Using blood lactate tests to check heart disease in dogs with mitral

Abstract

INTRODUCTION: Myxomatous mitral valve disease (MMVD) is a chronic cardiac condition that can have serious hemodynamic consequences and therefore requires lifelong monitoring. However, although echocardiography remains the gold standard for diagnosis and staging, its repetition at short intervals to assess therapeutic response can be limited by cost, logistics, and patient tolerance. In this context, biomarkers such as lactate could serve as a complementary tool to reflect clinical status and prognosis. This study aimed to evaluate the clinical utility of point-of-care (POC) whole blood lactate measurement in dogs with MMVD, with a particular focus on its ability to reflect clinical status within American College of Veterinary Internal Medicine (ACVIM) stages B2 and C. METHODS: This retrospective observational study included 33 client-owned dogs with MMVD examined between June 2025 and November 2025. The population had a mean age of 13.6 years and mean body weight of 4.3 kg. Dogs were classified according to ACVIM stage and clinical status at presentation into three groups: Stage B2 (=13), Stage C with controlled congestive heart failure (CHF) (=13), and Stage C with acute decompensated CHF (=7). Whole blood lactate concentrations were measured using a portable lactate meter (StatStrip Xpress) via paw pad capillary sampling within approximately 5-minute of acclimatization. RESULTS: Whole blood lactate concentrations differed significantly among the three groups (= 0.002). The Stage C with acute decompensation CHF group exhibited a markedly higher mean lactate concentration (5.61 &#xb1; 1.98 mmol/L) compared to the Stage B2 (2.17 &#xb1; 0.95 mmol/L) and Stage C with controlled CHF (2.50 &#xb1; 1.04 mmol/L) group (= 0.002). In contrast, no significant difference was observed between the Stage B2 and Stage C with controlled CHF groups (= 0.456). In receiver operating characteristic (ROC) analysis for distinguishing dogs with hemodynamic instability, the area under the curve (AUC) was 0.94 (95% CI: 0.85-1.00,< 0.001). At a cut-off value of 3.0 mmol/L, the assay demonstrated 100% sensitivity, 72% specificity, and a 100% negative predictive value (NPV). Lactate concentrations &#x2265; 3.0 mmol/L were observed in 2 of 13 dogs (15.4%) in the Stage B2 group, 3 of 13 dogs (23.1%) in the Stage C with controlled CHF group, and 7 of 7 dogs (100%) in the Stage C with acute decompensated CHF group. DISCUSSION: POC whole blood lactate measurement can serve as a valuable adjunctive screening tool for assessing clinical management status and acute hemodynamic condition in dogs with MMVD. However, lactate values approximating the identified cut-off of 3.0 mmol/L should not be interpreted as a binary decision threshold. Instead, values in this range indicate a zone of increased clinical uncertainty, warranting closer monitoring and hemodynamic reassessment in conjunction with standard clinical evaluation.