concrete dietary and training implications.