A Review of the Management of Pulmonary Atresia, Ventricular Septal Defect, and Major Aortopulmonary Collateral Arteries

Pulmonary flow-study can predict in-hospital prognosis of unifocalization and corrective repair of pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries

Objectives

With the development of perioperative treatment, the results of the unifocalization and corrective repair of pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries have been significantly improved. However, the in-hospital recovery is quite different individually. Therefore, it is essential to find prognostic indicators to avoid unsatisfactory recovery.

Design

This was a case-control study.

Setting

The study was conducted in the national center for cardiovascular diseases in China.

Participants

Pediatric patients between 2014 and 2022.

Interventions

None.

Measurements & main results

A total of 19 patients were included. The possible prognostic indicators included were commonly used clinical data. Unsatisfactory postoperative recovery was defined as mechanical ventilation≥ 7 days and/or in-hospital death. Satisfactory postoperative recovery was defined as mechanical ventilation<7 days and survival at discharge. We separated patients into two groups and compared the peri-operative data through univariable analysis. There were 8 patients in unsatisfactory recovery group (including 1 death) and 11 patients in satisfactory recovery group. Among all the possible prognostic indicators, through univariable analysis, pulmonary arterial pressure in pulmonary flow study was statistically different (p = 0.027 < 0.05). The ROC curve showed that the area under curve and cut-off values in predicting satisfactory recovery were 0.841 and 22 mmHg; the corresponding sensitivity and specificity were 100% and 72.7%. There was no statistical difference between the two groups in ventricular septal fenestration and pulmonary hypertension targeting drugs.

Conclusion

A pulmonary arterial pressure <22 mmHg in pulmonary flow study may avoid unsatisfactory in-hospital recovery after unifocalization and corrective repair of pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries.

Pulmonary Artery Hypoplasia in Neonates With Tetralogy of Fallot

BACKGROUND

Neonates with symptomatic tetralogy of Fallot (sTOF) with hypoplastic pulmonary arteries (hPA) are considered high risk. Data are needed to inform the impact of hPA on outcomes, and the ideal management strategy.

OBJECTIVES

The objectives of this study were to quantify the impact of hPA on outcomes in neonates with sTOF and measure the impact of strategy on pulmonary artery (PA) growth in this population.

METHODS

Neonates with sTOF from 2005 to 2017 were reviewed from the Congenital Cardiac Research Collaborative. Criteria for hPA included a unilateral PA z score <-2.0 and contralateral PA z score <0. Primary outcome was mortality. Secondary outcomes included reintervention and PA growth.

RESULTS

We included 542 neonates with sTOF, including 188 (35%) with hPA and 354 (65%) with normal PA, with median follow-up of 4.1 years. Median right and left hPA z scores were -2.19 (25th-75th percentile: -2.55 to -1.94) and -2.23 (25th-75th percentile: -2.64 to -1.91), respectively. Staged repair (vs primary TOF repair) was less common in the hPA cohort (36 vs 44%; P = 0.07). Survival was similar between groups (unadjusted P = 0.16; adjusted P = 0.25). Reintervention was more common in the hPA group (HR: 1.28; 95% CI: 1.01-1.63; P = 0.044); there was no difference after definitive repair (HR: 1.21; 95% CI: 0.93-1.58; P = 0.16). PA growth at 1 year was greater in the hPA cohort, particularly for the right PA (P < 0.001).

CONCLUSIONS

Despite perception, the presence of hPA in neonates with sTOF conferred no increase in overall hazard of mortality or reintervention after definitive repair. PA growth was superior in the hPA cohort. These findings suggest that the presence of hPA does not adversely impact outcomes in sTOF.

