10 Percutaneous Intervention in the Fetus, Including Postnatal Management
Abstract
Introduction
Severe Midgestation Aortic Stenosis With Evolving Hypoplastic Left Heart Syndrome
Nội dung
Abstract The goal of percutaneous fetal cardiac intervention is to alter the natural history of select forms of congenital heart disease in utero and improve postnatal morbidity and/or mortality Percutaneous fetal cardiac intervention may be performed for severe mid-gestation aortic stenosis with evolving hypoplastic left heart syndrome (HLHS); pulmonary atresia with intact ventricular septum and evolving hypoplastic right heart syndrome (HRHS); and established HLHS with a highly restrictive or intact atrial septum (IAS) Fetal aortic valvuloplasty and fetal pulmonary valvuloplasty are performed for evolving HLHS and HRHS, respectively, to achieve a biventricular circulation postnatally Among technically successful cases of fetal aortic valvuloplasty, approximately half achieve a biventricular outcome, often with postnatal left ventricular rehabilitation For evolving HRHS, selection of appropriate candidates has been challenging, but patients have undergone successful fetal pulmonary valvuloplasty from a technical perspective Fetal atrial septoplasty, with or without stent placement, is performed for established HLHS with a highly restrictive or intact atrial septum (IAS) in order to improve survival Although technical success and greater stability in the immediate postnatal period have been achieved, there has been no demonstrable improvement in survival to date The advent of new fetal therapies is on the horizon, with maternal safety and autonomy at its core Keywords Congenital heart disease; prenatal diagnosis; fetal echocardiography; fetal cardiac intervention; in utero therapy; hypoplastic left heart syndrome; pulmonary atresia with intact ventricular septum Introduction As fetal echocardiography has advanced over the past several decades, our understanding of the natural history of congenital heart disease in utero has progressed For select lesions that evolve in utero and lead to significant morbidity and/or mortality by the time of birth, relatively simple anatomic modifications may alter the natural history and improve prognosis This understanding, along with improvements in interventional obstetric and catheterization techniques, has led to minimally invasive percutaneous fetal cardiac interventions Since the first report of fetal cardiac intervention by Maxwell et al in London in 1991,1 the field has developed considerably However, fetal cardiac intervention is not curative and represents the first step toward a management strategy that must be pursued in the postnatal setting This chapter focuses on three forms of structural congenital heart disease for which fetal cardiac intervention is performed: severe aortic stenosis (AS) with evolving hypoplastic left heart syndrome (HLHS); pulmonary atresia with intact ventricular septum (PA/IVS) and evolving hypoplastic right heart syndrome (HRHS); and established HLHS with intact or highly restrictive atrial septum (IAS) Fetal aortic and pulmonary valvuloplasty are performed for severe AS with evolving HLHS and PA/IVS with HRHS, respectively, to promote a biventricular circulation The goal is to prevent the life-long morbidity and mortality that accompanies staged reconstruction for functionally univentricular heart (see also Chapters 71 and 73) In contrast, fetal atrial septoplasty (perforation/balloon dilation), often with atrial septal stent placement, is performed for established HLHS with IAS or highly restrictive atrial septum to improve survival of an otherwise nearly lethal disease Staged reconstruction remains necessary for such patients postnatally Patient selection for fetal cardiac intervention technical aspects of the procedures, and postnatal outcomes and management are discussed Maternal considerations of fetal cardiac intervention have been central to the development of the field, with no major adverse events reported to date Although maternal issues remain paramount to consider as new therapies evolve, they are beyond the scope of this chapter Severe Midgestation Aortic Stenosis With Evolving Hypoplastic Left Heart Syndrome Fetal aortic valvuloplasty for severe midgestation AS with evolving HLHS is the most commonly performed fetal cardiac intervention Although early surgical survival has improved for infants with HLHS, staged univentricular palliation to a Fontan circulation carries significant life-long morbidity and mortality.2–5 A subset of patients with HLHS have a common pathophysiologic etiology in utero; namely, severe valvar AS with left ventricular (LV) dilation and dysfunction Natural history studies have demonstrated that severe AS in the midgestation fetus initially leads to LV dilation as the ventricle attempts to overcome significant afterload (Fig 10.1) As gestation progresses, the LV becomes dysfunctional and ultimately growth arrest of left-sided structures ensues.6–10 By the time of birth, the left side of the heart is incapable of supporting the systemic circulation, resulting in HLHS FIG 10.1 Four-chamber view demonstrating severe left ventricular dilation as a result of aortic stenosis in a midgestation fetus