OUTCOMES OF PALLIATIVE RIGHT VENTRICLE TO PULMONARY ARTERY CONNECTION FOR TETRALOGY OF FALLOT WITH PULMONARY ATRESIA AND MAPCAS

BACKGROUND Tetralogy of Fallot with pulmonary atresia with major aorto pulmonary artery collaterals (TOF-PA MAPCAS) is a rare and complex cyanotic congenital heart malformation with a high incidence of early mortality and morbidity. Different surgical interventions have been described including construction of a systemic to pulmonary artery shunt (Modified Blalock-Taussig shunt or central shunt) and unifocalization, however the perioperative mortality remains significant due to the high incidence of thrombosis, obstruction, and pulmonary artery (PA) distortion. Another alternative is a palliative right ventricle to pulmonary artery connection (RVPAC) to bring antegrade flow to diminutive PAs. The objective of our study was to evaluate the impact of RVPAC on mortality, survival, morbidity, PA growth and eligibility for biventricular repair. We believe that the RVPAC approach allows for better PA growth and obviates the need for a conduit at the time of complete repair. METHODS AND RESULTS We performed a retrospective single-institution study from January 2016 to March 2021 that included 15 consecutive patients diagnosed with TOF-PA MAPCAS who underwent an RVPAC at CHU Sainte-Justine as their initial palliation. Median age at palliation and complete repair was 18 (4 -100) and 309 (96 – 1044) days respectively. Mortality after a RVPAC was 0 % with a median hospital length of stay of 14,5 days (6 - 55), while the late interstage mortality rate was 0 %. Overall survival was 100 %. 9 patients (60%) had a biventricular repair, and 6 patients (40%) are awaiting repair. RVPAC allowed significant growth of the native pulmonary arteries with a mean Nakata index at CT scan of 70 ± 48,04 mm2/m2 before the RVPAC and 251 ± 121,05 mm2/m2 after (P = 0.001). 4 patients (44%) required reinterventions after completed repair by catheterization for stenotic pulmonary artery branches, while no patients required a late reoperation. 8 patients (53,33%) had embolization of collaterals and none required unifocalization. CONCLUSION This reproducible and safe technique allows for excellent growth of the PA tree. Biventricular repair was possible in most cases without the use of a conduit or unifocalization of collaterals. This technique appears to be suitable for any type of TOF-PA MAPCAS with confluent native branch pulmonary arteries.