Half a century of experience with congenital heart disease: what have we learned about ventricular septal defects?

This editorial refers to ‘Survival of patients with congenital ventricular septal defect’, by F. Eckerström et al., https://doi.org/10.1093/eurheartj/ehac618. In this issue of the European Heart Journal, Eckerström and colleagues utilize data from Danish national medical registries to estimate survival in 9186 patients with congenital ventricular septal defect (VSD).1 Over a median follow-up of 22 years, they report that patients with VSD had a lower survival than the general population. These results persisted even when Eisenmenger syndrome was excluded, and were seen in both the repaired and the unrepaired groups. Additional findings included the fact that patients with VSD diagnosed prior to adulthood had a worse survival, and that cardiac-related events were the most common cause of death. Are these results surprising? Population-based studies are instructive, allowing large numbers of patients to be included, yet there are inherent assumptions and limitations with such data. As such, conclusions derived from national registry data over a nearly 30-year period including both repaired and unrepaired patients with VSDs must be balanced with the perspective of how the field of congenital heart disease has evolved over the same period of time. This study includes patients with a diagnosis of VSD spanning from 1977 through 2018, which represents a time frame in which there were vast improvements in both diagnostic modalities and treatment strategies for congenital heart conditions. In the early experience, indications for VSD closure were not uniform, and the decision to proceed with surgical intervention varied by clinical preference and institutional expertise. Historically, children with VSD often underwent a surgical palliation with a pulmonary artery (PA) band to limit pulmonary blood flow. This procedure often resulted in scarring down of the patch at the pulmonary band site with residual haemodynamic sequelae. In the Joint Study on the Natural History of Congenital Heart Defects (NIS-1), which included patients who underwent surgery largely in the 1960s, 75% of children <2 years of age with a surgically repaired VSD underwent a PA band as the initial surgical strategy.2 Additionally, several decades ago, myocardial preservation strategies during cardiopulmonary bypass were not as advanced, and suboptimal results were more common. Therefore, the survival curves of repaired patients may be reflective of different operative techniques. Not surprisingly, when this cohort was stratified by surgical era, results have been superior since 1990.