Effects of Jugular Vein Occlusion on Cardiovascular Parameters in Horses During Exercise on a Treadmill

Abstract

a b s t r a c tThe purpose of the present investigation was to examine the effects of unilateral and bilateral jugular vein occlusion by temporary surgical ligature on the heart rate and arterial and venous blood pressure in sedentary horses during progressive treadmill exercise. Six horses performed three exercise tests (ET). ET1, considered the control, was performed in horses without jugular occlusions. ET2 and ET3 were performed with unilateral and bilateral occlusion by temporary surgical ligature of the jugular veins, respectively. Heart rate, arterial pressure, and pressure of the occluded jugular vein were evaluated. Clinically, the horses presented apathy, head edema, congested mucous membranes, increased capillary refill time, and dysphagia. These signs were observed with the unilateral jugular vein occlusion and became more evident with the bilateral occlusion. Comparing ETs, no differences were observed in heart rate. However, jugular occlusions promoted a decrease in the mean arterial pressure and a severe increase in jugular pressure. Head edema caused by the jugular vein occlusion in the horses could interfere with the autonomic cardiovascular regulation of arterial blood pressure during exercise, likely leading to an impairment of tissue perfusion. Jugular occlusion, even unilateral, also causes severe head venous congestion, leading to venous hypertension that was aggravated by exercise, which could risk development of cerebral edema and neurological damage. The present results obtained from sedentary horses are preliminary data that lead us to suggest that sport horses presenting jugular occlusive thrombophlebitis, even unilateral, may be prevented from performing athletic activities.

Blood gases of horses subjected to jugular vein occlusion during treadmill exercise

“…This condition may evolve to recanalization of the vein when blood flow is restored, or the thrombus may become fibrous, resulting in permanent occlusion, either followed by the development of collateral circulation or not (LANKVELD et al, 2001;MOREAU;LAVOIE, 2009;RUSSELL et al, 2010;HUSSNI et al, 2012;DIAS et al, 2014). If the horse resumes its physical activities while presenting a jugular thrombotic occlusion, and collateral vascularization does not occur, its performance is suspected to be limited (MOREAU;LAVOIE, 2009;DIAS et al, 2013). The objective of the present study was to examine the effects of unilateral and bilateral jugular vein occlusion via temporary surgical ligature on the arterial blood gases of sedentary horses during progressive exercise on a treadmill, with the aim of understanding these effects in athletic horses presenting jugular thrombophlebitis.…”

“…Blood gas analysis was performed as a complement to an experimental protocol for studying hemodynamics in horses during treadmill exercise (DIAS et al, 2013). Thus, some procedures were similar, including the surgical technique to occlude jugular veins.…”