Creation of an Atrial Septal Defect In Utero for Fetuses With Hypoplastic Left Heart Syndrome and Intact or Highly Restrictive Atrial Septum

Abstract

Background-Infants born with hypoplastic left heart syndrome and an intact or highly restrictive atrial septum face a neonatal mortality of at least 48% despite early postnatal left atrial decompression and palliative surgery. Prenatal left atrial decompression has been suggested as a means of improving these outcomes. This study reports the feasibility of fetal catheterization to create an interatrial communication and describes technical considerations. Methods and Results-Seven fetuses at 26 to 34 weeks' gestation with hypoplastic left heart syndrome and intact or highly restrictive atrial septum underwent attempted prenatal intervention. Under ultrasound guidance, the atrial septum was approached with a needle introduced percutaneously from the maternal abdominal surface. In 6 of 7 fetuses, the atrial septum was successfully perforated, with balloon dilation of this iatrogenic defect resulting in a small but persistent interatrial communication. There were no maternal complications. One fetus died after the procedure. The remaining fetuses were liveborn at term, although 4 died as neonates. Conclusions-Ultrasound-guided fetal atrial septoplasty consisting of septal puncture and balloon dilation is feasible and can be performed percutaneously to minimize maternal risk. Although we have not demonstrated any positive clinical impact to date, it is our hope that further technical evolution will ultimately enable prenatal left atrial decompression and improvement of outcomes in fetuses with hypoplastic left heart syndrome and intact atrial septum.

Percutaneous Fetal Cardiac Catheterization Technique for Stenting the Foramen Ovale in a Midgestation Lamb Model

“…High risk of bleeding, cardiac tamponade, and the need for in utero resuscitation. [5][6][7] 2. High rate of stent dislocation.…”

“…High rate of stent dislocation. Although a balloonmounted stent prevents septal recoil and reclosure of the interatrial communication, 6 this is frequently hampered by stent dislocation, especially because of the need to retrieve the balloon after delivery of the stent. 18-gauge access (2-3 mm diameter).…”

“…First, in a previous publication, we have shown that diathermy of the fetal cardiac tissue using the percutaneous transhepatic approach under ultrasound guidance is a feasible method to create perforations. 21 Second, because IAS has been reported as showing recoil of the septum after balloon dilation alone, 6 we have addressed that by stent insertion, which is necessary to ensure sustained patency of the created intra-atrial communication. 13 In this study, we used self-expandable sinus-superflex-DS (Optimed) stents with a length of 12 mm and a diameter of 8 mm.…”

“…6,9 Because embolization of the intrahepatic section of the sheath entry tract is feasible in our transhepatic approach to minimize the risk of hemorrhage once the sheath is removed, the capability to deliver large, open-cell designed stents through a 4F sheath may improve the efficacy (most interventions could be completed within 45 minutes, including access to the fetal circulation) and safety of the procedure when compared with the use of small, balloon-mounted coronary stents, which are at an increased risk of early stent occlusion and stent embolization. 9,15 Even with timely postnatal treatment of HLHS-IAS after birth to decompress the LA, mortality before and after surgical reconstruction is still double that of HLHS infants with naturally open FO.…”

“…4 Consequently, fetal intervention with the goal of decompressing the LA by direct transcardiac puncture of the atrial septum followed by balloon dilatation of the FO has been performed and reported, mostly as a single-center experience. [5][6][7] Despite these fetal interventions, outcomes have not improved significantly, and Stenting the Foramen Ovale in Fetal Sheep there is an ongoing discussion about how best to create a persistent and adequately sized atrial septal defect. 8 Until now, attempts to access the atrial septum and FO by an alternative, less invasive route, such as via the fetal hepatic veins, have had only limited success.…”