[Problems posed by preparation of the left ventricle for anatomical correction in simple transposition of the great vessels].

Surgical correction of simple transposition of the great arteries by arterial detransposition can only be considered if the left ventricle is capable of functioning under systemic conditions. This is possible at birth but the operation is too big for it to succeed. After a few weeks the left ventricle may lose this capacity but it can be induced to redevelop if it is given a systolic stress by pulmonary banding. This was attempted initially in 30 children aged from 5 weeks to 3,5 years old (20 aged less than 2 months) but had to be abandoned for the following reasons: 8 immediate failures due to severe hypoxia and acidemia, 7 left ventricular failures, mainly in 3 children operated after 6 months of age; 7 severe hypoxemias, 5 pulmonary arterial lesions due to banding and/or the systemo-pulmonary anastomosis associated in some cases; in all, there were 8 failures out of the 17 anatomical corrections performed to date in 22 survivors of banding. The criteria of left ventricular readaptation after banding were difficult to determine. The final result did not appear to be related to either the duration of banding, the degree of aortic desaturation, the ratio of ventricular pressures, or to the various echocardiographic indices. Only the initial hypoxemia (less than 50 p. 100 saturation) with respect to the risk of banding, and the age at which banding was performed (over 6 months) with respect to the risk of anatomical correction, appeared to be obvious risk factors. This is the reason for a new protocol at present under study to try to maintain left ventricular growth by banding in the first days of life, so to ensure a more harmonious and effective, and also less dangerous preparation for anatomical correction. Six new born children have been "prepared" in this way: three had adequate loose banding and underwent atrial correction. Very good results were obtained in the other three patients who have already undergone detransposition at 2,5 and 3 months with excellent immediate results. We believe that neonatal pulmonary banding (before 5 days) when aortic saturation after atrioseptostomy is over 50 p. 100, provides a real alternative to the classical methods of treating simple transposition of the great arteries (Mustard or Senning). Anatomical correction can then be carried out a few weeks later under good conditions.