Transatrial Repair of Tetralogy of Fallot

Standard cardiopulmonary bypass with direct bicaval cannulation is achieved, even in the neonate, at a systemic temperature of 28°C to 32°C (cannulas removed for clarity). A vent is placed through the right superior pulmonary vein and cold blood cardioplegia administered after aortic cross clamping. A right atriotomy is made parallel and close to the right atrioventricular groove. Placing the incision in this location assists in the exposure by elevating the anterior wall of the right ventricle and tricuspid valve with the stay sutures inserted along the atriotomy. The ventricular septal defect is visible behind the anterior leaflet of the tricuspid valve. Traction sutures are placed in the anterior and septal leaflets of the tricuspid valve. In the neonate, a patent foramen ovale is generally left open, but is closed in older infants.

The traction sutures placed on the anterior and septal leaflets of the tricuspid valve are essential in providing exposure with minimal retractors in the field. Each suture is retracted directly toward the surgeon, which pulls the septum and VSD into view. A small right-angle retractor is then placed under the anterior leaflet and pulled superiorly. The anterior limb of the septal band is identified. A traction suture placed here can help in the visualization of the out flow tract and help in keeping the surgeon’s orientation. The traction suture placed in the anterior limb of the septal band, which marks the anterior edge of the VSD, can be very helpful in maintaining orientation and exposing the distal outflow tract. Anterior and superior to this point is the pathway to the pulmonary valve, and the marking suture serves as a useful frame of reference to avoid an incision into the VSD itself.

The malalignment VSD is exposed, but relief of the right ventricular outflow tract obstruction is performed first. In some cases, a small calibrated dilator can be passed retrograde through the pulmonary valve to assist in exposure. Although not generally necessary, this maneuver has been found to be helpful when first attempting transatrial repairs, particularly in very small patients.

(A) A right angle clamp is now placed around the right ventricular outflow tract muscle bundles until the pulmonary valve can be clearly seen. This is done on both the parietal and septal surfaces.

(B) Gentle probing with the clamp is important to avoid creating injury to the septum. In neonates and infants, this is generally easy to do as there is little secondary hypertrophy and the muscle bundles appear as “discrete” bands, which can be encircled for division. Resection is unnecessary as the outflow tract will expand sufficiently. It is important to realize that, although uncommon, some patients will not be suitable for transatrial muscle division secondary to hypoplasia of the right ventricular outflow tract. In such cases, an outflow tract patch will be required to enlarge the area of hypoplasia.

(A) A right angle clamp is now placed around the right ventricular outflow tract muscle bundles until the pulmonary valve can be clearly seen. This is done on both the parietal and septal surfaces.

(B) Gentle probing with the clamp is important to avoid creating injury to the septum. In neonates and infants, this is generally easy to do as there is little secondary hypertrophy and the muscle bundles appear as “discrete” bands, which can be encircled for division. Resection is unnecessary as the outflow tract will expand sufficiently. It is important to realize that, although uncommon, some patients will not be suitable for transatrial muscle division secondary to hypoplasia of the right ventricular outflow tract. In such cases, an outflow tract patch will be required to enlarge the area of hypoplasia.

(A and B) Following relief of right ventricular outflow obstruction, the VSD is closed. A continuous suture technique is preferred, beginning at the juncture between the anterior and posterior limbs of the septal band. The first arm of the suture is placed along the anterior limb and around the annulus of the aortic valve. The latter is exposed more easily after the muscle bundles are divided. This suture passes into the right atrium where the aortic and tricuspid valves come together at the ventriculoinfundibular fold.

(C–E) The opposite needle is then used to anchor the patch along the inferior limb of the septal band and along the septal leaflet of the tricuspid valve in the standard fashion using the usual techniques to avoid injury to the conduction system. It is often necessary to weave the suture under the chordal attachments of the tricuspid valve to avoid distortion. The two ends of the suture are tied over a small pericardial pledget. It is important to test the tricuspid valve with saline to ensure that the valve is fully competent. A suture placed at the anteroseptal commissure of the valve is occasionally needed to reinforce this area.

(A and B) Following relief of right ventricular outflow obstruction, the VSD is closed. A continuous suture technique is preferred, beginning at the juncture between the anterior and posterior limbs of the septal band. The first arm of the suture is placed along the anterior limb and around the annulus of the aortic valve. The latter is exposed more easily after the muscle bundles are divided. This suture passes into the right atrium where the aortic and tricuspid valves come together at the ventriculoinfundibular fold.

(C–E) The opposite needle is then used to anchor the patch along the inferior limb of the septal band and along the septal leaflet of the tricuspid valve in the standard fashion using the usual techniques to avoid injury to the conduction system. It is often necessary to weave the suture under the chordal attachments of the tricuspid valve to avoid distortion. The two ends of the suture are tied over a small pericardial pledget. It is important to test the tricuspid valve with saline to ensure that the valve is fully competent. A suture placed at the anteroseptal commissure of the valve is occasionally needed to reinforce this area.