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

Purpose: After the arterial switch operation (ASO) neo-aortic root (neo-AR) dilatation has been reported as a postoperative complication in children. However, little data concerning the progression of neo-AR dilatation in adults exists, even though it has been suggested neo-AR dilatation will stabilize over time. Our aim was to assess the prevalence and long term clinical outcome of neo-AR aneurysm after ASO in adults. Methods: Of all 119 ASO patients operated in a tertiary referral centre and born before 1995, 86 (73%) survived to adulthood (> 17yrs) and were included in this retrospective study. Neo-AR measurements performed in adulthood were collected from available echocardiographic, cardiovascular magnetic resonance and computed tomography images. Baseline was defined as the first measurement that was performed in adulthood. The time trend was analysed using a linear mixed model, adjusted for modality. In addition, all clinical events were collected and included death, myocardial ischemia, reoperation, arrhythmia and heart failure. Results: During a mean follow-up in adulthood of 7.3 years (IQR 4.1 to 10.1), 16 patients experienced 24 events; 3 (4%) death, 4 (5%) myocardial ischemia, 7 (9%) reoperation (3 aortic root dilation, 4 pulmonary stenosis), 7 (9%) arrhythmia, and 2 (3%) heart failure. Event-free survival at 27 years of age was 73%. Data on the neo-AR diameter were available in 77 (90%) adult patients and serial measurements in 63 (73%). At baseline (median age 18.1 yrs), mean neo-AR diameter was 3.6±0.5mm and neo-AR aneurysm (neo-AR >40mm) was present in 14 patients (18%). Mean neo-AR growth was 0.33mm per year (p<0.001 compared to the normal value of 0.09mm per year) and was linear over time. Of the 49 (78%)), patients without neo-AR aneurysm at baseline and serial measurements, 18 (37%) progressed to neo-AR aneurysm during follow-up. Conclusion: Aortic root dilation persisted throughout adulthood. Growth was linear and did not stabilize over time.