Natural history of the ventricular septal defect in tricuspid atresia and its surgical implications

Association of Bulboventricular Foramen Size and Need for Early Intervention in Infants with Tricuspid Atresia or Double-Inlet Left Ventricle with Normally Related Great Arteries

BACKGROUND

The association of bulboventricular foramen (BVF) size and systemic outflow adequacy has been studied in patients with tricuspid atresia (TA) or double-inlet left ventricle (DILV) with transposed great arteries. The aim of this study was to determine the relationship between initial BVF size and risk for progressive pulmonary outflow obstruction requiring intervention to increase pulmonary blood flow in patients with TA or DILV with normally related great arteries.

METHODS

Patients with TA or DILV with normally related great arteries were identified by retrospective chart review at a single center from 2005 to 2021. Patients were stratified by indexed BVF area (iBVFA) to determine the relationship of iBVFA size and the need for intervention before the Glenn operation to establish supplemental pulmonary blood flow with either a Blalock-Taussig-Thomas shunt (BTTS) or patent ductus arteriosus (PDA) stent. Patients were followed through the time of their Glenn operations. Logistic regression analysis was performed to determine optimal iBVFA cut points.

RESULTS

Thirty-seven patients with TA or DILV with normally related great arteries were included. Sixteen had iBVFA < 1 cm²/m², with all 16 (100%) requiring either a BTTS or PDA stent to increase pulmonary blood flow before the Glenn operation. Seventeen had iBVFAs of 1 to 2 cm²/m², with 10 (59%) requiring either a BTTS or PDA stent. Nine of those 10 demonstrated flow acceleration across the BVF and/or pulmonary outflow tract. Four had iBVFA > 2 cm²/m², with only one patient (25%) requiring a BTTS. Among our cohort, an iBVFA of <1.8 cm²/m² provided sensitivity of 96% with good positive and negative predictive values (81% and 80%, respectively) for requiring intervention with a BTTS or PDA stent before the Glenn operation.

CONCLUSIONS

An iBVFA of ≤1.8 cm²/m² on initial postnatal echocardiography is associated with the development of subpulmonary obstruction requiring intervention with a BTTS or PDA stent before the Glenn operation, with the highest risk noted in those with iBVFA of ≤1 cm²/m². Factors such as BVF flow acceleration or pulmonary outflow tract narrowing should also be considered in the decision to augment pulmonary blood flow.

Single Ventricle-A Comprehensive Review

In this paper, the author enumerates cardiac defects with a functionally single ventricle, summarizes single ventricle physiology, presents a summary of management strategies to address the single ventricle defects, goes over the steps of staged total cavo-pulmonary connection, cites the prevalence of inter-stage mortality, names the causes of inter-stage mortality, discusses strategies to address the inter-stage mortality, reviews post-Fontan issues, and introduces alternative approaches to Fontan circulation.

Management of Congenital Heart Disease: State of the Art-Part II-Cyanotic Heart Defects

In this review management of the most common cyanotic congenital heart defects (CHDs) was discussed; the management of acyanotic CHD was reviewed in Part I of this series. While the need for intervention in acyanotic CHD is by and large determined by the severity of the lesion, most cyanotic CHDs require intervention, mostly by surgery. Different types of tetralogy of Fallot require different types of total surgical corrective procedures, and some may require initial palliation, mainly by modified Blalock-Taussig shunts. Babies with transposition of the great arteries with an intact ventricular septum as well as those with ventricular septal defects (VSD) need an arterial switch (Jatene) procedure while those with both VSD and pulmonary stenosis should be addressed by Rastelli procedure. These procedures may need to be preceded by prostaglandin infusion and/or balloon atrial septostomy in some babies. Infants with tricuspid atresia require initial palliation either with a modified Blalock-Taussig shunt or banding of the pulmonary artery and subsequent staged Fontan (bidirectional Glenn and fenestrated Fontan with extra-cardiac conduit). Neonates with total anomalous pulmonary venous connection are managed by anastomosis of the common pulmonary vein with the left atrium either electively in non-obstructed types or as an emergency procedure in the obstructed types. Babies with truncus arteriosus are treated by surgical closure of VSD along with right ventricle to pulmonary artery conduit. The other defects, namely, hypoplastic left heart syndrome, pulmonary atresia with intact ventricular septum, double-outlet right ventricle, double-inlet left ventricle and univentricular hearts largely require multistage surgical correction. The currently existing medical, trans-catheter and surgical techniques to manage cyanotic CHD are safe and effective and can be performed at a relatively low risk.

