Ultrasonographic assessment of abdominal aortic elasticity in hypertensive dogs

Background: Systemic hypertension (SH) is a persistent and pathological increase in arterial blood pressure (BP). Chronic SH leads to an increase in aortic (Ao) stiffness, and measuring Ao elasticity is useful for estimating Ao stiffness in humans. Currently, no literature in veterinary medicine describes noninvasive assessment of abdominal Ao elasticity in dogs with SH. Objective: Compare ultrasonographic-derived abdominal Ao strain (AoSt) between hypertensive (HT) and normotensive (NT) dogs. Animals: Fifty privately-owned dogs with clinical signs, conditions, or both potentially associated with SH. Methods: Prospective observational case-control study. Aortic stiffness was estimated by calculating AoSt as follows: AoSt = ([AoDs − AoDd]/AoDd) × 100, where AoDs and AoDd are the Ao diameter in systole and in diastole, respectively. Aortic stiffness was calculated from 2 different Ao transverse sections, the first caudal to the left renal artery (K_AoSt), and the second cranial to the external iliac arteries (I_AoSt). Results: Thirty-two dogs were included in the HT group and 18 in the NT group. Both K_AoSt and I_AoSt in HT dogs were significantly lower (P <.05) than in NT dogs (7.4 ± SD 3.6) vs 10.3 (±3.8) and 5.7 (interquartile range [IQR], 3.9-7.5) vs 8.1 (IQR, 7-10.3), respectively. Only K_AoSt was significantly influenced by age. Conclusions and Clinical Importance: Ultrasonographic Ao elasticity assessment was feasible to compare HT and NT dogs. Results indicated that K_AoSt and I_AoSt indices can be used to assess SH-related Ao stiffness, especially when indirect BP measurements are inconsistent or inaccurate. Additional studies to assess the AoSt in healthy dogs of various ages are needed.