Right Ventricle-Pulmonary Artery Shunt in First-Stage Palliation of Hypoplastic Left Heart Syndrome

Arterial blood pressure monitoring lines were placed in the right radial artery and femoral artery in each patient preoperatively. Through a midline sternotomy, the thymus gland was excised. The aortic arch, its branches, and the ductus arteriosus were dissected out. To avoid the use of total circulatory arrest as much as possible, cardiopulmonary bypass was established by dual arterial perfusion and single atrial or bicaval drainage cannulations. Dual arterial cannulas were inserted into the ductus arteriosus and into a 3.0-mm polytetrafluoroethylene (PTFE) tube (Gore-Tex, WL Gore & Associates, Inc., Flagstaff, AZ) that was anastomosed to the innominate artery. Following insertion of a venous cannula into the right atrium, cardiopulmonary bypass was commenced at a flow rate of 150 to 180 mL/min/kg.

Before establishment of cardiopulmonary bypass, the shunt material was prepared on another table as follows. In the case of 5-mm shunt, a 5-mm PTFE tube was cut in an appropriate length as a shunt tube. A cuff for an anastomosis to the distal end of the main pulmonary artery was tailored by vertically opening a piece of the same PTFE tube. The center of the cuff was punched out in 5-mm diameter, and the tube was anastomosed to this opening using a 8-O PTFE or Prolene suture.

During the cooling phase, the isthmus was ligated and divided to obtain a better operative field. Following division of the duct proximal to the cannulation site, the descending thoracic aorta was extensively mobilized by blunt dissection as far distally as possible. The main pulmonary artery was transected just proximal to the bifurcation, and the PTFE cuff was anastomosed to the distal stump of the main pulmonary artery using either 8-O PTFE or 8-O Prolene suture.

Although we repaired the distal end of the main pulmonary artery with an autologous pericardial patch and anastomosed the shunt tube onto this patch in the first six patients, we abandoned this procedure because of intractable bleeding and the high incidence of late obstruction at the anastomotic site.

At a nasopharyngeal temperature of less than 22°C, the descending aorta was clamped. Following removal of the perfusion cannula from the duct, all duct tissue was excised from the descending aorta. The left carotid artery and left subclavian artery were snared. Isolated cerebral and myocardial perfusion was established by placing a clamp just distal to the innominate artery. With the heart beating, the aortic arch was opened inferiorly and the back wall of the descending aorta was anastomosed to the posterior wall of the aortic arch. At this stage, cold crystalloid cardioplegic solution (30 mL/kg) was administered over 3 minutes either from the aortic root or from a side port of the arterial cannula during temporary total circulatory arrest.

The innominate artery was snared proximal to the perfusion site, and the clamp on the arch was removed. Cardiopulmonary bypass was resumed for isolated cerebral perfusion through the innominate artery. The aortic arch reconstruction was performed by means of Brawn’s modification. ³

The opening of the aortic arch was extended down into the ascending aorta to the level of the transected end of the main pulmonary artery. The proximal main pulmonary artery was directly anastomosed to the transverse arch and the opened-out ascending aorta.

After completion of aortic arch reconstruction, the circulation was again arrested. The venous cannula was removed from the right atrium. The atrial septum was excised, working through the purse-string suture on the atrial appendage.

An appropriate site of ventriculotomy for the RV-PA shunt, which was 1.5 to 2 cm below the pulmonary valve, was made on the right ventricular outflow tract. In order to prevent late obstruction at the shunt anastomosis, it was important to punch out a piece of ventricular muscle underlying the ventriculotomy. The size of the ventricular hole is approximately 1 mm bigger than PTFE graft.

Cardiopulmonary bypass was reinstituted, and all snares were removed. The RV-PA shunt was placed to the left of the neoaorta in all patients and was anastomosed to the right ventriculotomy during rewarming using 6-0 prolene suture. The size of the RV-PA shunt used was 4 mm in five patients weighing less than 2.0 kg, 6 mm in one patient with a weight of 3.7 kg, and 5 mm in the other patients. Modified ultrafiltration was routinely used following weaning from cardiopulmonary bypass.