Interim Mortality in Pulmonary Atresia With Intact Ventricular Septum

Procedural Outcomes of Pulmonary Atresia Intact Ventricular Septum in Neonates: A Multicenter Study

BACKGROUND

Multicenter contemporary data describing short-term outcomes following initial interventions of neonates with pulmonary atresia intact ventricular septum (PA-IVS) are limited. This multicenter study aims to describe characteristics and outcomes of PA-IVS neonates following their initial catheter or surgical intervention and identify factors associated with major adverse cardiac events (MACE).

METHODS

Neonates with PA-IVS who underwent surgical or catheter intervention between 2009-2019 in 19 centers were reviewed. Risk factors for MACE, defined as cardiopulmonary resuscitation, mechanical circulatory support, stroke, or in-hospital mortality, were analyzed using multivariable logistic regression model.

RESULTS

We reviewed 279 neonates: 79 (28%) underwent right ventricular decompression, 151 (54%) underwent systemic-to-pulmonary shunt or ductal stent placement only, 36 (13%) underwent right ventricular decompression with shunt or ductal stent placement, and 11 (4%) underwent transplantation. MACE occurred in 57 patients (20%): 26 (9%) received mechanical circulatory support, 37 (13%) received cardiopulmonary resuscitation, 16 (6%) suffered stroke, 23 (8%) died. The presence of two major coronary artery stenoses (adjusted OR: 4.99; 95% CI: 1.16-21.39) and lower weight at first intervention (adjusted OR: 1.52, 95% CI: 1.01-2.27) were significantly associated with MACE. Coronary ischemia was the most frequent presumed mechanism of death (n=10).

CONCLUSIONS

In a multicenter cohort, one in five neonates with PA-IVS experienced MACE following their initial intervention. Patients with two major coronary artery stenoses or lower weight at time of initial procedure were most likely to experience MACE and warrant vigilance during pre-intervention planning and post-intervention management.

An improved congenital heart assessment tool: a quality improvement outcome

BACKGROUND

CHD was the most prevalent congenital anomaly (60.9 per 10,000, 95% CI 59.0-62.8) in England in 2018, with 1767 babies born with severe cardiac defects. The 30-day survival rates for complex procedures continue to improve; however despite care advances, the early post-operative period and first year of life remain a critical time for these infants. The Congenital Heart Assessment Tool was developed to support parental decision-making, standardise care provision, improve communication, and the safety and quality of care.

AIM

To further evaluate the Congenital Heart Assessment Tool.

DESIGN

A four centre collaborative mixed-methods quality improvement project funded by The Health Foundation, involving eight phases conducted during 2016-2018. Phases six to eight (clinical simulation exercise, parent workshop, and updated tool) are reported in this paper.

RESULTS

Four themes emerged from the clinical simulation exercise (phase six) including: improving documentation; preparation of parents; preparation of health care professionals; and communication. One main theme emerged from the parent workshop (phase seven): "what parents know versus what professionals know [about CHD]".

CONCLUSION

These phases further validated the effectiveness of the CHATm in terms of triggering amber and red indicators and demonstrated parents' ability to identify deterioration in their infant's clinical condition. Recommendations arising from the quality improvement project enabled the project team to create an updated version of the Congenital Heart Assessment Tool, CHAT2.

Concomitant Single-Stage Unifocalization and Cavopulmonary Anastomosis (Glenn Shunt) in an Adolescent Patient With Univentricular Physiology and Major Aortopulmonary Collateral Arteries: A Technically Challenging Case

Long-segment pulmonary atresia (PA), non-confluent branch pulmonary arteries, ventricular septal defect, tricuspid valve atresia (type 1A), and single ventricle physiology is a relatively rare and extremely heterogeneous form of congenital heart disease. This subset of patients having pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries (MAPCAs) have to undergo multiple unifocalization staging operations before a complete repair is attempted. Most of the patients were deemed inoperable. We report a rare case of a concomitant single-stage unifocalization and cavopulmonary anastomosis (bi-directional Glenn procedure) in an adolescent cyanotic girl with tricuspid valve atresia (type 1 A), long-segment pulmonary atresia, non-confluent branch pulmonary arteries, bilateral patent ductus arteriosus, MAPCAs, and single-ventricle physiology. Reconstruction of the absent central pulmonary artery and non-confluent branch pulmonary arteries was achieved by dividing the bilateral patent ductus arteriosus feeding the bilateral pulmonary arteries.

