Echocardiographic Characterization of Aortic Valve Cusps: Baseline Reference Values in Healthy Dogs and Structural Remodeling in Systemic Hypertension

Systemic hypertension (SH) is increasingly recognized in dogs and is associated with aortic valve cusp remodeling. Therefore, the present study was planned with the objective of establishing baseline echocardiographic reference values for aortic cusp diameters in healthy dogs and to evaluate cusp remodeling associated with SH. Echocardiographic measurements were performed in 46 healthy dogs (26 large breed, 20 small-medium breed) and 80 clinically ill dogs, classified according to systolic blood pressure (BP) as normotensive (≤139 mmHg), prehypertensive (140-159 mmHg), hypertensive (160-179 mmHg), or severely hypertensive (≥180 mmHg), with 20 animals in each group. Two-dimensional echocardiography was used to assess left (LAC-d), right (RAC-d), and noncoronary cusp diameters (NCC-d); mean cusp diameter; and aortic root dimensions (diameters at aortic annulus, sinus of Valsalva, sino-tubular junction, and proximal ascending aorta). Cusp asymmetry was determined using an asymmetry index (≥10% variation) and subjective variation (≥2 mm). Hypertensive dogs demonstrated enlargement of all cusps compared with controls, with cusp diameters correlating positively with systolic BP (LAC-d: r = 0.39; RAC-d: r = 0.37; NCC-d: r = 0.33; p < 0.001). The LAC-d and RAC-d exhibited the best diagnostic performance (sensitivity 80%-82.5%, specificity 76.9%-78.6%). Hypertensive dogs also had increased cusp asymmetry, particularly RAC asymmetry in severe hypertension (40% vs. 10.9% in healthy dogs; p = 0.004). Sinus of Valsalva diameter was the strongest predictor of cusp enlargement. Echocardiographic measurement of aortic cusps provides novel reference values for healthy dogs and demonstrates hypertension-associated cusp remodeling. The LAC-d and RAC-d are reliable markers for identifying and monitoring hypertensive cardiac changes.