Age-related differences in blood pressure, ultrasound-derived arterial diameters and arterial wall stiffness parameters in horses.
Authors: Vera Lisse, Van Steenkiste Glenn, Decloedt Annelies, Chiers Koen, van Loon Gunther
Journal: Equine veterinary journal
Summary
Arterial rupture represents a significant mortality risk in older horses, yet the vascular changes underlying this age-related vulnerability remain poorly characterised. Lisse and colleagues examined 50 young (3–7 years) and 50 aged (>18 years) Warmblood horses using non-invasive tail-cuff blood pressure measurement and ultrasound assessment of the aorta, common carotid and external iliac arteries, calculating both regional stiffness (via pulse wave velocity) and local wall mechanics (strain, compliance, distensibility). Whilst systemic blood pressure remained unchanged between age groups, older horses demonstrated significantly enlarged arterial lumens and thickened intima-media layers across measured vessels, accompanied by substantially increased arterial wall stiffness in the aorta and caudal common carotid artery—though notably not in the external iliac artery. The findings suggest that age-related arterial remodelling—characterised by simultaneous luminal expansion, wall thickening and increased stiffness—creates a biomechanical environment predisposing to catastrophic rupture, independently of elevated blood pressure. For practitioners, these insights reinforce the heightened vulnerability of geriatric horses to aortic and carotid rupture events and may inform clinical assessment protocols, particularly given that the external iliac artery's relative sparing suggests regionally heterogeneous ageing effects that warrant further investigation.
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Practical Takeaways
- •Older horses (>18 years) develop stiffer, enlarged arteries with thickened walls—monitor senior horses more closely for signs of vascular compromise
- •The increased arterial stiffness combined with luminal enlargement in aged horses may predispose them to rupture, suggesting careful management of cardiovascular stress in seniors is important
- •Normal blood pressure values do not guarantee healthy arteries in older horses; structural changes occur independently of pressure, so age alone warrants enhanced clinical vigilance
Key Findings
- •All arterial dimensions and intima-media thickness were significantly larger in horses >18 years compared to 3-7 year old horses
- •Local arterial wall stiffness was significantly higher in the aorta and caudal common carotid artery in older horses
- •Aortic and carotid pulse wave velocities were higher in older horses, indicating increased regional arterial stiffness
- •No significant differences in blood pressure were detected between young and old horses despite structural arterial changes