Predictors of death after receiving a modified Blalock-Taussig shunt in cyanotic heart children: A competing risk analysis

Objective

To determine risk factors affecting time-to-death ≤90 and >90 days in children who underwent a modified Blalock-Taussig shunt (MBTS).

Methods

Data from a retrospective cohort study were obtained from children aged 0–3 years who experienced MBTS between 2005 and 2016. Time-to-death (prior to Glenn/repair), time-to-alive up until December 2017 without repair, and time-to-progression to Glenn/repair following MBTS were presented using competing risks survival analysis. Demographic, surgical and anesthesia-related factors were recorded. Time-to-death ≤90 days and >90 days was analyzed using multivariate time-dependent Cox regression models to identify independent predictors and presented by adjusted hazard ratios (HR) and 95% confidence intervals (CI).

Results

Of 380 children, 119 died, 122 survived and 139 progressed to Glenn/repair. Time-to-death probability (95% CI) within 90 days was 0.18 (0.14–0.22). Predictors of time-to-death ≤90 days (n = 63) were low weight (<3 kg) (HR 7.6, 95% CI:2.8–20.4), preoperative ventilator support (HR 2.7, 95% CI:1.3–5.6), postoperative shunt thrombosis (HR 5.0, 95% CI:2.4–10.4), bleeding (HR 4.5, 95% CI:2.1–9.4) and renal failure (HR 4.1, 95% CI:1.5–10.9). Predictors of time-to-death >90 days (n = 56) were children diagnosed with pulmonary atresia with ventricular septal defect and single ventricle (compared to tetralogy of fallot) (HR 3.2, 95% CI:1.2–7.7 and HR 3.1, 95% CI:1.3–7.6, respectively), shunt size/weight ratio >1.1 vs <0.65 (HR 6.8, 95% CI:1.4–32.6) and longer duration of mechanical ventilator (HR 1.002, 95% CI:1.001–1.004). Shunt size/weight ratio ≥1.0 (vs <1.0) and ≥0.65 (vs <0.65) were predictors for overall time-to-death in neonates and toddlers, respectively (HR 13.1, 95% CI:2.8–61.4 and HR 7.8, 95% CI:1.7–34.8, respectively).

Conclusions

Perioperative factors were associated with time-to-death ≤90 days, whereas particular cardiac defect, larger shunt size/weight ratio, and longer mechanical ventilation were associated with time-to-death >90 days after receiving MBTS. Larger shunt size/weight ratio should be reevaluated within 90 days to minimize the risk of shunt over flow.

Long-term outcomes of single-ventricle palliation for pulmonary atresia with intact ventricular septum: Fontan survivors remain at risk of late myocardial ischaemia and death

OBJECTIVES

The specific outcomes of patients with pulmonary atresia with intact ventricular septum late after Fontan palliation are unknown. Patients with smaller right ventricles and myocardial sinusoids are known to have worse survival in the first years of life. Whether the potential for coronary ischaemia affects the long-term outcomes of these patients after Fontan palliation is still unknown.

METHODS

All patients with pulmonary atresia with intact ventricular septum who underwent the Fontan procedure from 1984 to 2016 in Australia and New Zealand were identified, and preoperative, perioperative and follow-up data were collected.

