Hypoplastic left heart syndrome: experience with palliative surgery

Aortic atresia is a form of hypoplastic left heart syndrome always complicated by associated severe hypoplasia of the ascending aorta and various degrees of mitral valve and left ventricular hypoplasia. At present it is a universally fatal lesion in early infancy. This is a report of a new palliative procedure for hypoplastic left heart syndrome that has resul;ed in early ongoing survival of two infants with aortic atresia. On the basis of experience with a third patient, an operation for future physiologic correction is proposed.     

Coronary artery abnormalities and right ventricular histology in hypoplastic left heart syndrome.

OBJECTIVES. To determine whether right ventricular preservation is compromised in any anatomic subgroup of hypoplastic left heart syndrome, we assessed the coronary artery anatomy and myocardial histologic features of 151 postmortem specimens with hypoplastic left heart syndrome. BACKGROUND. Although previous studies have shown that coronary artery abnormalities are more prominent in the subgroup of patients who have a patent mitral valve and obstructed aortic valve, it has not been established that these abnormalities compromise right ventricular perfusion. METHODS. Eighty-nine specimens with a patent mitral valve and aortic atresia, 52 with mitral and aortic atresia and 10 with patent mitral and aortic valves were examined. Histologic sections of the right ventricle, left ventricle and coronary arteries were obtained from 64 study hearts and 5 control hearts. RESULTS. Gross coronary anomalies included coronary-cameral communications (n = 29), single left coronary artery (n = 2), single right coronary artery (n = 1) and tortuosity (n = 19). Coronary-cameral communications and tortuosity were significantly associated with the subgroup that had mitral hypoplasia and aortic atresia. Coronary artery wall thickness relative to lumen diameter was not different among the subgroups. No areas of coronary artery stenosis or interruption were discovered. Although endocardial fibroelastosis of the left ventricle was strongly associated with the mitral hypoplasia and aortic atresia group, the right ventricular histologic findings were similar in all subgroups and were not differentially affected by older age. CONCLUSIONS. Although the incidence of coronary abnormalities is greater in patients with mitral hypoplasia and aortic atresia, in this study there was no apparent difference in perfusion of the right ventricle among the anatomic subgroups of hearts with hypoplastic left heart syndrome.     

Echocardiographic diagnosis of atrial septal aneurysm in an infant with hypoplastic right heart syndrome

Echocardiographic findings are described in a patient with hypoplastic right heart syndrome (pulmonary atresia type with intact ventricular septum and small right ventricular cavity) who had an associated atrial septal aneurysm. An unusual appearance of echoes behind the aorta bulging into the left atrium in diastole on both the M-mode and cross-sectional echo suggested this diagnosis prior to cardiac catheterization. The angiographic findings confirmed the diagnosis of right ventricular hypoplasia, pulmonary atresia and the large atrial septal aneurysm. The infant died after surgery and the atrial septal aneurysm was observed at autopsy. The importance of the diagnosis of the atrial septal aneurysm and its association with restriction of right-to-left atrial shunting prompts this report.     

Fistulous communications with the coronary arteries in the setting of hypoplastic ventricles

Neonates born with hypoplastic left heart syndrome now have a remarkably improved prognosis compared with the situation existing before the development of the Norwood sequence of operative procedures. Some of those born with hypoplastic right ventricles in the setting of pulmonary atresia with an intact ventricular septum, however, still have a relatively poor prognosis. In part this reflects the presence of fistulous communication between the cavity of the right hypoplastic right ventricle and the coronary arterial tree. Such fistulous communications are now increasingly recognised as being important in the setting of hypoplastic left heart syndrome. In this brief review, we describe the anatomy of the communications. Those found with hypoplastic right ventricles are seen most frequently when the cavity of the ventricle effectively represents only the inlet, this in turn reflecting mural overgrowth of the apical trabecular and outlet components during foetal development. This almost certainly reflects an earlier appearance of the pulmonary valvar lesion that promotes the cavitary hypoplasia. In those with hypoplastic left ventricles, the key feature differentiating those with fistulous communications is the presence of a patent mitral valve, since the left ventricle is typically no more than a virtual slit in postero-inferior ventricular wall in the setting of mitral valvar atresia or absence of the left atrioventricular connection.     

An infant with hypoplastic left heart syndrome and spinal muscular atrophy

We report an infant with hypoplastic left heart syndrome consisting of mitral valvar atresia, aortic valvar atresia, hypoplasia of the aortic arch and coarctation of the aorta, who demonstrated respiratory failure and global hypotonia, and who was eventually diagnosed with spinal muscular atrophy.     

Selective aortic root angiography in the hypoplastic left heart syndrome.

