Transplant-Free Survival and Interventions at 6 Years in the Single Ventricle Reconstruction Trial
Background—In the Single Ventricle Reconstruction (SVR) trial, one-year transplant-free survival was better for the Norwood procedure with right ventricle-to-pulmonary artery shunt (RVPAS) compared with a modified Blalock-Taussig shunt (MBTS) in patients with hypoplastic left heart and related syndromes. At 6 years, we compared transplant-free survival and other outcomes between the groups.
Methods—Medical history was collected annually using medical record review, telephone interviews, and the death index. The cohort included 549 patients randomized and treated in the SVR trial.
Results—Transplant-free survival for the RVPAS vs. MBTS groups did not differ at 6 years (64% vs. 59%, P=0.25) or with all available follow-up of 7.1±1.6 years (log-rank P=0.13). The RVPAS vs. MBTS treatment effect had non-proportional hazards (P=0.009); the hazard ratio (HR) for death or transplant favored the RVPAS before Stage II surgery (HR=0.66; 95% CI 0.48-0.92). The effect of shunt type on death or transplant was not statistically significant between Stage II to Fontan surgery (HR 1.36, 95% CI 0.86-2.17, p=0.17) or after the Fontan procedure (HR 0.76, 95% CI 0.33-1.74, p=0.52). By 6 years, RVPAS patients had a higher incidence of catheter interventions (0.38 vs. 0.23/patient-year, P<0.001), primarily due to more interventions between the Stage II and Fontan procedures (HR=1.72, 95% CI 1.00-3.03). Complications did not differ by shunt type; by 6 years, one in five patients had had a thrombotic event and one in six, seizures.
Conclusions—By 6 years, the hazards of death or transplant and catheter interventions were not different between the RVPAS vs. MBTS groups. Children assigned to the RVPAS group had 5% higher transplant-free survival but the difference did not reach statistical significance, and they required more catheter interventions. Both treatment groups have accrued important complications.
Clinical Trial Registration—Unique Identifier: NCT00115934 URL: http://clinicaltrials.gov
- Received May 15, 2017.
- Revision received January 2, 2018.
- Accepted January 16, 2018.