RESULTS

Late follow-up data were available for 120 patients. The median length of follow-up after the Fontan procedure was 9.1 years (interquartile range 4.2-15.4 years). Late death occurred in 9% of patients (11/120). Six were sudden, unexpected deaths; 4 of those occurred in patients known to have right ventricle-dependent coronary circulation (RVDCC). Those with RVDCC had a higher incidence of sudden death (4/20 vs 2/100; P = 0.007). RVDCC was associated with late death (P = 0.01) and the development of myocardial ischaemia after Fontan completion (P < 0.001). The 10-year survival rate was 77% (95% confidence interval 56-100%) for patients with RVDCC vs 96% (95% confidence interval 92-100%) for patients without RVDCC.

CONCLUSIONS

Long-term survival of patients with pulmonary atresia with intact ventricular septum after the Fontan procedure is excellent, but patients with RVDCC remain susceptible to coronary ischaemia and sudden death. Closer surveillance and investigation for exercise-induced ischaemia may be necessary.

Acceptability of a parental early warning tool for parents of infants with complex congenital heart disease: a qualitative feasibility study

AIM

To explore the acceptability and feasibility of a parental early warning tool, called the Congenital Heart Assessment Tool (CHAT), for parents going home with their infant between first and second stage of surgery for complex congenital heart disease.

BACKGROUND

Home monitoring programmes were developed to aid early recognition of deterioration in fragile infants between first and second surgical stage. However, this necessitates good discharge preparation to enable parents to develop appropriate knowledge and understanding of signs of deterioration to look for and who to contact.

DESIGN

This was a longitudinal qualitative feasibility study, within a constructivist paradigm. Parents were taught how to use the CHAT before taking their infant home and asked to participate in semistructured interviews at four time points: before discharge (T0), 2 weeks after discharge (T1), 8 weeks after discharge (T2) and after stage 2 surgery (T3). Interviews were transcribed verbatim and thematically analysed.

SETTING

One tertiary children's cardiac centre in the UK.

SUBJECTS

Twelve parents of eight infants who were discharged following first stage cardiac surgery for complex congenital heart disease, between August 2013 and February 2015.

RESULTS

Four main themes emerged: (1) parental preparation and vigilance, (2) usability, (3) mastery, and (4) reassurance and support.

CONCLUSIONS

The study highlighted the benefit of appropriately preparing parents before discharge, using the CHAT, to enable identification of normal infant behaviour and to detect signs of clinical deterioration. The study also demonstrated the importance of providing parents with information about when and who to call for management advice and support.

Mechanical and microstructural analysis of a radially expandable vascular conduit for neonatal and pediatric cardiovascular surgery

In pediatric cardiovascular surgery, there is a significant need for vascular prostheses that have the potential to grow with the patient following implantation. Current clinical options consist of nonexpanding conduits, requiring repeat surgeries as the patient outgrows the device. To address this issue, PECA Labs has developed a novel ePTFE vascular conduit with the capability of being radially expanded via balloon catheterization. In the described study, a systematic characterization and comparison of two proprietary ePTFE expandable conduits was conducted. Conduit sizes of 8 and 16 mm inner diameters for both conduits were evaluated before and after expansion with a 26 mm balloon. Comprehensive mechanical testing was completed, including quantification of circumferential, and longitudinal tensile strength, suture retention strength, burst strength, water entry pressure, dynamic compliance, and kink radius. Scanning electron microscopy was used to investigate the microstructural properties. Automated extraction of the fiber architectural features for each scanning electron micrograph was achieved with an algorithm for each conduit before and after expansion. Results showed that both conduits were able to expand significantly, to as much as 2.5× their original inner diameter. All mechanical properties were within clinically acceptable values following expansion. Analysis of the microstructure properties of the conduits revealed that the circumferential main angle of orientation, orientation index, and spatial periodicity did not significantly change following expansion, whereas the node area fraction decreased post expansion. Successful proof-of-concept of this novel product represents a critical step toward clinical translation and provides hope for newborns and growing children with congenital heart disease. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 659-671, 2018.

