Transplant-Free Survival and Interventions at 3 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). At 3 years, we compared transplant-free survival, echocardiographic right ventricular ejection fraction (RVEF), and unplanned interventions in the treatment groups.
Methods and Results—Vital status and medical history were ascertained from annual medical record, death index and phone interviews. The cohort included 549 patients randomized and treated in the SVR trial. Transplant-free survival for the RVPAS vs. MBTS groups did not differ at 3 years (67% vs. 61%, P=.15) or with all available follow-up of 4.8±1.1 years (logrank P=.14). Pre-Fontan RVEF was lower in the RVPAS vs. MBTS group (41.7±5.1% vs. 44.7±6.0%, P=.007), and RVEF deteriorated in RVPAS (P=.004) but not MBTS subjects (P=.40) (pre-Fontan minus 14-month mean -3.25±8.24% vs. 0.99±8.80%, P=.009). The RVPAS vs. MBTS treatment effect had non-proportional hazards (P=.004); the hazard ratio (HR) favored the RVPAS before 5 months (HR=0.63; 95% CI 0.45-0.88), but the MBTS beyond one year (HR=2.22; 95% CI 1.07-4.62). By 3 years, RVPAS subjects had a higher incidence of catheter interventions (P<.001), with an increasing HR over time (P=0.005): <5 months HR= 1.14 (95% CI, 0.81-1.60); 5 months-1 year HR=1.94 (1.02-3.69), and >1 year HR=2.48 (1.28-4.80).
Conclusions—By 3 years, the Norwood procedure with RVPAS, compared with MBTS, was no longer associated with superior transplant-free survival. Moreover, RVPAS subjects had slightly worse RVEF and underwent more catheter interventions, with increasing hazard ratio over time.
Clinical Trial Registration Information—clinicaltrials.gov. Identifier: NCT00115934.
- Norwood procedure
- hypoplastic left heart syndrome
- congenital cardiac defect
- congenital heart disease
- cardiac surgery
- single ventricle
- Received September 19, 2013.
- Revision received February 12, 2014.
- Accepted February 19, 2014.