Artery Growth Research Articles

Global Sensitivity Analysis of a Homogenized Constrained Mixture Model of Arterial Growth and Remodeling

Growth and remodeling in arterial tissue have attracted considerable attention over the last decade. Mathematical models have been proposed, and computational studies with these have helped to understand the role of the different model parameters. So far it remains, however, poorly understood how much of the model output variability can be attributed to the individual input parameters and their interactions. To clarify this, we propose herein a global sensitivity analysis, based on Sobol indices, for a homogenized constrained mixture model of aortic growth and remodeling. In two representative examples, we found that 54–80% of the long term output variability resulted from only three model parameters. In our study, the two most influential parameters were the one characterizing the ability of the tissue to increase collagen production under increased stress and the one characterizing the collagen half-life time. The third most influential parameter was the one characterizing the strain-stiffening of collagen under large deformation. Our results suggest that in future computational studies it may - at least in scenarios similar to the ones studied herein - suffice to use population average values for the other parameters. Moreover, our results suggest that developing methods to measure the said three most influential parameters may be an important step towards reliable patient-specific predictions of the enlargement of abdominal aortic aneurysms in clinical practice.

Right Ventricular Outflow Tract Stenting as Palliation of Critical Tetralogy of Fallot: Techniques and Results

Background. Despite current trends toward early primary repair, the surgical systemic-to-pulmonary shunt is still considered the first-choice palliation in patients with critical tetralogy of Fallot (TOF) and duct-dependent pulmonary circulation unsuitable for primary repair. However, stenting of the right ventricular outflow tract (RVOT) is nowadays emerging as an effective alternative to surgical palliation in selected patients. Methods and results. RVOT stenting is usually performed from a venous route, either femoral or, in selected cases, the right internal jugular vein. Less frequently, mostly in pulmonary infundibular/valvar atresia, this procedure can be performed using a hybrid surgical/interventional approach by surgical exposure of the RVOT, puncture of the atretic valve, and stent deployment under direct vision. The size and type of the most appropriate stent may be chosen, based on ultrasound measurements of the RVOT, to cover the right ventricular infundibulum completely and, at the same time, sparing the pulmonary valve, unless significant pulmonary valve annulus hypoplasia and/or supra-valvular stenosis is a significant component of the obstruction. In the large series so far published, early mortality of RVOT stenting is less than 2%, comparing favourably with either Blalock-Thomas-Taussig shunt or early primary repair. In addition, morbidity and clinical sequelae of this approach do not significantly differ from surgical palliation, even if RVOT stenting shows lesser durability and a higher rate of trans-catheter re-interventions over a mid-term follow-up. Finally, similar but more balanced pulmonary artery growth than surgical palliation following RVOT stenting is reported over a mid-term follow-up. Conclusions. RVOT stenting is a technically feasible, well-tolerated, and effective palliation in critical TOF. This approach is cost-effective with respect to surgical palliation either in high-risk neonates or whenever a short-term pulmonary blood flow source is anticipated due to the early surgical repair. It effectively increases pulmonary blood flow, improves arterial saturation, and promotes balanced pulmonary artery growth over a mid-term follow-up.

Blalock-Taussig shunt versus duct stenting for congenital heart diseases with ductal-dependent pulmonary circulation: Multicenter international study (BLADE)

Ductal stenting (DS) procedure has been proposed as an alternative to aortopulmonary shunts in congenital heart disease with ductal-dependent pulmonary blood flow. Most reports comparing both techniques have limited numbers of patients and describe single-centre experience. The primary aim was to compare procedural overall survival to next-stage palliative or surgical repair. The secondary objectives were: – survival to 30 days, discharge, 1-year survival and up to the present; – early hospital morbidity; – incidence of re-interventions; – risk factors for morbidity and mortality; – predictive factors of success; – pulmonary artery growth. Infants < 1 year of age with duct- dependent pulmonary blood flow palliated, either mBTS or DS, as their first procedure were included. This is a retrospective, international multicenter study conducted in tertiary European centers with paediatric and congenital cardiology activity. A total of 644 patients were included. In total, 178 patients underwent DS procedure, and in 466 patients a mBTS was attempted. All baseline characteristics were similar between the 2 groups. DS procedure was elective in 78%. DS was approached predominantly from a femoral approach (65%). Most stents placed were mounted on 3.5- to 4-mm balloon and most cases required 1 or 2 stents (45%). DS was successful in 81%. DS failed was often related to univentricular physiology and duct morphology. A slightly increased risk of reintervention DS group was observed. Subsequent analysis (including the propensity score adjustment) is currently undertaken and would be available within the next months, to be described during the congress. There is a lack of data on large paediatric cohort comparing these techniques. Experienced shared from high-volume institutions would be a major interest to better define issues and may help to better establish the risk–benefit balance of the two therapeutic options.