Parents' preparedness for their infants' discharge following first-stage cardiac surgery: development of a parental early warning tool

Aim The aim of this study was to explore parental preparedness for discharge and their experiences of going home with their infant after the first-stage surgery for a functionally univentricular heart.

BACKGROUND

Technological advances worldwide have improved outcomes for infants with a functionally univentricular heart over the last 3 decades; however, concern remains regarding mortality in the period between the first and second stages of surgery. The implementation of home monitoring programmes for this group of infants has improved this initial inter-stage survival; however, little is known about parents' experiences of going home, their preparedness for discharge, and parents' recognition of deterioration in their fragile infant.

METHOD

This study was conducted in 2011-2013; eight sets of parents were consulted in the research planning stage in September, 2011, and 22 parents with children aged 0-2 years responded to an online survey during November, 2012-March, 2013. Description of categorical data and deductive thematic analysis of the open-ended questions were undertaken.

RESULTS

Not all parents were taught signs of deterioration or given written information specific to their baby. The following three themes emerged from the qualitative data: mixed emotions about going home, knowledge and preparedness, and support systems.

CONCLUSIONS

Parents are not adequately prepared for discharge and are not well equipped to recognise deterioration in their child. There is a role for greater parental education through development of an early warning tool to address the gap in parents' understanding of signs of deterioration, enabling appropriate contact and earlier management by clinicians.

External counterpulsation of a systemic-to-pulmonary artery shunt increases coronary blood flow in neonatal piglets

BACKGROUND

Systemic-to-pulmonary artery shunt (SPS) palliation reduces coronary blood flow (CBF), which may precipitate myocardial ischemia postoperatively.

HYPOTHESIS

Counterpulsation (CP) of SPS augments CBF.

METHODS

Seven neonatal piglets (4.3 ± 0.23 kg) underwent sternotomy and ductus ligation. With a 5-mm polytetrafluoroethylene graft, SPS was created from innominate to pulmonary artery. A rigid shell holding a 9.5-mm diameter balloon was placed around the graft for CP. Using electrocardiographic signal, CP was initiated to trigger balloon inflation/deflation during the diastolic/systolic intervals, respectively. Instantaneous proximal and distal pulmonary artery and mid-anterior descending coronary artery flow rates were measured using transit time flow probes. Blood pressure and flow rates were recorded during three states: shunt closed, shunt open, and shunt open with CP.

STATISTICAL COMPARISON

Friedman's test and repeated measures analysis of variance.

RESULTS

Diastolic pressure decreased significantly with the shunt open (39 ± 8.4 to 28 ± 4.5 mm Hg, P = .05), then increased with CP (33 ± 2.3 mm Hg, P = .03). Median ratio of pulmonary to systemic flow (Qp/Qs) was 1.19, 1.9, and 1.53 with shunt closed, open, and open with CP, respectively. With CP, both diastolic coronary flow per minute (P = .018) and average diastolic flow rate per diastolic interval (P = .03) increased as well as total coronary flow per minute (P = .066; 19.6% ± 11.7%, 25.2% ± 17.0%, and 15.4% ± 13.9% change from shunt open, respectively). The percentage increase in average diastolic flow rate per diastolic interval correlated strongly with Qp/Qs (R (2) = .838).

CONCLUSIONS

In this model of SPS, CP increased diastolic blood pressure and CBF while maintaining significant augmentation of pulmonary blood flow (Qp/Qs). Shunt CP may aid in early postoperative management of palliative congenital heart disease.

Pulmonary atresia/intact ventricular septum: influence of coronary anatomy on single-ventricle outcome

BACKGROUND

We investigated the influence of coronary artery abnormalities on outcome in patients with pulmonary atresia/intact ventricular septum (PA-IVS) for planned single-ventricle palliation.

METHODS

Catheterization and medical records were reviewed in patients with PA-IVS for planned single-ventricle palliation at our institution between 2000 and 2012. Primary outcome was death or transplantation. Patients with confirmed or strong suspicion of stenosis in 2 or more main coronary arteries or coronary ostial atresia were defined as having right ventricle-dependent coronary circulation (RVDCC); those with stenosis of 1 main vessel or normal anatomy were defined as having non-RVDCC.

