Alteration of clinical parameters before mortality and prognostic outcomes of pulmonary hypertension in dogs with myxomatous mitral valve disease

Background: Myxomatous mitral valve degeneration (MMVD) is a prevalent canine heart condition often accompanied by pulmonary hypertension (PH). Echocardiography is a valuable diagnostic tool for MMVD, but its accessibility is limited in small veterinary clinics. Aim: This study aimed to identify clinical parameters and biochemistry and cardiac biomarkers as prognostic indicators for cardiac mortality in MMVD dogs with and without PH. Animals: Ninety-nine MMVD dogs and nineteen normal dogs. Methods: In a five-year longitudinal study, data including clinical and laboratory measurements as well as echocardiographic parameters were collected every 6 months. Dogs were monitored until death or loss to follow-up, and the cause of death was determined when possible. Statistical analysis was performed to identify factors that predicted death. Results: Alterations in body condition score, total protein, fractional shortening percentage, and mean corpuscular volume were predictive of impending cardiac mortality. High blood urea nitrogen-to-creatinine ratio, heart rate, and low hemoglobin levels were associated with an increased risk of death. N-terminal pro-B-type natriuretic peptide was also a significant predictor of cardiac-related mortality, with higher levels indicating increased risk. Moreover, MMVD dogs with PH had a significantly lower survival rate than those with MMVD without PH. However, no significant difference in survival was observed between MMVD stage C and D with PH and MMVD stage C and D without PH groups. Conclusion: These findings provide valuable insights into the monitoring of MMVD progression in dogs using clinical parameters and biomarkers, especially when echocardiography cannot be performed.