Pulmonic stenosis is an abnormal narrowing of the pulmonary artery. The pulmonary arterty is the major vessel of the heart that carries blood away from the heart and to the lungs to be oxygenated. This is a relatively common congenital defect in dogs. In moderate to severe cases there is restricted blood flow to the lungs during exercise which can lead to exercise intolerance, collapse and fainting.
Because of restricted blood flow out of the heart, the right side of the heart enlarges to handle the increased work load. Some animals develop tricuspid regurgitation and/or right heart failure secondary to the changes in the right heart. Signs of right heart failure in animals include exercise intolerance, collapse, fluid accumulation in the abdomen (ascites), fluid accumulation in the chest cavity (pleural effusion), increased respiratory effort and rate and abdominal distension.
The treatment for pulmonic stenosis depends on the severity of the disease. In mild to moderate cases the animal is often asymptomatic and has a normal life span. In more severe cases the animal develops exercise intolerace, right heart failure, arrhythmias, and may experience sudden death.
A procedure called balloon valvuloplasty is often recommended for animals with moderate to severe disease. In this procedure a balloon catheter is inserted into the heart through the jugular vein, and is used to dilate the obstruction/stenotic area. This procedure helps to decrease the pressures in the right heart before heart failure develops, and is often performed as a prophylactic procedure. It is possible to perform a balloon angioplasty in animals that have experienced heart failure, but it can be difficult to stabilize the animal sufficiently to undergo anesthesia if the animal is in right heart failure.
Changes in the heart can be seen on echocardiogram, electrocardiogram, and chest radiographs (x-rays). It is important to follow up with your cardiologist if you notice any changes in your pet’s health, including any signs of right heart failure. A repeat echocardiogram is usually recommended 6 months following diagnosis.