Right ventricular growth in a case of pulmonic stenosis with intact ventricular septum and hypoplastic right ventricle

Differences in Right Ventricular Physiologic Response to Chronic Volume Load in Patients with Repaired Pulmonary Atresia Intact Ventricular Septum/Critical Pulmonary Stenosis Versus Tetralogy of Fallot

BACKGROUND

Patients with pulmonary atresia with intact ventricular septum and critical pulmonary stenosis (PAIVS/CPS) have wide variation in right ventricle (RV) size, systolic function, and diastolic function at birth. Establishment of antegrade pulmonary blood flow creates the potential for RV dilation from chronic pulmonary insufficiency. Future surgical decisions are based on RV size and function, largely supported by longitudinal studies of patients with Tetralogy of Fallot (TOF). Given potential differences in RV physiology and lack of similar data in PAIVS/CPS, the objective of this study was to determine differences in RV size, systolic function, and diastolic function between patients with PAIVS/CPS versus TOF.

METHODS

We retrospectively collected cardiovascular magnetic resonance (CMR) data in 27 patients with PAIVS/CPS (ages 13.3 ± 8.8 years) and 78 with TOF (11.4 ± 5.4 years). RV volumes, ejection fraction (EF), regurgitant fraction, end-diastolic forward flow across the pulmonary valve, and right atrial cross-sectional area were calculated.

RESULTS

There was no difference between the groups in RV end-diastolic volume (RVEDVi), RVEF, or pulmonary regurgitation. RVEF tended to decrease in TOF when RVEDVi exceeded 164 ml/m². In PAIVS/CPS, RVEDVi less frequently reached 164 ml/m² and was not associated with RVEF. There was worse RV diastolic dysfunction in PAIVS/CPS, with 1.5 times larger right atrial area and two times higher pulmonary end-diastolic forward flow (p < 0.0001).

CONCLUSIONS

Patients with PAIVS/CPS have similar RV size, systolic function, and pulmonary regurgitation as TOF. However, impaired RV diastolic function may limit extremes of RV dilatation and impact long-term management of PAIVS/CPS.

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.

Recent advances in pediatric cardiology--electrophysiology, transcatheter and surgical advances

Whereas the medical advances were reviewed in the previous paper, electrophysiological, transcatheter and surgical advances will be the focus in this review. Greater understanding of the arrhythmias, development of non-pharmacological treatment, namely catheter ablation and internal cardioverter-defibrillator (ICD) and miniaturization pacemakers and IDs have occurred in the last decade so that the methods could be applied to smaller and more complex patient population. Surgery has been the traditional treatment option for palliation and correction of congenital and acquired heart defects in infants and children. During the last one to one and one-half decades, a remarkable number of transcatheter methods were developed and refined. These developments during the last decade were reviewed and include long-term results of balloon dilatation procedures, transcatheter closure of atrial septal defects, patent ductus arteriosus, and ventricular septal defect, percutaneous valve replacement, intravascular stents to manage vascular obstructive lesions that can not be satisfactorily balloon-dilated, catheter completion of Fontan procedure, myocardial reduction in hypertrophic cardiomyopathy and other miscellaneous procedures. Recent advances in the transcatheter modes of therapy have added a new dimension to the management of neonates, infants and children with heart disease. They should now be added to the armamentarium available to the Pediatrician and Pediatric Cardiologist in the management of cardiac problems in the pediatric patient. Surgical methods and concepts have been greatly refined such that surgery can be undertaken even in the sickest and most complex patient. The majority of congenital heart defects can be corrected by open heart surgery; some require prior palliation and others can be operated without prior palliation. Recent advances in various defects were reviewed.

Pulmonary Atresia with Intact Ventricular Septum

The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with and without conventional surgical treatment. Because of this reason, a comprehensive program of medical, transcatheter, and surgical treatment is necessary to improve the long-term outlook of these infants. Algorithms of management plans should be developed based on the presence of right ventricular-dependent coronary circulation as well as size and morphology of the right ventricle. In a tripartite or bipartite right ventricle, transcatheter radiofrequency perforation is preferable. Alternatively, surgical valvotomy may be performed. Augmentation of pulmonary blood flow by prolonged infusion of prostaglandin E(1), stenting the ductus, or a surgical modified Blalock-Taussig shunt may be necessary in some of these patients. In patients with a unipartite or very small right ventricle or a right ventricular-dependent coronary circulation (Tricuspid valve Z score < -2.5), augmentation of pulmonary flow along with atrial septostomy should be undertaken. Follow-up studies to determine the feasibility of biventricular repair should be undertaken and, if feasible, surgical or transcatheter methods may be used to achieve the goals. If not suitable for biventricular repair, one-ventricle (Fontan) or one and one-half ventricular repair should be considered. Comprehensive and well-planned treatment algorithms may help improve survival rate.

