Often times, pulmonic stenosis is first identified during a routine examination. Listening to the heart with a stethoscope may reveal a loud murmur on the left side of the organ. An electrocardiogram will be needed to further test the heart's condition. X-rays will then be taken to see if the heart has begun to enlarge, and an echocardiogram will be used to assess how severe the defect is. Blood work will then be run to determine the overall health of the dog, and decide whether general anesthesia can be used or not.
The dog will be required to fast for several hours preceding the operation. The dog will then be sedated and its chest will be shaved and cleaned. For a patch-graft valvuloplasty, an incision is made to the middle of the chest. The dog's temperature must be lowered somewhere between 30 and 32° celsius to proceed with the surgery. The veins leading to the affected area must be tied off to stop all blood flow.
The patch-graft can then be sutured to the incision and the pulmonary artery. The abnormal valve leaflets may then be removed or the artery passage surgically widened. The artery can then be sutured shut and attached to the patch-graft. This process can take up to three hours. The clamps stopping blood flow may then be removed, and the heart can be massaged if resuscitation is needed.