Major aorto-pulmonary collateral arteries (MAPCA) are frequent in patients with simple transposition of the great arteries (TGA). However, only few studies describe postoperative management. We analyzed predictive factors of hemodynamically significant MAPCAs, their clinical impact and we reported treatment and outcome after embolisations of these collaterals.

All neonates admitted with simple TGA between January 2014 and December 2019 in our center were retrospectively reviewed and divided in 2 groups according to the presence of significant MAPCAS. Demographic data at birth, surgical data, pre- and post-procedural data if catheterization was performed, and outcome were reported.

In total, 129 patients were included. Twenty-five had significant MAPCAS diagnosed on TTE and confirmed on angiography. All of them were successfully embolized, with a mean of 1.9±0.77 MAPCA closure. Mean delay between surgery and catheterization was 6.8±8.1days. There were no complication reported after embolization. Mean days between catheterization and extubation were 2.9±3.3days. When comparing the 2 groups, weight, gestational age and prenatal diagnosis rate were similar but there was a statistically significant higher need of Rashkind's manoeuver (P=0.04) and prostaglandin infusion (P=0.03) in the MAPCAS group. Mean age at surgery was 7.4±4.4 in the group with MAPCAS and 6±7.8 in the second group (P=0.48). Bypass time was similar in both groups: 138±24minutes in the MAPCAS group versus 137±37minutes in the second group. Coronary anatomy was different in the 2 groups with higher rate of type A anatomy in the group without MAPCAS (60% versus 11%, P=0.01). When comparing the 2 groups in the postoperative period, the MAPCA group had a more complex course: ICU stay (12.8 versus 5.8days, P=0.037), inotropic support (9 versus 5.35days, P=0.024) and hospital stay (21.18 versus 13.9days, P=0.0019) were longer.

Patients with simple TGA with hemodynamically significant MAPCAS were more cyanosed at birth with higher need of prostaglandins and Rashkind procedure.

They had a more complex postoperative course with higher inotropic support and longer ICU and hospitalization time. These results suggest the importance of diagnosing MAPCAs and treating them as quickly as possible in order to ease postoperative course.