Transcatheter management of neonates with pulmonary atresia and intact ventricular septum

This report describes a 1 day-old infant with valvar pulmonary atresia with intact ventricular septum in whom we were successful in performing transcatheter guidewire perforation and balloon pulmonary valvuloplasty to establish right ventricle-to-pulmonary artery continuity and flow. Also described is implantation of a 4 mm coronary stent into ductus arteriosus in lieu of surgical aortopulmonary shunt to treat pulmonary oligemia and systemic arterial hypoxemia. Details of transcatheter guidewire perforation are presented and it is suggested that this method be used as an alternative to Laser/radio frequency wires, especially in the absence of approval of the latter wires by the regulatory agencies. Stenting of the ductus may be considered an alternative to surgical aortopulmonary shunt. Role of transcatheter technology in the management of selected patients with pulmonary atresia and intact ventricular septum is discussed.

Transcatheter treatment of pulmonary outflow tract obstruction: a review

The role of transcatheter methods in the management of pulmonary outflow tract obstruction are discussed in this review. Balloon pulmonary valvuloplasty for relief of isolated pulmonary valve stenosis has been successfully used by many investigators and is the procedure of choice for the management of these lesions. Supravalvar pulmonic stenosis, if discrete, can be relieved by balloon dilatation. Cyanotic children with interatrial right-to-left shunts secondary to severe valvar pulmonary stenosis respond in a manner similar to that observed with isolated pulmonary valve stenosis. In these patients, balloon valvuloplasty is the treatment of choice and may be corrective in most patients. In patients with interventricular right-to-left shunting secondary to pulmonary outflow tract obstruction and in patients with narrowed BT shunts, balloon dilatation may be an effective palliative procedure in a substantial proportion of patients obviating the need for an initial or second palliative shunt. Balloon dilatation is recommended if the patient's size or cardiac anatomy make them unsuitable for safe total surgical correction. In patients with pulmonary atresia, either initial opening of the atretic pulmonary valve by laser or by surgery with subsequent balloon dilatation are potentially beneficial in reducing the total number of surgical procedures that these children are likely to require. However, further clinical trials are needed before their general use.

Transcatheter management of cyanotic congenital heart defects: a review

In this review, the role of transcatheter methods in the management of cyanotic congenital heart defects is discussed. In patients with interventricular right-to-left shunting secondary to pulmonary outflow tract obstruction (most commonly tetralogy of Fallot), balloon dilatation may be an effective palliative procedure in a substantial proportion of patients, obviating the need for a palliative shunt. We would recommend this if the patient's size or cardiac anatomy makes that patient an unsuitable candidate for safe total surgical correction. Infundibular myectomy with atherectomy catheter in tetralogy of Fallot patients may become a useful adjunct in the management of these infants. Cyanotic children with interatrial right-to-left shunt secondary to severe valvar pulmonary stenosis respond to balloon pulmonary valvuloplasty in a manner similar to that seen with isolated pulmonary valve stenosis. In these patients, balloon valvuloplasty is the treatment of choice and may be corrective in most cases. In patients with a narrowed Blalock-Taussig shunt, balloon angioplasty may improve pulmonary oligemia and systemic arterial hypoxemia and may obviate the need for a second systemic-to-pulmonary artery shunt. Balloon angioplasty is recommended if the patient's cardiac defect is not amenable to surgical correction at a low risk either because of the size of the patient or because of the complexity of the cyanotic heart defect. In patients with pulmonary valve atresia, initial opening of the atretic pulmonary valve by either laser or surgery with subsequent balloon dilatation is potentially beneficial in reducing the total number of surgical procedures that these children are likely to require. However, further clinical trials are needed prior to their general use.

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.

Morphology of pulmonary atresia with intact ventricular septum in patients dying after operation

In 1976, we adopted staged surgical management of pulmonary atresia with intact ventricular septum: stage 1 = establishment of a systemic to pulmonary artery shunt; stage 2 = open reconstruction of the right ventricular outflow tract and pulmonary valve; and stage 3 = closure of the shunt and interatrial communication. The morphological features of nine specimens obtained from 10 patients who died were reviewed. Special attention was given to features that might have influenced the poor surgical outcome in these patients. Survival after stage 1 depends on adequate systemic to pulmonary artery blood flow, initially as a combination of ductus arteriosus and shunt flow, with subsequent modification if the ductus closes. After stage 2, survival is influenced by left ventricular function and mitral valve function. The success of final correction (stage 3) depends largely on the morphology of both ventricles and their atrioventricular valves. It appears that the behavior of the ductus arteriosus and the size of the shunt are of vital importance for the survival of the infant. In 3 of the specimens, no right ventricular outflow tract was present, and in 2 others, short chordal attachments of the mitral valve were observed. Staged surgical correction appears to be a satisfactory approach if these considerations are taken into account.