The Journey of an Indian Pediatric Cardiologist : Dr. K. C. Chaudhuri Lifetime Achievement Award/Oration at AIIMS, New Delhi, September 2017

The life journey of an Indian pediatric cardiologist, who bestowed considerable attention to the development of new knowledge and train/teach physicians around the world while providing care of patients with heart disease over a 45-y period, is reviewed. This appraisal focuses particular attention on the scientific contributions to the literature. These include spontaneous closure of physiologically advantageous ventricular septal defects, various issues related to a congenital heart defect namely, tricuspid atresia and transcatheter and, interventional pediatric cardiac procedures.

A review of spontaneous closure of ventricular septal defect

Ventricular septal defect (VSD) is the most common congenital heart malformation and can be detected during the prenatal and postnatal period, in childhood, and in adulthood. Spontaneous closure of VSD can be determined through a variety of methods-echocardiography, Doppler color flow imaging, angiography, auscultation, and cardiac catheterization-and can be proven by pathological evidence at necropsy. There are two major types of VSD, membranous and muscular, as well as the perimembranous variety, which comprises variable portions of the adjacent muscular septum but lacks the membranous septum. VSD appears either as an isolated cardiac defect without other abnormalities or with several complex malformations. It has long been recognized that VSD can close spontaneously, but the incidence of spontaneous VSD closure is still uncertain. Since necropsy study of the hearts with VSD has rarely been reported, information on morphological features of spontaneous VSD closure remains limited. In addition, the mechanisms for spontaneous VSD closure are not fully understood. Herein, we present a brief review of the incidence of spontaneous VSD closure, morphological characteristics of the closure, and the main mechanisms responsible for the closure.

Consensus on timing of intervention for common congenital heart diseases: part II - cyanotic heart defects

The purpose of this review/editorial is to discuss how and when to treat the most common cyanotic congenital heart defects (CHDs); the discussion of acyanotic heart defects was presented in a previous editorial. By and large, the indications and timing of intervention are decided by the severity of the lesion. While some patients with acyanotic CHD may not require surgical or transcatheter intervention because of spontaneous resolution of the defect or mildness of the defect, the majority of cyanotic CHD will require intervention, mostly surgical. Total surgical correction is the treatment of choice for tetralogy of Fallot patients although some patients may need to be palliated initially by performing a modified Blalock-Taussig shunt. For transposition of the great arteries, arterial switch (Jatene) procedure is the treatment of choice, although Rastelli procedure is required for patients who have associated ventricular septal defect (VSD) and pulmonary stenosis (PS). Some of these babies may require Prostaglandin E1 infusion and/or balloon atrial septostomy prior to corrective surgery. In tricuspid atresia patients, most babies require palliation at presentation either with a modified Blalock-Taussig shunt or pulmonary artery banding followed later by staged Fontan (bidirectional Glenn followed later by extracardiac conduit Fontan conversion usually with fenestration). Truncus arteriosus babies are treated by closure of VSD along with right ventricle to pulmonary artery conduit; palliative banding of the pulmonary artery is no longer recommended. Total anomalous pulmonary venous connection babies require anastomosis of the common pulmonary vein with the left atrium at presentation. Other defects should also be addressed by staged correction or complete repair depending upon the anatomy/physiology. Feasibility, safety and effectiveness of treatment of cyanotic CHD with currently available medical, transcatheter and surgical methods are well established and should be performed at an appropriate age in order to prevent damage to cardiovascular structures.

Diagnosis and management of cyanotic congenital heart disease: part II

In this review, the clinical features and management of less commonly encountered cyanotic cardiac lesions are reviewed. Pathophysiology, clinical features, laboratory studies and management are discussed. The clinical and non-invasive laboratory features of these cardiac defects are sufficiently characteristic for the diagnosis and invasive cardiac catheterization and angiographic studies are not routinely required. Such studies may be needed either to define features that could not be clearly defined by non-invasive studies or prior to performing trans-catheter interventions. Surgical correction or effective palliation is possible at relatively low risk. But, residual defects, some requiring repeat catheter or surgical intervention, may be seen in a significant percentage of patients and consequently, continued follow-up after surgery is recommended.