Intrapulmonary artery septation for unilateral absence of the pulmonary artery.

We describe a seven-month-old boy with tetralogy of Fallot and an absent left pulmonary artery. Due to the diminutive size of the left pulmonary artery, we performed a native tissue left pulmonary artery reconstruction and intrapulmonary artery septation procedure with a left modified Blalock-Taussig shunt. After confirming left pulmonary artery growth, the patient underwent tetralogy of Fallot repair, removal of septation patch, and division of the Blalock-Taussig shunt. Nine months post-surgery, we confirmed his balanced lung perfusion (R/L ratio 6:4). The intrapulmonary artery septation procedure would be suitable for both the resuscitation and reconstruction of the hypoplastic absent pulmonary artery.

Right ventricular outflow tract stenting in symptomatic infants without the use of a long delivery sheath.

Right ventricular outflow tract (RVOT) stenting improves systemic oxygenation and facilitates pulmonary arterial growth in symptomatic infants prior to repair of tetralogy of Fallot. The aim of this study was to evaluate the safety and efficacy of RVOT stenting without the use of a long delivery sheath. Retrospective data analysis of patients under 1 year of age undergoing RVOT stenting from January 2010 to January 2020 at a single tertiary pediatric cardiology center. Sixty-three RVOT stents were deployed during 53 procedures into 44 patients. The median age and weight at insertion were 41 days (range 2-204) and 3.6kg (range 1.59-7) respectively. Thirty-one procedures were semi-elective and 22 were emergencies. Stent positioning was guided by transthoracic echocardiogram and/or RV angiography from a pigtail micro-catheter placed via the aorta. The median total procedure and fluoroscopy times were 67.5 (range 15-145) and 19 min (1-107), respectively. The median length of hospital stay was 7 days (range 1-258). Twenty-one patients were admitted to ICU post-procedure with a median ICU length of stay of 3 days (range 3-11). There were three major complications including two deaths within 30 days of the procedure. A patient with Cornelia de Lange Syndrome (1.8 kg) died following stent migration and inability to wean from emergency cardiopulmonary bypass and the second infant had an unexplained asystolic arrest post-procedure while awaiting transfer to ICU. RVOT stenting is technically possible with minimal complications without the need for a long delivery sheath. Additional imaging with transthoracic echocardiography can facilitate the safe deployment of the stent.

Experimental and Clinical Applications of Red and Near-Infrared Photobiomodulation on Endothelial Dysfunction: A Review.

Background: Under physiological conditions, endothelial cells are the main regulator of arterial tone homeostasis and vascular growth, sensing and transducing signals between tissue and blood. Disease risk factors can lead to their unbalanced homeostasis, known as endothelial dysfunction. Red and near-infrared light can interact with animal cells and modulate their metabolism upon interaction with mitochondria’s cytochromes, which leads to increased oxygen consumption, ATP production and ROS, as well as to regulate NO release and intracellular Ca2+ concentration. This medical subject is known as photobiomodulation (PBM). We present a review of the literature on the in vitro and in vivo effects of PBM on endothelial dysfunction. Methods: A search strategy was developed consistent with the PRISMA statement. The PubMed, Scopus, Cochrane, and Scholar electronic databases were consulted to search for in vitro and in vivo studies. Results: Fifty out of >12,000 articles were selected. Conclusions: The PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation. Among the studies, 808 nm and 18 J (0.2 W, 2.05 cm2) intracoronary irradiation can prevent restenosis as well as 645 nm and 20 J (0.25 W, 2 cm2) can stimulate angiogenesis. PBM can also support hypertension cure. However, more extensive randomised controlled trials are necessary.

The role of vascular complexity on optimal junction exponents

We examine the role of complexity on arterial tree structures, determining globally optimal vessel arrangements using the Simulated AnneaLing Vascular Optimization algorithm, a computational method which we have previously used to reproduce features of cardiac and cerebral vasculatures. In order to progress computational methods for growing arterial networks, deeper understanding of the stability of computational arterial growth algorithms to complexity, variations in physiological parameters (such as metabolic costs for maintaining and pumping blood), and underlying assumptions regarding the value of junction exponents is needed. We determine the globally optimal structure of two-dimensional arterial trees; analysing how physiological parameters affect tree morphology and optimal bifurcation exponent. We find that considering the full complexity of arterial trees is essential for determining the fundamental properties of vasculatures. We conclude that optimisation-based arterial growth algorithms are stable against uncertainties in physiological parameters, while optimal bifurcation exponents (a key parameter for many arterial growth algorithms) are affected by the complexity of vascular networks and the boundary conditions dictated by organs.