Surgical intervention in neonates with critical pulmonary stenosis

The surgical experience with 18 consecutive neonates with critical pulmonary stenosis (PS) and intact ventricular septum was reviewed. All patients had cardiac catheterization with calculation of right ventricular volume. Group A patients (N = 8) had a small right ventricular end-diastolic volume (RVEDV less than 72% of predicted). Group B patients (N = 10) had a normal or enlarged RVEDV. All patients had a closed pulmonary valvotomy. Five Group A patients required a systemic-pulmonary shunt or prostaglandin (PGE1) after operation; one patient died. Nine Group B patients did well after valvotomy; one moribund patient died after valvotomy and shunt. Six of 16 survivors required reoperation: valvectomy in four patients and shunt takedown in two patients. Four of the six patients who had reoperation also had a transannular patch. There was one unrelated late death. All long-term survivors are asymptomatic. Recatheterization in four patients with a small right ventricle (RV) documented significant RV growth. In conclusion, most neonates with critical PS can be managed with closed valvotomy. Patients with a small RV may require PGE1 or a shunt after operation for persistent hypoxemia. Some patients with a small RV will have significant RV growth after valvotomy.

Comprehensive management of pulmonary atresia with intact ventricular septum

The prognosis for patients with pulmonary atresia with intact ventricular septum is poor with or without conventional surgical intervention. Therefore, a comprehensive program of medical and surgical treatment is necessary to improve long-term outlook for these infants. Such a program consists of management of the neonate at initial presentation with prompt administration of prostaglandins and institution of a combination of surgical procedures (isolated pulmonary valvotomy, valvotomy plus modified Blalock-Taussig shunt, Blalock-Taussig shunt plus balloon atrial septostomy, or Blalock-Taussig shunt alone) depending on the results of morphological analysis of the right ventricle; this treatment regimen is designed to relieve hypoxemia, encourage right ventricular growth, and provide adequate egress of blood from the right atrium. Another important element of management is to perform follow-up hemodynamic and angiographic studies when the patient is between 6 and 12 months old to ensure that the objectives of the comprehensive program are being met. Finally, a definitive repair should be offered. This can be done by using or bypassing the right ventricle, depending on whether it can support the pulmonary circuit.

Surgical management of hypoplastic right ventricle with pulmonary atresia or critical pulmonary stenosis and intact ventricular septum

Our experience with the surgical management of hypoplastic right ventricle with intact ventricular septum includes 26 patients with pulmonary atresia and 4 with critical pulmonary stenosis. Group 1 consisted of 8 neonates managed initially by transventricular valvotomy; 6 later required a secondary procedure, with 100% survival. Group 2 had 11 neonates managed by aorta-pulmonary artery shunting without operative death. However, only 3 have survived over the long term and 1 has required an additional shunt procedure. Group 3 had 9 infants who underwent concomitant valvotomy and shunting. There were 4 operative deaths and 1 late death. Finally, Group 4 included 2 infants managed by primary repair at 3 days and 6 days old with prosthetic enlargement of the right ventricle; 1 required the addition of a shunt. Both are alive. Seven of the 15 patients in Groups 1, 2, and 3 who survived neonatal palliative procedures have undergone reparative operations. Two had no growth of the right ventricle and underwent repair after conversion to tricuspid atresia, by a Fontan procedure. Five had prosthetic enlargement of the right ventricle in childhood with 1 late death. Findings of this review were as follows: (1) effective palliation of pulmonary atresia and intact ventricular septum or critical pulmonary stenosis with cavitary hypoplasia of the right ventricle is rare unless transventricular flow can be established; (2) establishment of transventricular flow produces a high incidence of cavitary "growth," which permits later repair; (3) the Fontan operation is available for repair in patients who have no cavitary growth; and (4) when all three portions of the right ventricular cavity can be identified by angiography, a primary repair can be performed in the neonatal period with a good long-term prognosis.

Transcatheter blade atrial septostomy

Six infants, four with transposition of the great arteries and one each with mitral atresia and tricuspid atresia, who did not improve following balloon atrial septostomy are presented. Each patient underwent transcatheter blade atrial septostomy with resultant improvement of interatrial mixing (immediate improvement in three transposition patients and delayed improvement in one) or interatrial obstruction (in the mitral and tricuspid atresia patients). It is suggested that blade atrial septostomy is a safe and effective technique for nonsurgical palliation of congenital heart defects to enlarge a restrictive interatrial communication, especially if balloon atrial septostomy has not been successful.

Extreme right ventricular hypoplasia after relief of severe pulmonary stenosis. Use of balloon catheter occlusion of atrial septal defect in assessing right ventricular function

A patient is described in whom extreme right ventricular hypoplasia and right-to-left shunting through an atrial septal defect occurred after relief of severe pulmonary stenosis. The ability of the hypoplastic right ventricle to deal with an increased volume load was assessed at cardiac catheterisation by occluding the atrial septal defect with a balloon tipped catheter.