Unique Pulmonary Hypertensive Vascular Diseases Associated with Heart and Lung Developmental Defects

Although pediatric pulmonary hypertension (PH) shares features and mechanisms with adult PH, there are also some significant differences between the two conditions. Segmental PH is a unique pediatric subtype of PH with unclear and/or multifactorial pathophysiological mechanisms, and is often associated with complex congenital heart disease (CHD), pulmonary atresia with ventricular septal defect, and aortopulmonary collateral arteries. Some cases of complex CHD, associated with a single ventricle after Fontan operation, show pathological changes in the small peripheral pulmonary arteries and pulmonary vascular resistance similar to those observed in pulmonary arterial hypertension (PAH). This condition is termed as the pediatric pulmonary hypertensive vascular disease (PPHVD). Recent advances in genetics have identified the genes responsible for PAH associated with developmental defects of the heart and lungs, such as TBX4 and SOX17. Targeted therapies for PAH have been developed; however, their effects on PH associated with developmental heart and lung defects remain to be established. Real-world data analyses on the anatomy, pathophysiology, genetics, and molecular biology of unique PPHVD cases associated with developmental defects of the heart and lungs, using nationwide and/or international registries, should be conducted in order to improve the treatments and prognosis of patients with these types of pediatric PH.

An unusual case of pulmonary atresia with ventricular septal defect and multiple major aortopulmonary collateral arteries: undiagnosed until adulthood

Pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries is an extremely complex, heterogeneous, and rare anomaly. This group of patients may not be able to survive until adulthood without any interventions or treatment. Although surgical management of patients diagnosed in newborn, infant, or early childhood is clear, treatment of patients diagnosed in adulthood still remains a significant problem. The pre-operative clinical status, imaging methods, and operative findings might be helpful for planning the most appropriate management. Herein, we report a unique case of pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries who remained asymptomatic until the age of 18 years.

Clinical Characteristics of Coronary-to-Pulmonary Artery Fistula in Patients with Pulmonary Atresia and Ventricular Septal Defect

The existence of a coronary-to-pulmonary artery fistula (CPF) in pulmonary atresia with ventricular septal defect (PAVSD) potentially affects treatment; however, its clinical features have not been comprehensively described due to the disease's rarity. We reviewed 69 cases from 42 studies to reveal the clinical overview of patients with CPF and PAVSD. Among the included patients, the male-to-female ratio was exactly 1:1, and only two patients (3%) exhibited the 22q11.2 microdeletion syndrome. Regarding anatomical features, CPFs originated from the left coronary artery in 65% of patients, and 62% had other major aortopulmonary collateral arteries. Thirty-nine percent of patients had a definitive CPF diagnosis at 0 years of age, whereas 10% were diagnosed in adulthood. Seventy percent underwent catheter angiography to obtain a definitive CPF diagnosis. Ninety-five percent of patients underwent cardiac surgery, and among them, 43% underwent palliative surgery, whereas 52% underwent one-stage repair. Four patients including three adult patients developed cardiac dysfunction due to myocardial ischemia, and three of them exhibited improved cardiac function after the intervention for CPF. Of all the patients, 88% survived and 12% died. The surgical strategy and prognosis were similar to those in PAVSD patients without CPF. This review provides detailed clinical phenotypes that are potentially useful in enhancing the management of patients with this rare disease.

Staged correction of pulmonary atresia, ventricular septal defect, and collateral arteries

Objectives

Pulmonary atresia (PA) with ventricular septal defect (VSD) and systemic‐pulmonary collateral arteries (SPCAs) presents with variable anatomy with regard to the pulmonary vasculature, requiring personalized surgical treatment. A protocol consisting of staged unifocalization and correction was employed.

Methods

Since 1989, 39 consecutive patients were included (median age at first operation 13 months). In selected cases, a central aorto‐pulmonary shunt was performed as the first procedure. Unifocalization procedures were performed through a lateral thoracotomy. Correction consisted of shunt takedown, VSD closure, and interposition of an allograft between the right ventricle and the reconstructed pulmonary artery. Echocardiographic data were obtained postoperatively and at interval follow‐up.

