An Analysis of Left Ventricular Retraining in Patients With Dextro- and Levo-Transposition of the Great Arteries.

BACKGROUND: Patients with dextro (D)-transposition of the great arteries (TGA) who have undergone a previous atrial switch and for some patients with levo (L)-TGA (ie, no ventricular septal defect or outflow tract obstruction), the left ventricle (LV) may require retraining before late arterial switch. The purpose of this study was to analyze the results of LV retraining for these two entities.

METHODS: This was a retrospective review of 51 patients enrolled in an LV retraining program. There were 25 patients with D-TGA and 26 with L-TGA. The median age of the D-TGA patients was 15 years, and 22 of 25 were in New York Heart Association class III or IV. The median age of the L-TGA patients was 12 months, and 3 of 26 patients were in New York Heart Association class III or IV.

RESULTS: LV retraining was successful in 13 of the 25 patients (52%) with D-TGA, and 10 these 13 patients (77%) underwent successful late arterial switch. Of the 26 patients with L-TGA, LV retraining was successful in 24 (92%), and a double-switch operation was successful in 19 of 19 (100%) who subsequently underwent that procedure. A mathematical formula based on the incremental gain in left-to-right ventricular pressure ratio correctly predicted the success or failure in 94% of the patients.

CONCLUSIONS: The data demonstrate differences in the success of LV retraining and late arterial switch for D-TGA and L-TGA. We would propose that the LV retraining ratio may be useful in objectively selecting patients eligible for late arterial switch.