Severity of myxomatous mitral valve disease in dogs may be predicted using neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratio

OBJECTIVE To investigate the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) in dogs with myxomatous mitral valve disease (MMVD). ANIMALS 106 dogs with MMVD and 22 healthy dogs were included in the study. PROCEDURES CBC data were obtained retrospectively, and NLR, MLR, and PLR were compared between dogs with MMVD and healthy dogs. The ratios were also analyzed according to MMVD severity. RESULTS NLR and MLR were significantly higher in dogs with MMVD C and D (NLR of 4.99 [3.69–7.27]; MLR of 0.56 [0.36–0.74]) than in healthy dogs (NLR: 3.05 [1.82–3.37], P < .001; MLR: 0.21 [0.14–0.32], P < .001), MMVD stage B1 (NLR: 3.15 [2.15–3.86], P < .001; MLR: 0.26 [0.20–0.36], P < .001), and MMVD stage B2 dogs (NLR: 3.22 [2.45–3.85], P < .001; MLR: 0.30 [0.19–0.37], P < .001). The area under the receiver operating characteristic curves of the NLR and MLR to distinguish dogs with MMVD C and D from those with MMVD B were 0.84 and 0.89, respectively. The optimal cutoff value for NLR was 4.296 (sensitivity, 68%; specificity, 83.95%), and the MLR value was 0.322 (sensitivity, 96%; specific-ity, 66.67%). NLR and MLR were significantly decreased after treatment in dogs with congestive heart failure (CHF). CLINICAL RELEVANCE NLR and MLR can be used as adjunctive indicators of CHF in dogs.