Results

In 39 patients 66 unifocalization procedures were performed. Early mortality was 5%. Seven patients were considered not suitable for correction, of which four have since died. One patient is awaiting further correction. A correction was performed successfully in 28 patients. Operative mortality was 3% and late mortality was 11%. Median follow‐up after the correction was 19 years. Eleven patients required homograft replacement. Freedom from conduit replacement was 88%, 73%, and 60% at 5, 10, and 15 years respectively. Right ventricular function was reasonable or good in 75% of patients. All but one patient were in NYHA Class I or II.

Conclusions

After complete unifocalization 30/37 patients (81%) were considered correctable. The staged approach of PA, VSD, and SPCAs results in adequate correction and good functional capacity. RV function after correction remains reasonable or good in the majority of patients.

Identification of Rare Variants in Right Ventricular Outflow Tract Obstruction Congenital Heart Disease by Whole-Exome Sequencing

Background

Pulmonary atresia (PA) is a kind of congenital heart disease characterized by right ventricular outflow tract obstruction. It is divided into PA with intact ventricular septum (PA/IVS) whose favorable form is pulmonary valvular stenosis (PS), and PA with ventricular septal defect (PA/VSD) whose favorable form is tetralogy of Fallot (TOF). Due to limitations in genetics etiology, whole-exome sequencing (WES) was utilized to identify new variants associated with the diseases.

Methods

The data from PS-PA/IVS (n = 74), TOF-PA/VSD (n = 100), and 100 controls were obtained. The common sites between PS and PA/IVS, PA/VSD and TOF, were compared. The novel rare damage variants, and candidate genes were identified by gene-based burden analysis. Finally, the enrichment analysis of differential genes was conducted between case and control groups.

Results

Seventeen rare damage variants located in seven genes were predicted to be associated with the PS through burden analysis. Enrichment analysis identified that the Wnt and cadherin signaling pathways were relevant to PS-PA/IVS.

Conclusion

This study put forth seven candidate genes (APC, PPP1R12A, PCK2, SOS2, TNR, MED13, and TIAM1), resulting in PS-PA/IVS. The Wnt and cadherin signaling pathways were identified to be related to PS-PA/IVS by enrichment analysis. This study provides new evidence for exploring the genetic mechanism of PS-PA/IVS.

Establishment of a Dihydrofolate Reductase Gene Knock-In Zebrafish Strain to Aid Preliminary Analysis of Congenital Heart Disease Mechanisms

Background: The dihydrofolate reductase (DHFR) gene is imperative in development, therefore it is essential to explore its effects on heart development. Thus, here a dhfr zebrafish knock-in (KI) strain was constructed.

Methods: CRISPR/Cas9 technology was used to establish the dhfr KI zebrafish strain. This strain was hybridized with TgG fluorescent strain zebrafish to observe the phenotypes of heart shape, size, and circularization direction. Wild-type (WT) and KI zebrafish were then dissected and histologically stained to observe pathological changes. Western blot analysis was used to verify the increased expressions of zebrafish genes after KI. Hybridization experiments were used to confirm the presence of abnormal gonadal dysplasia.

Results: The zebrafish dhfr KI strain was successfully constructed through CRISPR/Cas9 technology. At 6 days post fertilization (dpf), microscopic examinations of KI (homozygous) specimens revealed pericardial effusions, heart compressions, and curled tails. Compared with WT, the Hematoxylin and Eosin (H&E) tissue sections of KI-homozygous zebrafish showed defects such as reduced atria and ventricles. Western blot analysis indicated that the expression of the DHFR protein increased in both heterozygotes and homozygotes of dhfr KI zebrafish. Hybridization experiments revealed that dhfr KI may affect gonadal function.

Conclusion: The DHFR gene plays an important regulatory role in the process of heart development, and copy number variations (CNVs) of this gene may constitute a new pathogenic mechanism of congenital heart disease (CHD).

