Hypoplastic Left Heart Complex Research Articles

Borderline left ventricle

The first problem to solve when dealing with the topic 'borderline left ventricle' is to find the appropriate definition. Several parameters have been taken into consideration, either morphometric (diameter of the mitral valve, indexed mitral valve area, left ventricular inflow dimension, left ventricular cross-sectional area, ratio between the apex-to-base left ventricular dimension and right ventricular dimension, left ventricular long axis to heart long axis ratio, left ventricular end diastolic volume, left ventricular mass index, ratio of the right/left ventricular wall thickness, presence of endocardial fibroelastosis, cardiac apex not formed by the left ventricle, diameter of the ventriculo-aortic junction, diameter of the aortic valve annulus and indexed aortic root diameter) as well as functional (left ventricular ejection fraction, left ventricular end diastolic pressure, mean pulmonary artery pressure, direction of the blood flow in the ascending aorta and at the level of the patent ductus arteriosus). Pre-operative determination whether the left ventricle is adequate to sustain the systemic circulation, or it may became adequate with the available surgical approaches, and therefore a bi-ventricular type of repair is feasible, can be extremely difficult, particularly in the presence of a 'borderline left ventricle'. In the clinical practice pediatric cardiologists and cardiac surgeons are faced with the problem of the 'borderline left ventricle' in four different groups of congenital heart defects: (a) aortic valve stenosis, (b) aortic coarctation, with or without hypoplastic aortic arch, (c) hypoplastic left heart complex, (d) right ventricular pressure and/or volume overload. In all the above situations in the presence of a left ventricle smaller than normal a very exhaustive approach has been reviewed in the decision making process, taking in account the literature reports as well as the personal experience. In each patient with 'borderline left ventricle' the elements to be considered for the decision making process between uni- and bi-ventricular type of repair, or for less ideal options of management, are the following: morphometric and functional parameters, hemodynamic data, available surgical options, results of the personal and institutional experience.

Indications, criterions, and principles for biventricular repair.

The hypoplastic left heart syndrome constitutes a wide spectrum of cardiac malformations, characterized by varying degrees of underdevelopment of the structures of the left heart and aortic arch. At the severe end of the spectrum, there is aortic and mitral atresia, and the left ventricle is vestigial. In contrast, at the mild end, there is hypoplasia of the left ventricle in the absence of overt stenosis of either the aortic or mitral valves, the combination we have described as hypoplastic left heart complex.1Until recently, debate with regard to the optimal surgical approach has centered on the choice between the Norwood operation and neonatal cardiac transplantation. In the last several years, nonetheless, it has been shown that of biventricular repair can be achieved in those patients at the favorable end of the spectrum that we designated as having the complex rather than the syndrome.1,2It is well recognized that an ongoing difficulty is the inconsistent and imprecise definition of hypoplastic left heart syndrome. In this presentation, I summarize our own criterions, and our principles for biventricular repair, as based on our experience at the Montreal Children's Hospital, for those patients we judge to have the hypoplastic left heart complex.

Biventricular repair in the management of hypoplastic left heart syndrome.

Hypoplastic left heart syndrome is the term introduced by Noonan and Nadas1to describe a spectrum of cardiac anomalies characterized by varying degrees of significant underdevelopment of the left heart and aortic arch. These cardiac anomalies include mitral valvar disease, left ventricular hypoplasia, aortic stenosis at subvalvar, valvar, and supravalvar levels, hypoplasia of the ascending aorta and aortic arch, and aortic coarctation. Although descriptive, hypoplastic left heart syndrome suffers from being a very unspecific term, since it encompasses multiple degrees and combinations of abnormalities involving the left sided structures. In an attempt to provide gradings of severity, Kirklin and Barratt-Boyes2categorized these patients falling into the syndrome into four classes, according to whether obstruction was found at one, two, or more levels, or whether there is aortic atresia. Then, in 1998, Tchervenkov and colleagues3introduced the term hypoplastic left heart complex to describe a set of patients falling within the spectrum of hypoplasia of the left heart, but in the absence of intrinsic aortic or mitral valvar stenosis, this concept subsequently being endorsed by the International Committee established by the Society of Thoracic Surgeons, together with the European Association of Cardiothoracic Surgery, to rationalize the approach to nomenclature and databases.4The analysis offered by Tchervenkov et al.3showed that, in certain circumstances, there are potentially patients considered to have hypoplasia of the left heart who might be candidates for biventricular repair. If this is the case, then it is important to establish how this subset can be recognized, and how they are best treated.

