Pulmonary atresia with and without ventricular septal defect: a different etiology and pathogenesis for the atresia in the 2 types?

Brugada Syndrome and Pulmonary Atresia with Intact Interventricular Septum: Fortuitous Finding or New Genetic Connection?

Brugada syndrome is a rare arrhythmogenic syndrome associated mainly with pathogenic variants in the SCN5A gene. Right ventricle outflow tract fibrosis has been reported in some cases of patients diagnosed with Brugada syndrome. Pulmonary atresia with an intact ventricular septum is characterized by the lack of a functional pulmonary valve, due to the underdevelopment of the right ventricle outflow tract. We report, for the first time, a 4-year-old boy with pulmonary atresia with an intact ventricular septum who harbored a pathogenic de novo variant in SCN5A, and the ajmaline test unmasked a type-1 Brugada pattern. We suggest that deleterious variants in the SCN5A gene could be implicated in pulmonary atresia with an intact ventricular septum embryogenesis, leading to overlapping phenotypes.

Novel rare genetic variants of familial and sporadic pulmonary atresia identified by whole-exome sequencing

Pulmonary atresia (PA) is a severe cyanotic congenital heart disease. Although some genetic mutations have been described to be associated with PA, the knowledge of pathogenesis is insufficient. The aim of this research was to use whole-exome sequencing (WES) to determine novel rare genetic variants in PA patients. We performed WES in 33 patients (27 patient-parent trios and 6 single probands) and 300 healthy control individuals. By applying an enhanced analytical framework to incorporate de novo and case-control rare variation, we identified 176 risk genes (100 de novo variants and 87 rare variants). Protein‒protein interaction (PPI) analysis and Genotype-Tissue Expression analysis revealed that 35 putative candidate genes had PPIs with known PA genes with high expression in the human heart. Expression quantitative trait loci analysis revealed that 27 genes that were identified as novel PA genes that could be affected by the surrounding single nucleotide polymorphism were screened. Furthermore, we screened rare damaging variants with a threshold of minor allele frequency at 0.5% in the ExAC_EAS and GnomAD_exome_EAS databases, and the deleteriousness was predicted by bioinformatics tools. For the first time, 18 rare variants in 11 new candidate genes have been identified that may play a role in the pathogenesis of PA. Our research provides new insights into the pathogenesis of PA and helps to identify the critical genes for PA.

Lodewyk H.S. van Mierop (March 31, 1927-October 17, 2021): a true giant

We honour a great man and a true giant. Lodewyk H.S. van Mierop (March 31, 1927 - October 17, 2021), known as Bob, was not only a Paediatric Cardiologist but also a dedicated Scientist. He made many significant and ground-breaking contributions to the fields of cardiac anatomy and embryology. He was devoted as a teacher, spending many hours with medical students, Residents, and Fellows, all of whom appreciated his regularly scheduled educational sessions. Those of us who were fortunate to know and spend time with him will always remember his great mind, his willingness to share his knowledge, and his ability to encourage spirited and fruitful discussions. His life was most productive, and he will long be remembered by many through his awesome and exemplary scientific contributions.His legacy continues to influence the current and future generations of surgeons and all providers of paediatric and congenital cardiac care through the invaluable archive he established at University of Florida in Gainesville: The University of Florida van Mierop Heart Archive. Undoubtedly, with these extraordinary contributions to the fields of cardiac anatomy and embryology, which were way ahead of his time, Professor van Mierop was a true giant in Paediatric Cardiology. The invaluable archive he established at University of Florida in Gainesville, The University of Florida van Mierop Heart Archive, has been instrumental in teaching medical students, Residents, Medical Fellows, and Surgical Fellows. Only a handful of similar archives exist across the globe, and these archives are the true legacy of giants such as Dr. van Mierop. We have an important obligation to leave no stone unturned to continue to preserve these archives for the future generations of surgeons, physicians, all providers of paediatric and congenital cardiac care, and, most importantly, our patients.

Perioperative and Anesthetic Considerations in Tetralogy of Fallot With Pulmonary Atresia

Tetralogy of Fallot with pulmonary atresia (ToF-PA) is a rare diagnosis that includes an extraordinarily heterogeneous group of complex anatomical findings with significant implications for physiology and prognosis. In addition to the classic findings of ToF, this particular diagnosis is characterized by complete failure of forward flow from the right ventricle to the pulmonary arterial system. As such, pulmonary blood flow is entirely dependent on shunting from the systemic circulation, most frequently via a patent ductus arteriosus, major aortopulmonary collaterals, or a combination of the two. The pathophysiology of ToF-PA is largely attributable to the abnormalities of the pulmonary vasculature. Ultimately, these patients require operative intervention to create a reliable, controlled source of pulmonary blood flow and ideally complete intracardiac repair. Even after operative correction, these patients remain at risk for pulmonary arterial stenoses and pulmonary hypertension. Although there have been significant advances in surgical and interventional management of ToF-PA leading to dramatic improvements in survival and long-term functional status, there is ongoing debate about the optimal management strategy given the risk of development of irreversible abnormalities of the pulmonary vasculature and the morbidity and mortality associated with sometimes multiple, complex operative interventions often occurring early in infancy. This review will discuss the findings in patients with ToF-PA with a focus on the perioperative and anesthetic management and will highlight challenges faced by the anesthesiologist in caring for these patients.

