Percutaneous balloon valvotomy in pulmonary atresia with intact ventricular septum: impact on patient care

Catheter-based therapy for small preterm infants with pulmonary atresia/intact ventricular septum

Catheter-based therapy is the preferred treatment for term infants with pulmonary atresia and intact ventricular septum without right ventricular-dependent coronaries, membranous atresia with patent infundibulum, and acceptable-sized tricuspid valve. However, in smaller preterm infants, it is more difficult to determine the adequacy of the tricuspid valve and right ventricle for two-ventricle repair and there are increased procedural risks. An excellent result in a small preterm infant with pulmonary atresia and intact ventricular septum is described using the following algorithm: determination of the tricuspid/mitral annular ratio, right-sided catheter-based intervention, and a combination of transthoracic echocardiography and angiography.

Outcomes in neonates with pulmonary atresia and intact ventricular septum underwent pulmonary valvulotomy and valvuloplasty using a flexible 2-French radiofrequency catheter

PURPOSE

Outcomes in 6 neonates with pulmonary atresia and intact ventricular septum (PAIVS) undergoing radiofrequency pulmonary valvulotomy and valvuloplasty (RPVV) were reported to identify the factors favorable for RPVV as the treatment of choice.

MATERIALS AND METHODS

From May 2000 to January 2008, 6 patients with PAIVS were included in this retrospective study. They were aged 1 day to 90 days old. Study modalities included review of recordings of presentations and profiles of chest radiography, electrocardiography, echocardiography, and cardiac catheterization with angiography. Hemodynamic profiles from the echocardiography and the cardiac catheterization were analyzed.

RESULTS

Echocardiography showed severe tricuspid regurgitation, membranous atresia of the pulmonary valve, intact ventricular septum, patent ductus arteriosus, and hypoplastic right ventricle in 6 patients. The pulmonary valve annulus were 4.2 to 6.9 mm in diameters, and those of the tricuspid valve were 7.1 to 10.1 mm. Elevated serum level of cardiac enzymes were found in 1 patient with ventriculocoronary communication (VCC). At cardiac catheterization, the ratio of systolic pressure of the right ventricle to that of the left ventricle ranged from 1.43 to 2.33 before RPVV, and from 0.54 to 1.15 after RPVV (p=0.027). The pressure gradients ranged from 76 to 136 mmHg before RPVV, and from 15 to 39 mmHg after RPVV (p=0.028). The echocardiographic gradients ranged from 16 to 32 mmHg within 24 hours after RPVV, and from 15 to 50 mmHg at the follow-ups.

CONCLUSION

RPVV can be a treatment of choice for neonates with PAIVS, if there is patent infundibulum, no right-ventricular dependent coronary circulation, and adequate tricuspid valve and pulmonary valve.

Interventional therapy for neonates with critical congenital heart disease

Transcatheter interventional therapies for children continue to evolve at a remarkable rate. Perhaps no where are these procedures more important than in the critically ill newborn. In this core curriculum review article several of the most commonly performed interventions performed in critically ill newborns are discussed with regards to technique and outcomes.

Success and limitations of right ventricular sinus myectomy for pulmonary atresia with intact ventricular septum

OBJECTIVES

Right ventricular sinus myectomy has been proposed for pulmonary atresia with intact ventricular septum for morphology falling within the uncertain area for eventual biventricular repair. Our objective was to evaluate right ventricular sinus myectomy by characterizing the morphologic spectrum of these patients, determining whether biventricular repair was achieved, ascertaining growth of right-sided structures, and assessing survival.

METHODS

We evaluated medical records, all imaging studies, and follow-up data (complete in all but 1 patient) from 43 patients with pulmonary atresia with intact ventricular septum treated from October 1993 to July 2005, 16 of whom underwent right ventricular sinus myectomy. Serial echocardiographic measurements of right-sided cardiac structures were converted to Z values to estimate their growth relative to somatic growth.