Selective aortic root angiography was performed in 18 patients with the clinical diagnosis of hypoplastic left heart syndrome in order to allow more precise correlation with echocardiography. Aortic valve atresia and severe hypoplasia of the left heart chambers subsequently were substaniated at necropsy in each instance. Wide variation in the size and shape of the aortic root and ascending aorta was demonstrated angiographically in these patients. In some patients, despite aortic valve atresia, the dimensions of the aortic root and sinuses of Valsalva at angiography were almost normal. In addition, this technique allowed the demonstration of primitive vascular communications between the coronary artery and left ventricular cavity in 1 patient (coronary-cameral fistula). The realization that the aortic root may approach nearly normal size in some patients with the hypoplastic left heart syndrome is essential to the echocardiographic diagnosis of this disease and to the differential diagnosis from other cardiac and noncardiac causes of severe neonatal congestive heart failure.     

Hypoplastic left heart syndrome: report of a unique survivor

A remarkable patient is described, a child who has survived until the age of 7 years with hypoplastic left heart syndrome (mitral and aortic atresia) without surgical intervention. The child has led an active, normal life and, aside from minimal cyanosis, has remained asymptomatic. The unique clinical course for this patient is the result of a number of favorable hemodynamic factors that have not been previously reported in an individual patient with hypoplastic left heart syndrome and intact ventricular septum widely patent ductus arteriosus, adequate retrograde coronary flow, unrestricted pulmonary venous return, and absence of significant vascular obstructive disease. This documentation of long-term survival in a child without surgical treatment for mitral and aortic atresia suggests that successful early palliative treatment for infants with this syndrome could also result in a favorable prognosis.     

Experimental production of hypoplastic left heart syndrome in the chick embryo

The hypothesis is examined that hemodynamic alterations at the site of the primordial mitral valve may induce malformations that simulate the clinical findings of hypoplastic left heart syndrome. Surgical placement of a nylon device, approximately 90 μ in diameter, into the region of the left atrioventricular (A-V) canal was accomplished in 192 embryos (Hamburger-Hamilton stages 23 to 25). Thirty-nine pairs of experimental and control embryos survived more than 12 days. Twenty-six experimental embryos exhibited various malformations: hypoplastic left atrium and ventricle, mitral valvular atresia, aortic valvular stenosis and tubular hypoplasia of the aorta and brachlocephalic vessels. These findings reemphasize the probable morphogenetic role of blood flow pathways. The findings further implicate involvement of the left A-V canal as well as premature closing of foramen ovale and aortic valvular abnormalities in the hypoplastic left heart syndrome.     

Noonan's syndrome associated with hypoplastic left heart

A case of a week old female baby, admitted because of apathy, hypothermia, dyspnea, jaundice and cyanosis is described. She had the characteristic phenotype of Turner's syndrome with normal karyotype. Signs of severe heart failure were present. Therapy with diuretics, digoxin, dopamine and mechanical ventilation were unsuccessful, and the patient died several hours after her admission. The anatomopathological examination revealed the presence of hypoplastic left heart syndrome with mitral atresia and aortic atresia, atrial septal defect, double outlet right ventricle, and a patent ductus arteriosus.     

The nomenclature, definition and classification of hypoplastic left heart syndrome

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.     

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.     

Scimitar syndrome

We studied 15 cases of the scimitar syndrome. The diagnosis was suspected in 87% of the patients by x-rays studies. Bronchography is useful in order to detect bronchial anomalies, such as hypoplasia or agenesis of the medial lobe which is responsible for the left isomerism. The hemodynamic study is important in symptomatic patients in order to demonstrate associated congenital heart disease as well as the degree of pulmonary hypertension. Angiography is fundamental in determining the anomalous venous drainage of the right lung, whether complete or partial, and in demonstrating the exact site of the connection which may be to the right atrium or more frequently to the inferior vena cava above or below the diaphragm. There are variant forms in so far as the pathway, extension and connection of the anomalous venous trunk which gives rise to the scimitar sign. This syndrome is due to a persistent connection of the right pulmonary veins to the proximal portion of the right vitelin vein which normally forms the suprahepatic segment of the inferior vena cava. Asymptomatic patients should have medical treatment symptomatic ones with an associated congenital heart disease and moderate pulmonary hypertension must be subject to surgery.     

Hypoplastic left heart syndrome: report of an operation utilizing the ductus arteriosis in outflow reconstruction

An operation utilizing the ductus arteriosus to construct an outflow tract from the right ventricle is described. This operation uses the right ventricle for pulsatile flow to both systemic and pulmonary arteries, provides complete reconstruction of the ascending aorta and arch, and delivers predictable pulmonary blood flow. Although unsuccessful in this case report, which involves a hypoplastic left heart syndrome patient, the technique may provide successful palliation with the use of ductal tissue. This method has not been previously described.     

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.     

