Longitudinal Follow-Up of Children With HLHS and Association Between Norwood Shunt Type and Long-Term Outcomes: The SVR III Study

Abstract

OBJECTIVE: In the SVR trial (Single Ventricle Reconstruction), newborns with hypoplastic left heart syndrome were randomly assigned to receive a modified Blalock-Taussig-Thomas shunt (mBTTS) or a right ventricle-to-pulmonary artery shunt (RVPAS) at Norwood operation. Transplant-free survival was superior in the RVPAS group at 1 year, but no longer differed by treatment group at 6 years; both treatment groups had accumulated important morbidities. In the third follow-up of this cohort (SVRIII [Long-Term Outcomes of Children With Hypoplastic Left Heart Syndrome and the Impact of Norwood Shunt Type]), we measured longitudinal outcomes and their risk factors through 12 years of age. METHODS: Annual medical history was collected through record review and telephone interviews. Cardiac magnetic resonance imaging (CMR), echocardiogram, and cycle ergometry cardiopulmonary exercise tests were performed at 10 through 14 years of age among participants with Fontan physiology. Differences in transplant-free survival and complication rates (eg, arrhythmias or protein-losing enteropathy) were identified through 12 years of age. The primary study outcome was right ventricular ejection fraction (RVEF) by CMR, and primary analyses were according to shunt type received. Multivariable linear and Cox regression models were created for RVEF by CMR and post-Fontan transplant-free survival. RESULTS: Among 549 participants enrolled in SVR, 237 of 313 (76%; 60.7% male) transplant-free survivors (mBTTS, 105 of 147; RVPAS, 129 of 161; both, 3 of 5) participated in SVRIII. RVEF by CMR was similar in the shunt groups (RVPAS, 51±9.6 [n=90], and mBTTS, 52±7.4 [n=75]; P =0.43). The RVPAS and mBTTS groups did not differ in transplant-free survival by 12 years of age (163 of 277 [59%] versus 144 of 267 [54%], respectively; P =0.11), percentage predicted peak V o 2 for age and sex (74±18% [n=91] versus 72±18% [n=84]; P =0.71), or percentage predicted work rate for size and sex (65±20% versus 64±19%; P =0.65). The RVPAS versus mBTTS group had a higher cumulative incidence of protein-losing enteropathy (5% versus 2%; P =0.04) and of catheter interventions (14 versus 10 per 100 patient-years; P =0.01), but had similar rates of other complications. CONCLUSIONS: By 12 years after the Norwood operation, shunt type has minimal association with RVEF, peak V o 2 , complication rates, and transplant-free survival. RVEF is preserved among the subgroup of survivors who underwent CMR assessment. Low transplant-free survival, poor exercise performance, and accruing morbidities highlight the need for innovative strategies to improve long-term outcomes in patients with hypoplastic left heart syndrome. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT00115934.

Morphology of the native ascending aorta after the Norwood procedure for aortic atresia: impact on survival and right ventricular dysfunction

“…Interestingly, the presence of a systemic-to-pulmonary shunt at stage I was a significant protective factor for RV dysfunction after stage II, which is consistent with our previous report on our extended ( n = 146) HLHS/AA cohort and with several other studies [ 15–17 ]. However, recent data from a study on HLHS teenagers ( n = 168) revealed no association between the initial shunt type at the Norwood procedure and RV function at the age of 10 years (10.4–11.5) [ 18 ]. Of note, this study did not focus on HLHS/AA types.…”

The Second Interstage Period Is Just as “Risky” as the First in HLHS

“…As demonstrated by the results of the Single Ventricle Reconstruction III study, these patients remain at ongoing risk for mortality and morbidity. 14 The “ideal” shunt type at Norwood remains elusive. One modifiable factor is a careful assessment of the timing of Stage II.…”

The Conduit to Improving Outcomes

“… 2 While TFS was higher with the RVPAS than with the mBTTS (74% vs 64%, P = 0.01) at 1 year, it did not differ at 3, 6, or, most recently, 12 years (59% vs 54%, P = 0.11). 2 , 3 The sobering fact that nearly half of the SVR cohort died or underwent heart transplantation by 12 years of age, nearly one-third in the first year of life, clearly underscores the opportunity for improvement in our care.…”