Hypoplastic left heart complex: Surgical approaches for two-ventricle repair in borderline patients

Hypoplastic left heart complex: Surgical approaches for two-ventricle repair in borderline patients

Two-Ventricle Repair for Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome encompasses a spectrum of structural cardiac malformations characterized by severe underdevelopment of the structures in the left heart-aorta complex. The severe end of the spectrum consists of aortic atresia and mitral atresia, whereas at the mild end patients have aortic valve and mitral valve hypoplasia without intrinsic valve stenosis, recently described as hypoplastic left heart complex. These patients may be candidates for biventricular repair. Since November 1988, 12 of 13 patients (92%) with hypoplastic left heart complex have undergone two-ventricle repair and one patient the Norwood operation. Median age at surgery was 7 days (5 to 45 days) and median weight was 3.59 kg (2.6 to 4.3 kg). Biventricular repair consisted of pulmonary homograft patch aortoplasty of the aortic arch and ascending aorta and closure of the interatrial and interventricular communications. The left heart was able to support the systemic circulation in 11 of 12 patients undergoing biventricular repair (92%). The early mortality was two patients (15.4%). The mean follow-up was 67 months (range, 11 months to 133 months). There was one late death at 39 months. Reoperations were necessary in four patients for left ventricular outflow tract obstruction and in two patients for recurrent coarctation. We have successfully achieved biventricular repair in most patients with hypoplastic left heart complex, a subset of patients with hypoplastic left heart syndrome. Reoperation, particularly for left ventricular outflow tract obstruction, appears likely. Finally, with increased experience, predictive criteria for the feasibility and optimal outcome of biventricular repair will be more accurately defined.

Congenital Heart Surgery Nomenclature and Database Project: hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) encompasses a spectrum of structural cardiac malformations that are characterized by severe underdevelopment of the structures in the left heart-aorta complex, including the left ventricular cavity and mass. The severe end of the spectrum consists of aortic atresia and mitral atresia with a nonexistent left ventricle, whereas at the mild end patients have aortic valve and mitral valve hypoplasia without intrinsic valve stenosis, and milder degrees of left ventricular hypoplasia, recently described as hypoplastic left heart complex (HLHC). Although the overwhelming majority of the patients can only have a univentricular repair, a small minority of patients with HLHS, particularly those that are described as having HLHC, may be candidates for biventricular repair. In this paper, the extant nomenclature for HLHS is reviewed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Nomenclature and Database Committee and representatives from the European Association for Cardiothoracic Surgery. Efforts were made to include all relevant nomenclature categories using synonyms where appropriate. A comprehensive database set is presented, which is based on a hierarchical scheme. Data are entered at various levels of complexity and detail that can be determined by the clinician. These data can lay the foundation for comprehensive risk stratification analyses. A minimum database set is also presented which will allow for data sharing, and would lend itself to basic interpretation of trends. Outcome tables relating diagnoses, procedures, and various risk factors are presented.

Single-stage repair of aortic arch obstruction and associated intracardiac defects with pulmonary homograft patch aortoplasty

Objective: Intracardiac malformations associated with coarctation and aortic arch hypoplasia have traditionally been repaired in 2 stages, with a high mortality rate. We review our experience with single-stage biventricular repair of intracardiac defects associated with aortic arch hypoplasia by means of pulmonary homograft patch aortoplasty. Methods: Between October 1988 and October 1997, 39 of 40 consecutive patients underwent single-stage biventricular repair for aortic arch obstruction and associated intracardiac defects. The median age at operation was 17 days and the mean weight was 3.71 ± 1.09 kg. Nineteen patients had either dextrotransposition of the great arteries or the Taussig-Bing anomaly. Sixteen patients had multiple left-sided obstructive lesions (2 cases of critical aortic stenosis, 3 of subaortic stenosis and ventricular septal defect, and 11 of hypoplastic left heart complex). One patient had an associated complete atrioventricular septal defect. Four patients had only an associated ventricular septal defect. Through a median sternotomy, the hypoplastic aortic arch was enlarged with a pulmonary homograft patch in 36 patients. In 4 patients an extended end-to-end anastomosis was performed. Results: There were 2 early deaths (5%) and 2 late deaths (5%). One late death was not cardiac related. The mean follow-up time was 36 months (range 1 month-9 years). The recoarctation rate after pulmonary homograft patch aortoplasty was 8.3%, but after exclusion of those patients with associated left-sided obstructive lesions this decreased to 0%. No aneurysm formation in the aorta has occurred. The actuarial survival at 8 years is 89% ± 10%. Conclusions: Single-stage biventricular repair of aortic arch obstruction and associated intracardiac defects can achieve excellent survival. We recommend pulmonary homograft patch aortoplasty because it achieves complete relief of anatomic afterload with a tension-free anastomosis and low incidence of recoarctation. (J Thorac Cardiovasc Surg 1998;116:897-904) J Thorac Cardiovasc Surg 1998;116:897-904