Diagnosis and management of cyanotic congenital heart disease: part I

Most commonly encountered cyanotic cardiac lesions in children, namely, tetralogy of Fallot, transposition of the great arteries and tricuspid atresia are reviewed. Pathology, pathophysiology, clinical features, non-invasive and invasive laboratory studies and management are discussed. The clinical and non-invasive laboratory features are sufficiently characteristic for making the diagnosis and invasive cardiac catheterization and angiographic studies are not routinely required and are needed either to define features, not clearly defined by non-invasive studies or as a part of catheter-based intervention. Surgical correction or effective palliation can be undertaken with relatively low risk. However, residual defects, some requiring repeat catheter or surgical intervention, are present in a significant percentage of patients and therefore, continued follow-up after surgery is mandatory.

Tricuspid Atresia

Untreated, the prognosis for patients with tricuspid atresia (TA) is poor. Recent advances in medical and surgical therapy, particularly the application of Fontan principle, have markedly improved the long-term outlook for children with this condition. Palliative procedures to normalize the pulmonary blood flow and to relieve interatrial or interventricular obstruction should be undertaken promptly. Staged total cavopulmonary connection to bypass the right atrium and right ventricle by an initial bidirectional Glenn procedure and followed by extracardiac conduit diversion of inferior vena caval flow into the pulmonary arteries appears to be the current procedure of choice in the surgical management of TA. Total cavopulmonary diversion appears to be superior to conventional Fontan-Kreutzer operations, but long-term follow-up results are needed to confirm this impression.

Surgical management of congenital heart defects: current trends

Surgical treatment for congenital heart disease has become available over the last five decades. Palliative procedures have been designed to improve physiologic abnormalities, for example systemic artery (or venous) to pulmonary artery shunts of various types to increase the pulmonary blood flow, pulmonary artery constriction (banding) to decrease the pulmonary blood flow, and surgical or transcatheter atrial septostomy to augment intracardiac mixing. These can be performed with a low mortality. The majority of congenital heart defects can be corrected by open heart surgical techniques; some require prior palliation and others can be operated without prior palliative surgery. Recent surgical advances include early total surgical correction for tetralogy of Fallot, arterial switch procedure for transposition of the great arteries, Fontan operation and its modifications for tricuspid atresia and single ventricle, new operations for hypoplastic left heart syndrome, newer prosthetic valves, myocardial preservation and cardiac transplantation.

Angiocardiographic evaluation of right ventricular size and morphology in tricuspid atresia

The potential for right ventricular growth and physiological repair in tricuspid atresia may influence the type of Fontan procedure. To evaluate preoperative right ventricular assessment, we compared the right ventricular size and morphology determined by selective right ventricular catheterization with axial left ventricular angiography. In seven consecutive patients with tricuspid atresia and ventriculo-arterial concordance, the right ventricular volume was 12.8 +/- 9.4 cc, with a predicted normal volume (based on body surface area) of 31 +/- 16 cc, 43% (range 24-78%) of normal. Right ventricular injection outlined a right ventricular area twice that visualized from an axial left ventricular injection (33.2 vs. 16.5 cm). All patients had a well developed but small trabecular portion of the right ventricle, often unopacified with left ventricular injection. Subinfundibular narrowing adjacent to the ventricular septal defect was invariably present, creating, in effect, a two-chambered right ventricle. Selective right ventriculography demonstrates the unique morphology of the right ventricle in patients with tricuspid atresia not visualized by axial left ventriculography.

