Fetal interventions for structural heart disease

Fetal cardiac intervention (FCI) offers the potential to alter in utero anatomy and physiology. For aortic stenosis with evolving hypoplastic left heart syndrome and pulmonary atresia with intact ventricular septum with evolving hypoplastic right heart syndrome, FCI may result in maintenance of a biventricular circulation, thus avoiding single‐ventricle palliation and its attendant complications. In the case of hypoplastic left heart syndrome with intact atrial septum, FCI may ameliorate in utero pathophysiology and portend a more favorable postnatal prognosis. In all cases, a detailed fetal echocardiographic assessment to identify the appropriate FCI candidate is essential. This article reviews the three aforementioned lesions for which FCI can be considered. The pathophysiology and rationale for intervention, echocardiographic assessment, patient selection criteria, and outcomes for each lesion will be reviewed. A primary focus will be the echocardiographic evaluation of each lesion.     

Radiofrequency perforation and cutting balloon septoplasty of intact atrial septum in a newborn with hypoplastic left heart syndrome using transesophageal ICE probe guidance.

Newborns with hypoplastic left heart syndrome and intact atrial septum present an emergent and unique challenge to a children's heart center. This case report describes new transcatheter techniques (use of radiofrequency energy to perforate the atrial septum followed by cutting balloon and static balloon septoplasty) and novel use of a transesophageal ICE probe.     

Implantation of stents to ensure an adequate interatrial communication in patients with hypoplastic left heart syndrome

AIMS: To assess the feasibility of interatrial stenting for left atrial decompression in infants with hypoplastic left heart syndrome treated by a "hybrid-approach", with bilateral surgical banding of the pulmonary arteries and percutaneous stenting of the arterial duct. PATIENTS AND METHODS: We stented the atrial septum in 5 infants aged from 21 to 77 days, making the intervention as an elective procedure in 4, but as a rescue procedure in the fifth patient, who had a restrictive foramen. The stents, comprising 2 Jo-stents of 17 millimetres hand-crimped on a balloon catheter with dimensions of 10 by 20 millimetres, and 3 premounted Genesis stents with dimensions of 10 by 19 millimetres, were placed using a 6 French long or short sheath by femoral venous access. The stents were expanded under fluoroscopic guidance to create a slightly diabolo-shaped form that fitted the septum. RESULTS: The percutaneous interventions were successfully performed in all cases, producing significant improvement in clinical condition after placement. The saturations of oxygen increased from an average of 64% plus or minus 18% to 88% plus or minus 7%, (p < 0.05). During a mean follow up of 2.5 months, without any anticoagulant therapy, there were no complications related to the stenting. Surgical removal of the stents was uneventful during reconstruction of the aortic arch and creation of a bidirectional cavopulmonary connection in 4 patients, and during cardiac transplantation in one. CONCLUSION: In the context of the hybrid approach, definitive decompression of the left atrium can be achieved by stenting the atrial septum in infants with hypoplastic left heart syndrome. Placement of the stents is safe and effective, with insertion in the form of a diabolo reducing the risk of dislocation, as well as embolisation of the stent.     

Pattern of pulmonary venous blood flow in the hypoplastic left heart syndrome in the fetus

OBJECTIVE: To determine whether restriction at the atrial septum in the newborn with hypoplastic left heart syndrome can be predicted accurately by examining the pattern of pulmonary venous flow in the fetus. A restrictive atrial septum can contribute to haemodynamic instability before surgery for this lesion and has been associated with an increased mortality. DESIGN: Pulmonary venous pulsed Doppler tracings were compared between fetuses with hypoplastic left heart syndrome and controls. The size of the atrial septal defect on the postnatal echocardiogram was graded according to the degree of restriction. Pulsed Doppler tracings of pulmonary venous blood flow were obtained in 18 fetuses with left atrial outflow atresia and compared with 77 controls, adjusted for gestational age. Postnatal echocardiograms were available for analysis in 13 of 18 neonates. SETTING: A tertiary referral centre for fetal cardiology and paediatric cardiac surgery. RESULTS: Fetuses with hypoplastic left heart syndrome were different from controls in all pulmonary vein indices measured. As assessed from the postnatal echocardiogram, there were seven fetuses with a restrictive atrial septum. In these fetuses, the systolic flow velocity (p < 0.01), S/D ratio (p < 0.01), and peak reversal wave (p < 0.001) in the pulmonary vein tracing showed a good correlation with the degree of restriction. CONCLUSIONS: The Doppler pattern of pulmonary venous flow in the fetus with hypoplastic left heart syndrome appears to be a reliable predictor of restriction of the atrial septum in the neonate. This may help in the immediate post-delivery management of these infants before surgery.     

