Pulmonary hypertension in dogs with myxomatous mitral valve disease

Pulmonary hypertension (PH) is a clinically significant and increasingly recognized complication of myxomatous mitral valve disease (MMVD) in dogs, contributing to worsening morbidity and mortality. The development of PH in the context of MMVD is associated with increased symptom burden, including exercise intolerance, syncope, and respiratory distress, and has been correlated with reduced survival times. Echocardiography is the primary modality for detection and monitoring, relying on Doppler estimation of tricuspid regurgitation velocity, but limitations in sensitivity and accuracy remain. Therapeutic strategies typically focus on management of the underlying MMVD and heart failure and to control left atrial pressure, with diuretics, angiotensin-converting enzyme inhibitors, and pimobendan. Sildenafil and other pulmonary vasodilators have been used with variable clinical benefits in dogs with MMVD and concurrent PH, though evidence remains limited and sometimes conflicting. Prognosis is influenced by both severity of valve disease and degree of pulmonary vascular involvement, underscoring the importance of timely recognition and individualized management. Understanding the interplay between MMVD and PH is critical for optimizing outcomes, guiding treatment decisions, and informing future clinical research in veterinary cardiology.