Although a previous study (Tangmahakul et al. 2023) reported that there were not statistically significant changes in RBC indexes (except MCH and MCHC) in dogs with MMVD complicated with pulmonary hypertension, whether the presence and severity of pulmonary hypertension and mitral regurgitation can affect on CBC indices such as NLR and RDW/PLT ratio needs to be clarify with further studies. This evidence concerns the gene PMCH and pulmonary arterial hypertension.