Quantitative Echocardiographic Evaluation of Mitral Endocardiosis in Dogs Using Ratio Indices

Abstract

This study compares M-mode echocardiographic ratio indices (ERIs) in dogs with mitral regurgitation due to chronic valvular disease (CVD/MR) for their ability to discriminate and quantify associated echocardiographic changes. Weight-based M-mode ERIs were determined retrospectively for 2 groups of dogs, normal (n = 47) and CVD/MR (n = 176). The CVD/MR group was further subdivided into those with (CVD/MR B, n = 74) and without (CVD/MR A, n = 102) left-sided congestive heart failure (LCHF). ERIs were compared descriptively (summary statistics) and also by receiver-operator characteristic curve areas (ROCAs) for their ability to discriminate between groups. Univariate logistic regression (LR) models were used to estimate the odds ratio for each ERI as a predictor of the CVD/MR condition as well as to predict LCHF within the CVD/MR group. A novel ERI (wdeltaA), designed to express body size-normalized short-axis stroke area, was sensitive (90%) and specific (98%) to discriminate between normal and CVD/MR at a cutoff value of 1.8 standard deviations (wdeltaA = 2.1). Prediction of LCHF within the CVD/MR group was more problematic, but an ERI expressing left atrial size (wLA) showed 76% sensitivity and 81% specificity at a cutoff value of 5.2 standard deviations (wLA = 1.55). Ours was a descriptive study of echocardiographic patterns of pathology associated with CVD/ MR and determined which ERIs are sensitive and specific for CVD/MR and for LCHE ERIs normalize echocardiographic data for body size in dogs and are well-suited to quantitative descriptions and analysis.

Effects of Dietary Modification in Dogs with Early Chronic Valvular Disease

“…The cardiac diet group also had significant reductions in dimensions of the left atrium and left ventricle and in the change in left ventricular internal area (wDA), which is the most likely echocardiographic measurement to be increased in dogs with CVD. 23 These echocardiographic changes were not seen with the low-sodium run-in diet alone (ie, from visit 1 to visit 2) or with the placebo diet from visit 2 to visit 3. The fact that these changes were not seen with the low-sodium run-in diet, which had a lower sodium content than the cardiac diet, suggests that the effects on cardiac measurements were not the result of sodium restriction alone.…”

Echocardiographic Ratio Indices in Overtly Healthy Boxer Dogs Screened for Heart Disease

“…They are derived by indexing echocardiographic measurements to a weight-based predicted aortic dimension, which serves as an ''internal yardstick'' for comparison of cardiac dimensions among individuals of various sizes. Weight-based ERIs have been described for normal dogs 18 and dogs with chronic valvular disease, 19 and may be useful for studying morphologic differences in cardiac structure in dogs within and across various dog breeds. Boxer dogs were excluded from analysis in the previous ERI publications because they were recognized at that time to have M-mode echocardiographic characteristics that may not conform with those of other dogs.…”