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.