RESULTS

Patients undergoing right ventricular sinus myectomy had mild-to-moderate right ventricular size diminution (grade -1.2 +/- 3.2) and a tricuspid valve Z value of -4.9 +/- 1.9. Thirteen (87%) of the 16 patients achieved biventricular repair. After right ventricular sinus myectomy, mean right ventricular cavity size grade increased to 1.4 +/- 0.66, but the tricuspid valve Z value did not change appreciably over time. Five-year survival after sinus myectomy was 85%; late deaths were in patients with the smallest tricuspid valves at presentation (Z value < -7).

CONCLUSIONS

Right ventricular sinus myectomy in the uncertain area for biventricular repair of pulmonary atresia with intact ventricular septum leads to immediate increase in right ventricular volume. It, in combination with establishing right ventricle-pulmonary trunk continuity, allowed early biventricular repair in 87% of patients. However, tricuspid valve growth in relation to somatic growth was minimal. Thus, small tricuspid valve size might limit the long-term success of biventricular repair achieved by means of right ventricular sinus myectomy.

Outcome and growth potential of left heart structures after neonatal intervention for aortic valve stenosis

OBJECTIVES

The purpose of this study was to determine trends of growth of left heart structures after intervention for neonatal aortic valve stenosis.

BACKGROUND

The growth potential of left heart structures in neonatal aortic valve stenosis after relief of obstruction might influence risk for subsequent outcomes.

METHODS

From 1994 to 2004, 53 patients underwent neonatal (< or =30 days old) balloon aortic valve dilation. Factors associated with time-related outcomes (death, reintervention, aortic valve replacement) and longitudinal changes in normalized left heart dimensions were sought.

RESULTS

The median age at intervention was 3.5 days (range 1 to 30 days). During a median follow-up of 3.2 years ranging up to 10.9 years, there were 31 reinterventions on the aortic valve in 21 (40%) patients and 7 deaths (13%). The presence of moderate or severe left ventricular (LV) endocardial fibroelastosis was the only independent predictor for time-related mortality (hazard ratio 22.1; p = 0.004), and a smaller initial aortic valve annulus z-score was a significant independent predictor for aortic valve replacement (hazard ratio 0.63 per 1-U change; p = 0.007). Aortic valve annulus, aortic sinus, and LV dimension z-scores significantly increased over time, whereas mitral valve z-scores remained below normal. The structure's initial z-score and concomitant size of other left heart structures were significant independent factors associated with subsequent z-scores.

CONCLUSIONS

There is potential catch-up growth of the aortic valve and LV over time for neonates after intervention for aortic valve stenosis. However, the continued hypoplasia of the mitral valve warrants further consideration in the long-term management of these patients.

The prevalence of coronary arterial abnormalities in pulmonary atresia with intact ventricular septum and their influence on surgical results

BACKGROUND

The relatively high mortality in patients with pulmonary atresia and intact ventricular septum may be related to the presence of significant coronary arterial anomalies. This retrospective review of cineangiocardiograms was undertaken to further elucidate the types and variety of such coronary arterial abnormalities, and to assess their effect on postoperative survival.

MATERIAL AND RESULTS

Details regarding coronary arterial anatomy and abnormalities were assessed in 116 patients. We noted the site and severity of lesions, and the presence of fistulous communications from the right ventricle to the coronary arteries, assessing the proportion of left ventricular myocardium affected by coronary arterial interruptions or significant stenoses, in other words, the amount dependent on coronary circulation from the right ventricle. We also measured diameters of the tricuspid and mitral valves. Fistulas were found in 87 patients (75%), interruptions of major coronary arteries in 40 patients (34%), lack of connections between the coronary arteries and the aorta in 18 patients (16%), and single origin of a coronary artery, with the right coronary artery arising from the left, in 6 patients (5%). We found increased mortality in 47 patients (40%) who had a right ventricular-dependent coronary arterial circulation. The presence of fistulas in itself was not associated with higher mortality, but the presence of coronary arterial interruptions (p = 0.05), and a higher myocardial score (p = 0.0009), were.

