Right heart failure due to pulmonary hypertension after mitral valve repair in a dog

Abstract

A 14-year-old castrated male Shih Tzu weighing 5.4 kg presented for refractory pulmonary edema evaluation. The dog was diagnosed with myxomatous mitral valve disease, ACVIM guidelines stage D with an intermediate probability of pulmonary hypertension. Four months after the initial visit, the dog underwent surgical mitral valve repair. The dog recovered well from surgery and was discharged 4 days after the procedure without complications. One month after surgery, the dog presented for ascites and multiple episodes of syncope. The dog was diagnosed with right sided congestive heart failure due to pulmonary hypertension and died 69 days after mitral valve repair from apparent respiratory distress despite aggressive medical treatment, including sildenafil, furosemide, and pimobendan. While the cause of this patientʼs pulmonary hypertension remains unknown, pulmonary thromboembolism was suspected based on blood coagulation tests and clinical course. This case suggests that increased age and preoperative tricuspid regurgitation severity might be associated with postoperative pulmonary hypertension.