Spontaneous closure of uncomplicated ventricular septal defect

The charts of 222 patients with a diagnosis of ventricular septal defect (VSD) were reviewed to determine the overall incidence, the prevalence of membranous and muscular defects and the rates of spontaneous VSD closure. VSD diagnosis and location were determined primarily from reports of 2-dimensional and pulsed Doppler echocardiograms. In a 5-year period, VSDs occurred in 3.85/1,000 live full-term births and 7.06/1,000 live premature births. The VSD closed spontaneously in 20 of 44 patients (45%) followed from birth (University Hospital group) during a mean follow-up of 12 months. Of 165 patients not followed from birth (referred group), the VSD closed spontaneously in 37 (22%). Overall, VSD location was determined in 101 of 209 patients (48%) and was distributed as follows: membranous 66 (65%), muscular 32 (32%) and subpulmonic 3 (3%). Rates of spontaneous closure for membranous and muscular VSDs were 37% and 50%, respectively, for the University Hospital group and 9% and 9%, respectively, for the referred group (no significant difference in either case). Surgical closure was required in 30 of 165 referred patients (18%) and only 1 of 44 University Hospital patients (2%). There was no significant difference in rate of closure for premature vs full-term infants or small vs larger defects. Data for patients followed from birth more likely reflect the true natural history of VSD.

The progressive nature of subaortic stenosis in congenital heart disease

Data derived from serial hemodynamic and angiocardiographic investigations on pediatric patients not subjected to intervening intracardiac operations support the view that subaortic stenosis in congenital heart disease tends to be a progressive disorder. Our data are obtained from two groups of patients. The first comprised 22 patients with discrete subaortic stenosis in relative isolation. The second was made up of 19 patients with the fibrous or fibromuscular forms of discrete subaortic stenosis associated with a perimembranous ventricular septal defect. The results from both groups support our initial contention. The progressive character of subaortic stenosis in these two situations illustrates the dynamic nature of congenital heart disease, and the tendency of a changing form and function.

Spontaneous closure of ventricular septal defect in a case of double outlet right ventricle

A 5 year old child, previously diagnosed as having tetralogy of Fallot, was admitted to hospital in severe congestive heart failure. The electrocardiogram showed left anterior hemiblock and incomplete right bundle-branch block, neither of which was previously present. The child died in intractable congestive heart failure and the necropsy showed a double outlet right ventricle with complete spontaneous closure of the subaortic ventricular septal defect by fibrous tissue. The possible mechanism involved in the production of this unusual complication of double outlet right ventricle is discussed, together with an explanation for the electrocardiographic changes.

Left to right atrial shunting in tricuspid atresia

In tricuspid atresia, an obligatory right to left shunt occurs at the atrial level. We have observed several patients with left to right interatrial shunts. Data from cardiac catheterisation in 40 consecutive patients were reviewed to determine the frequency and mechanism of left to right shunting in tricuspid atresia. An increase of 6% or more in oxygen saturation between the superior vena cava and the right atrium in two or more sets of saturations, representing a left to right shunt, was present in 29 out of 50 (58%) catheterisations in which the data were adequate. In most, the shunt was also seen cineangiographically in the laevophase. In only two catheterisations was an anatomical cause (ostium primum atrial septal defect in one and anomalous pulmonary venous return in the other) found. In the remaining 27 catheterisations, no anatomical cause was found. Age, Qp:Qs, and mean atrial pressure difference were similar between the shunt and non-shunt groups. In the shunt group right atrial "a" waves were equal to or higher than left atrial "a" waves and left atrial "v" waves were equal to or higher than right atrial "v" waves. Simultaneous pressure recordings (in one patient with left to right atrial shunt) from the left atrium and right atrium with isosensitised miniature pressure transducers mounted 5 cm apart showed (1) a higher pressure in the right atrium than in the left atrium during atrial systole and (2) a higher pressure in the left atrium than in the right atrium during atrial disatole. It is concluded that (a) left to right shunt across the atrial septum occurs frequently in tricuspid atresia and (b) the left to right shunt is the result of instantaneous pressure differences between the atria.