Pulmonary Atresia With an Intact Ventricular Septum: Preoperative Physiology, Imaging, and Management

Pulmonary atresia with intact ventricular septum (PA-IVS) is a rare complex cyanotic congenital heart disease with heterogeneous morphological variation. Prenatal diagnosis allows for developing a safe plan for delivery and postnatal management. While transthoracic echocardiography allows for detailed delineation of the cardiac anatomy, additional imaging modalities such as computed tomography, magnetic resonance imaging, and catheterization may be necessary to further outline features of the cardiac anatomy, specifically coronary artery anatomy. The size of the tricuspid valve and right ventricular cavity as well as the presence of right ventricle–dependent coronary circulation help to dichotomize between biventricular repair versus univentricular palliation or heart transplantation, as well as predicting the expected survival. The delineation and understanding of these features help to dictate both medical and surgical management.

Pulmonary atresia with intact ventricular septum and hypoplastic right ventricle in an Arabian foal

Pulmonary atresia with intact ventricular septum, rudimentary tricuspid valve, hypoplastic right ventricle, and right-to-left atrial shunting were identified in a four-day-old, male Arabian foal with clinical signs of cyanotic heart disease. Pulmonary blood flow was apparently derived from a ductus arteriosus. Echocardiographic evaluation revealed the majority of cardiac abnormalities and also findings compatible with right-sided congestive heart failure. Congenital cardiac defects have a high incidence in this breed, and this is the first description of this combination of congenital cardiac defects.

Pulmonary valvuloplasty for pulmonary atresia-restrictive ventricular septal defect

Pulmonary atresia with restrictive ventricular septal defect is a rare congenital cardiac anomaly. A Blalock-Taussig shunt and surgical perforation of the atretic pulmonary valve is often performed as the initial palliation. We present our experience of utilizing both transesophageal and epicardial echocardiography during surgical pulmonary valvuloplasty in a 22-day-old neonate with pulmonary atresia with restrictive ventricular septal defect. The atretic pulmonary valve was perforated using a sheath introduced through the pulmonary artery.

Comparison of contrast enhanced magnetic resonance angiography with invasive cardiac catheterization for evaluation of children with pulmonary atresia

Complete assessment of the source of pulmonary blood supply and delineation of the anatomy of pulmonary arteries are essential for the management and prognostic evaluation of pulmonary atresia (PA) patients. Invasive cardiac catheterization is considered the gold standard imaging modality to achieve this. We investigated the role of contrast enhanced magnetic resonance angiography (MRA) to evaluate the pulmonary blood supply and the anatomy of the pulmonary arteries and compared this with cardiac catheterization in children with PA. We studied 20 children with PA. Median age was 2.5 years (range 6 months–13 years). All patients were examined with cardiac catheterization and contrast enhanced MRA, and the results of both modalities were compared. There was a complete agreement between both modalities in the detection of the main pulmonary artery morphology and determination of the confluence state of the central pulmonary arteries. There was an 88% agreement for patency of the ductus arteriosus and 66% for patency of the surgically placed shunt. There was a complete agreement between both techniques on determining the presence of collaterals more than 2.5 mm. Twenty-eight collaterals of less than 2.5 mm were detected only by contrast enhanced MRA. There was a strong correlation between both modalities in measuring the pulmonary arteries and collaterals diameter (P<0.001). Contrast enhanced MRA is a safe and accurate non-invasive technique to evaluate the pulmonary artery morphology and the sources of pulmonary blood supply in children with PA.

Natural History of Pulmonary Atresia With Intact Ventricular Septum and Right-Ventricle–Dependent Coronary Circulation Managed by the Single-Ventricle Approach

BACKGROUND

Long-term outcome of patients with pulmonary valvar atresia and intact ventricular septum with right-ventricle-dependent coronary circulation (PA/IVS-RVDCC) managed by staged palliation directed toward Fontan circulation is unknown, but should serve as a basis for comparison with management protocols that include initial systemic-to-pulmonary artery shunting followed by listing for cardiac transplantation.

METHODS

Retrospective review of patients admitted to our institution with the diagnosis of PA/IVS-RVDCC from 1989 to 2004. All angiographic imaging studies, operative reports, and follow-up information were reviewed. Right-ventricle-dependent coronary circulation was defined as situations in which ventriculocoronary fistulae with proximal coronary stenosis or atresia were present, putting significant left ventricle myocardium at risk for ischemia with right ventricle decompression.

RESULTS

Thirty-two patients were identified with PA/IVS-RVDCC. All underwent initial palliation with modified Blalock-Taussig shunt (BTS). Median tricuspid valve z-score was -3.62 (-2.42 to -5.15), and all had moderate (n = 13) or severe (n = 19) right ventricular hypoplasia. Median follow-up was 5.1 years (9 months to 14.8 years). Overall mortality was 18.8% (6 of 32), with all deaths occurring within 3 months of BTS. Aortocoronary atresia was associated with 100% mortality (3 of 3). Of the survivors (n = 26), 19 have undergone Fontan operation whereas 7, having undergone bidirectional Glenn shunt, currently await Fontan. Actuarial survival by the Kaplan-Meier method for all patients was 81.3% at 5, 10, and 15 years, whereas mean survival was 12.1 years (95% confidence interval: 10.04 to 14.05). No late mortality occurred among those surviving beyond 3 months of age.

