The EPIC Trial reported three cardiac size inclusion criteria including radiographic vertebral heart size (VHS) >10.5, and echocardiographically derived normalized left ventricular internal dimension in diastole (LVIDDN) >1.7 and left atrial to aortic ratio (LA:Ao) >1.6 as measured by the Swedish method. However, echocardiography may not always be available and, therefore, there is interest in identification of a VHS cutoff that predicts EPIC echocardiography inclusion criteria (EPIC-ECHO+) in dogs with preclinical myxomatous mitral valve disease (MMVD). Medical records from 8 sites were searched for MMVD cases that had contemporaneous thoracic radiographic and echocardiographic studies. A total of 247 cases were identified and descriptive statistics are reported as mean, median, and interquartile range for VHS (11.4, 11.2, 10.8–11.9), LVIDDN (1.80, 1.79, 1.58–2.05), and LA:Ao (1.78, 1.69, 1.42–2.06). Dogs that were EPIC-ECHO+ (N=126) were identified and compared to the remaining population (N=121). Receiver operator curves were constructed for VHS and performance was explored for optimal cutoffs. The percent correct, sensitivity, specificity, false positive and negative rates for a VHS of 11.1 (72%, 0.730, 0.707, 12%, 16%), 11.7 (60%, 0.439, 0.85, 6%, 34%) and 11.9 (58%, 0.365, 0.90, 4%, 38%) were determined. Based on these data, dogs with MMVD and a VHS >11.7 have a high likelihood of meeting EPIC-ECHO+ (85% specificity) and an acceptable false positive rate (6%), however, approximately 34% dogs with a VHS between 10.6–11.7 may meet EPIC-ECHO+ and warrant further echocardiographic evaluation. These results may help veterinarians apply the results of the EPIC Trial to dogs with preclinical MMVD when an echocardiogram is not readily available.

Disclosures

Disclosures to report.
Drs. Vitt, Gordon, Estrada, and Achen have received funding from Boehringer Ingelheim Animal Health GmbH and IDEXX Laboratories within the last 5 years for some or all of the following activities: research, travel, speaking fees, consultancy fees, and preparation of educational materials. No funding was provided by Boehringer Ingelheim for this study and is a retrospective evaluation, so no funding was used. The statistical analysis was also performed by an independent party.