Further observations on the spontaneous closure of physiologically advantageous ventricular septal defects in tricuspid atresia: surgical implications

Clinical, angiographic, and pathological findings in 40 consecutive patients with tricuspid atresia were reviewed. In 14 patients, there was evidence of closure of the ventricular septal defect (VSD); it was complete in 8 and partial in the other 6. Eleven of these VSD closures occurred in type I patients (without transposition of the great arteries) and 3 in type II patients (with transposition). Progressive cyanosis, along with increasing polycythemia or the disappearance of a previously heard murmur, or both, was observed in all patients. The incidence of closure of VSD in this lesion was 42%. Progressive muscular "encroachment" of the margins of the VSD with subsequent fibrosis and covering by endocardial proliferation is thought to be the most likely mechanism of closure. For initial palliation of this defect, a Blalock-Taussig shunt--preferably on the left side--is recommended in preference to a Glenn anastomosis, because the latter may leave the left pulmonary circuit without blood supply if the VSD closes. If further palliation is required prior to a Fontan procedure, a Blalock-Taussig shunt on the right side, Glenn anastomosis, or enlargement of the VSD may be performed. In type II patients, a large and nonrestrictive VSD is essential for survival following a Fontan operation. Therefore, the size of the VSD should be evaluated prior to and at the time of surgical correction. If the VSD is small in type II patients, complete bypass of the defect and right ventricle by a pulmonary artery-ascending aorta shunt or by a left ventricle-descending aorta conduit should be performed.

New surgical approach to palliate tricuspid atresia in infants

An experimental surgical technique is proposed to increase pulmonary blood flow in tricuspid atresia with normally related great arteries. The method consists of the creation of ventricular septal defect in the infundibular septum by means of a closed surgical procedure. The expected advantage would be the growth of the right ventricular cavity. This would permit performance of a Fontan's procedure later, using the right atrium and the right ventricle. Microscopic sections from the hearts of 4 infants showed no damage in the conduction system. When performed in the beating hearts of dogs, the feasibility of the procedure was tested repeatedly without production of rhythm disturbances.

Tricuspid atresia in adults

Congenital atresia of the tricuspid valve is still uncommon in adult patients. However, increasingly successful palliative surgery in children now has increased its incidence after age 15 years. This investigation updates the clinical features of this disease in adults in light of modern diagnostic and surgical techniques. The data on all 18 adults with tricuspid atresia having angiography after age 15 years at this institution since 1970 were reviewed. The patients' ages ranged up to 45 years; 12 had had previous palliative surgery. Left cineventriculography, particularly biplane, with the long axial view (60 degrees left anterior oblique with cranial angulation) is the most important diagnostic mode and reveals the ventricular and great vessel relations. According to standard classification, 11 patients had type I anatomy (normal great arterial relations), 4 type II (transposed great arteries) and 2 type III ("corrected transposition of the great arteries"). One patient with inverted ventricles could not be classified. Associated additional congenital defects were uncommon. On the basis of these data, a new anatomic classification of tricuspid atresia is given which encompasses all possible atrial-ventricular-great arterial combinations. Seven patients had further surgery after study, including two procedures of the Fontan type (right atrium to pulmonary arterial conduit). Follow-up data on all 18 patients revealed two deaths (one early after operation, one late after study without further surgery). The remaining 16 patients survive 2 to 120 months after study. Four patients had naturally balanced pulmonary and systemic circulations and have survived to ages 21 to 41 years without surgery. Prudent surgical decision based on accurate anatomic diagnosis and the need for optimal effective pulmonary blood flow may result in a relatively optimistic prognosis in adults with this disease.

Morphological and topographical variations of the outlet chamber in complex congenital heart disease: an angiocardiographic study

The outlet chamber of the human heart can show considerable variations in its morphology and topography (relationship to main ventricular chamber), and such variations in anatomy and spacial relationship may be predictive of the associated intracardiac anatomy. Although there is considerable debate about whether the position of the outlet chamber is indicative of the type of bulboventricular loop (whether D- or L-), a right-sided and anterior outlet chamber has different implications than a left-sided, superior, and more posterior positioned one. The inflows into the outlet chamber can vary anatomically, and progressive changes in the calibers of these communications can adversely alter the natural history. One or both of the greak vessels, or neither, or a persistent truncus arteriosus can originate from the outlet chamber, and any significant morphological change in the outlet chamber may or may not adversely affect either the pulmonary or systemic blood supply, or both. Finally, any consideration of the outlet chamber raises important conceptual difference in terminologies. At present, there is not unanimity as to what constitutes either an outlet chamber (as compared to a "small right ventricle" in tricuspid atresia) or a single (primitive) ventricle. Any discussion of the morphological and topographical variations of the outlet chamber must be viewed with respect to the terminology employed.