Patch-Graft Valvuloplasty in Dogs

A patch-graft valvuloplasty is a surgical procedure to help limit the effects of a very common heart defect in dogs, pulmonic stenosis. Dogs born with this deformity experience restricted blood flow to the heart, which can result in intolerance to exercise, a distended abdomen, stunted growth and fainting episodes. 

Only dogs who exhibit symptoms and whose systolic pressure gradient (the difference in pressure between two separate chambers of the heart) is more than 75mm require treatment. Without surgical intervention, these dogs have a heightened risk of dying suddenly from heart failure or developing progressive failure over time. The surgery uses a fabric, Gore-Tex patch to repair the affected ventricle wall after it has been widened. As this surgery requires the heart to be stopped for up to two minutes, it should be performed by an ACVS board-certified veterinary surgeon who specializes in complications of the heart.

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.

The overall effectiveness of this surgery heavily depends on how much of the obstruction has been fixed. It is a permanent treatment, but should be seen as a remedy and not a cure of pulmonic stenosis. If the procedure is successful, the risk of sudden or progressive heart failure will greatly be decreased. It has been found to decrease the systolic pressure gradient back into more normal ranges. A patch-graft valvuloplasty is more effective in small breeds. A balloon valvuloplasty may be preferred in some instances as it is less invasive to the dog. 

The dog should be closely monitored as the anesthesia wears off. Its heart will be closely monitored during this time, to ensure regular activity is present. The incision will be bandaged and a chest wrap will be used to keep the dressings in place. Pain medication will need to be administered for several days following the operation. An echocardiogram will be run right after the surgery, and again on the following day. In one to three months’ time, another echocardiogram will be required to assess if the surgery was successful. Sutures will need to be removed two weeks after the operation. Overall, this procedure carries a fast recovery time.

Heart surgery has the potential of being high in cost. If there are no complications, the total price of a patch-graft valvuloplasty may range from $2,000 to $6,000. If it is deemed that a heart-lung machine is needed, the cost may triple. Medication, special diagnostic imaging, and an electrocardiogram are all needed in the preparation and maintenance of this procedure. In addition to this, a specialist is often required to perform the operation, which tends to cost more than if a standard veterinary surgeon was to complete it. In mild cases, medication alone may be enough to give the dog a normal life, however, regular vet visits will be needed to see if the condition is worsening. 

As with all surgeries, the use of general anesthesia can result in serious reactions in the dog. The overall lifespan of the affected dog may not greatly increase with surgery, especially in dogs with very severe defects. If the dog's heart has become enlarged, it may also be anemic, which complicates sedation as the heart must beat harder to compensate. There is also the possibility that the dog will suffer from a heart attack during the procedure due to arrhythmias. An owner may chose to delay surgery, opting to monitor the dog closely until its condition worsens.

Dogs who carry deformities of the heart should be kept from breeding. Once the defect is present, nothing can be done to naturally reverse it. That being said, keeping your dog as healthy as it can be with a high quality diet and moderate regular exercise may decrease the chance of heart failure. It is also imperative to keep your dog at the proper weight, as overweight dogs suffer from more complications than normal and underweight dogs. 

Breeds that are most commonly affected by this defect include bull mastiffs, English bulldogs, cocker spaniels, Samoyeds, boxers and various terriers. The Boykin spaniel is plighted with a hereditary version of pulmonic stenosis. When obtaining a dog, always request its full family health history. If your puppy is diagnosed with pulmonic stenosis, continue to closely monitor its condition with regular visits to the veterinarian.