Delayed surgical repair of truncus arteriosus with interrupted aortic arch following bilateral banding of branch pulmonary arteries: a case report

BackgroundBanding of the bilateral branch pulmonary arteries (PA) has evolved as a palliative method to limit the pulmonary blood flow in various complex congenital heart diseases. Although beneficial in small patients and in those with multiple co-morbidities, the duration of pulmonary artery banding along with growth and status of branch pulmonary arteries following de-banding are of concern in these patients.Case presentationWe present a case of truncus arteriosus with interrupted aortic arch in whom bilateral PA banding was done in neonatal life. The corrective surgery was delayed by 13 months due to multiple infections and underlying co-morbid conditions. Although the surgery was delayed, the branch pulmonary arteries were of adequate size following the debanding procedure.ConclusionBranch PA augmentation may not always be necessary even in delayed corrective surgery following bilateral PA banding.

Computational modeling of vascular growth in patient-specific pulmonary arterial patch reconstructions

Recent progress in vascular growth mechanics has involved the use of computational algorithms to address clinical problems with the use of three-dimensional patient specific geometries. The objective of this study is to establish a predictive computational model for the volumetric growth of pulmonary arterial (PA) tissue following complex cardiovascular patch reconstructive surgeries for congenital heart disease patients. For the first time in the literature, the growth mechanics and performance of artificial cardiovascular patches in contact with the growing PA tissue domain is established. An elastic-growing material model was developed in the open source FEBio software suite to first examine the surgical patch reconstruction process for an idealized main PA anatomy as a benchmark model and then for the patient-specific PA of a newborn. Following patch reconstruction, high levels of stress and strain are compensated by growth on the arterial tissue. As this growth progresses, the arterial tissue is predicted to stiffen to limit elastic deformations. We simulated this arterial growth up to the age of 18 years, when somatic growth plateaus. Our research findings show that the non-growing patch material remains in a low strain state throughout the simulation timeline, while experiencing high stress hot-spots. Arterial tissue growth along the surgical stitch lines is triggered mainly due to PA geometry and blood pressure, rather than due to material property differences in the artificial and native tissue. Thus, non-uniform growth patterns are observed along the arterial tissue proximal to the sutured boundaries. This computational approach is effective for the pre-surgical planning of complex patch surgeries to quantify the unbalanced growth of native arteries and artificial non-growing materials to develop optimal patch biomechanics for improved postoperative outcomes.

Anterograde blood flow associated with modified Blalock–Taussig shunt does not modify pulmonary artery growth compared with modified Blalock–Taussig shunt alone

The main difference between extreme tetralogy of Fallot (TOF) and pulmonary atresia with ventricle septal defect (PA/VSD) is anterograde pulmonary blood flow (APBF). It is speculated that the association of modified Blalock-Taussig shunt (mBTS) with APBF favours shunt thrombosis, but promotes better pulmonary artery growth. To compare pulmonary artery growth after mBTS between TOF and PA/VSD. From 1995 to 2018, 77 mBTS procedures were performed in infants (aged<1 year): 45 for TOF; 32 for PA/VSD. Using a 1/1 propensity score-matched analysis, 38 patients were included (19 per group). Delta Nakata was defined as the difference in the Nakata index before biventricular repair and before mBTS. After matching, the preoperative Nakata index was similar in the two groups (TOF 101±34 vs. PA/VSD 106±35 mm2/m2; P=0.75). Age and weight were similar (TOF 24±20 days, 3.3±0.6kg vs. PA/VSD 24±33 days, 3.3±0.9kg; P=0.84 and P=0.77, respectively). There was no difference in rates of in-hospital mortality (TOF 0% vs. PA/VSD 10%; P=0.13) or mBTS thrombosis (TOF 15% vs. PA/VSD 10%; P=0.63). The left and right pulmonary artery diameters at time of biventricular repair were similar (TOF 7.5±2.2 and 6.7±2.1 vs. PA/VSD 8±2.7 and 7.1±2.5mm; P=0.43 and P=0.78, respectively), as were delta Nakata (TOF 112±102 vs. PA/VSD 107±66 mm2/m2; P=0.89), median age for biventricular repair (P=0.83) and reintervention rates (TOF 10% vs. PA/VSD 15%; P=0.67). We found no difference in pulmonary artery growth between APBF with mBTS versus mBTS alone. Thus, we could not show an increase in mBTS thrombosis with APBF.