Outcome of patients with tetralogy of Fallot with pulmonary atresia

OBJECTIVE

Tetralogy of Fallot patients with pulmonary atresia (TOFPA) have a largely varying source of pulmonary perfusion with often hypoplastic and even absent central pulmonary arteries. A retrospective single center study was undertaken to assess outcome of these patients regarding type of surgical procedures, long-term mortality, achievement of VSD closure and analysis of postoperative interventions.

METHODS

76 consecutive patients with TOFPA operated between 01.01.2003 and 31.12.2019 are included in this single center study. Patients with ductus dependent pulmonary circulation underwent primary single stage full correction including VSD closure and right ventricular to pulmonary conduit implantation (RVPAC) or transanular patch reconstruction. Children with hypoplastic pulmonary arteries and MAPCAs without double supply were predominantly treated by unifocalization and RVPAC implantation. The follow up period ranges between 0 and 16,5 years.

RESULTS

31 patients (41%) underwent single stage full correction at a median age of 12 days, 15 patients could be treated by a transanular patch. 30 days mortality rate in this group was 6%. In the remaining 45 patients the VSD could not be closed during their first surgery which was performed at a median age of 89 days. A VSD closure was achieved later in 64% of these patients after median 178 days. 30 days mortality rate after the first surgery was 13% in this group. The estimated 10-year-survival rate after the first surgery is 80,5% ± 4,7% showing no significant difference between the groups with and without MAPCAs (p > 0,999). Median intervention-free interval (surgery and transcatheter intervention) after VSD closure was 1,7 ± 0,5 years [95% CI: 0,7-2,8 years].

CONCLUSIONS

A VSD closure could be achieved in 79% of the total cohort. In patients without MAPCAs this was possible at a significant earlier age (p < 0,01). Although patients without MAPCAs predominantly underwent single stage full correction at newborn age, the overall mortality rate and the interval until reintervention after VSD closure did not show significant differences between the two groups with and without MAPCAs. The high rate of proven genetic abnormalities (40%) with non-cardiac malformations did also pay its tribute to impaired life expectancy.

Pediatric heart-lung transplantation: Technique and special considerations

Heart-lung transplantation has historically been used as a definitive treatment for children with end-stage cardiopulmonary failure, although the number performed has steadily decreased over time. In this review, we discuss current indications, preoperative risk factors, outcomes, and heart-lung transplantation in unique patient subsets, including infants, children with single-ventricle physiology, tetralogy of Fallot/major aortopulmonary collateral arteries, and prior Potts shunt palliation. We also describe the different surgical techniques utilized in pediatric heart-lung transplantation.

Accuracy of Fetal Echocardiography in Defining Pulmonary Artery Anatomy and Source of Pulmonary Blood flow in Pulmonary Atresia with Ventricular Septal Defect (PA/VSD)

Precise delineation of central and branch pulmonary artery anatomy, patent ductus arteriosus, and major aorto-pulmonary collateral artery anatomy in the fetal diagnosis of pulmonary atresia with ventricular septal defect is challenging but important to prenatal counseling and postnatal management. We aimed to evaluate the accuracy of fetal echocardiography to determine these anatomical nuances in pulmonary atresia with ventricular septal defect. This was a retrospective, single-institution, 10-year chart review of consecutive prenatal diagnosis of pulmonary atresia with ventricular septal defect for assessment of pulmonary artery, patent ductus arteriosus, and major aorto-pulmonary collateral artery anatomy and comparison with postnatal imaging including echocardiography, cardiac catheterization, and computerized tomography angiography. Twenty-six fetuses were diagnosed with pulmonary atresia with ventricular septal defect during the review period and complete postnatal follow-up was available in 18, all confirming the basic prenatal diagnosis. Fetal echocardiography accurately predicted central and branch pulmonary artery anatomy in 16 (89%) [confluent in 14, discontinuous in 2], patent ductus arteriosus status in 15 (83%) [present in 10, absent in 5], and major aorto-pulmonary collateral arteries in 17 (94%) [present in 9, absent in 8]. Accuracy increased to 100% for pulmonary artery anatomy (16/16) and major aorto-pulmonary collateral artery (17/17) when excluding patients whose anatomy was reported as uncertain on fetal echocardiography. Fetal echocardiography can provide accurate anatomical details in the vast majority of fetuses with pulmonary atresia with ventricular septal defect. This allows for more anatomy-specific counseling, prognostication, and improved selection of postnatally available management options.