Hypoplastic left heart syndrome: is echocardiography accurate enough to guide surgical palliation?

Two-dimensional echocardiography can diagnose hypoplastic left heart syndrome. However, with the advent of the possibility of palliative open heart surgery, complete anatomic diagnosis is necessary. The anatomic findings of 15 neonates with hypoplastic left heart syndrome (age 1 to 10 days, mean 4.1) who had two-dimensional Doppler echocardiographic studies were compared with the results obtained by angiography (6 cases), surgery (11 cases) and autopsy (8 cases). Complete two-dimensional echocardiographic examination of the aortic arch, pulmonary and systemic venous return, atrial septum, ductus arteriosus and proximal coronary arteries was possible in all 15 neonates and correctly diagnosed hypoplastic left heart syndrome in each. Anatomic two-dimensional echocardiographic assessment was accurate in 13 (86%) of the 15 neonates and there were no false positive results. Undiagnosed associated abnormalities were hypoplasia of a left pulmonary artery in one patient and left superior vena cava in another. Accurate quantitation of the size of the tricuspid valve anulus, ascending aorta, pulmonary anulus and right and left pulmonary arteries was possible. Doppler examination was performed in seven patients and confirmed retrograde aortic arch flow and right to left systolic shunting in the patent ductus arteriosus. In selected neonates, surgical palliation can be attempted without angiography.     

The hypoplastic left heart syndrome with intact atrial septum: atrial morphology, pulmonary vascular histopathology and outcome.

OBJECTIVES: The purpose of this study was to investigate the outcome in infants with hypoplastic left heart syndrome and intact atrial septum and to evaluate the relationship of atrial morphology, left atrial decompression pathway and lung histopathology to outcome. BACKGROUND: In the hypoplastic left heart syndrome, severe restriction at the atrial level results in marked systemic hypoxemia after birth. Infants with intact atrial septum may be at high risk for mortality after Norwood operation. METHODS: Of 316 infants with hypoplastic left heart syndrome seen at our center over a 6.5-year period, 18 (5.7%) had intact atrial septum. Medical records and echocardiograms were reviewed. RESULTS: On echocardiography, three types of intact atrial septal morphology were identified: 1) large left atrium, thick prominent septum secondary with thin septum primary adherent (type A, n = 12); 2) small left atrium with thick, muscular atrial septum (type B, n = 4), and 3) giant left atrium, thin atrial septum with severe mitral regurgitation (type C, n = 2). Seven infants had left atrial decompression pathways that were severely obstructed (3/12 type A, 4/4 type B). Norwood operation was performed in 17 infants; one underwent emergency balloon atrial septostomy and died. Of six early survivors, all with type A atrial morphology and unobstructed decompression pathway, three died after subsequent cavopulmonary surgery. Lung histopathology revealed severely dilated lymphatics and "arterialization" of the pulmonary veins in those with the severest degree of obstruction to left atrial egress (type B atrial morphology). CONCLUSIONS: Despite aggressive intervention, outcome for infants born with hypoplastic left heart syndrome and intact atrial septum is poor. Maldevelopment of the pulmonary vasculature contributes to the high mortality seen. Atrial morphology can be used as a marker for the severity of pulmonary vascular disease.     

Balloon Atrial Septostomy by a Right Internal Jugular Venous Approach in a Newborn with Hypoplastic Left Heart Syndrome with a Restrictive Atrial Septum

Hypoplastic left heart syndrome with an intact or highly restrictive atrial septum requires urgent decompression of the left atrium. Catheter‐based interventions from the femoral or umbilical veins represent the standard method of atrial decompression. Restrictive atrial septal defects located at the superior portion of the fossa ovalis can be difficult to cross from these access sites. Here, we describe a successful Rashkind balloon atrial septostomy performed from an internal jugular approach.     

