# Early Versus Delayed Bidirectional Superior Cavopulmonary Anastomosis (BSCA) in Infants: A Comparison of Outcomes

## TL;DR

This study compares outcomes of early versus delayed bidirectional Glenn shunt surgery in infants with a rare heart defect, finding higher early risk but potential long-term benefits.

## Contribution

The study provides new insights into the outcomes of early BDG in infants in the Indian context, emphasizing patient selection and long-term benefits.

## Key findings

- Early BDG was associated with higher early mortality (18.52% vs 4.79%) compared to delayed BDG.
- Preoperative mechanical ventilation and inotropic scores were stronger mortality predictors than age.
- Early BDG led to better systemic ventricle unloading and less pulmonary artery distortion over time.

## Abstract

Background and aims

Functionally univentricular hearts (UVH) are a relatively rare congenital heart defect and often require staged palliation leading to the Fontan circulation. The bidirectional superior cavopulmonary anastomosis (BSCA) or bidirectional Glenn shunt (BDG) is a key intermediate procedure that partially separates systemic and pulmonary circulations. Although traditionally delayed until six months of age, earlier BDG has become common. This study compared outcomes in patients undergoing BDG at six months or younger versus seven months to one year and examined time to Fontan completion (FO), outcome predictors, and the influence of early BDG in the Indian context.

Methods

In this retrospective observational study, 173 patients with UVH underwent BDG at age one year or younger from January 2011 to December 2020 at a single tertiary care center. Twenty-seven patients (Group A) were six months or younger, and 146 (Group B) were seven to 12 months. Preoperative, intraoperative, and postoperative data were collected, including morbidity, mortality, and follow-up assessments. The data were statistically analyzed by Fisher’s exact test, Pearson’s chi-square test, and Cox proportional hazards or logistic regression modeling.

Results

Early mortality was 6.93% (12/173). Mortality was significantly higher in Group A (5/27; 18.52%) than in Group B (7/146; 4.79%; p=0.01). On multivariate analysis, preoperative mechanical ventilation, maximum inotropic score, and maximum vasoactive inotropic score (VIS) were independent predictors of mortality rather than patient age alone. Despite the higher initial risk, infants in Group A benefited from earlier unloading of the systemic ventricle and demonstrated less pulmonary artery (PA) distortion at follow-up.

Conclusions

Although BDG before age six months carries a higher early mortality risk, primarily linked to clinical severity rather than age, it can offer important advantages in systemic ventricle offloading and reduced PA distortion over time. These findings underscore the need for careful patient selection and highlight the potential for improved long-term outcomes with early BDG in appropriately selected infants.