Biventricular repair in neonates with hypoplastic left heart complex

Background. Multiple obstructions in the left heart–aorta complex have been associated with poor survival. No consensus exists as to whether these patients will have a favorable outcome with biventricular repair where most advocate a univentricular approach. Methods. Since late 1988, all 11 neonates seen with hypoplastic left heart complex, which includes aortic arch obstruction, underwent biventricular repair. All patients had antegrade aortic flow and no intrinsic aortic or mitral stenosis. Elimination of the extracardiac afterload was achieved by extensive ascending aorta and aortic arch reconstruction with a pulmonary homograft patch. All intracardiac shunts were eliminated to fully preload the left heart. The median age at first operation was 7 days and the mean weight, 3.59 ± 0.49 kg. The echocardiographic variables used to evaluate the left heart–aorta complex were reviewed, and the preoperative and postoperative measurements were compared. Results. There were two early deaths. Four patients had six reoperations for left ventricular outflow tract obstruction, 2 of whom have required prosthetic valve replacement (1, aortic and mitral; 1, aortic), and 2 patients had three reoperations for recurrent coarctation. There was one late death at 3 years from pulmonary hypertension. Mean follow-up was 44 ± 35 months. The 8 current survivors are all in New York Heart Association class I or II. The actuarial survival rate at 8 years is 63%, and the freedom from reoperation at 3 years is 25%. Conclusions. We have successfully achieved biventricular repair in most of the patients with hypoplastic left heart complex, a subset of patients with hypoplastic left heart syndrome. Some growth of the left ventricular structures was already observed at the time of hospital discharge. However, reoperation, particularly for left ventricular outflow tract obstruction, appears likely. Increasing experience will more accurately define predictive criteria for the feasibility of biventricular repair.

Ossification centre of the hyoid bone in complete transposition of great vessels, Ivemark asplenia syndrome, and Down's syndrome with congenital heart disease: correlation with the humeral capital epiphysis.

The incidence of radiographic visibility of the ossification centres of the body of the hyoid bone and of the humeral capital epiphysis in antero-posterior or lateral chest radiographs taken during the first month of life of 63 autopsied infants were analysed. The group comprised patients with Down's syndrome (DS) with congenital heart disease, 15; complete transposition of the great vessels (TGV), 10; Ivemark asplenia syndrome (IS), 17; and a control group of infants with congenital heart disease (CHD) who had none of the above conditions, nor tetralogy of Fallot, interrupted aortic arch, DiGeorge syndrome or hypoplastic left-heart complex, 31. The incidence of radiographically visible hyoid ossification centre (HOC) in the control group was 71% and of humeral capital epiphysis (HE), 16.1%. Autopsied infants with TGV, IS or DS with CHD showed increased visibility of HOC (100%); the incidence of visible HE was increased in neonates with IS (71.4%) and with TGV (50%). The differences in the incidence of radiographic visibility of HOC and HE in neonates with CHD, in this study and in others in the literature, appear to have diagnostic value.

Hepatic Cell Necrosis in the Newborn

One hundred and forty-seven infants who died from birth to 7 days of age were studied for the relation of hepatic cell necrosis to other pathological conditions. Disseminated hepatic necrosis was significantly correlated with congenital heart disease, and hypoplastic left heart complex and coarctation of the aorta were more frequently associated with disseminated hepatic necrosis than were other types of congenital heart disease. The microscopic features of the liver in these types of congenital heart disease are not those of congestive heart failure, and the hepatic changes observed are considered more probably due to decreased arterial blood flow than to passive venous congestion. Localized hepatic necrosis was significantly correlated with gastroschisis, omphalocele, or diaphragmatic hernia, and hemorrhage in portal areas was associated with the presence of intracranial hemorrhage.

FACTORS IN THE GENESIS OF BILE STASIS IN INFANCY

Forty-two of 340 infants dying before 3 months of age had bile stasis in the liver. Statistical comparison of these infants with 81 jaundiced infants and 217 with neither jaundice nor bile stasis demonstrated that bile stasis was associated with hepatitis, galactosemia, erythroblastosis fetalis, prematurity, esophageal atresia with tracheoesophageal fistula, duodenal atresia and lower small intestinal obstruction. High proportions of the infants with bile stasis also had one or more of: infection with gram-negative organisms, significant internal hemorrhage and dehydration. Infants with congenital heart disease were statistically unlikely to have either jaundice or bile stasis, and the transposition complex was associated with a lower incidence of jaundice than was the hypoplastic left heart complex. The data indicate that biochemical dysfunction of liver cells is a cause of bile stasis, as is duct obstruction, and suggest that disturbance of hepatic blood flow is also a causative factor. Statistically, bile stasis in the liver is associated with elevation of conjugated bilirubin in serum, and the causative factors listed are thus relevant to the genesis of the inspissated bile syndrome in infancy. The spectrum of causes of bile stasis in older children differs strikingly from that seen in young infants.