CONCLUSIONS

In patients with PA/IVS-RVDCC, early mortality appears related to coronary ischemia at the time of BTS. Single-ventricle palliation yields excellent long-term survival and should be the preferred management strategy for these patients. Those with aortocoronary atresia have a particularly poor prognosis and should undergo cardiac transplantation.

Significance of reverse orientation of the ductus arteriosus in neonates with pulmonary outflow tract obstruction for early intervention

Reverse orientation of the ductus arteriosus (RDA), defined as an inferior angle at the aortic junction of <90 degrees , is associated with pulmonary atresia; however, the significance of RDA in nonatretic pulmonary outflow tract obstruction (POTO) is unknown. The purpose of this study was to evaluate the relation between ductal morphology and the need for early intervention. Ductal morphology was retrospectively reviewed in 76 neonatal cases of POTO. Patients were stratified to those with conotruncal (CT) or primary pulmonary valve (PV) abnormalities. The prevalence of RDA was 40 of 68 (59%) and was higher in patients with CT defects (28 of 30, 93%) compared with PV abnormalities (12 of 38, 32%; chi-square = 26.4, p <0.0001). Early intervention was required in 29 of 40 patients with RDA (73%) compared with only 8 of 28 patients with normal ductal morphology (31%; chi-square = 12.8, p <0.001). The proportion of patients with RDA who required early intervention was greater in PV abnormalities (12 of 12, 100%) compared with CT defects (17 of 28, 61%; chi-square = 6.5, p <0.02). Importantly, after excluding patients with pulmonary atresia, these analyses were unchanged. In patients with nonatretic POTO, a threshold inferior angle of 65 degrees was predictive of the need for early intervention. RDA in patients with PV abnormalities, or CT defects and an inferior angle <65 degrees , is a specific indicator for early intervention. These findings demonstrate an association between RDA in the context of atretic and nonatretic POTO and the need for early intervention. The need for early intervention should be considered when RDA is identified in this population.

Cannulation of patent arterial duct in patients with pulmonary atresia and ventricular septal defect

During cardiac catheterization in patients with pulmonary atresia and ventricular septal defect, cannulation of the arterial duct was attempted in 23 children via antegrade approach. It was successful in all but two children. Injection of contrast through antegradely placed catheter resulted in improved opacification of pulmonary arteries. This technique facilitated transcatheter dilation of spontaneously closed arterial duct in two children.

Pulmonary atresia with intact ventricular septum: range of morphology in a population-based study

OBJECTIVES

We describe the morphologic variability in pulmonary atresia with intact ventricular septum (PAIVS) within a population-based study.

BACKGROUND

An uncommon disease, PAIVS shows considerable morphologic heterogeneity. Clinical reports, based mostly on small samples of patients, may not reflect the true spectrum of pathology of this condition. We have studied the entire range of morphology in a prospective population-based study of patients over a five-year period (1991 to 1995). METHODS; As part of the United Kingdom and Ireland Collaborative Study of PAIVS, all 18 pediatric cardiac centers were visited by a single investigator. Morphologic features of each case were determined by direct review of the echocardiograms and angiocardiograms, from surgical and autopsy reports, and by review of pathology specimens where available.

RESULTS

Among 183 live-born infants, atresia was valvar (membranous) in 74.7% and muscular in 25.3%. Muscular obliteration of the apical trabecular cavity, and in some cases its infundibulum, resulted in "bipartite" right ventricle (RV) in 33.6%, and a "unipartite" chamber in 7.7%. The remaining 58.7% had "tripartite" morphology. Coronary arterial abnormalities were identified in 45.8%, including arterial stenoses, interruptions and ectasia in 7.6%. Ebstein's malformation coexisted in 18 patients. Median tricuspid valvar size and RV inlet Z-scores were -5.2 and -5.1, respectively.

CONCLUSIONS

This study provides unique data on the diverse pathology of PAIVS in an unselected population. This will help determine if published reports reflect the true spectrum of pathology of the condition.

