Native Bicuspid Pulmonary Valve in D-Loop Transposition of the Great Arteries: Outcomes of the Neo-Aortic Valve Function and Root Dilation After Arterial Switch Operation.

Background Neo-aortic root dilation and neo-aortic regurgitation (AR) are common after arterial switch operation for D-loop transposition of the great arteries. We sought to evaluate these outcomes in patients with bicuspid native pulmonary valve (BNPV). Methods and Results A retrospective analysis of patients with transposition of the great arteries undergoing arterial switch operation at Boston Children's Hospital from 1989 to 2018 matched BNPV patients 1:3 with patients with tricuspid native pulmonary valve by year of arterial switch operation. Kaplan-Meier analyses with log-rank test compared groups for time to first neo-aortic valve reoperation, occurrence of ≥moderate AR, and neo-aortic root dilation (root z score ≥4). A total of 83 patients with BNPV were matched with 217 patients with tricuspid native pulmonary valve. Patients with BNPV more often had ventricular septal defects (73% versus 43%; P<0.001). Hospital length of stay (11 versus 10 days) and 30-day surgical mortality (3.6% versus 2.8%) were similar. During median 11 years follow-up, neo-aortic valve reoperation occurred in 4 patients with BNPV (6.0%) versus 6 patients with tricuspid native pulmonary valve (2.8%), with no significant difference in time to reoperation. More BNPV had AR at discharge (4.9% versus 0%; P=0.014) and during follow-up (13.4% versus 4.3%; hazard ratio [HR], 3.9; P=0.004), with shorter time to first occurrence of AR; this remained significant after adjusting for ventricular septal defects. Similarly, neo-aortic root dilation was more common in BNPV (45% versus 38%; HR, 1.64; P=0.026) with shorter time to first occurrence. Conclusions While patients with BNPV have similar short-term arterial switch operation outcomes, AR and neo-aortic root dilation occur more frequently and earlier compared with patients with tricuspid native pulmonary valve. Further long-term studies are needed to determine whether this results in greater need for neo-aortic valve reoperation.