RESULTS

Of 58 patients with PA-IVS, 17 (30%) underwent single-ventricle palliation. Ten (59%) had RVDCC (3 with ostial atresia) and 7 (41%) had non-RVDCC. Median follow-up time was 8.2 years (0 months-11.3 years), with 1 patient in each group lost to follow-up. Five patients with RVDCC died, including the 3 patients with ostial atresia, and 1 underwent transplantation at 6 months of life. No deaths occurred after second-stage palliation. Three of the 4 surviving patients with RVDCC completed a Fontan operation, and 2 of these patients had evidence of cardiac ischemia on follow-up. No deaths occurred among patients with non-RVDCC. Kaplan-Meier analysis demonstrated significantly better survival in patients with non-RVDCC (100%) than in patients with RVDCC (40%) (p = 0.026).

CONCLUSIONS

In patients with PA-IVS undergoing single-ventricle palliation, RVDCC is associated with high early mortality, especially with coronary ostial atresia. There should be early consideration of transplantation in neonates with RVDCC. Patients with non-RVDCC undergoing single-ventricle palliation have excellent long-term outcomes, with no mortality seen in this series.

Outcomes of systemic to pulmonary artery shunts in patients weighing less than 3 kg: analysis of shunt type, size, and surgical approach

OBJECTIVE

To evaluate outcomes of systemic to pulmonary artery shunts (SPS) in patients weighing less than 3 kg with regard to shunt type, shunt size, and surgical approach.

METHODS

Patients weighing less than 3 kg who underwent modified Blalock-Taussig or central shunts with polytetrafluoroethylene grafts at our institution from January 1, 2000, to May 31, 2011, were reviewed. Patients who had undergone other major concomitant procedures were excluded from the analysis. Primary outcomes included mortality (discharge mortality and mortality before next planned palliative procedure or definitive repair), cardiac arrest and/or extracorporeal membrane oxygenation (ECMO), and shunt reintervention.

RESULTS

In this cohort of 80 patients, discharge survival was 96% (77/80). Postoperative cardiac arrest or ECMO occurred in 6/80 (7.5%), and shunt reintervention was required in 14/80 (17%). On univariate analysis, shunt reintervention was more common in patients with 3-mm shunts (11/30, 37%) compared with 3.5-mm (2/36, 6%) or 4-mm shunts (1/14, 7%) (P < .003). There were no statistically significant associations between shunt type, shunt size, or surgical approach and cardiac arrest/ECMO or mortality. Multiple logistic regression demonstrated that a shunt size of 3 mm (P = .019) and extracardiac anomaly (P = .047) were associated with shunt reintervention, whereas no variable was associated with cardiac arrest/ECMO or mortality.

CONCLUSIONS

In this high-risk group of neonates weighing less than 3 kg at the time of SPS, survival to discharge and the next planned surgical procedure was high. Outcomes were good with the 3.5- and 4-mm shunts; however, shunt reintervention was common with 3-mm shunts.

Changing trends in the management of pulmonary atresia with intact ventricular septum: the Melbourne experience

OBJECTIVE

Management of pulmonary atresia with intact ventricular septum (PAIVS) can be directed to either biventricular repair or univentricular palliation. The optimal management strategy has yet to be defined.

METHODS

All patients operated at the Royal Children's Hospital, Melbourne for PAIVS between 1990 and 2006 (n = 81) were reviewed. Patients were retrospectively stratified into a simple three-tiered classification based on right ventricle (RV) size. Multivariate logistic regression analysis was performed to identify risk factors of mortality.

