Dramatic Remodeling of Hypoplastic Pulmonary Arteries by Pulmonary Valve Opening, Right Ventricular Outflow Stenting, and Aortopulmonary Collateral Lung Territory Incorporation.

Background: Pulmonary atresia with severely hypoplastic pulmonary arteries (PAHP), with or without major aortopulmonary collateral arteries (MAPCA), is a significant clinical conundrum. This case series aims to present a strategy being evaluated for patients with PAHP, highlighting the effectiveness of pulmonary valve opening, right ventricular outflow tract (RVOT) stenting, and staged serial interventions in promoting pulmonary artery (PA) growth and improving PA architecture. This study also describes a technique of dilation of the junction between the distal PA and the collaterals to incorporate them into the "true PA territory," potentially negating the need for unifocalization. Methods: A retrospective review was performed of 4 patients with PA/HP/MAPCA treated with pulmonary valve opening, RVOT stenting, and PA balloon rehabilitation. Procedural techniques, outcomes, and PA growth are described. Results: The procedure was successful in 3 of the 4 patients, all without major complications. In these patients, significant PA growth was achieved, with the Nakata index increasing from a baseline median of 10.8 to as high as 483.6. Dilation of a connection between a MAPCA and the true PA was performed in 1 patient, allowing recruitment of additional lung territory. All 3 subsequently completed septation, with 2 requiring unifocalization of only a single collateral vessel. In the fourth patient, unfavorable RVOT-main PA malalignment prevented successful wire crossing; thus, right ventricular perforation/stenting was not performed. Conclusions: Pulmonary valve opening and RVOT stenting with PA rehabilitation, including dilation of the connections of the MAPCA to the true PA, is a promising strategy to promote PA growth in PAHP with MAPCA, facilitating progression to surgical repair while minimizing the need for unifocalization.