Decompressing vein and bilateral superior venae cavae in a patient with hypoplastic left heart syndrome

The levoatrial cardinal vein (LACV), first described in 1926, acts as a decompressing vessel for pulmonary venous return in cases of severe left‐sided obstruction with an intact or significantly restrictive atrial septum. The LACV and the persistent left superior vena cava (LSVC) are thought to share similar embryologic origins. To challenge this notion, we present a unique case of a neonate with hypoplastic left heart syndrome, cor triatriatum, and a decompressing LACV in the presence of bilateral superior venae cavae.     

Echocardiographic spectrum of the hypoplastic left heart syndrome: A clinicopathologic correlation in 19 newborns

Ultrasonic studies were performed in 19 neonates with the hypoplastic left heart syndrome whose diagnosis was confirmed at angiography or autopsy, or both. The patients were classified in two echocardiographic groups: Group I, 10 infants whose ventricular septum could be recorded, and Group II, 9 infants whose septum could not be recorded. The findings in these groups were compared with those in 60 neonates without congenital heart disease also studied with ultrasound. Two additional neonates who presented with signs of shock were also studied.The diagnostic echocardiographic features of hypoplastic left heart syndrome were: (1) a left ventricular end-diastolic dimension of less than 9 mm; (2) an aortic root diameter of less than 6 mm; (3) a ratio of left ventricular end-diastolic to right ventricular end-diastolic dimension of less than 0.6; and (4) a mitral valve echo that is absent or greatly distorted and of small amplitude. These echocardiographic criteria differed significantly from findings in the normal group (P < 0.01). Echocardiography proved valuable in neonates with shock. It is a safe, reliable technique that can be used to delineate the intracardiac anatomy in sick neonates with the hypoplastic left heart syndrome.     

Fetal stenting of the atrial septum: Technique and initial results in cardiac lesions with left atrial hypertension

Background

Hypoplastic left heart syndrome with a highly restrictive or intact atrial septum (HLHS-RAS) has a very high mortality. Fetal left atrial (LA) hypertension results in abnormal lung development with lymphangiectasia and pulmonary vein muscularization. We report our initial experience with percutaneous ultrasound-guided stenting of the fetal atrial septum to decompress the LA.

Methods

Retrospective review of fetuses with HLHS-RAS or a variant that underwent active perinatal management from 2000 to 2012.

Results

Ten fetuses were identified. Two died in utero (33, 29 weeks). Four required the urgent creation of an atrial communication immediately after birth but died subsequently (5–54 days). Four fetuses (28–36 weeks) underwent percutaneous stenting of the atrial septum, with ultrasound guidance and intravenous maternal sedation. Elevated LA pressure, pulmonary vein dilation and MRI estimated pulmonary perfusion all improved after stenting. Three of four stented fetuses were delivered vaginally. Atrial septectomy was performed within 48 h of delivery to ensure complete LA decompression, rather than for hypoxemia. Intraoperative lung biopsy demonstrated muscularized pulmonary veins and lymphangiectasia in all four. Two fetuses developed stent stenosis in utero and died after birth, from pulmonary hypertension and sepsis respectively. Two are alive, representing an improved outcome over our previous experience (p = 0.03).

Conclusion

Fetal atrial septal stenting is feasible without maternal complications and allows vaginal delivery of a more stable neonate. Fetal LA decompression ameliorates rather than reverses lung injury, and is one component of an approach that may improve survival in HLHS-RAS.     

Radiofrequency-assisted atrial septoplasty for an intact atrial septum in complex congenital heart disease.

Septoplasty of the atrial septum was performed with sequential balloon dilation following radiofrequency-assisted perforation of an intact atrial septum in two newborn infants with hypoplastic left heart syndrome and one with double-outlet right ventricle.     

Electrosurgical energy in combination with a transseptal needle: A novel method for the creation of an atrial communication in hypoplastic left heart syndrome with intact atrial septum

Neonates with hypoplastic left heart syndrome (HLHS) and intact atrial septum (IAS) usually present with severe acidosis and hypoxemia that necessitate immediate intervention to create an atrial septal defect (ASD). Transcatheter creation of an ASD in these patients requires transseptal puncture of a thickened atrial septum in the setting of a very small left atrium. We report on a novel method of perforating the atrial septum using radio‐frequency energy in combination with a transseptal needle to facilitate transseptal puncture and subsequent stent placement in a very thick atrial septum of a newborn with HLHS/IAS and a small left atrium. © 2008 Wiley‐Liss, Inc.     

