The impact of a bicuspid pulmonary valve in the aortic position after arterial switch for transposition of the great arteries on neoaortic root dimension and function: a propensity score matched analysis

OBJECTIVES: This study investigated the effect of a bicuspid pulmonary valve on neoaortic root morphology, function, and the clinical outcomes of early survivors after the arterial switch operation using propensity score matching. METHODS: From 1997 to 2018, a total of 442 patients underwent the arterial switch operation for transposition of the great arteries. After exclusion of patients who underwent a staged repair, were repaired beyond 1 year of age, died before discharge and who lacked echocardiographic data at discharge, propensity score matching was used for analysis. RESULTS: Among 352 eligible patients, 18 patients (5.1%) had a bicuspid pulmonary valve. After propensity score matching (1:4), 15 patients with bicuspid valve (bicuspid group) and 60 patients with tricuspid valve (tricuspid group) were enrolled. The median follow-up duration was 9.9 years (4 months∼22.3 years). All-cause reoperation-free survival at 10 years was 93.3% in the bicuspid group and 87.0% in the tricuspid group (P = 0.839), and reoperation for neoaortic valve or root was required in 2 patients in the bicuspid group and 1 in the tricuspid group without intergroup difference. The z-score of the neoaortic annulus did not change in either group, although there was an increasing tendency in the z-score of the neoaortic sinus without intergroup difference (P = 0.690). Deterioration in neoaortic valve function was more prominent in the bicuspid group (p = 0.028). CONCLUSIONS: The neoaortic sinus might outgrow the norm regardless of the number of neoaortic valve cusps, whereas the neoaortic annulus remained unchanged. Deterioration of valve function was more prominent in the bicuspid group, which suggests that a bicuspid valve might play a significant role in deterioration of neoaortic valve function, without an additional effect on root pathology.