CONCLUSION

We encountered a higher prevalence of both coronary arterial abnormalities and right ventricular-dependent circulation than previously reported. Awareness of the severity of the coronary arterial abnormalities should assist in planning treatment.

Determinants of outcome in fetal pulmonary valve stenosis or atresia with intact ventricular septum

Pulmonary valve stenosis or atresia with intact ventricular septum represents a spectrum of severity. This study aimed to identify ultrasound markers of biventricular versus non-biventricular outcome. The fetal echocardiograms of 41 fetuses diagnosed with pulmonary stenosis or atresia and right ventricular (RV)/left ventricular (LV) length ratios >0.4 from 17 to 31 weeks of gestation were reviewed. Of 27 live-born patients with intention to treat, 8 had non-biventricular outcomes and 19 had biventricular circulation. At the time of diagnosis, poor RV function, flow reversal in the arterial duct, the degree of tricuspid valve (TV) regurgitation, and inferior vena cava Doppler flow pattern did not differ between the 2 outcome groups. However, RV sinusoids, the RV/LV length ratio, the TV/mitral valve ratio, and TV inflow duration were significantly different. Cut-off values derived from receiver-operating characteristic curves yielding the best sensitivity and specificity for a non-biventricular outcome were TV/mitral valve ratio <0.7, RV/LV length ratio <0.6, TV inflow duration <31.5% of cardiac cycle length, and the presence of RV sinusoids. If 3 of these 4 criteria were fulfilled, this predicted a non-biventricular outcome with sensitivity of 100% and specificity of 75%. In conclusion, in fetuses < or =31 weeks of gestation with pulmonary stenosis or atresia and intact ventricular septum, progression to a non-biventricular outcome can be predicted by a 4-criterion scoring system. The criteria may be useful in selecting fetuses for prenatal catheter intervention to prevent progressive RV hypoplasia.

Radiofrequency perforation of the right ventricular outflow tract as a palliative strategy for pulmonary atresia with ventricular septal defect

BACKGROUND

Radiofrequency perforation (RF) of the right ventricular outflow tract (RVOT), while an effective management strategy in children with an intact ventricular septum, has not been fully detailed in those presenting with a ventricular septal defect.

OBJECTIVE

To determine whether transcatheter perforation of the atretic pulmonary valve is an acceptable management strategy prior to surgical repair.

RESULTS

Valve perforation was attempted in eight children seen between May 2000 and March 2006, five being infants between 1 and 9 days of age. In five children, this was the first of two procedures, the second a planned surgical correction. The RF was successful in six children with one child requiring additional stenting of the RVOT. Of these children, three attained a biventricular repair within the next year without additional palliative surgical procedures. Of the remaining three patients, one is awaiting surgical correction, one did not require further surgery, and one had this procedure as the only planned palliation. The two children in whom RF was not possible were referred for surgical augmentation of pulmonary blood flow.

CONCLUSION

A treatment strategy that includes pulmonary valve perforation as initial palliation to increase pulmonary blood flow may be effective. Additional experience to better define those children who would benefit from this treatment algorithm is required.

Echocardiographic predictors of outcome in fetuses with pulmonary atresia with intact ventricular septum

OBJECTIVE

We sought to identify in utero predictors of postnatal outcomes in fetal patients with pulmonary atresia with intact ventricular septum (PAIVS) or critical pulmonary stenosis.

BACKGROUND

Although PAIVS or critical pulmonary stenosis can be diagnosed in utero by echocardiography, our ability to predict outcomes is limited.

METHODS

Fetal echocardiograms from 28 patients with PAIVS/critical pulmonary stenosis were retrospectively reviewed. Tricuspid valve (TV) annulus, right and left ventricular internal dimensions, and degree of tricuspid regurgitation were recorded. To establish normal fetal values, echocardiograms from healthy patients were analyzed in an identical fashion.

RESULTS

Both a fetal TV z score of -4 or less beyond 23 weeks of gestation and a fetal TV annulus of 5 mm or less beyond 30 weeks of gestation were predictive of poor postnatal outcomes. In addition, right:left ventricular length or width less than 0.5 and/or the absence of tricuspid regurgitation were predictive of poor outcome.