Gudnason J, Synnergren M, Sunnegårdh J. Outcome after surgery for pulmonary atresia with ventricular septal defect, a long-term follow-up study

Aim

To study the long‐term outcome after surgery for pulmonary atresia and ventricular septal defect (PA‐VSD), and to determine association between the contribution of major aorto‐pulmonary collateral arteries (MAPCAs) to the pulmonary blood flow, comorbidity and cause of death.

Methods

Patients who had undergone surgery for PA‐VSD from January 1st 1994 to December 31st 2017 were studied retrospectively. Survival was cross‐checked against the Swedish National Population Register.

Results

Seventy patients were identified, giving an incidence of 5.3 newborns per 100 000 live births. In 41 patients (59%) the pulmonary blood flow originated from a patent ductus arteriosus (PDA), while 29 patients (41%) had contribution of the pulmonary blood flow from MAPCAs. Extracardiac disease was found in 34 patients (49%), 16 of whom had 22q11‐microdeletion syndrome (23%). Survival at follow‐up was similar in patients with and without MAPCAs (72.4% vs. 75.6%, n.s.), with a median follow‐up time of 14.3 years (3.2–41.8 years). No difference was found in mortality in patients with or without any syndrome or extracardiac disease.

Conclusion

Long‐term survival did not differ between those with and without MAPCAs and no difference in mortality was seen in patients with and without concomitant extracardiac disease or any kind of syndrome.

Outcomes After Repair of Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collateral Arteries: A Tailored Approach in a Developing Setting

Objectives: Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) is complex and diverse that has led to a variety of treatment strategies. Experience has been largely obtained in the advanced countries. The clinical diversity is greater in China. We evaluated our surgical approaches and outcomes of these patients. Methods: We reviewed 127 patients undergoing varied surgeries in our center in 2010-2019. Results: Thirty patients underwent single-stage complete repair by unifocalizing MAPCAs and VSD closure (aged 3.9-131.4 months, median 22) with 3 (10%) early deaths. Ninety-seven underwent the first-stage rehabilitation strategy including systemic-to-pulmonary shunt in 29 (aged 0.5-144 month, median 8), and palliative RV-PA conduit in 68 (aged 2.2-209.6 months, median 14) with 5 (5.2%) early deaths. Eight-one patients (63.8%) eventually achieved complete repair with a median right/left ventricular (RV/LV) pressure ratio of 0.7 (ranged 0.4-1.0). Fourteen patients (11.0%) accepted palliation as final destination. Survival for the entire cohort was 89.5, 85.2, and 76.1% at 1, 5, and 10 years, respectively. Survival for those undergoing complete repair was 88.2 and 76.6% at 1 and 5 year, respectively. RV/LV pressure ratio ≥0.8 was risk factor for mortality (HR10.3, p = 0.003). Conclusions: Our cohort, the largest from China, had distinctive clinical features with substantially wider age range and higher RV/LV pressure ratio. Using the combined approaches tailored to individual patients, complete repair was achieved in 64% of patients. The early and intermediate outcomes are acceptable compared to many of the previous reports.

Fate of the Arterial Origin of Major Aortopulmonary Collateral Arteries After Unifocalization

BACKGROUND

During unifocalization procedures for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries, collateral arteries are either ligated or detached. Not much is known of the fate of the remaining arterial origins in the long term. Available computed tomography (CT) or magnetic resonance (MR) imaging of the intrathoracic arteries was examined to investigate possible abnormalities at the former position of the collateral arteries as well as ascending aortic diameters.

