Fifth decennium after the arterial switch operation for transposition of the great arteries

From 1977 onwards, patients with both simple and complex transposition of the great arteries (TGA) have been treated with the arterial switch operation (ASO) in the Wilhelmina Children's Hospital/University Medical Center Utrecht the Netherlands. In this study, we compared mortality and morbidity between two patient groups: A. operated before and B. after 1991, specifically focusing on late ventricular function and reinterventions.

A single institution retrospective cohort study was performed on patients who had an ASO for either simple or complex TGA. Data were collected from medical records. The entire patient cohort (n = 283) was divided in a group with more than 30 years of follow-up (A) and a group with less than 30 years of follow-up (B). Clinical and standardized echocardiographic follow-up was evaluated.

Group A consisted of 79 patients, of whom follow-up was available in 59 patients (median follow-up 34.8 years, IQR 33.0-36.9). Group B consisted of 204 patients, of whom 195 long-term survivors (median follow-up 14.9 years, IQR 10.0-21.2). Early survival was best in group B (A: 67.8% vs. B: 96.6%, p < 0.001), whereas late mortality (in total 1.8%) was similar for both groups. Reinterventions, corrected for follow-up time, were more frequent in group A (p = 0.005). In total 65 patients (25.1%) required 105 late reinterventions including 4 late aortic valve replacements. The mode of reinterventions has shifted over time, from surgical to more catheter-based (p = 0.03). The vast majority of patients functioned in NYHA class I. In contrast to the recent cohort, who have a normal average LVEF (%), the average LVEF in the oldest cohort was in the bottom percentile of normal range.

The majority of patients in their fifth decade after ASO are in functional class I. Early outcome improved showing reduced mortality and need for reoperation. However, a trend towards reduced left ventricular function and late aortic valve replacements justify further research.