Pulmonary root translocation for borderline complex coarctation of aorta and multiple ventricular septal defects Free

INTRODUCTION

The best treatment option for neonates and small infants with complex left ventricular outflow tract (LVOT) obstruction, ventricular septal defects (VSDs) and aortic arch obstruction is controversial.

CASE REPORT

A 1-month old infant, weighing 2.5 kg, was referred to our department because of heart murmur. Echocardiography revealed [S,D,D] coarctation of aorta, a posteriorly malaligned perimembranous VSD, multiple muscular VSDs, patent ductus arteriosus (PDA) and balanced ventricles. She had a complex LVOT with severe subaortic stenosis (3.5 mm diameter, z-score −6.3), borderline aortic valve stenosis (4.7 mm diameter, z-score −3.3) and a bicuspid aortic valve. Figure 1 shows further details. She had mild pulmonary regurgitation (PR), respiratory difficulty due to tracheobronchomalacia.

Figure 1:

Preoperative CT. (A) Anterior view. (B) Posterior view. Five individual cervical branches arise separately. The transverse arch is severely hypoplastic. Left and aberrant right subclavian arteries arise from the descending aorta. RV: right ventricle; LV: left ventricle; mPA: main pulmonary artery.

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We initially chose bilateral pulmonary artery banding and maintained PDA with continuous prostaglandin E1 infusion, leaving time to decide on further surgical options. Definite biventricular repair was scheduled when she presented with a drop in saturation of around 75%, at 4 months of age, weighing 4 kg. Her LVOT had not showed any apparent increase in size, and PR remained trivial. Because of the operative demands to deal with multiple muscular VSDs, we decided against conventional repair with LVOT resection and aortic valvotomy.

After cardiac arrest was achieved, the intracardiac structure was inspected through the right ventricular outflow tract (RVOT) and the right atrium. Considering operative demands and a risk of LVOT obstruction of rerouting VSD and closing multiple muscular VSDs, we chose pulmonary translocation for LVOT reconstruction. The pulmonary autograft was harvested, the ascending aorta was transected and coronary buttons were created. The bridge of the conal septum was removed, enlarging the perimembranous VSD, and the protruding subaortic muscle was resected (Fig. 2A). Muscular VSDs were inspected through the left and right ventricles under broad views and were closed using the sandwich technique (Fig. 2B). The pulmonary autograft was implanted into the LVOT. The enlarged VSD was rerouted using an expanded polytetrafluoroethylene (ePTFE) patch (Fig. 2C). An 8-mm ePTFE graft was interposed between the neo-ascending and descending aorta to reduce operative demands and risk of airway compression (Fig. 2D). A 14-mm ePTFE graft with a handmade tricuspid valve was placed as RVOT in the anatomical position.

Figure 2:

(A) After pulmonary autograft removal, the subaortic valvular muscle protrusion was resected (black arrows). Muscular ventricular septal defect (VSD) (black stars) and a perimembranous VSD (white star) are indicated. (B) The right angle clamp was inserted from muscular VSDs on right ventricule side to the perimembranous VSD through LV. The sandwich technique was applied. (C) A pulmonary autograft was implanted in the left ventricular outflow tract, and the VSD was rerouted using patch. (D) The aortic arch was bridged with an 8-mm expanded polytetrafluoroethylene graft.

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Cardiac arrest lasted 180 min. She was extubated on the 10th postoperative day and discharged 25 days after surgery. Postoperative CT showed a straight LVOT and sufficient retrosternal space for RVOT reconstruction. Echocardiography, 47 months after the operation, revealed mild neo-aortic valve regurgitation and mild LVOT obstruction (PG: 36 mmHg). Moderate pulmonary valve stenosis (PG: 61 mmHg) was detected and successfully reduced to 20 mmHg by balloon dilatation.

DISCUSSION

This definite biventricular repair involved LVOT reconstruction, multiple muscular VSD closure and aortic arch repair.

Nakano et al. [1] proposed a minimum LVOT diameter of body weight plus 1 mm as an indication for the Yasui operation. We decided against conventional repair, because of total surgical demands and her small LVOT.

To establish an LV-to-aorta connection, VSDs need to have some relation to the aorta. Generally, inlet VSD or apically located muscular VSDs are not suitable for intraventricular rerouting. Hazekamp et al. [2] described a surgical procedure for transposition of the great arteries and LVOT obstruction, with detachment of the aortic root from the right ventricle and resection of the outlet septum, facilitating exposure for ventricular septation. In cases with normally related great arteries and LVOT obstruction, detachment of the pulmonary root from the right ventricle and resection of the conal septum have a similar effect. In the present case, the choice of pulmonary root translocation was made during the surgery, when the surgeon inspected VSDs. Harvesting the pulmonary autograft and removing the bridge of the conal septum made it easier to detect the perimembranous and muscular VSDs, giving a better surgical view for rerouting and closure. Despite its greater invasiveness, biventricular repair, using pulmonary root translocation, is worth employing in selected cases with multiple muscular VSDs, and complex LVOT lesions.

Conflict of interest: none declared.

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