Central pulmonary artery anatomy in right ventricular outflow tract obstructions

We reviewed the cine-angiograms of 190 patients with right ventricular outflow tract (RVOT) obstructions for size and anatomy of pulmonary arteries, patent ductus arteriosus (PDA) and major aorto pulmonary collateral arteries (MAPCAs). Patients were grouped into three, Tetralogy of Fallot (TOF) with pulmonary atresia (group 1, N=86), TOF with pulmonary stenosis (group 2, N=97) and 7 cases of pulmonary atresia with intact interventricular septum (group 3). Out of 86 patients in group 1, 49 had PDA alone, 30 had MAPCAs alone, six had both and one had none. In group 2, 31 patients had persistent PDA and one patient had MAPCAS and PDA. A discrete stenosis (DS) of pulmonary artery was seen significantly more in patients with RVOT obstructions associated with PDA compared to patients without PDA (67/84 vs. 5/96). Out of the 84 cases with ducti, 53 had stenosis of the pulmonary artery at the site of ductus insertion. Thus presence of PDA was an important factor in the development of DS. The likely cause of pulmonary artery stenosis in TOF with PDA may be the opposing flows through RVOT and PDA producing a watershed effect at the ductus-pulmonary artery junction. Diffuse hypoplasia of pulmonary arteries (DH) was seen more significantly in RVOT obstructions associated with MAPCAs, compared to other patient groups (19/36 vs. 14/87). These small pulmonary arteries had no discrete stenosis and this diffuse hypoplasia might be the result of inadequate blood flow during intrauterine life [Harikrishnan S, Tharakan J, Titus T, Bhat A, Sivasankaran S, Bimal F, Syam Sunder KR, James, KJ. Central pulmonary artery anatomy in right ventricular outflow tract obstructions. Indian Heart Journal 1997;49:624 (Abstract)[18]].

Congenital Heart Surgery Nomenclature and Database Project: pulmonary atresia--ventricular septal defect

Pulmonary atresia (PA) and ventricular septal defect (VSD) is a complex and extremely heterogeneous cardiopulmonary malformation that has not been accurately defined, as evidenced by the synonymous use of the term with tetralogy of Fallot with PA. The anatomy and morphology of the pulmonary circulation to a large extent determines the surgical approach and overall outcome, with the intracardiac anatomy playing a secondary role. Based on the characterization of the pulmonary circulation a new classification of PA-VSD is proposed. In type A, there are only native pulmonary arteries (NPA). In type B, pulmonary blood flow is provided by both NPA and by major aortopulmonary collateral arteries [MAPCA(s)]. In type C, there are only MAPCA(s) and no NPA. This new classification is proposed for the purpose of establishing a unified reporting system. The subject was debated and reviewed by members of the STS-Congenital Heart Surgery Database Committee and representatives from the European Association for Cardiothoracic Surgery. All 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 which 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.

Reference ranges for two-dimensional echocardiographic examination of the fetal ductus arteriosus

OBJECTIVES

To establish reference ranges for 2D-echocardiographic examination of the fetal ductus arteriosus and its relationship to the main pulmonary artery and the aorta.

METHODS

A prospective cross-sectional echocardiographic study was performed in 222 normal fetuses from 13 to 41 weeks of gestation using high resolution/color Doppler ultrasound equipment.

RESULTS

Gestational age-specific reference ranges are given for the diameter of the pulmonary valve anulus, diameter of the ductus arteriosus at its beginning, middle, and end, ductal length, ductal diameter-to-pulmonary valve anulus diameter ratio, and the spatial relationship of the ductus arteriosus to the main pulmonary artery and to the aorta.

CONCLUSIONS

The presented data derived from a study group of 222 normal fetuses provide in-vivo insights into the morphology of the ductus arteriosus and its relationship to the adjacent vessels. The reference ranges may be helpful in prenatal diagnosis of cardiac malformations and abnormalities of the ductus arteriosus, such as obstruction or aneurysm from 13 to 41 weeks of gestation.

Prenatal diagnosis of right ventricular outflow tract obstruction with intact ventricular septum, and detection of ventriculocoronary connections

OBJECTIVES

To determine the accuracy of prenatal diagnosis of pulmonary atresia and intact ventricular septum (PAIVS), and pulmonary stenosis, including prenatal detection of ventriculocoronary connections, to evaluate heart size during the prenatal period, and to evaluate the outcome.

DESIGN AND PATIENTS

Medical records of 20 cases with prenatally diagnosed PAIVS and pulmonary stenosis were reviewed retrospectively. Prenatal and postnatal echocardiography were also reviewed and dimensions of the ventricles and vessels were measured retrespectively.

RESULTS

Of 20 prenatal diagnoses (15 PAIVS and five pulmonary stenosis), 16 were confirmed as correct. One critical pulmonary stenosis case had been diagnosed as PAIVS prenatally; three had no confirmation. Eight pregnancies were terminated, three had no active treatment, and nine were treated; all survived. Of 13 assessed with ventriculocoronary connections prenatally, seven were diagnosed correctly (four with, three without ventriculocoronary connections), but one was falsely positive; five had no confirmation. The more prominent hypoplasia of the main pulmonary artery and the tricuspid valve annulus, and the sigmoid shape of the ductus arteriosus, seemed to be associated with the presence of ventriculocoronary connections.

CONCLUSIONS

Current prenatal echocardiography can accurately diagnose right ventricular outflow tract obstruction and ventriculocoronary connections. Prenatal detection of this constellation of abnormalities aids in family counselling and decisions on postnatal management.

Persistence of the left superior caval vein: can it potentiate obstructive lesions of the left ventricle?