Aortic morphometry and microcephaly in hypoplastic left heart syndrome

Microcephaly is a marker of abnormal fetal cerebral development, and a known risk factor for cognitive dysfunction. Patients with hypoplastic left heart syndrome have been found to have an increased incidence of abnormal neurodevelopmental outcomes. We hypothesized that reduced cerebral blood flow from the diminutive ascending aorta and transverse aortic arch in the setting of hypoplastic left heart syndrome may influence fetal growth of the brain. The purpose of our study, therefore, was to define the prevalence of microcephaly in full-term infants with hypoplastic left heart syndrome, and to investigate potential cardiac risk factors for microcephaly. We carried out a retrospective review of full-term neonates with hypoplastic left heart syndrome. Eligible patients had documented indexes of birth weight, and measurements of length, and head circumference, as well as adequate echocardiographic images for measurement of the diameters of the ascending aorta and transverse aortic arch. We used logistic regression for analysis of the data. A total of 129 neonates met the criteria for inclusion, with 15 (12%) proving to have microcephaly. The sizes of their heads were disproportionately smaller than their weights (p less than 0.001) and lengths (p less than 0.001) at birth. Microcephaly was associated with lower birth weight (p less than 0.001), lower birth length (p equal to 0.007), and a smaller diameter of the ascending aorta (p equal to 0.034), but not a smaller transverse aortic arch (p equal to 0.619), or aortic atresia (p equal to 0.969). We conclude that microcephaly was common in this cohort of neonates with hypoplastic left heart syndrome, with the size of the head being disproportionately smaller than weight and length at birth. Microcephaly was associated with a small ascending aorta, but not a small transverse aortic arch. Impairment of somatic growth may be an additional factor in the development of microcephaly in these neonates.     

The use of reconstructive surgery to improve quality of life and survival in prenatal hypoplastic left heart syndrome

Outcomes for hypoplastic left heart syndrome have improved substantially in the era of prenatal diagnosis. Current stage 1 survival rates are in excess of 90% in the absence of risk factors. However, fetuses with an intact atrial septum continue to have poor postnatal survival. Accurate diagnosis of these fetuses with an intact atrial septum relies upon careful assessment of the patent foramen ovale, pulmonary venous Doppler flow patterns and branch pulmonary artery Doppler flow patterns. Prenatal and perinatal interventions, such as the placement of an atrial stent in utero or delivery at a center where a stent may be placed immediately after birth to relieve left atrial hypertension, may improve survival in this particularly high-risk group.     

Emergency Hybrid Correction in a Newborn with Critical Aortic Valve Stenosis with Acute Pulmonary Edema in the First Hour after Birth

Critical aortic valve stenosis in newborns is the cause of a severe clinical condition with the onset of symptoms during first hours after birth. We present a clinical case of a successful surgical correction of a critical aortic stenosis using a hybrid method applied in a newborn during the first day of life. The infant was diagnosed with a hypoplastic left heart complex with an intact atrial septum (aortic and mitral valves stenosis variant), that led to the cardiogenic shock and acute pulmonary edema. The procedure included bilateral banding of the pulmonary artery branches and atrioseptostomy with stenting of the interatrial septum. The surgery was performed through a median sternotomy.     

Preoperative management of pulmonary venous hypertension in hypoplastic left heart syndrome with restrictive atrial septal defect

