Repair of Tetralogy of Fallot with Absent Pulmonary Valve Syndrome

The chest is entered through a median sternotomy and the thymus gland is removed. The pericardium is opened and a portion is harvested and placed in glutaraldehyde for later use. Examination of the external cardiac anatomy shows the main pulmonary artery to be slightly enlarged and the right and left pulmonary arteries to be quite dilated, equal to or larger in size than the aorta. The segmental branches of these vessels are small. For larger patients we utilize aorto-bicaval cannulation and continuous cardiopulmonary bypass. For smaller patients, especially those with small superior venae cavae, we place aortic and right atrial cannulae. The patient is then cooled to 18°C. During cooling, the branch pulmonary arteries are mobilized out to the hilar branches. The aorta is then cross-clamped and 30 mL/kg of cold blood cardioplegia is administered via the aortic root. We then perform the operation under circulatory arrest with 2-minute periods of intermittent perfusion every 15 minutes. Additional doses of cardioplegia are given at these times as well.

A longitudinal incision is made in the main pulmonary artery and continued proximally across the mildly to moderately hypoplastic pulmonary annulus and into the infundibulum of the right ventricle. This incision allows visualization of the anterior malalignment ventricular septal defect and obstructing muscle bundles in the right ventricular outflow tract. The nonfunctional pulmonary valve leaflets can be seen as well.

Infundibular muscle bundles are divided so there is no obstruction of flow out of the right ventricle.

(A, B) The ventricular septal defect is closed with a Gore-Tex patch. A combination of plegeted, interrupted sutures and non-plegeted running prolene sutures are used. The plegeted sutures are used along the base of the septal leaflet of the tricuspid valve and the running sutures for the remainder of the closure. The sutures are kept on the right side of he septum in the region of the bundle of His in order to minimize the chance of heart block.

The main pulmonary artery incision is carried distally to expose the pulmonary artery bifurcation.

The main pulmonary artery is detached from the right ventricle at the level of the pulmonary valve annulus.

The left pulmonary artery is divided leaving only a narrow cuff of tissue at the level of the origin of the lobar branches.

The right pulmonary artery is divided at the same level resulting in the removal of almost all abnormal pulmonary artery tissue.

The posterior walls of the divided right and left pulmonary arteries are then approximated with a running prolene suture. Mobilization of the branch pulmonary arteries facilitates this anastamosis. The relative short distance between the divided branch pulmonary arteries allows for a tension free anastamosis in the neonate. In older patients, we occasionally leave more posterior wall tissue in order to facilitate a tension free anastomosis.

An appropriate sized pulmonary homograft is anatamosed to the pulmonary artery reconstruction distally using a running prolene suture. During this time, the patient is rewarmed and at the completion of the suture line, the left side of the heart is deaired and the aortic cross clamp is removed.

The proximal end of the homograft is anastomosed to the infundibulum of the right ventricle.

The pericardium that was harvested at the beginning of the operation and placed in glutaraldehyde is now used to augment the right ventricular outflow tract so there is no obstruction. The right side of the heart is deaired prior to completion of this suture line. The foramen ovale is left open in order to allow right to left decompression in the immediate postoperative period. If a secundum atrial septal defect is present we downsize it to 4 millimeters by cinching a purse string suture around an appropriately sized dilator. A left atrial line is left in place for monitoring. Two atrial and two ventricular pacing wires are placed as well. The patient is weaned from cardiopulmonary bypass and the adequacy of the repair is checked with transesophageal echocardiography.