The coexistence of pulmonary stenosis and ventricular septal defect is commonly referred to as a Fallot-type situation. Pulmonary atresia with ventricular septal defect (PA-VSD) represents the extreme end of this spectrum. This conotruncal anomaly is characterized by the absence of luminal continuity between the right ventricle and pulmonary arteries. The symptomatology depends on the degree of pulmonary blood flow, which dictates the clinical management of these patients.

There are three subgroups of PA-VSD:

1. Normal pulmonary arteries with typically ductal-dependent flow.
2. Hypoplastic pulmonary arteries with variable arborization defects (absence of blood flow to certain pulmonary segments), frequently accompanied by major aortopulmonary collateral arteries (MAPCAs) with variable distribution and number.
3. Absence of pulmonary arteries with exclusive flow from MAPCAs.

This discussion focuses on the first subgroup—those with normal pulmonary arteries—and specifically on their treatment options. Currently, these patients can be managed through various equally valid approaches. One strategy involves early complete repair, including VSD closure and implantation of a conduit between the right ventricle and pulmonary arteries, to avoid morbidity and mortality associated with shunts and the need for subsequent surgeries. Another approach is staged repair, beginning with systemic-to-pulmonary shunting for palliation, followed by definitive repair at a later stage to mitigate the risks of complex neonatal surgeries and the frequent reoperations required for small conduits. Some groups advocate for a hybrid correction—resolving right ventricular outflow obstruction with a conduit or transannular patch in one stage, followed by VSD closure in a second stage. There is no perfect solution; the strategy should be tailored to the individual patient.

In this article, Macalister et al. describe a 30-year experience (1989–2019) at the Royal Children’s Hospital of Melbourne in managing PA-VSD with systemic-to-pulmonary shunts. Patients included were those with PA-VSD without MAPCAs, even if the initial palliation was performed at another institution. Excluded were patients unsuitable for biventricular repair, those undergoing primary complete repair, and one patient who received a transannular patch during palliation. Management involved various shunt types: modified Blalock-Taussig shunts from the innominate or ipsilateral subclavian artery, central Gore-Tex shunts via sternotomy or thoracotomy, with or without cardiopulmonary bypass. The ductus arteriosus was not ligated in all cases. Final repair utilized diverse conduits and patches. The cohort was divided into two periods before and after 2009, reflecting a shift in preference for central shunts and systematic ductal closure.

Among 107 patients analyzed, 91 (85%) achieved complete repair at a median age of 1 year. Median follow-up was 10.5 years. Survival at 6 months, 20 months, and 10 years was 90%, 85%, and 81%, respectively. Chromosomal abnormalities were present in one-third of patients, with no significant differences between periods. During the second period (n = 40), cardiopulmonary bypass use increased (72% vs. 20%; p < .001), primarily due to the choice of central shunts. This period saw reduced early mortality, decreased interstage mortality (not statistically significant), and earlier completion of repair (0.7 years vs. 1.3 years; p < .001). Ninety percent of patients treated in the second period achieved complete repair. Logistic regression identified that shunts <3.5 mm (p < .006) and those performed post-2009 (p < .001) facilitated earlier complete repair. However, smaller shunts were an independent risk factor for morbidity (HR = 4.2; p < .039) without increasing mortality or impeding repair rates. Atrioventricular discordance and genetic syndromes independently increased mortality risk before complete repair (p < .05).

The authors concluded that survival following staged repair of PA-VSD is high. Smaller shunts allow earlier repair without increasing mortality but are associated with higher morbidity.

COMMENTARY:

Scientific evidence guides clinical practice, and the highest level of evidence comes from randomized controlled trials. However, in pediatric cardiology, such trials often pose ethical challenges. This limitation forces practitioners to rely on institutional experiences described in the literature. PA-VSD is a complex condition, with outcomes influenced not only by surgical decisions but also by pre- and postoperative management. Adding to this complexity are genetic anomalies with extracardiac malformations, which independently worsen outcomes regardless of the surgical technique employed.

The results reported by Macalister et al. represent some of the best published outcomes for staged PA-VSD repair. Their complete repair rate of 85% and 10-year survival rate of 81% rival outcomes reported for primary early repair. It is worth noting that outcomes for staged repair in other studies have been inferior due to higher proportions of patients with genetic anomalies. This study’s findings should be interpreted with caution, given its retrospective nature, long study period, and heterogeneous cohort in terms of surgical techniques, reconstruction materials, and ductal ligation during palliation. Postoperative management of palliated patients is challenging, requiring a highly experienced team. Thus, the results reported by Macalister et al. may not be generalizable to other centers.

In conclusion, with the current evidence, both early repair and staged approaches are equally valid for managing PA-VSD. The most reasonable approach is to select the technique and strategy best suited to the experience and outcomes of the treating institution.

REFERENCE:

Macalister SJ, Buratto E, Naimo PS, Ye XT, Fulkoski N, Weintraub RG, et al. Long-term Outcomes of Staged Complete Repair of Pulmonary Atresia With Ventricular Septal Defect. Ann Thorac Surg. 2023 Feb;115(2):445-451. doi: 10.1016/j.athoracsur.2022.09.022.