Left ventricular regression after balloon atrial septostomy in d-transposition of the great arteries

Balloon atrial septostomy (BAS) is an effective palliative procedure in children with transposition of the great arteries and poor intercirculatory mixing. While the subpulmonary left ventricle (LV) is known to regress with time in these newborns due to the declining afterload, it has not been studied how it behaves following BAS and a consequent decrease in preload. The study was designed to examine the effects of BAS on the LV in infants with simple d-transposition of the great arteries by serial 2D echocardiographic monitoring.

This was a prospective echocardiographic follow-up study of all consecutive children with simple d-transposition of the great arteries who underwent BAS for restrictive interatrial communication and oxygen saturation below 75% between January 2014 and June 2015. Left ventricular mass estimation was done by M-mode transthoracic echocardiography before balloon septostomy and serially on follow-up till surgery.

The median age of the 25 children studied was 4 days (1-95 days) when they underwent BAS. Twenty patients underwent arterial switch operation at a mean of 9 days from balloon septostomy. The mean baseline left ventricular mass was 47.9 g/m², which decreased to 38.5, 36.2, 32.1, 32.4, 25.7 and 25.2 g/m² on Days 1, 3, 6, 9, 12 and 15, respectively. The left ventricular mass decreased by 1.5 g/m² every day during the first 2 weeks following balloon septostomy adjusted for the age of the child in days. Children who underwent BAS beyond 3 weeks of life had faster LV regression than those who underwent the procedure earlier (unstandardized regression coefficient β 0.892, P < 0.001).

BAS is associated with accelerated regression of the LV in infants with simple d-transposition of the great arteries in the first 2 weeks after the procedure. Regression of the LV is faster in children who underwent BAS after 3 weeks of age.