Persistent neo-aortic growth during adulthood in patients after an arterial switch operation

Objective After the arterial switch operation (ASO), disproportional neo-aortic growth during childhood has been reported. Even though it has been suggested neoaortic dilation will stabilise in adulthood, data are lacking. The aim of this study was to assess the change in neo-aortic dimensions, prevalence of neo-aortic dilation >40 mm and long-term outcome in adults who underwent ASO in childhood. Methods All 116 ASO patients operated in a tertiary referral centre and born before 1995 were included. Of these, 83 (72%) survived to adulthood (>17 years) and six were lost to follow-up. Neo-aortic measurements performed in adulthood were collected from available echocardiographic, cardiovascular magnetic resonance and CT images. The time trend was analysed using a mixed model, adjusted for imaging modality. Results Clinical data with at least one measurement of the neo-aortic diameter were available in 77 (93%) adult patients and serial measurements in 65 (78%). At baseline (median age 18.1 years), mean neo-aortic diameter was 36 +/- 5 mm. Mean neo-aortic growth was 0.31 mm/year (p<0.001 compared with normal value 0.08 mm/year) and was linear over time. Freedom from neo-aortic dilation beyond a diameter of 40 mm was 23% at 28 years of age. During a mean clinical follow-up in adulthood of 7.2 years (IQR 4.0 to 10.1), 3 (4%) patients underwent neo-aortic replacement. No other neo-aortic complications occurred. Conclusions In early adulthood, neo-aortic growth was on average linear and did not stabilise over time.