Abstract 14744: 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

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Introduction: Neo-aortic root dilation (ARD) is common after arterial switch operation (ASO) for D-loop transposition of the great arteries (TGA). We sought to compare short and long-term outcomes for bicuspid native pulmonary valve (BNPV) patients to those with normal trileaflet variants (TNPV). Methods: A retrospective cohort of TGA patients undergoing ASO at Boston Children’s Hospital from 1989-2018 was analyzed, matching BNPV patients 1:3 with TNPV patients by year of ASO; those with >mild subpulmonary stenosis or complex TGA were excluded. Categorical and continuous variables were compared using Fisher’s exact and Wilcoxon rank sum tests, respectively. Kaplan-Meier analyses with log-rank test compared groups for time to first reoperation on the neo-aortic valve, first occurrence of ≥moderate neo-aortic regurgitation (AR), and ARD defined as root z-score ≥4. Hazard ratios were estimated based on the Cox proportional hazards model. Results: A total of 83 BNPV patients were matched with 217 TNPV. BNPV patients were more likely to have a VSD (75% vs 44%, p <0.001). Early surgical outcomes including hospital LOS (11 vs 10 days) and 30-day mortality (3.6% vs 2.8%) were similar. During median 10 years follow-up, neo-aortic valve reoperation occurred in 4 BNPV (6%) vs 6 TNPV (3%) patients, with no statistically significant difference in time to reoperation. More BNPV patients had AR at discharge (4.9% vs 0%, p=0.014) and during follow-up (13.4% vs 4.3%, HR 3.9, p=0.004), with shorter time to first occurrence of AR (Figure 1A); this remained significant after adjusting for presence of VSD. Similarly, ARD was more common in BNPV (45% vs 37%, HR 1.64, p=0.02) with shorter time to first occurrence (Figure 1B). Conclusions: While patients with BNPV have similar short-term ASO outcomes, AR and ARD occur more frequently and earlier compared with TNPV patients. Further long-term studies are needed to determine whether this results in greater need for neo-aortic valve reoperation.