C15 - CANCELLED: Echocardiographic Dimensions of the Aortic Root in Healthy Dogs: Reference Values by Anatomical Site

Abstract:

Background: The aortic root is commonly used as a reference structure in canine echocardiography. Accurate aortic measurements are therefore essential. However, normative data across different anatomical sites are limited, and single-site measurements may not capture anatomical variability.
Hypothesis/

Objectives: aortic root diameters in healthy dogs vary significantly according to the anatomical site evaluated.
Animals: Forty-five healthy client-owned dogs of various breeds, body sizes, and ages.

Methods: Prospective cross-sectional study. Two-dimensional echocardiography was performed using a right parasternal long-axis view optimized for visualization of the left ventricular outflow tract. Aortic diameters were measured at four anatomical sites: aortic annulus, sinus of Valsalva, sinotubular junction, and proximal ascending aorta. Measurements were obtained at end-diastole and mid-systole, in triplicate. Values were indexed to body weight and body surface area (BSA). Correlation and linear regression analyses were performed, and intra- and interobserver reproducibility were assessed using intraclass correlation coefficients (ICC).

Results: No differences were identified between sexes or cardiac cycle phases at any anatomical site (p>0.05). Aortic diameters showed strong positive correlations with body size, with BSA demonstrating the strongest association (R²=0.77–0.85). The sinus of Valsalva exhibited the largest diameters and accounted for most inter-site variability. Intraobserver reliability was excellent for all measurements (ICC>0.90), while interobserver reliability ranged from moderate to excellent.
Conclusions and Clinical Importance: Aortic root dimensions in dogs are dependent on anatomical site and body size. Although body weight influenced aortic measurements, BSA showed the strongest association, supporting the use of BSA-adjusted reference values for standardized measurements and improved clinical interpretation.