Recent evidence has suggested that persistence of the left superior caval vein is associated with a high incidence of obstructive lesions of the left heart. To shed more light on this issue 1085 patients with congenital heart disease were studied retrospectively, with the aim of estimating the prevalence of a persistent left superior caval vein and its associated anomalies, focusing attention on obstructive lesions in the left and right ventricles. Patients with isomerism of the atrial appendages, or hypoplastic left heart syndrome, were excluded. A persisting left superior caval vein was present in 57 patients (5.2%). The overall incidence of obstructive lesions of the left heart was higher in patients with than in those without a persistent left superior caval vein (31.6 versus 7.8%,p < 0.001). Relative hypoplasia of the left ventricle was also higher in patients with persistent left superior caval vein (14 versus 0.8%, p < 0.001). The obstructive lesions found in the left heart, compared with the number in those without a left caval vein, were: mitral stenosis, 5.2 versus 0.7%; subaortic stenosis, 5.3 versus 0.9%; aortic coarctation, 17.5 versus 5.8% (p < 0.01); all of these in association, 3.5 versus 0.4%. In contrast, the incidence of obstructive lesions of the right heart was similar in the two groups of patients. It is concluded that persistence of the left superior caval vein can perturb the normal development of the left ventricle, being strongly associated with obstructions to left ventricular inflow and outflow.

Evaluation and management of pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PA/IVS) is a spectrum of diseases with varying severity of right ventricle hypoplasia and potential for biventricular, univentricular, or hybrid repairs. Pessimistic outcome measures for PA/IVS may give way to optimism with the refinement of early diagnosis and early intervention to encourage right ventricle flow and optimize growth. To this end, PA/IVS has become a focus of innovative interventions (e.g., fetal surgery) and new catheter-based and surgical techniques.

Prospective echocardiographic analysis of progressive obstruction of the proximal pulmonary artery in congenital heart disease and obstructed pulmonary flow

BACKGROUND

It is uncertain whether proximal pulmonary artery (PA) obstruction exists soon after birth and whether its progress relates directly to postnatal ductal constriction in congenital heart disease and obstructed pulmonary flow.

METHODS

Serial morphometric analyses of the PA branches by echocardiogram were performed in 28 patients (mean age at initial study 2.5 days) until severe constriction of the ductus occurred (mean age 47 days). These patients were divided into 2 groups by subsequent angiographic or postmortem confirmation; 10 with proximal PA obstruction (group 1) and 18 without obstruction (group 2).

RESULTS

At the time of initial examination, the mean indexed diameter of the proximal PA on the side of the ductus arteriosus in group 1 was significantly smaller than that on the contralateral side (5.2+/-0.7 versus 9.0+/-0.7 mm/BSA0.5, P < .001) or that in group 2 (8.0+/-0.4 mm/BSA0.5, P < .001). In group 1, 8 patients had a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5, which was less than those of any group 2 patients. After severe constriction of the ductus, the proximal PA index on the ductal side further decreased only in group 1 (P < .01).

CONCLUSIONS

These data indicate that unilateral obstructive lesion of branch PA is present shortly after birth and its progression relates directly to ductal constriction. Neonates with branch PA obstruction can be identified on their initial echocardiogram as having a proximal PA index on the ductal side < or = 5.5 mm/BSA0.5.

Prenatal Diagnosis of Pulmonary Atresia With Intact Ventricular Septum

Pulmonary atresia with intact ventricular septum is a rare and complicated congenital cardiac anomaly. Pulmonary outflow is obstructed, which results in hypertrophy and hypoplasia of the right ventricle. The fetal echocardiographic findings include a small pulmonary artery with an atretic pulmonary valve, right ventricular hypertrophy, dilated right atrium, and absent flow in the pulmonary artery on Doppler interrogation. The left ventricle, left atrium, and aortic root also may be enlarged. Nonimmune hydrops may develop in utero, which is the result of poor left ventricular function. Surgical treatments vary, depending on the presence of associated cardiovascular anomalies, but generally include a systemic-to-pulmonary artery anastomosis and a pulmonary valvulotomy.

Pulmonary atresia, "intact ventricular septum", and aortopulmonary collateral arteries

In muscular pulmonary atresia, major aortopulmonary collateral arteries are characteristic of pulmonary atresia with ventricular septal defect and are rarely seen in pulmonary atresia with intact ventricular septum. Two unusual cases of muscular pulmonary atresia are reported, one with an intact septum and one with a perimembranous ventricular septal defect, closed in utero by aneurysmal tricuspid tissue. In both cases the pulmonary blood supply came entirely from aortopulmonary collaterals. In case 1 a collateral artery connected the left subclavian artery and hypoplastic pulmonary arteries, and several aortopulmonary collaterals arose from the descending aorta, without overlap between these two circulations. In case 2 the pulmonary trunk and arterial duct were absent and the pulmonary blood supply came entirely from collateral arteries. The right ventricle was of normal size and tripartite with a closed perimembranous ventricular septal defect, discovered only at postmortem examination. These observations suggest right ventricular outflow tract obstruction early in fetal development, with involution of the pulmonary trunk and sixth arch derivatives, and persistence of primitive aortopulmonary connections. The morphology in case 1 is at odds with the theoretical division of pulmonary atresia with intact septum and pulmonary atresia with ventricular septal defect into two separate pathological entities that occur at different stages in fetal development.

