Surgical Repair for Absent Right Pulmonary Artery Utilizing a Main Pulmonary Artery Flap

Introduction: Absent right pulmonary artery (RPA) is a rare congenital heart disease due to malformation of the ipsilateral sixth aortic arch during embryogenesis. Restoration of physiologic circulation is essential to prevent long-term complications. However, surgical repair can be challenging in cases of long discontinuity. We present a case of semi-autologous reconstruction of an absent RPA using a main pulmonary artery (MPA) flap in a 2 month old infant.

Case Description: The patient was born at 36 weeks gestation. He was intubated for 2 weeks and was discharged home with Oxygen supplementation to maintain saturations above 90%. An echocardiogram showed a patent foramen ovale and a left-sided patent ductus arteriosus but no other evidence of congenital heart disease. The family presented to our facility for a second opinion. There was no audible murmur on exam. Echocardiogram confirmed that the ductus was closed; there were an unusual number of bronchial collateral vessels seen. A CT angiogram was obtained and showed absence of a central RPA with the right lung supplied by multiple collaterals. Cardiac catheterization was performed and showed a distal right pulmonary hilar stump with a 1.5cm distance from the MPA to the right pulmonary stump.
Surgical reconstruction of the RPA was planned utilizing a flap of the patient’s MPA. At the time of surgical intervention, the innominate artery was dissected out. A right-sided ductus was found on the inferior aspect and was followed to the right hilar stump laterally. A small band of fibrous tissue connected the RPA stump to the MPA medially. A left ductus was also noted in the usual position, both ducti were ligated. During cardiopulmonary bypass the aorta was transected for exposure. An appropriately sized flap was created from the MPA and turned down to serve as the back wall for the RPA reconstruction. The distal end of this flap was sutured to the back wall of the diminutive hilar stump (about 4mm in diameter). A patch of Matracell ™ was cut to size to form the front wall and reconstruct the defect in the MPA. This created a well-formed RPA with distal diameter of 4mm, similar to the diameter of the hilar stump. Postoperative CT showed intact proximal and distal anastomoses. Pre-discharge echocardiogram showed a mean gradient across the RPA of 8 mmHg. The patient was weaned off oxygen and discharged home on postoperative day 10.

Discussion: Absent RPA is a rare anomaly with a variable time of presentation and symptoms. Utilization of a pulmonary artery flap can be considered as an appropriate surgical approach for repair.

Conclusion: Regardless of the surgical technique used, restoration of the physiologic blood supply is necessary to allow for appropriate growth and development of the lung and avoid long-term complications such as pulmonary hypertension.