En Bloc Double Root Translocation
The patient was a six-month-old, 7.6 kg male with an antenatal diagnosis of dexto-transposition of the great arteries (d-TGA), large perimembranous ventricular septal defect (VSD) with outlet extension, a bicuspid and severely stenotic pulmonary valve (PS) with a peak gradient of 92 mmHg, and a posteriorly-deviated conal septum causing left ventricular outflow tract obstruction (LVOTO).
Background
The patient underwent a balloon atrial septostomy in the neonatal period (DOL12), was convalesced without incident, and was subsequently discharged home. At two months of age, the patient required another catheter-based intervention in the form of balloon valvuloplasty of the pulmonary valve. Indication for pulmonary valvuloplasty was for worsening hypoxia and cyanosis. Both procedures were performed at an outside hospital. The patient was then referred for definitive repair.
The patient was presented at the case management conference, where many surgical intervention strategies were discussed. The Nikaidoh procedure, Rastelli, and Double Root Translocation (en bloc and separated) were all discussed with the final decision to be made intraoperatively.
Surgical Approach
The patient was taken to the operating room for complete repair at six-months of age. A median sternotomy and subtotal thymectomy was then performed (left lobe preserved). Prior to cardiopulmonary bypass, the coronary arteries and great vessel were inspected. The coronary artery origins and branching pattern were normal, and the great vessels were in anterior/posterior orientation. The patient was then heparinized and aorto-bicavally cannulated. Once on cardiopulmonary bypass, the patient’s anatomy was inspected thoroughly. As the Nikaidoh was still in the differential, approximately 5 mm of the proximal coronary arteries were circumferentially dissected off the surface of the epicardium. Both the ascending aorta and main pulmonary artery were transected at approximately the same level. Upon inspection, the aortic valve was normal, and the pulmonary valve was hypoplastic and thickened. This led to the decision to proceed with the en bloc double-root translocation.
The circular coronary buttons were excised from the aortic root. Next, the proximal coronary arteries were mobilized further off the surface of the epicardium. Following this, a right-angle clamp was placed through the pulmonary root, and the free wall of the right ventricle was marked. The aortopulmonary root (conotruncus) was then excised. The previously marked site on the free wall of the right ventricle was incised with a 15-blade. The incision was carried posterolaterally around the pulmonary root and in between the mobilized coronary arteries and aortic root. The incision was extended through the ventricular septal defect by dividing accessory tricuspid valve attachments. It is important to be careful to avoid injury to the primary and secondary chords and the conduction system.
The en-bloc aortopulmonary root was then rotated 180 degrees and reimplanted. The reimplantation started at the posterior aspect of the neoaortic root. The neoaortic was then attached to the left ventricular outflow tract. Once the suture lines reached the divided outlet septum, the ventricular septal defect was closed with a bovine pericardial patch. This was completed with a row of pledget-supported 5-0 Tevdek sutures bookended by two pledget-supported Prolene sutures along the posterior and inferior aspect of the ventricular septal defect. These were passed through the bovine patch and tied down. The ends of the Prolene sutures were then run along the edge of the ventricular septum and margin of the neoaortic root, where they were joined and tied. Additional pledget-supported sutures were placed in the corners of the divided septum to help secure the aortopulmonary root. The pulmonary aspect of the aortopulmonary root was then secured to the right ventricular outflow tract. Anteriorly, the neopulmonary root was divided at the commissure between the cusps of the stenotic valve. Additional obstructing muscle was resected from the outflow tract. A transannular patch of pulmonary homograft was then used anteriorly to finish the right ventricular outflow tract reconstruction.
The coronary buttons were then reimplanted into the aortic root. Next, the lateral edge of the left coronary artery button was directly sutured to the neoaortic root. A small piece of pulmonary homograft patch was then sutured to the edge of neoaortic root, creating a medially based trapdoor. The medial edge of the button was then sutured to the homograft patch, and then the right coronary artery defect on the neoaortic root was closed with a circular patch of pulmonary homograft. Following this, a smaller circular defect better suited to accommodate the right coronary artery button was created. The right coronary artery button was then anastomosed directly to the defect in the pulmonary homograft patch. A Lecompte maneuver was then performed, and the ascending aorta was anastomosed to the neoaortic root.
The atrial septal defect was closed primarily.
Next, both the right and left pulmonary arteries were enlarged by incising along the underside of both vessels. The distal main pulmonary artery was then anastomosed to the neopulmonary root.
Then, the atrium was closed. The patient was weaned from cardiopulmonary bypass without difficulty in normal sinus rhythm.
A transesophageal echo showed good biventricular function, no left ventricular outflow tract obstruction, no right ventricular outflow tract obstruction, and the mitral and tricuspid valves showed no stenosis or regurgitation. Hemostasis was achieved, the chest was closed, and the patient was transported to the cardiac intensive care unit.
Postoperative Notes
The patient had an uneventful postoperative course and was discharged home on postoperative day seven. The most recent surveillance transthoracic echocardiogram (approximately two years post-op) showed nearly identical results to the immediate postoperative transesophageal echocardiogram. The patient has not required any additional admissions or reinterventions.