RESULTS

The distribution of RV sizes was normal in 11 (14%), moderate hypoplasia in 45 (56%), and severe hypoplasia in 25 (31%) patients. RV-to-coronary-artery connections were present in 33 (41%) and RV coronary dependence in six patients (7%). Sixteen patients died (20%). The end-status of the remaining patients was biventricular repair in 31/81 (38%), 1½-ventricle repair in 10/81 (12%), Fontan circulation in 14/81 (17%), transplantation in 1/81 (1%), and still awaiting repair in 9/81 (11%). Ten-year survival was 80% (95% confidence interval (CI): 71-87%). Independent predictors of mortality were lower tricuspid valve (TV) annulus size Z-score and the presence of RV-to-coronary-artery connections.

CONCLUSIONS

A simple three-tiered classification based on RV size may allow initial stratification into biventricular or univentricular repair for patients with normal RV size and severe RV hypoplasia. In patients with moderate RV hypoplasia, the presence of RV-to-coronary-artery connections or a TV Z-score<-2 should caution one against attempting biventricular repair.

[Pulmonary stenosis and atresia with intact ventricular septum]

Pulmonary atresia and critical pulmonary stenosis with intact ventricular septum includes a wide spectrum of cardiopathies with great morphological heterogeneity. The pulmonary valve may be completely atretic or may contain a puncture hole if stenosis is present. The obstruction may be membranous and/or muscular. All components of the right ventricle can be affected, even the coronary circulation with ventriculocoronary connections and stenosis or atresia of the pulmonary arteries. Prenatal diagnosis is made when the right ventricle is hypoplastic and hypertrophic. The pulmonary valve is thickened and the pulmonary artery is perfused retrogradely through the ductus arteriosus. Right ventriculocoronary connections may sometimes be seen with fetal echocardiography. Postnatal survival depends on the patency of the ductus arteriosus, requiring prostaglandin E1 infusion. When hypoplastic right ventricle and/or ventricle-dependent coronary circulation exists, biventricular circulation is not possible. In these cases, surgical treatment is palliative. In cases with well-developed right ventricle, transcatheter therapy is usually provided with perforation and balloon dilation of the pulmonary valve. In cases of muscular obstruction of the right ventricle outflow tract, surgery may be considered as first-line therapy. In case of prenatal diagnosis, the medical termination of pregnancy is possible when severe right ventricular hypoplasia exists, precluding biventricular circulation. Postnatally, the prognosis of the patients is highly variable, mainly related to the size of the right cavities and the presence of coronary anomalies.

Controversies of fetal cardiac intervention

Remarkable advances in ultrasound imaging technology have made it possible to diagnose fetal cardiovascular lesions as early as 12-14 weeks of gestation and to assess their physiological relevance by echocardiography. Moreover, invasive techniques have been developed and refined to relieve significant congenital heart disease (CHD), such as critical aortic and pulmonary stenoses in the pediatric population including neonates. Recognition of the fact that certain CHDs can evolve in utero, and early intervention may improve the outcome by altering the natural history of such conditions has led to the evolution of a new fetal therapy, i.e. fetal cardiac intervention. Two entities, pulmonary valvar atresia and intact ventricular septum (PA/IVS) and hypoplastic left heart syndrome (HLHS), are associated with significant morbidity and mortality even with postnatal surgical therapy. These cases are believed to occur due to restricted blood flow, leading to impaired growth and function of the right or left ventricle. Therefore, several centers started the approach of antenatal intervention with the primary goal of improving the blood flow through the stenotic/atretic valve orifices to allow growth of cardiac structures. Even though centers with a reasonable number of cases seem to have improved the technique and the immediate outcome of fetal interventions, the field is challenged by ethical issues as the intervention puts both the mother and the fetus at risk. Moreover, the perceived benefits of prenatal treatment have to be weighed against steadily improving postnatal surgical and hybrid procedures, which have been shown to reduce morbidity and mortality for these complex heart defects. This review is an attempt to provide a balanced opinion and an update on fetal cardiac intervention.

