Echocardiographic classification of dogs with aortic stenosis: potential utility of a novel staging system.

Introduction: Severity of aortic stenosis (AS) in humans is classified using a staging system based on two-dimensional echocardiographic changes, which considers the extent of global cardiac damage. Currently, classification of canine AS is based on trans-aortic pressure gradient (PG) alone. This study aimed to retrospectively classify dogs with AS based on an adapted human staging system, exploring feasibility of classification and the association between stage and features such as PG and clinical signs.

Animals: This study included 87 client-owned dogs.

Materials And Methods: Clinical and echocardiographic data were retrieved from computerised records. Dogs were classified according to a modified human staging system (stages: 0/1/2+). Descriptive statistics were explored. Differences in signalment, PG, and clinical signs between stages were evaluated using appropriate statistical tests. Significance was identified if P<0.05 after correction for multiple comparisons.

Results: Forty-one dogs were classified as stage 0, 36 as stage 1, and 10 as stage 2+. No difference in signalment or weight was identified between stages. Dogs classified as stage 2+ were more likely to have clinical signs than those in stages 0 or 1 (50% vs. 7% [P=0.004] and 17% [P=0.043], respectively) and had a higher PG than dogs in stage 0 (90 mmHg [35-143 mmHg] vs. 25 mmHg [18-182 mmHg], P=0.001).

Conclusions: This study presents an alternative way to classify dogs with AS. Data support further study of the staging system to compare whether or not this classification has additional value over assessment of PG alone.