CONCLUSIONS

TV annulus size, right:left ventricular ratios, and presence of tricuspid regurgitation on fetal echocardiograms may aid in guiding prenatal counseling regarding postnatal outcome in PAIVS.

Management algorithm in pulmonary atresia with intact ventricular septum

Pulmonary atresia with intact ventricular septum (PAIVS) is a disease with remarkable morphologic variability, affecting not only the pulmonary valve but also the tricuspid valve, the RV cavity and coronary arteries. With advances in interventional techniques and congenital heart surgery, the management of PAIVS continues to evolve. This review is an attempt at providing a practical approach to the management of this disease. The basis of our approach is morphologic classification as derived from echocardiography and angiography. Group A, patients with good sized RV and membranous atresia, the primary procedure at presentation is radiofrequency (RF) valvotomy. Often it is the only procedure required in this group with the most favourable outcome. Patients with severely hypoplastic RV (Group C) are managed along the lines of hearts with single ventricle physiology. The treatment at presentation is patent ductus arteriosus (PDA) stenting with balloon atrial septostomy or conventional modified Blalock Taussig (BT) shunt. Bidirectional Glenn shunt may be done 6-12 months later followed by Fontan completion after a suitable interval. Patients in Group B, the intermediate group, are those with borderline RV size, usually with attenuated trabecular component but well developed infundibulum. The treatment at presentation is RF valvotomy and PDA stenting +/- balloon atrial septostomy. Surgical re-interventions are not uncommonly required viz. bidirectional Glenn shunt when the RV fails to grow adequately (11/2 - ventricle repair) and right ventricular outflow tract (RVOT) reconstruction for subvalvar obstruction or small pulmonary annulus. Catheter based interventions viz. repeat balloon dilatation or device closure of patent foramen ovale (PFO) may also be required in some patients.

Determinants of exercise function following univentricular versus biventricular repair for pulmonary atresia/intact ventricular septum

This study aimed to determine whether the exercise capacity of patients with pulmonary atresia/intact ventricular septum (PA/IVS) who have undergone biventricular repair is superior to that of patients with single ventricle repairs and to account for any differences. PA/IVS is generally treated with either biventricular (outflow tract reconstruction) or univentricular (Fontan) palliation. Although biventricular repair is believed to result in superior exercise function, this theory is untested. Symptom-limited programmed bicycle ergonometry with expiratory gas analysis was prospectively performed on all patients with PA/IVS >7 years old seen over 18 months. Nineteen biventricular and 10 Fontan patients (mean age 16.5 +/- 6.5 vs 12.7 +/- 5.0 years, p = 0.12) were enrolled. The exercise capacity of biventricular patients was not statistically superior to that of Fontan patients (predicted peak VO2 83.5 +/- 21% vs 76.0 +/- 17.5%, p = 0.34), although chronotropic function and ventilatory efficiency were significantly better in the former. The peak exercise capacity varied widely within each group, and there was considerable overlap between biventricular and Fontan patients. Within groups, imaging studies did not reliably predict exercise capacity. Most patients in each group had subnormal peak VO2, and there was a trend toward impaired performance with increasing age regardless of type of repair. In conclusion, biventricular repair may not guarantee superior exercise performance over single-ventricle palliation in PA/IVS. Regardless of repair type, aerobic capacity may deteriorate with age and is not reliably predicted by noninvasive imaging. These findings underscore the need for a quantitative, proactive approach to the assessment and preservation of exercise function.

Regression of cardiac enzyme and ventriculocoronary communication in an infant with pulmonary atresia and intact ventricular septum after radiofrequency valvulotomy and valvuloplasty

I report on a 3-month-old infant with pulmonary atresia-intact ventricular septum and ventriculocoronary communication (VCC) who underwent percutaneous radiofrequency valvulotomy and valvuloplasty (RFVV). The patient's cardiac troponin-I, creatine kinase (CK), and myocardial fraction of (CK-MB) were elevated before RFVV and were gradually regressed to normal levels 12 days after RFVV. The VCC disappeared after RFVV. The transvalvular pressure gradients across the pulmonary valve were less than 30 mmHg in the follow-up echocardiography at 4-12 months of age. Oxygen saturation was approximately 90% in room air. Dipyridamole-thallium myocardial scintigraphy showed positive reperfusion over the apex and interventricular septum.