Arterial duct stent versus surgical shunt for patients with duct-dependent pulmonary circulation: a meta-analysis

BackgroundBoth systemic-pulmonary shunt and arterial duct stent could be the palliation of duct-dependent pulmonary circulation. We aimed to compare the safety and efficacy of the two approaches.MethodsThe PubMed, EMBASE, and Cochrane Library databases were searched through December 2019 for studies comparing stent implantation and surgical shunt in duct-dependent pulmonary circulation. The baseline characteristics included ventricle physiology and cardiac anomaly. The main outcomes were hospital stay and total mortality. Additional outcomes included procedural complications, intensive care unit (ICU) stay, pulmonary artery growth at follow-up, and other indexes. A random- or fixed-effects model was used to summarize the estimates of the mean difference (MD)/risk ratio (RR) with 95% confidence intervals (CIs).ResultsIn total, 757 patients with duct-dependent pulmonary circulation from six studies were included. Pooled estimates of hospital stay (MD, − 4.83; 95% CI − 7.92 to − 1.74; p < 0.05), total mortality (RR 0.44; 95% CI 0.28–0.70; p < 0.05), complications (RR 0.49; 95% CI 0.30–0.81; p < 0.05) and ICU stay (MD, − 4.00; 95% CI − 5.96 to − 2.04; p < 0.05) favored the stent group. Significant differences were found in the proportions of patients with a single ventricle (RR 0.82; 95% CI 0.68–0.98; p < 0.05) or a double ventricle (RR 1.23; 95% CI 1.07–1.41; p < 0.05) between the stent and shunt groups. Additionally, pulmonary artery growth showed no significant differences between the two groups.ConclusionArterial duct stent appears to have not inferior outcomes of procedural complications, mortality, hospital and ICU stay, and pulmonary artery growth in selected patients compared with a surgical shunt.Trial registrationCRD42019147672.

Growth of the Branch Pulmonary Arteries After Employing ‘Shunt-Only’ Strategy for Neonates With Pulmonary Atresia or Stenosis

We sought to determine the impact of juxtaductal stenosis (JDS) on branch pulmonary artery (PA) growth after systemic-to-pulmonary shunt (SPS) placement without pulmonary arterioplasty (ie the 'shunt-only' strategy). This was a retrospective review of 91 patients, 54 (59.3%) with pulmonary atresia and 27 (29.7%) with a functionally single ventricle, who underwent neonatal SPS placement without pulmonary arterioplasty between 2008 and 2017. The median age and body weight at SPS procedure were 16 day's (interquartile range [IQR], 11-22) and 3.10 kg (IQR: 2.85-3.40), respectively. All patients had pre-SPS computed tomography (CT) followed by post-SPS CT at a median interval of 5.8 months' (IQR: 4.5-7.2). The ratio of the diameters of the juxtaductal PA over the non-SPS-side hilar PA (JD and/or PA) on preoperative CT-a surrogate for JDS severity-was 0.93 (IQR: 0.67-1.09). The median diameter (Z) of the SPS-side and non-SPS-side PA on postoperative CT were 1.0 (IQR: -0.07-1.73) and 0.99 (IQR: -0.45-1.70), respectively. The pulmonary artery index (Nakata index) increased significantly from 124.0 ± 50.2 mm2/m2 to 240.8 ± 88.7 mm2/m2 (P < .001). Unplanned surgical interventions on the non-SPS-side PA were performed on 7 patients. Logistic regression identified lower preoperative JD and/or PA as a risk factor for unplanned intervention on the non-SPS-side PA (odds ratio, 1.27 per 0.1 decrease; 95% confidence interval, 1.10-2.16, P = 0.025). PA growth on the non-SPS side is generally adequate without pulmonary arterioplasty among patients with JDS. However, unplanned interventions for the non-SPS-side PA are caveats for 'shunt-only' strategy in neonates with significant JDS.

