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.
Surgery
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).
Overall, timely diagnosis and management of AV canal defects are crucial to prevent complications and ensure optimal outcomes for pediatric patients with congenital heart defects. Organizations like the Nemours Foundation play a vital role in raising awareness, providing resources, and supporting research efforts to advance the treatment of complex heart conditions like AV canal defects.
AV Canal FAQs
1. What is AV canal defect, and how does it affect the heart?
AV canal defect, short for atrioventricular canal defect, is a common congenital heart disease where the middle portion of the heart doesn’t form properly. This leads to abnormal blood flow and valve formation, eventually causing heart enlargement and potential failure.
2. How is AV canal defect typically addressed?
Surgery is the primary treatment for AV canal defect. It involves patching the defects in the heart’s middle part, closing atrial and ventricular septal defects and repairing faulty heart valves.
3. Why is it essential to undergo surgery for AV canal defect?
Surgery is crucial for AV canal defect as it aims to achieve complete repair, ensuring that the heart functions efficiently and prevents complications like heart failure.
4. What materials are commonly used for patches in AV canal defect surgery?
Pericardium and Gore-Tex are often used as patch materials during AV canal defect surgery. These materials are durable and pose no long-term issues as the child grows.
5. What follow-up care is necessary after surgical repair of AV canal defect?
Regular follow-up examinations are vital after surgical repair of AV canal defect to monitor valve function and detect any potential issues early on. In some cases, additional valve surgery may be required, though this is uncommon.