Evolution of the management approach for pulmonary atresia with intact ventricular septum

OBJECTIVE

To review the evolution of the management approach for pulmonary atresia with intact ventricular septum (PAIVS) in the past two decades and to assess its impact on patient outcomes.

DESIGN AND PATIENTS

Retrospective review of the management and outcomes of 94 patients (55 male patients) with PAIVS diagnosed between July 1980 and August 2003.

SETTINGS

Tertiary paediatric cardiac centre.

RESULTS

Seven patients died before interventions. Of the remaining 87 patients who underwent intervention at a median age of 9 days (from 1 day to 2 years), 12 had right ventricular outflow tract reconstruction (RVOTR), 42 had closed pulmonary valvotomy (CPV), and 15 had laser assisted valvotomy with balloon valvoplasty. A systemic-pulmonary shunt was inserted in 18 patients, six of whom had subsequent RVOTR (n = 4) or laser assisted valvotomy (n = 2). Since 1990, catheter intervention accounted for 38% (17 of 45) of the right ventricular outflow procedures. The mean (SEM) freedom from reintervention was 93 (7)%, 71 (12)%, and 57 (13)% after RVOTR, 75 (7)%, 40 (8)%, and 14 (6)% after CPV, and 54 (13)%, 24 (12)%, and 16 (10)% after laser assisted valvotomy at one month, six months, and one year, respectively (RVOTR versus CPV, p < 0.001; RVOTR versus laser assisted valvotomy, p = 0.001). Low cardiac output syndrome was significantly less common after catheter intervention than after RVOTR (0% v 44%, p = 0.003) or CPV (0% v 29%, p = 0.01). The overall mean (SEM) survival was 77 (5)% and 70 (5)% at one and five years, respectively, and the overall mortality was 33% (29 of 87). There were no significant differences in survival between the three groups.

CONCLUSIONS

Multiple interventions are often required in the treatment algorithm of PAIVS. The shift towards increased use of the transcatheter approach has reduced the occurrence of postprocedural low cardiac output syndrome.

Risk factors for augmentation of the flow of blood to the lungs in pulmonary atresia with intact ventricular septum after radiofrequency valvotomy

Some patients with pulmonary atresia with an intact ventricular septum, mild to moderate right ventricular hypoplasia, and a patent infundibulum remain duct dependent on the flow of blood through the arterial duct despite adequate relief of the obstruction within the right ventricular outflow tract. The objective of our study was to review the risk factors for stenting of the patent arterial duct, or construction of a Blalock-Taussig shunt, in the patients with pulmonary atresia and an intact ventricular septum who remain duct-dependent following radiofrequency valvotomy and dilation of the imperforate pulmonary valve. We reviewed the data from 53 patients seen between November 1995 and December 2001. Of the 47 patients who survived, 6 required stenting of the patent arterial duct, while 4 needed construction of a modified Blalock-Taussig shunt to augment the flow of blood to the lungs at a mean of 7 plus or minus 5.7 days following the initial intervention. The remaining 37 patients required no additional procedures. We compared the findings in these two groups. The mean diameter of the tricuspid valve in the patients requiring early reintervention was 8.5 plus or minus 3.7 millimetres, giving a Z-score of -1.1 plus or minus 1.47, whilst those in the group without early reintervention had values of 10.7 plus or minus 2.2 millimetres, giving a Z-score of -0.58 plus or minus 1.18 (p equal to 0.003). No statistically significant differences were found in right ventricular morphology, McGoon ratio, or residual obstruction across the right ventricular outflow tract after decompression of the right ventricle. The diameter of the tricuspid valve, therefore, appears to be the only factor predicting the need for augmentation of flow of blood to the lungs. As just over one-fifth of our survivors required such augmentation, we hypothesize that stenting of the patent arterial duct may be performed as an integral part of primary transcatheter therapy in patients with pulmonary atresia and intact ventricular septum who have moderate right ventricular hypoplasia and a small tricuspid valve.

