Abstract 4565: Optimal Timing Of Stage-2 Palliation For Hypoplastic Left Heart Syndrome
Background Because optimal timing of stage-2 palliation of HLHS is contentious, we explored associations between length of time between stage-1 and stage-2 (“interstage interval”) and survival.
Methods A multi-institutional cohort of neonates (N=703;1994 –2001) who underwent Norwood palliation for HLHS was studied. Survival models were constructed for each of stage-1 and stage-2 and their combined cumulative hazard was defined.
Results A constant, persisting hazard for death was prominent ≈2 months after Norwood (“interstage death”). Risk factors for interstage death included: smaller weight at diagnosis, longer DHCA duration, smaller indexed tricuspid annulus, mitral stenosis, older age at Norwood, smaller distal arch dimension and sternal splinting (all P<.01, >50% bootstrap reliability). Following stage-2 palliation (N=404, median interval 5.8 months after Norwood), 32 died before subsequent Fontan completion. Risk factors for these deaths included: earlier stage-2 (P<.0001, 60% reliability), younger age at Norwood and smaller RV dimensions at diagnosis. Performing stage-2 within 2 months of Norwood conferred exponential increased risk of death. Cumulative hazard exposure (figure⇓) was minimized with interstage interval ≈ 3 months. For low risk patients intervals >4 months were optimal. For high-risk children survival was optimized with ≈ 2 month interstage interval.
Conclusions Optimal timing of stage-2 palliation is dependent on patients’ risk category. High-risk children may have improved survival by early progression to stage-2; no such benefits are seen for lower risk children. The interstage interval will not be safely reduced below 2 months.