METHODS

From 1989 to 2018, we performed 66 unifocalization procedures in 39 patients. One hundred and twenty-nine collateral arteries were ligated or detached. In 52% (15) of the surviving patients (with a total of 55 ligated or detached collaterals), sufficient imaging of the thoracic aorta from CT (11) and/or MR (9) was available for evaluation.

RESULTS

The median interval between unifocalization procedure and imaging was 15 years (interquartile range [IQR]: 9-19 years). In 93% (14) of the scanned patients, 18 blunt ends were detected at the location of a former collateral artery. No aneurysm formation of the descending aorta was observed. The median diameter of the ascending aorta was 35 mm (IQR: 31-40 mm). During follow-up, no aortic dissection or rupture occurred.

CONCLUSIONS

Aortic imaging late after unifocalization showed abnormalities in 93% of the scanned patients. Abnormalities consisted mostly of blunt ends of the former collateral artery. We recommend to include routine imaging of the aorta during late follow-up to detect eventual future abnormalities and monitor aortic diameters. Ascending aortic diameters showed slight dilatation with no clinical implications so far.

Angiographic Anatomy of Major Aortopulmonary Collateral Arteries and Association With Early Surgical Outcomes in Tetralogy of Fallot

Background Due in part to the heterogeneity of the pulmonary circulation in patients with tetralogy of Fallot and major aortopulmonary collateral arteries (MAPCAs), research on this condition has focused on relatively basic anatomic characteristics. We aimed to detail pulmonary artery (PA) and MAPCA anatomy in a large group of infants, assess relationships between anatomy and early surgical outcomes, and consider systems for classifying MAPCAs. Methods and Results All infants ( <1 year of age) undergoing first cardiac surgery for tetralogy of Fallot/MAPCAs from 2001 to 2019 at Stanford University were identified. Preoperative angiograms delineating supply to all 18 pulmonary segments were reviewed for details of each MAPCA and the arborization and size of central PAs. We studied 276 patients with 1068 MAPCAs and the following PA patterns: 152 (55%) incompletely arborizing PAs, 48 (17%) normally arborizing PAs, 45 (16%) absent PAs, and 31 (11%) unilateral MAPCAs. There was extensive anatomic variability, but no difference in early outcomes according to PA arborization or the predominance of PAs or MAPCAs. Patients with low total MAPCA and/or PA cross-sectional area were less likely to undergo complete repair. Conclusions MAPCA anatomy is highly variable and essentially unique for each patient. Though each pulmonary segment can be supplied by a MAPCA, central PA, or both, all anatomic combinations are similarly conducive to a good repair. Total cross-sectional area of central PA and MAPCA material is an important driver of outcome. We elucidate a number of novel associations between anatomic features, but the extreme variability of the pulmonary circulation makes a granular tetralogy of Fallot/MAPCA classification system unrealistic.

Tetralogy of Fallot With Pulmonary Atresia: Anatomy, Physiology, Imaging, and Perioperative Management

Tetralogy of Fallot (ToF) with pulmonary atresia (ToF-PA) is a complex congenital heart defect at the extreme end of the spectrum of ToF, with no antegrade flow into the pulmonary arteries. Patients differ with regard to the sources of pulmonary blood flow. In the milder spectrum of disease, there are confluent branch pulmonary arteries fed by ductus arteriosus. In more severe cases, however, the ductus arteriosus is absent, and the sole source of pulmonary blood flow is via major aortopulmonary collateral arteries (MAPCAs). The variability in the origin, size, number, and clinical course of these MAPCAs adds to the complexity of these patients. Currently, the goal of management is to establish pulmonary blood flow from the right ventricle (RV) with RV pressures that are ideally less than half of the systemic pressure to allow for closure of the ventricular septal defect. In the long term, patients with ToF-PA are at higher risk for reinterventions to address pulmonary arterial or RV-pulmonary artery conduit stenosis, progressive aortic root dilation and aortic insufficiency, and late mortality than those with less severe forms of ToF.

