Inflammatory Biomarkers Are Associated with Left Atrium Sizes and Pulmonary Diameter in Mitral Valve Degeneration Dogs

Mitral valve regurgitation (MR) remains a common health problem in dogs. The typical pathophysiological consequences of mitral valve diseases, regardless of the etiology, are left atrial (LA) dilatation and pulmonary hypertension (PH). Medical records of dogs diagnosed with mitral valve disease between June 2023 and June 2025 were retrospectively reviewed. Mitral valve cases were evaluated for signalment, blood profiles, echocardiographic parameters, and survival. Client-owned dogs (n = 94) had a mean age of 11.18 ± 2.9 years; 46.8% were males with MMVD stages B to D, as assessed using the ACVIM consensus guidelines (2019). LA volume was evaluated using the Simpson biplane method. PH was defined on the basis of transthoracic echocardiography. Dogs were followed monthly and underwent a physical examination, blood work, and echocardiogram assessment. Ninety-four dogs had a history of left atrial dilation, which was present in 84.0% of cases. Left ventricular (LV) fractional shortening was 33.37 ± 8.41%. The LA volume and MR SV were 5.87 ± 4.21 ml and 1.28 ± 2.09 mm², respectively. Age, body weight, left ventricular end-diastolic volume, left atrial volume, and mitral valve stroke volume were univariately associated with both the CRP level and the NLR. The CRP level and NLR were related to LA volume according to correlation analyses using Pearson’s r (P < 0.01), yet the NLR was not predictive of pulmonary hypertension according to univariate models. In this population of dogs at high risk for developing pulmonary hypertension, the CRP level and NLR were associated with left atrial (LA) volume and were not predictive of pulmonary hypertension. In contrast, the indexed LA volume was related to clinical risk factors for predicting the development of pulmonary hypertension. CRP demonstrated good diagnostic performance with a statistically significant discriminatory ability, whereas the NLR showed limited diagnostic value with no statistical significance. Higher CRP levels and NLRs were associated with a decreased survival probability, and canine patients without pulmonary hypertension had significantly better outcomes at lower biomarker levels. CRP levels and the NLR may serve as valuable prognostic markers, particularly in non-PH populations.