Therapeutic effects of sildenafil combined with low-dosage imatinib on pulmonary hypertension in five dogs

Abstract

Five dogs were diagnosed with pulmonary hypertension (PH) secondary to chronic degenerative mitral valve disease or ventricular septal defect. They were initially administered low-dose imatinib mesylate (3 mg/kg, q24h) without changes to the background therapy to treat PH. The low-dose imatinib improved the right ventricular (RV) function parameters including estimated systolic and mean pulmonary arterial pressures (sPA and mPAP) and clinical symptoms. On day 53 to day 168 after imatinib administration, as PH and clinical signs worsened, low-dose sildenafil (0.5 mg/kg, q12h) was administered in combination with imatinib. This combination greatly reduced the estimated sPA and mPAP, and improved clinical symptoms and RV function parameters without worsening left ventricular function. A low-dose imatinib and sildenafil combination may provide a promising treatment alternative for canine PH.