A severely restrictive atrial septal defect (ASD) in neonates with hypoplastic left heart syndrome (HLHS) results in pulmonary venous hypertension, pulmonary edema, and intractable hypoxia. Between January 1983 and June 1998, 21 of 355 neonates presenting with HLHS (5.9%) underwent cardiac catheterization at median age 1 day (range 0 to 25), for creation or enlargement of a restrictive or absent interatrial communication. One patient died during preliminary angiography. Three underwent blade septostomy with 2 procedure-related deaths, and 1 had balloon atrial septostomy (BAS); all 4 died before surgical intervention. Fifteen underwent Brockenbrough atrial septoplasty with transatrial needle puncture and serial balloon dilations of the new ASD, 5 after unsuccessful BAS. The most recent patient had a stent placed across the atrial septum after transatrial needle puncture. In the 16 patients treated with septoplasty or stent, oxygen saturation increased from 50 +/- 4% to 83 +/- 2% (p <0.0001) and transatrial pressure gradient decreased from 16 +/- 1 to 6 +/- 1 mm Hg (p <0.0001). One patient died awaiting transplantation, supportive care only was requested in 1, and 14 underwent stage 1 palliation. Eight of 14 (57%) survived to hospital discharge. Six of 7 (86%) survived bidirectional Glenn and the 3 who have undergone fenestrated Fontan are alive. In neonates with HLHS, a restrictive ASD resulting in profound cyanosis demands urgent intervention. BAS is frequently unsuccessful and blade septostomy has high mortality. Pulmonary venous hypertension can be adequately relieved by Brockenbrough atrial septoplasty or stenting, allowing stabilization before reconstructive surgery or while awaiting transplant.     

Novel approach to the newborn with hypoplastic left heart syndrome and intact atrial septum.

A prenatally diagnosed fetus with hypoplastic left heart syndrome and intact atrial septum was delivered in the cardiac catheterization suite. Using radio frequency energy, a transseptal perforation of the thickened and intact atrial septum was immediately performed following transcatheter cannulation of the right atrium via the umbilical vein. Serial cutting balloon septostomies followed by static balloon septostomies resulted in effective left atrial decompression, atrial mixing, and optimal pulmonary and systemic perfusion. The child is now thriving after both stage I Norwood and bidirectional Glenn procedures.     

Cross sectional echocardiographic identification of hypoplastic left heart syndrome and differentiation from other causes of right ventricular overload.

To identify the echocardiographic features that can be used to distinguish between hypoplastic left heart syndrome and other causes of right ventricular overload in the sick neonate cross sectional echocardiographic studies of 10 neonates with hypoplastic left heart syndrome were analysed and compared with those in 15 neonates with other causes of right ventricular overload and 15 normal controls. Left ventricular and right ventricular cavity dimensions and the shape and size of the mitral valve annulus and aortic root were recorded and presented both as absolute values (mm) and corrected for body surface area (mm/m2). Logistic regression was used to produce a classification rule to estimate the probability of a neonate having hypoplastic left heart syndrome. The diameter of the mitral valve annulus was the single most discriminative variable. There was, however, considerable overlap of all the calculated features between neonates with hypoplastic left heart syndrome and those with other causes of right ventricular overload. The diagnosis of hypoplastic left heart syndrome should not be based on any one single echocardiographic feature but the general appearance of abnormal left heart valves, small cavity dimensions, and the size of the mitral valve annulus.     

Cross sectional echocardiographic identification of hypoplastic left heart syndrome and differentiation from other causes of right ventricular overload

To identify the echocardiographic features that can be used to distinguish between hypoplastic left heart syndrome and other causes of right ventricular overload in the sick neonate cross sectional echocardiographic studies of 10 neonates with hypoplastic left heart syndrome were analysed and compared with those in 15 neonates with other causes of right ventricular overload and 15 normal controls. Left ventricular and right ventricular cavity dimensions and the shape and size of the mitral valve annulus and aortic root were recorded and presented both as absolute values (mm) and corrected for body surface area (mm/m2). Logistic regression was used to produce a classification rule to estimate the probability of a neonate having hypoplastic left heart syndrome. The diameter of the mitral valve annulus was the single most discriminative variable. There was, however, considerable overlap of all the calculated features between neonates with hypoplastic left heart syndrome and those with other causes of right ventricular overload. The diagnosis of hypoplastic left heart syndrome should not be based on any one single echocardiographic feature but the general appearance of abnormal left heart valves, small cavity dimensions, and the size of the mitral valve annulus.     

Bedside transseptal balloon dilation atrial septostomy for decompression of the left heart during extracorporeal membrane oxygenation

A 10-year-old male presented with severe heart failure secondary to myocarditis. Venoarterial extracorporeal membrane oxygenation was instituted. He developed severe left heart distention with acute pulmonary hemorrhage. Balloon dilation of the atrial septum to decompress the left atrium was performed at the bedside with transesophageal echocardiographic guidance. Cathet. Cardiovasc. Intervent. 46:197–199, 1999. © 1999 Wiley-Liss, Inc.