Intermediate results after complete repair of tetralogy of Fallot in neonates

From July 1988 through September 1993, 30 neonates with symptomatic tetralogy of Fallot underwent complete repair. Sixteen patients had tetralogy and pulmonary stenosis, 9 had pulmonary atresia, 3 had nonconfluent pulmonary arteries, and 2 had both pulmonary atresia and nonconfluent pulmonary arteries. The median age at operation was 11 days (mean +/- standard error of the mean, 12.6 +/- 2.9 days), with a mean weight of 3.1 +/- 0.1 kg (range 1.5 to 4.4 kg). Preoperatively, 14 patients were receiving an infusion of prostaglandin, 13 were mechanically ventilated, and 6 required inotropic support. Right ventricular outflow tract obstruction was managed by a limited transannular patch in 25 patients, infundibular muscle division with limited resection in 15, and insertion of a right ventricle-pulmonary artery valved aortic homograft conduit in 5 patients. Follow-up was complete at a median interval of 24 months (range 1 to 62 months). There were no hospital deaths and two late deaths, for 1-month, 1-year, and 5-year actuarial survivals of 100%, 93%, and 93%, respectively. The hazard function for death had a rapidly declining single phase that approached zero by 6 months after the operation. Both late deaths occurred in patients with tetralogy of Fallot and pulmonary atresia who had undergone aortic homograft conduit reconstruction, so that the only independent risk factor for death was the use of a valved homograft conduit (p < or = 0.005). Eight patients required reoperation, resulting in 1-month, 1-year, and 5-year freedom from reoperation rates of 100%, 93%, and 66%, respectively. Indications for reoperation were branch left pulmonary artery stenosis in 5 patients, residual right ventricular outflow tract obstruction in 2 patients, and severe pulmonary insufficiency in 1 patient. Independent risk factors for reoperation included an intraoperative pressure ratio between the right and left ventricles of 0.75 or greater (p = 0.01), Doppler residual left pulmonary artery stenosis of 15 mm Hg or more, or Doppler right ventricular outflow tract obstruction gradient of 40 mm Hg or more at hospital discharge (p = 0.002 and 0.02, respectively). This series demonstrates the safety of early hemodynamic repair of symptomatic tetralogy of Fallot in neonates. It also emphasizes the importance of relieving all sources of right ventricular outflow tract obstruction at the initial operation, particularly that located at the site of insertion of the ductus arteriosus, which may be difficult to diagnose in the neonate before ductal closure occurs. The safety and efficacy of valved aortic homograft conduits in neonates requires further investigation.

Pulmonary circulation in pulmonary atresia associated with the asplenia cardiac syndrome

OBJECTIVE

The goal of this study was to determine the patterns of the pulmonary circulation in patients with pulmonary atresia and asplenia.

BACKGROUND

The asplenic cardiac syndromes characteristically have complex cardiac anomalies including pulmonary stenosis or atresia. Definition of the pulmonary artery circulation and pulmonary venous connections is needed for consideration of surgical procedures.

METHODS

In 35 patients, the sources of pulmonary blood flow, anatomic features of pulmonary arteries and pulmonary venous connections were determined from angiograms or autopsy specimens.

RESULTS

The main pulmonary artery was absent or hypoplastic in 91% of patients; most had a ductus arteriosus. The right and left pulmonary arteries were confluent in 90% and usually of normal size (right 71%, left 63%). Total anomalous pulmonary venous connections were present in 38%.

CONCLUSIONS

The anatomic features of the pulmonary arteries in pulmonary atresia associated with the asplenic cardiac syndrome are usually favorable for palliative surgical procedures. Total anomalous pulmonary venous connection may exist as a complicating factor.

Pathogenesis of various forms of double outlet right ventricle in mouse fetal trisomy 13

The pathogenesis of double outlet right ventricle with or without pulmonary infundibular atresia in mouse fetal trisomy 13 was studied at the organ level using microdissection and scanning electron microscopy. Altogether, 394 karyotyped trisomic embryos were collected between 11 days and 16 hours of gestation (presence of a vaginal plug = day 1) and 15 days of gestation at intervals of 8 hours, and at 16 days of gestation. The hearts were perfusion-fixed, microdissected, and prepared to be observed in scanning electron microscope in the following standardized orientations: frontal, right or left profile, septal and parietal halves of the right ventricle and outflow tract (conotruncus). Comparison of 276 trisomic hearts with their normal counterparts described previously has shown that: the first pathognomonic feature is the abnormal anterior position of the proximal part of the parietal outflow tract ridge or of both ridges (at 12 days and 16 hours of gestation); the abnormal anterior fusion of these ridges ("coalescence") results in a mesenchymal mass behind which is deviated the pulmonary part of the outflow tract lumen; from 14 days and 16 hours of gestation on, this lumen is either obstructed, resulting in a supravalvar stenosis of the pulmonary trunk and subsequently evolving into double outlet right ventricle with pulmonary infundibular atresia; or, in a minority of cases, this lumen is not obstructed and the heart develops into double outlet right ventricle without pulmonary infundibular atresia. The pathogenesis of these malformations differs from most of the known hypotheses based on deductions from human malformed hearts, as well as from observations of the pathogenesis of similar outflow tract malformations, such as those found in the Keeshond dog or rats treated with trimethadione.