Abnormalities in myocardial perfusion after surgical correction of pulmonary atresia with intact ventricular septum

We describe the results of myocardial perfusion scintigraphy performed 4 to 15 years after surgery in 12 patients with pulmonary atresia and intact ventricular septum. We used single photon emission computed tomography after injection of technetium Tc-99m tetrofosmin at submaximal exercise test. The patients, 7 girls and 5 boys, with a mean age of 11 years, and a range from 6 to 19 years, had either undergone biventricular repair, in 5 cases, or univentricular palliation in the remaining 7. This second group included 4 patients with ventriculo-coronary arterial communications. Of the children, 3 with biventricular repair and 6 with univentricular palliation had perfusion defects. Children with biventricular repair had perfusion defects in the ventricular septum, while those having univentricular palliation also had defects located to the left ventricular free wall. All children with ventriculo-coronary arterial communications had perfusion defects both in the ventricular septum and in the left ventricular free wall.

Decreased Left Ventricular Coronary Artery Density in Pulmonary Atresia and Intact Ventricular Septum

BACKGROUND

The prognosis for pulmonary atresia and intact ventricular septum (PAIVS) has been poor. Our hypothesis is that intrinsic abnormal left ventricular (LV) intramyocardial circulation might be related to the poor outcomes of these patients.

METHODS

Neonatal heart specimens were examined microscopically in four groups of 6 cases each. Group I had PAIVS with ventriculocoronary artery connections (VCAC), group II had PAIVS without VCAC, group III had normal hearts, and group IV had LV hypertrophy. A projection microscope with grid overlay was used to count the LV intramyocardial coronary artery density (IMCAD), which was expressed as the number of profiles/mm(2).

RESULTS

The LV IMCAD of groups I (0.40 +/- 0.14/mm(2)) and II (0.45 +/- 0.15/mm(2)) were significantly lower than those of groups III (0.77 +/- 0.11/mm(2)) and IV (0.76 +/- 0.09/mm(2); all with p = 0.002). There was no significant difference between either groups I and II (p = 0.394) or groups III and IV (p = 0.818).

CONCLUSIONS

This study demonstrates lower LV IMCAD in a widely heterogeneous spectrum of neonatal hearts with PAIVS, which might potentially predispose these patients to myocardial ischemia and in turn contribute to the poor prognosis of this disease.

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.

Unifocalization of Major Aortopulmonary Collaterals in Single-Ventricle Patients

BACKGROUND

Unifocalization of major aortopulmonary collateral arteries (MAPCAs) in pulmonary atresia with ventricular septal defect and intracardiac repair has become the standard of care. However, there are no reports addressing unifocalization of MAPCAs in single-ventricle patients. It is unknown whether their pulmonary vascular bed can be reconstructed and low enough pulmonary vascular resistance achieved to allow for superior or total cavopulmonary connections.

METHODS

We reviewed data on all patients with functional single ventricles and unifocalization procedures of MAPCAs. From 1997 to 2005, 14 consecutive children with various single-ventricle anatomies were operated on.

RESULTS

Patients had a median of three surgical procedures (range, 1 to 5). Two patients had absent, all others diminutive central pulmonary arteries, with an average of 3.5 +/- 1.2 MAPCAs. Seven patients (50%) had bidirectional Glenn procedures, and 3 of these had Fontan procedures. Median postoperative pulmonary artery pressures measured 12.5 mm Hg (Glenn) and 14 mm Hg (Fontan), respectively. Six patients are alive today (46%), with 1 patient lost to follow-up. Three patients died early and 3 late after initial unifocalization to shunts. One other patient survived unifocalization, but was not considered a candidate for a Glenn procedure and died after high-risk two-ventricle repair. Another patient with right-ventricle-dependent coronary circulation died of sepsis late after Glenn.

CONCLUSIONS

In selected patients with functional single ventricles and MAPCAs, the pulmonary vascular bed can be reconstructed sufficiently to allow for cavopulmonary connections. Venous flow to the pulmonary vasculature decreases cardiac volume load and is likely to increase life expectancy and quality of life for these 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.

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.