Pediatric interventional catheterization: reasonable expectations and outcomes

This article considers the role transcatheter therapy plays in the treatment of each major type of congenital heart lesion. The focus is on the clinical ramifications of the interventions rather than their technical aspects.

Interim Mortality in Pulmonary Atresia With Intact Ventricular Septum

BACKGROUND

Recent work has focused attention on interim mortality (death after hospital discharge and before second-stage surgery) in hypoplastic left heart syndrome. This study investigates interim mortality in infants undergoing systemic-to-pulmonary artery shunts for pulmonary atresia with intact ventricular septum.

METHODS

At two centers in 11 years (January 1991 through December 2001), 35 infants underwent placement of shunts for palliation of pulmonary atresia with intact septum. Patients were identified from the cardiology database at each institution, and data were collected retrospectively. The infants were classified into two groups, with and without severe right ventricular hypoplasia, based on the initial surgical plan (Fontan or two-ventricle repair).

RESULTS

The mean age and weight of the infants were 9 days and 3.1 kg. The right ventricle was severely hypoplastic in 22 of 35 infants. Hospital death occurred in 2 patients (9.1%), 1 with severe right ventricular hypoplasia. The remaining 33 patients form the study population. There were a total of 5 deaths (15%) after discharge and before second-stage operation, all in patients with severe right ventricular hypoplasia. Two patients, 1 with hypoplastic right ventricle, died after second-stage operation.

CONCLUSIONS

These data confirm a significant incidence of interim death in infants with pulmonary atresia and hypoplastic right ventricle. The interim mortality rate in the current two-institution study of infants with pulmonary atresia with intact ventricular septum is similar to that in hypoplastic left heart syndrome if all patients are considered (15%), and is somewhat higher (24%) than that for hypoplastic left heart syndrome if only patients with severe right ventricular hypoplasia are considered. This rate of interim death must be considered when different treatment options (such as shunt or transplant) are contemplated.

Transcatheter closure of atrial septal defects in children with a hypoplastic right ventricle

The efficacy and safety of device closure of atrial defects in children with complex congenital heart disease and a hypoplastic right ventricle have not been detailed. The objective of this study was to determine the clinical impact and outcomes of a staged surgical catheter-based management strategy. A retrospective analysis of 17 children with a hypoplastic right ventricle who had undergone cardiac catheterization and attempted device occlusion of an atrial defect was undertaken. Clinical data, anatomical diagnoses, previous surgeries, and interventions were noted. The clinical course and echocardiographic findings were compared before and after defect closure (6 +/- 4 months of follow-up). Nine children had pulmonary atresia with an intact ventricular septum, six had Ebstein's anomaly of the tricuspid valve, and two had isolated right ventricular hypoplasia. The mean age at defect closure was 6.6 +/- 3.4 years. Under general anesthesia, closure of the atrial defect was undertaken after initial temporary test occlusion. The Qp:Qs ratio before closure was 1.1 +/- 0.4. Oxygen saturation improved in all children from 91% +/- 1% to 98% +/- 1% (P < 0.0005). Mean right atrial pressure increased from 9 +/- 3 to 11 +/- 4 mm Hg after closure, but the difference was not statistically significant (P = 0.2). Follow-up revealed an increased right ventricular length (P = 0.009) and Z-score (P = 0.02), although no significant increase in the diameter of the tricuspid valve annulus was observed in children with pulmonary atresia. Right ventricular systolic pressures or systolic function did not change significantly during follow-up (P = 0.5 and 0.29, respectively). Exercise tolerance improved in all children and clinical evidence of right ventricular decompensation was absent. Catheter closure of atrial defects in children with a hypoplastic right ventricle is well tolerated, safe, and effective as a treatment strategy in the staged management.