Abstract 14163: The Single Ventricle Reconstruction (SVR) Trial at 6 Years: Transplant-Free Survival, Catheter Interventions, and Morbidity

Background: In the SVR trial, 1-year (y) transplant (tx)-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) vs modified Blalock-Taussig shunt (MBTS). At 6 y, we compared tx-free survival, unplanned interventions, morbidities, New York Heart Association (NYHA) Class, and RV ejection fraction (RVEF) by assigned shunt. Methods and Results: The SVR trial treated 549 pts. Vital status and medical history were ascertained annually. Tx-free survival in the RVPAS (63.5%) vs MBTS (58.7%) groups did not differ (Figure; log-rank P=.13). Similarly, neither mortality nor tx alone differed by shunt type. By 6 y, RVPAS pts had a higher incidence of any catheter intervention (.38 vs .23/pt-yr, P<.001), balloon angioplasty (P=.014), stent (P=.009), and coiling (P<.001). The % of pts with morbidities by 6 y were similar in the groups, with overall rates: pacemaker 3%, thrombosis 16%, stroke 7%, seizures 13%, protein losing enteropathy 3%, plastic bronchitis 0.5%, and 6-y NYHA Class I 71%, II 21%, III 3%, and IV 5%. Among pre-specified subgroups, worse tx-free survival was associated with low birth weight (<2500 g); worse pre-Norwood tricuspid regurgitation (≥2.5 mm jet width); lower surgeon Norwood volume; preterm birth (<37 wks); and combined aortic atresia and pre-term birth (all P<.01). Subgroup x shunt interaction was significant only for surgeon volume levels (P<.05); in the highest volume group (n >15/y), the MBTS was beneficial (P<.04), and in 3 lower volume groups, the RVPAS was qualitatively better. In 6-y echoes read to date, RVEF was similar in the RVPAS vs MBTS groups (46±7, n=55 vs 46±6%, n=48; P=.9). Conclusions: By 6 y, tx-free survival was an absolute 4.8% higher for pts assigned to the RVPAS vs MBTS group, but the difference no longer reached statistical significance, and they needed more catheter interventions. Rates of death, tx, and morbidities; distribution of NYHA Class; and RVEF were each similar in the shunt groups.