Use of oversized injectable valves in growing children for total repair of right ventricular outflow tract anomalies (preliminary results)

Abstract

Right ventricular outflow tract surgery was originally confined to transannular patching, in the belief that pulmonary regurgitation was well tolerated. Because follow-up evaluations revealed the deleterious effects of pulmonary regurgitation, surgery today aims to spare or replace the valve. Available replacement devices have short lifetimes, considering growth mismatch in children. We hypothesize that oversizing the right infundibulum anticipates growth and that a squeezed prosthesis can complete the expansion process. The No-React® Injectable BioPulmonic Valve is designed for right infundibular surgery in adults, and hundreds of implants have shown promising results. We used this device for surgery in babies, with the addition of an innovative oversizing technique. This study evaluates our preliminary results and investigates whether such a technique might reduce growth mismatch. From September 2010 through July 2012, we implanted 11 injectable pulmonic valves. The median age of our patients was 23 months. After opening the right infundibulum, we enlarged it as much as possible with a wide patch. Before completing the patch suture, we injected an oversized valve. No problems occurred during surgery. No major insufficiency or leak was observed. We conclude that prostheses can be quite oversized and perform well even when not completely expanded. Oversized injectable pulmonic valves, shrunken to a smaller diameter, enabled the implantation of a device wider than otherwise possible, without affecting performance. Moreover, the prosthesis tended to return to its original size following growth, thereby reducing growth mismatch. Longer follow-up and larger numbers of patients are needed for verification.

Keywords: Bioprosthesis; cardiac surgical procedures/methods/pediatric; child; constriction, pathologic; heart defects, congenital; heart valve prosthesis implantation; infant; prostheses and implants; pulmonary regurgitation; pulmonary valve insufficiency; pulmonary valve/abnormalities/surgery; right ventricular outflow tract; time factors; treatment outcome; ventricular outflow obstructions.

Fig. 1.

A) Intraoperative photograph shows the BioPulmonic valve injected into the right ventricular outflow tract. The enlarged tract is seen from the cephalic perspective. The enlargement patch has been sutured onto the pulmonary trunk, and the infundibular suture is yet to be completed. B) The same valve is shown from the caudal perspective. The prosthetic cusps are closed.

Fig. 2.

A) Schematic drawing of the BioPulmonic valve. Porcine aortic cusps have been sewn inside a porcine pericardium conduit. The device is completed by a nitinol self-expanding stent, located outside the conduit. B) Schematic drawing of the introducer, which consists of a trocar and a plunger. After the trocar has received the crimped BioPulmonic valve, the plunger is inserted and pushed to eject the valve from the trocar tip.

Fig. 3.

Axial computed tomogram at 18-month follow-up shows the stent of a 16-mm BioPulmonic valve in the enlarged right ventricular outflow tract and a completely expanded prosthesis.

Fig. 4.

Three-dimensional computed tomograms of the pulmonary artery. A) This anterior view, obtained at 17 months of follow-up, shows the stent of a 16-mm BioPulmonic valve in the enlarged right ventricular outflow tract. The suture line of the patch on the left pulmonary branch is evident (arrow). B) The right lateral view shows the suture line of the patch on the right pulmonary branch (arrow).