AV Canal (Atrioventricular Canal Defect)
AV canal is short for atrioventricular canal defect. It is a relatively common form of congenital heart disease in which the middle portion of the heart does not form. It can be thought of as an apple which grew without its core, such that the core (middle portion) is missing. With the middle portion missing, blood is allowed to flow in different directions than would ordinarily be allowed and some of the valves are formed abnormally. Over time (months), this leads to heart enlargement and failure. In the era before safe cardiac surgery was possible, infants and toddlers would thus develop heart failure and almost all would die from this disease.
Thankfully, surgery can now be safely performed in the vast majority of cases with patients expected to live full and active lives. Surgery for AV canal, however, remains a major cardiac operation that requires heart surgeons specifically trained in infant heart surgery. There are many different sub-types of AV canal, and it is important to be treated in a program with experience in imaging and treating all forms. The goal of surgery is to achieve a complete repair, whereby all the defects in the middle of the heart are patched closed (including an ASD and a VSD), and two of the heart valves must be repaired. This always requires an incision and the use of cardiopulmonary bypass.
For patch material, we prefer to use something called pericardium (the tough lining around the heart) or Gore-Tex (the durable material that rain jackets are made from). Both are time-tested materials which produce no problems for the child as they grow, even years later. The valves can require complex repair and this can be a difficult portion of the operation. Sometimes more than one operation is required to achieve complete repair, but most cases in the current era can be accomplished in one operation, and if your child requires a two-staged approach, the results are similar in the end.
Because of the intricate valve work required in the surgery, some children after complete repair of AV canal will continue to have valve related problems and some will require additional valve surgery. Although this is true only in the minority of patients (<5-10 percent in the published literature), this can be a few years later or many years later, and you or your child should have regular follow-up examinations after surgical repair.
At Rady Children’s Hospital-San Diego, we have been treating AV canal defect for more than 30 years, and our surgeons have been specifically trained in these types of complex infant operations. From 2009-2013 alone, we have performed complete repair on more than 80 AV canal operations with over a 98 percent survival. During this time period we have also performed additional valve surgery for children, teenage or young adult patients who had previously had their AV canal defects repaired here or elsewhere (see teenage and adult congenital heart surgery).