Two-dimensional and Doppler echocardiographic assessment of variably shaped ductus arteriosus by the parasternal approach

Parasternal two-dimensional and Doppler echocardiography were compared with angiographic, surgical, and postmortem data in 213 patients with various forms of congenital heart disease for its accuracy in determining patency and anatomy of the ductus arteriosus (DA). The age range of the examined patients was from 1 day to 4 years (mean, 7.4 months). Echocardiography was always performed before any invasive procedure. An adequate window for imaging the DA was obtained by parasternal, two-dimensional echocardiography in 209 patients (98%). A persistent ductus arteriosus (PDA) was detected by invasive methods in 79 of 209 patients (38%), and by two-dimensional and Doppler echocardiography in 76 (sensitivity, 96%; specificity, 100%). The echocardiographic and angiographic findings agreed closely as to the duct's morphology. Our technique permits an accurate visualization of the duct in neonates, infants, and small children with various forms of congenital heart disease.

Tricuspid valve disease with significant tricuspid insufficiency in the fetus: diagnosis and outcome

The echocardiographic studies and clinical course of 27 fetuses (mean gestational age 26.9 weeks) diagnosed in utero with tricuspid valve disease and significant tricuspid regurgitation were reviewed. The diagnosis of Ebstein's anomaly was made in 17 of the fetuses, 7 had tricuspid valve dysplasia with poorly developed but normally attached leaflets and 2 had an unguarded tricuspid valve orifice with little or no identifiable tricuspid tissue. One fetus was excluded from data analysis because a more complex heart lesion was documented at autopsy. All fetuses had massive right atrial dilation and most who were serially studied had progressive right-sided cardiomegaly. Hydrops fetalis was found in six cases and atrial flutter in five. Associated cardiac lesions included pulmonary stenosis in five cases and pulmonary atresia in six. Four fetuses with normal forward pulmonary artery flow at the initial examination were found at subsequent study to have retrograde pulmonary artery and ductal flow in association with the development of pulmonary stenosis (n = 1) and pulmonary atresia (n = 3). On review of the clinical course of the 23 fetuses (excluding 3 with elective abortion), 48% of the fetuses died in utero and 35% who were liveborn died despite vigorous medical and, when necessary, surgical management, many of whom had severe congestive heart failure. Of the four infants who survived the neonatal period, three had a benign neonatal course, all of whom were diagnosed with mild to moderate Ebstein's anomaly; only one had pulmonary outflow obstruction. An additional finding at autopsy was significant lung hypoplasia documented in 10 of 19 autopsy reports.(ABSTRACT TRUNCATED AT 250 WORDS)

Solitary aorta with bilateral ductal origin of non-confluent pulmonary arteries in pulmonary atresia with intact ventricular septum

We report an exceptional case of pulmonary atresia with intact ventricular septum in which non-confluent pulmonary arteries were supplied by bilateral arterial ducts, the existence of which had been diagnosed in life. One should be aware of this arterial pattern, even when the ventricular septum is intact in the setting of pulmonary atresia, because it requires a different surgical approach than when atresia is associated with a ventricular septal defect, namely construction of bilateral shunts for palliation followed by reconstitution of the pulmonary arterial confluence for definitive repair.

Right ventricular concentric hypertrophy and left ventricular dilatation by ductal constriction in fetal rats

Fetal cardiac changes due to ductal constriction by maternal ingestion of nonsteroidal anti-inflammatory drugs were studied morphologically in near-term rats as an animal model, and results were compared with values of control 1 (C1, twenty-first day) and control 2 (C2, twenty-second day). The fetal ductus was constricted (-70%) (p less than 0.05) by maternal administration of 10 mg/kg indomethacin. Dilatation of the right ventricle and evidence of congestive heart failure including increased pericardial effusion (+200%) (p less than 0.05) and an increase in water content in the abdominal wall were present at 1, 4, and 8 hours after drug administration. At 24 hours after drug administration, concentric right ventricular hypertrophy was shown by a diminished right ventricular cavity (-36% vs. C2) (p less than 0.05), increased right ventricular wall thickness (+70% vs. C2) (p less than 0.05), and increased right ventricular mass (+31% vs. C1) (p less than 0.05). Left ventricular dilatation was indicated by an increased cavity volume (+87% vs. C2) (p less than 0.05) and increased muscle mass (+29% vs. C1 [p less than 0.05] or +9% vs. C2 [p greater than 0.05]). Both the wet and dry weights of the ventricles were increased. In conclusion, fetal ductal constriction caused right ventricular hypertrophy, diminished right ventricular cavity, and left ventricular dilatation and hypertrophy at 24 hours after drug administration in rats after initial congestive failure.

Pulmonary stenosis with intact ventricular septum: documentation of development of the lesion echocardiographically during fetal life

We describe a case of severe pulmonary stenosis with intact interventricular septum diagnosed during fetal life at 34 weeks gestational age. An echocardiographic examination had been performed on the same fetus at 20 weeks, when no cardiac anomalies were observed. It is concluded that this form of pulmonary stenosis might be a lesion either acquired during fetal life or becoming progressively more severe in the prenatal period.