Impact of placing a conduit from the right ventricle to the pulmonary arteries as the first stage of further palliation in the Norwood sequence for hypoplasia of the left heart

OBJECTIVE: We describe the experience from a single institution with the Norwood sequence of palliation for hypoplasia of the left heart, emphasizing complications related to placement of a conduit from the right ventricle to the pulmonary arteries and their management. METHODS: Between November, 2002 and January, 2006, we palliated 32 patients with hypoplastic left heart syndrome or its variants by placing a conduit from the right ventricle to the pulmonary arteries. We reviewed retrospectively the charts and angiograms from these patients. RESULTS: Hospital survival after construction of the conduit was 90.6%. There were 3 interstage deaths, of which 2 were likely due severe obstruction of the conduit. Stents were implanted into the proximal or medial portions of the conduits of 3 patients. Early revision of the distal anastomosis, and shortening the conduit, was performed early postoperatively in 2 patients. So far, 24 out 26 survivors of the first stage underwent a bi-directional cavopulmonary anastomosis after a mean interval of 4.3 plus or minus 1.4 months. Of these, 3 required a semi-urgent second stage of palliation because of worsening cyanosis, with one patient dying after the second stage. Completion of the Fontan circulation by insertion of an extracardiac conduit was performed in 8 patients at the mean age of 19.8 plus or minus 2.2 months. We were able to achieve biventricular repair in 1 patient, with aortic atresia, hypoplastic arch and ventricular septal defect, 4.3 months after the initial palliative procedure. Overall survival of the whole cohort of 32 patients was 78.9%, plus or minus 7.8%, at 5 months, and 74.3%, plus or minus 8.6%, up to 25 months. CONCLUSIONS: The introduction of the conduit placed from the right ventricle to the pulmonary arteries has led to an improved outcome in the complex entity of hypoplastic left heart syndrome and its variants. Stenosis of the conduit, nonetheless, may account for significant interstage morbidity, and often requires intervention or early installation of the second stage of palliation.     

Antegrade flow in the aorta ascendens despite aortic atresia: 2 case reports with retrograde coronary perfusion through coronary fistulas and sinusoids

In aortic atresia, coronary perfusion normally occurs through retrograde blood flow in the ascending aorta. We report on two patients with antegrade flow in the ascending aorta despite aortic atresia. In one patient with hypoplastic left heart syndrome (aortic atresia, severe mitral stenosis), an intact interatrial septum/premature closure of the foramen ovale was found. While no other way of left atrial or ventricular decompression was found, echocardiography, angiography and the post-mortem examination showed left ventricular to coronary sinusoids as the sole pathway for systemic oxygenation. In a second patient with complex congenital heart disease, including aortic atresia, antegrade flow in the ascending aorta was through a left coronary fistula with shunt flow originating from the pulmonary trunk. This report describes systemic perfusion depending on retrograde coronary flow due to coronary-cameral (sinusoids) and coronary arterio-venous fistulas leading to the phenomenon of antegrade blood flow in the ascending aorta despite aortic atresia.     

Freedom from Neoaortic Insufficiency: A Comparison of Classic Norwood and Norwood–Sano Procedures

Objectives. To investigate the incidence of neoaortic insufficiency in patients with hypoplastic left heart syndrome treated with the Norwood–Sano palliation and to compare it with that occurring after the classic Norwood procedure. Design, Setting, Patients, Interventions. This was a retrospective review of all echocardiograms of patients diagnosed with hypoplastic left heart syndrome (concomitant presence of left ventricular and aortic and mitral severe hypoplasia or atresia) who underwent staged palliation of the Norwood or Norwood–Sano type at a single academic institution between September 1999 and February 2005 and who survived a minimum of 3 months. Outcome Measures. Neoaortic insufficiency was categorized as absent or mild <1 mm jet width, moderate 1–3 mm jet width, or severe >3 mm jet width. The patients were grouped according to initial palliation, that is, classic Norwood and Norwood–Sano operation. Results. Fifty‐nine consecutive patients (median age of 20 months with a range from 3 to 66 months) satisfied inclusion criteria. Neoaortic insufficiency was absent or mild in 55 of 59 (93.22%) of the patients. There were 4 cases of significant neoaortic insufficiency at late follow‐up: 2 moderate following the classic Norwood and 1 moderate and 1 severe following the Norwood–Sano procedure, one of whom required valve replacement. Conclusions. In this series of patients with hypoplastic left heart syndrome, the Sano modification was not associated with an increased incidence of significant neoaortic insufficiency. When present, moderate/severe neoaortic insufficiency appeared late after initial palliation and was associated with recurrent ascending aortic or aortic arch pathology in every case.     

Fetal hydrops in a newborn with hypoplastic left heart syndrome: tricuspid valve "stopper"

Fetal hydrops in a newborn infant with hypoplastic left heart syndrome led to the discovery of tricuspid stenosis and insufficiency from an unusual malformation of the right venous valve of the embryonic sinus venosus. This unfortunate combination of lesions precluded surgical palliation for the hypoplastic left heart.     

Right-sided scimitar syndrome in a patient with a single aortic trunk and coronary-cameral venous fistula

Scimitar syndrome (SS) is a rare congenital anomaly characterized by partial or complete anomalous pulmonary venous drainage of the right or left lung into the inferior vena cava. The syndrome is commonly associated with hypoplasia of the right lung, pulmonary sequestration, persistent left superior vena cava, and dextroposition of the heart. We report a rare variant of SS in a 44-year-old man together with a single aortic trunk, as well as a coronary-cameral venous fistula.     

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.