Impact of pulmonary artery reduction during arterial switch operation: 14 years follow-up

Pulmonary artery/aorta (PA/Ao) size discrepancy plays an important role in the development of neoaortic root growth and valve regurgitation. Since 2004, we started using PA reduction to manage severe great vessels root mismatch at the time of arterial switch operation. The purpose of this study is to evaluate the impact of this technique in the mid- and long-term follow-up.

Patients considered to have severe PA/Ao mismatch (>2:1 ratio) underwent resection of a 3- to 4-mm flap of the posterior PA wall. Patients submitted to this technique were followed up with clinical and image examinations. Echocardiographic findings were reviewed, and Z-scores were recorded to evaluate the incidence and progression of neoaortic root dilatation and valve regurgitation.

The median (Q1-Q3) follow-up time was 8 years (3-11). Before arterial switch operation, the median (Q1-Q3) Z-score of the PA annulus was 2.90 (2.75-3.75). At the latest follow-up, the median Z-score of the neoaortic annulus was 1.34 (0.95-1.66). The mean difference between the Z-scores of PA annulus and neoaortic annulus was 1.56 (P < 0.0001). The mean value of the sinus of Valsalva was +0.29 ± 1, that of sinotubular junction was +0.71 ± 0.6 and that of ascending Ao was +1.09 ± 0.7. There was no severe dilatation of the neoaortic annulus, neoaortic root or ascending Ao during follow-up. Neoaortic valve regurgitation was none or mild in 93% of patients.

PA reduction proved to be a feasible and low-risk procedure to approach PA/Ao mismatch in arterial switch operation. Mid- and long-term follow-up showed a tendency towards stabilization of the neoaortic root dilatation and satisfactory valve performance after the procedure. Further investigation is required with a larger population and longer-term follow-up.