Indication for systemic-pulmonary artery shunts guided by two-dimensional and Doppler echocardiography: criteria for patient selection

From June, 1983, to February, 1987, 91 patients with pulmonary outflow tract obstruction underwent a systemic-to-pulmonary artery shunt without an invasive study. The surgical indication was based on two-dimensional (2-D) and Doppler echocardiography only. In 82 patients (90.1%), 2-D and Doppler echocardiography allowed correct assessment of the intracardiac anatomy and of the morphology of the pulmonary arteries, pulmonary veins, and aortic arch. The aortic arch anatomy was misdiagnosed in 6 patients (6.6%) who underwent a modified instead of a classic Blalock-Taussig shunt. In 3 patients (3.3%), the indication for the systemic-pulmonary artery shunt was inappropriate; in 1, operative death resulted from the incomplete diagnosis. After the preselection of patients based on knowledge of the anatomical patterns, a systemic-pulmonary artery shunt may be performed without cardiac catheterization if these rules for definitive patient selection are followed: (1) accurate clinical assessment to identify the patients with restricted pulmonary blood flow; (2) precise intracardiac diagnosis by 2-D and Doppler echocardiography; and (3) definitive 2-D echocardiographic visualization of the pulmonary venous connection and the confluence of the pulmonary arteries.

The ductus arteriosus and stenoses of the pulmonary arteries in pulmonary atresia

Forty-one specimens with pulmonary atresia and confluent pulmonary arteries were studied to establish the frequency and the nature of anomalies of both the ductus arteriosus and the central pulmonary arteries and their possible interrelation. The specimens were divided according to the type of pulmonary atresia: valvar atresia (12 cases) versus "muscular" atresia of the pulmonary orifice (29 cases). Abnormal connexions between the duct and the adjacent great arteries, as well as stenosis of a pulmonary artery, were common in cases with atresia of the pulmonary orifice and relatively rare in cases with imperforate valve. The abnormal connexions consisted of a proximal displacement of the origin of the duct from the aorta and displacement of the entry site of the duct into the pulmonary trunk towards one of the main pulmonary arteries. A left duct thus connected to the left and a right duct to the right pulmonary artery. Pulmonary artery stenosis, exclusively occurring in those specimens with a duct connecting to a pulmonary artery, were located in the segment of pulmonary artery between the pulmonary trunk and the duct. Histological examination revealed ductal tissue in the wall of a pulmonary artery in more than half of the cases with atresia of the pulmonary orifice. Ductal tissue in a pulmonary artery and pulmonary artery stenosis frequently coexisted. It is concluded that stenoses in the central pulmonary arteries may be related to the duct. The relationship resembles that between the duct and coarctation of the aorta.

Juxtaductal left pulmonary artery obstruction in pulmonary atresia

The morphology of the central pulmonary artery was studied by selective angiography in 21 previously unoperated patients (aged 11 days-21 years, median 4 years) with pulmonary atresia associated with various types of congenital heart disease. Angiographic findings were confirmed at operation in 10 patients. There was juxtaductal obstruction of the left pulmonary artery in two thirds of the patients with complete atresia in a quarter. Six of seven patients without juxtaductal obstruction had pulmonary valve atresia, but all nine patients with juxtaductal stenosis had truncal atresia. No patient had stenosis of the right pulmonary artery.

Functional aortic valve atresia in transposition of the great arteries

The criterion for the diagnosis of functional atresia of a patient semilunar valve is met when the pressure in a ventricle remains lower than that in the related great artery throughout systole so that no forward flow can occur. Functional pulmonary valve atresia has been well recognized in infants with normally related great arteries and massive tricuspid valve incompetence. The cardiac physiology and anatomy of an infant with transposed great arteries and functional aortic valve atresia is reported for the first time. The peak systolic pressure in the right ventricle was 30 mm Hg and in the aorta 64 mm Hg. The causes for right ventricular incompetence were abnormalities of the tricuspid valve and hypoplasia of the ventricular free wall. Three other cases with similar ventricular anatomy and physiology but with anatomic atresia of the aortic valve are reviewed. The possibility that under these physiologic circumstances during fetal life functional atresia develops first, and that anatomic fusion of idle semilunar cusps develops as a secondary phenomenon, is discussed.

Transient neonatal tricuspid regurgitation: possible relation with premature closure of the ductus arteriosus

Normal fetal circulation requires patency of the ductus arteriosus. Prenatal ductal closure causes profound circulatory changes, such as massive tricuspid regurgitation. After delivery, the clinical picture of these severely distressed cyanotic newborns usually improves rapidly as the circulation is no longer dependent on ductal patency after onset of respiration. This case report deals with a newborn infant with severe tricuspid regurgitation and a large atrial right to left shunt who was treated with prostaglandin E1 infusion at 12 hours of age and in whom cardiac angiography revealed no evidence of either patent or functionally closed ductus arteriosus and no anatomic cardiac abnormalities at 30 hours of age. On the basis of physiologic and morphologic observations in this infant, the possible role of premature ductal narrowing or closure in the pathogenesis of transient neonatal tricuspid regurgitation is discussed. It is recommended that documentation of ductal presence or absence should become part of the diagnostic evaluation of newborns with transient tricuspid regurgitation.