Introduction to the Single Ventricle Reconstruction trial

Abstract

The Single Ventricle Reconstruction (SVR) trial, sponsored by the National Heart, Lung, and Blood Institute and carried out by 15 clinical centers, randomized 549 neonates and showed that transplantation-free survival at 14 months was significantly higher overall with the right ventricleto-pulmonary artery shunt (RVPAS) compared with the modified Blalock-Taussig shunt (MBTS). Any surgical procedure that does not exceed 65% survival at 1 year deserves to be studied and scrutinized relentlessly. Although the primary outcome was clear when considering the entire study cohort, many questions remained regarding the impact of comorbidities; intraoperative, postoperative, and interstage management strategies on morbidity and mortality; and the mechanisms of death throughout the study period. The compilation of 5 follow-up articles represents secondary analyses of the SVR trial, and their main value is that they provide a more detailed analysis of areas that could not be covered in the New England Journal of Medicine article. The SVR trial fortunately included enough study patients, and collected a vast amount of data, to permit analysis of the interaction of risk factors with shunt type; the risk factors of hospital morbidity and mortality after the Norwood; the impact of shunt type and other risk factors on interstage mortality; the cause, timing, and location of death after the Norwood; as well as a descriptive study on practice variation in perioperative care found across centers. Some of the findings confirm the findings of previous retrospective studies or database extraction studies, such as the impact of center/surgeon volume, the major and independent role of extracardiac anomalies, genetic syndromes, low gestational age and birth weight, smaller ascending aorta, obstructed pulmonary venous return, and lower socioeconomic status play on outcomes. Patients with aortic stenosis/mitral stenosis did better than any other subgroup, presumably because of the presence of antegrade aortic flow, and patients with aortic atresia/mitral stenosis did not exhibit a higher mortality, although the presence or