An Unusual Cause of Hypoxia: Ventricular Septal Defect, Pulmonary Artery Atresia, and Major Aortopulmonary Collaterals Diagnosed in the Adult Cardiac Catheterization Lab

The association of pulmonary atresia, ventricular septal defect (VSD) and major aortopulmonary collaterals (MAPCA) is an extreme form of tetralogy of Fallot (TOF). It carries a high mortality risk if not intervened on during infancy with only 20% of unoperated patients surviving into adulthood. We present the case of a 40-year-old man who presented for evaluation prior to retinal surgery and was found to have hypoxia and a loud murmur. Cardiac catheterization was performed in the general catheterization laboratory, demonstrating a membranous VSD, pulmonary atresia, and MAPCA. We highlight the challenges and limitations that an adult interventional cardiologist may have when encountering these patients.

Patient-Specific 3-Dimensional-Bioprinted Model for In Vitro Analysis and Treatment Planning of Pulmonary Artery Atresia in Tetralogy of Fallot and Major Aortopulmonary Collateral Arteries

Background Tetralogy of Fallot with major aortopulmonary collateral arteries is a heterogeneous form of pulmonary artery (PA) stenosis that requires multiple forms of intervention. We present a patient-specific in vitro platform capable of sustained flow that can be used to train proceduralists and surgical teams in current interventions, as well as in developing novel therapeutic approaches to treat various vascular anomalies. Our objective is to develop an in vitro model of PA stenosis based on patient data that can be used as an in vitro phantom to model cardiovascular disease and explore potential interventions. Methods and Results From patient-specific scans obtained via computer tomography or 3-dimensional (3D) rotational angiography, we generated digital 3D models of the arteries. Subsequently, in vitro models of tetralogy of Fallot with major aortopulmonary collateral arteries were first 3D printed using biocompatible resins and next bioprinted using gelatin methacrylate hydrogel to simulate neonatal vasculature or second-order branches of an older patient with tetralogy of Fallot with major aortopulmonary collateral arteries. Printed models were used to study creation of extraluminal connection between an atretic PA and a major aortopulmonary collateral artery using a catheter-based interventional method. Following the recanalization, engineered PA constructs were perfused and flow was visualized using contrast agents and x-ray angiography. Further, computational fluid dynamics modeling was used to analyze flow in the recanalized model. Conclusions New 3D-printed and computational fluid dynamics models for vascular atresia were successfully created. We demonstrated the unique capability of a printed model to develop a novel technique for establishing blood flow in atretic vessels using clinical imaging, together with 3D bioprinting-based tissue engineering techniques. Additive biomanufacturing technologies can enable fabrication of functional vascular phantoms to model PA stenosis conditions that can help develop novel clinical applications.

Imaging of Pulmonary Atresia With Ventricular Septal Defect

The aim of this article was to review computed tomography angiography and magnetic resonance angiography of pulmonary atresia with ventricular septal defect. This disorder is a rare complex congenital heart disease. Preoperative imaging of pulmonary atresia with ventricular septal defect with computed tomography angiography and magnetic resonance angiography is important for complete anatomical delineation and planning for treatment. Preoperative imaging used for assessment of the main pulmonary artery (its size, valve, and confluence), aortopulmonary collaterals (its origin, insertion, course, and size), presence of patent ductus arteriosus, other sources of collaterals as bronchial and coronary arteries, and pattern of pulmonary arborization. Imaging can detect associated aortic, pulmonary venous and coronary anomalies, and other congenital heart disease. Postoperative imaging after unifocalization and stent is for assessment of patency, stenosis, and occlusion of stent or perivascular lesions as seroma.