Surgical management and indication of left ventricular retraining in arterial switch for transposition of the great arteries with intact ventricular septum.

OBJECTIVE

Arterial switch is the operation of reference for the surgical treatment of transposition of the great arteries. In cases of late referral, perinatal complications or early left ventricular (LV) dysfunction, the one stage arterial switch is contra indicated. Anatomical repair remains possible in these patients following a LV retraining.

METHODS

From January 1992 to January 2000, a LV retraining was attempted in 22 patients with transposition of the great arteries with intact ventricular septum (TGA IVS), whereas 470 direct arterial switch and 2 Senning were performed. Indication for LV retraining was based on a combination of factors including: an age older than 3 weeks, a "banana shape" aspect of the inter-ventricular septum and mainly a LV mass <35G/m(2).

RESULTS

The mean age at LV retraining was 3.2 months ranging from 9 days to 8 months. Usually conducted by sterntomy, it associated a loose PA banding with a LV/RV at 65% with a systemico-pulmonary shunt. The first stage was associated with frequent LV dysfunction and the LV retraining was discontinued in two patients in favor of one Senning and one early switch followed by ECMO. One patient died at first stage from a mediastinitis. Nineteen patients underwent a second stage arterial switch that was performed when the LV mass had reached 50 G/m(2) after a mean delay of 10 days, ranging from 5 days to 6 weeks. After a mean follow up of 25 months, there was one non-cardiac late death. The 17 patients followed and leaving with an arterial switch are in NYHA class I, with a mean LV shortening fraction of 39%.

CONCLUSIONS

Arterial switch following LV retraining in TGA IVS is a satisfactory option. The inferior limit of 35 G/m(2) adopted, to indicate LV retraining, seems a safe landmark. The quality of the myocardium generated and the respective roles played by the LV afterload, LV wall shear stress, LV inflow and outflow to induce the LV remodeling remain under debate.