Introduction: Management of the failed Fontan is a challenge for cardiologists, riddled by issues such as imbalanced pulmonary blood flow.  We report a unique strategy for increasing blood flow to one lung in a patient with chronic, diminished left lung flow after acute Fontan failure.

Case Description: The patient is a 10-year-old male with history of tricuspid atresia with malposed great arteries who underwent initial modified Norwood procedure, atrial septectomy, and modified right BT shunt in the neonatal period followed by bidirectional cavopulmonary anastomosis at 4 months of age.  At age 2, he underwent Fontan completion with a fenestrated extracardiac conduit with concomitant left pulmonary vein repair.  In the immediate post-operative period, he developed low cardiac output syndrome (hypotension, acidosis, and oliguria).  The Fontan was taken down the following day.  At age 4, he underwent a repeat attempted sutureless repair of the left pulmonary vein repair.  He subsequently underwent stent implantation in both left pulmonary veins but, due to persistently elevated vascular resistance in the left lung, cavopulmonary flow to the left lung was minimal.  To increase left lung blood flow, a novel strategy was carried out involving transcatheter creation of an aorta-to-left pulmonary artery (LPA) shunt using radiofrequency (RF) perforation and covered stent implantation from the descending aorta to the LPA.  This was followed by placement of a microvascular plug between the right pulmonary artery (RPA) and LPA, allowing the flow through the aorto-pulmonary shunt to perfuse the high-resistance left lung instead of the low-resistance right lung. 

Discussion: Preferential RPA flow from the superior cavopulmonary anastomosis with resultant poor LPA flow was likely the main driving force for the development of recurrent left-sided pulmonary vein stenosis.  The placement of a microvascular plug dividing the RPA and LPA flows with the LPA supplied by the aorto-pulmonary shunt and the RPA flow supplied by the superior cavopulmonary anastomosis allowed for a higher driving pressure of flow to the LPA.  Redirection of pulmonary blood flow can be used to rehabilitate a hypoplastic lung to promote growth of the lung tissue itself in addition to the pulmonary arteries and veins.  However, there are considerable risks with the creation of a transcatheter aorto-pulmonary shunt including reperfusion injury, pulmonary hemorrhage, and intrathoracic bleeding.  With ongoing experience in this and other cases, this technique has proven to be an attractive option for creation of aortopulmonary communications that avoids a sternotomy and some of the risks of surgical alternatives.  Conscientious patient selection is necessary to ensure that risks of the procedure are acknowledged and outweighed by the potential benefits.

Conclusion: Transcatheter shunt creation may be an option for increasing pulmonary blood flow in complex situations where conventional palliative measures are not an option.