Material and methods
Since 1989 thirty-nine consecutive patients (21 boys, 18 girls) were included in this protocol. A 22Q11 deletion was diagnosed in 10 patients. The median age at the time of the first unifocalization was 13 months (range 2 weeks to 189 months). Diagnostic catheterization was performed to assess the pulmonary vascularity and perfusion. In 13 patients with a hypoplastic central confluent pulmonary artery a central aorto-pulmonary shunt was performed, intended to allow the confluent pulmonary artery to grow to improve the starting point for unifocalization.
Unifocalization was performed through a lateral thoracotomy with identification of all collateral arteries at that side. When adequate intrapulmonary connection was confirmed on preoperative angiography or intra-operatively, the dual supply SPCA could be closed. When such connection was not established, the collateral artery was anastomosed to the native pulmonary artery as close as possible to the hilar pulmonary vasculature. In case of an absent confluent pulmonary artery and in cases where further augmentation was indicated a modified Blalock-Taussig shunt was constructed to the ipsilateral subclavian artery. In 27 patients an additional unifocalization procedure on the contra-lateral side was performed to augment the blood supply to that lung. Before and after each procedure an angiogram was made.
To evaluate the growth of the pulmonary arterial system we retrospectively measured the pre- and post-unifocalization Nakata-index.[9]
The change in lung perfusion on angiogram pre- and post-unifocalization was studied retrospectively to evaluate the result of the procedure. We studied the total lung perfusion including perfusion by the SPCA’s versus the lung perfusion by flow through the confluent pulmonary artery alone.
Based on the angiographic findings and data from catheterization measurements patients were selected for total correction. Pulmonary hypertension or unfavorable anatomic result of unifocalization at angiogram were contraindications for total correction. The total correction was performed through a median sternotomy with the use of extracorporeal circulation and moderate hypothermia. The modified Blalock-Taussig and central shunts were divided. The VSD was closed with a Gore-Tex® patch and a cryopreserved pulmonary homograft was interposed between the RVOT and the proximal pulmonary arterial system. Postoperative recovery and hospital or 30-day mortality is reported.
Long-term follow up was derived from the records. In 24 survivors, with a complete repair, echocardiographic data were available except in one patient who was lost to follow up. From 17 patients after successful correction MR imaging was available for analysis of the right ventricular function.
This study was approved by the Ethical Committee with no need for informed consent.
Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software, version 24.0 (SPSS Inc., Chicago, IL). Frequencies were given as absolute numbers and percentages. The data were expressed as median with range. The paired t-test was performed for statistical analysis. We applied the χ 2 test to compare frequencies in the two groups. The Kaplan-Meier method was applied to estimate freedom from reintervention and for survival. A P value less than 0.05 was considered to indicate statistical significance.