Growth of the Pulmonary Valve Annulus after the Modified Blalock-Taussig Shunt in Patients with Tetralogy of Fallot

Background: The surgical outcomes of tetralogy of Fallot (TOF) have evolved dramatically and have resulted in lower mortality rate. Currently, the many cardiac centers have a trend to early single-stage complete repair more than a staged repair. However, the patients who have an early primary repair were required transannular patch augmentation of a pulmonary valve frequently. This effect has been developed a chronic pulmonary insufficiency may lead to right ventricular dilation, dysfunction. In this era, the aim of treatment of TOF is attempted to preserve pulmonary valve annulus for prevent right ventricular dysfunction in the future. The systemic to pulmonary artery shunt is a palliative procedure or known as staged repair for symptomatic patients with TOF. The modified Blalock-Taussig shunt (mBTS) is the most useful systemic to pulmonary shunt and perform as an initial procedure before complete repair. The mBTS can provide increase pulmonary blood flow as well as improve oxygenation and also promote pulmonary artery (PA) growth. However, the effect of this procedure to promote growth of a pulmonary valve annulus is still debate. Objectives: To compare a growth of pulmonary valve annulus between after staged repair and primary repair in patients with TOF (without pulmonary atresia). Methods: A retrospective case-control study, review of patients with TOF underwent total repair at our hospitals from January 2005 and December 2017 was performed, a total number of 112 patients underwent TOF repair. Twenty-nine patients (26%) underwent a staged repair (mBTS group) and 83 (74%) underwent total repair only or primary repair (PR group). We evaluated diameter of pulmonary valve annulus by using echocardiography at the time of first diagnosis and before complete repair on both groups. Results: The age of diagnosis of mBTS group were younger than PR group (p = 0.011). Therefore, pulmonary valve annuls were smaller in mBTS group. (Z-score, −2.93 ± 1.42 vs. −1.89 ± 0.97; p = 0.001). However, the growth potential of pulmonary valve annulus was increase more than PR group significantly (Z-score, −1.46 ± 1.02 vs. −2.11 ± 1.19; p = 0.009) Even though a patent ductus arteriosus was found commonly in PR group (p = 0.018). Conclusions: Our results suggest the systemic to pulmonary shunt or mBTS can promote growth of pulmonary valve annulus in patients with TOF.

Finite Element Simulation of In-Stent Restenosis with Tissue Growth Model

In this study, a finite element simulation of in-stent restenosis (ISR) is conducted to simulate the deployment and expansion of a stent in an occluded artery with a contact model and a mechanics-based growth model. A tissue growth model based on the multiplicative decomposition of deformation is applied to investigate the growth of the plaque and artery wall upon the stent’s implantation. Due to the high stresses at the contact points between the stent struts and the tissue, further tissue injury or restenosis is observed. The simulation results show that after the stent deployment, the von Mises stress is significantly larger in the plaque compared to the artery wall, especially in the region that is in contact with the stent. However, the growth of the plaque and artery tends to even out the stress concentration over time. The tissue growth is found to be more significant near the inner wall than the outer layer. A 0.77 mm restenosis is predicted, which agrees with published clinical observations. The features of the artery growth are carefully analyzed, and the underlying mechanism is discussed. This study is the first attempt to apply finite element analysis to artery restenosis, which establishes a framework for predicting ISR’s occurrence and severity. The results also provide insights into understanding the underlying mechanism of in-stent restenosis.

Post-Fontan pulmonary artery growth in patients with a bidirectional cavopulmonary shunt with additional antegrade pulsatile blood flow.

Patients with antegrade pulmonary blood flow after a bidirectional cavopulmonary shunt (Glenn) may have better pulmonary artery growth. This study evaluated pulmonary artery growth in patients with and without prior additional pulsatile antegrade flow in a Glenn shunt at midterm follow-up after a Fontan procedure. We reviewed 212 patients who had single-ventricle palliation in a 10-year period;103 (33 in pulsatile group 1 and 70 in nonpulsatile group 2) were selected for analysis. Data on demographics, procedures, perioperative course, and midterm follow-up after the Fontan procedure were compared. Echocardiography data were collected. Pulmonary artery sizes measured at cardiac catheterization and follow-up echocardiograms were used to calculate the Nakata index. Perioperative details were comparable in both groups, mean pulmonary artery pressure and systemic oxygen saturations were higher in group 1 compared to group 2. Venovenous collaterals were increased in group 1. There was a significant difference in the pre-Fontan and follow-up Nakata index between groups. There was a significant increase in the Nakata index in group 1 between the pre-Glenn and pre-Fontan assessments as well as the Nakata index between the pre-Fontan and midterm follow-up. There was no significant change in the Nakata index in group 2 between assessments. A pulsatile Glenn shunt is associated with better pulmonary artery growth which continues long after the additional pulsatile flow is eliminated. It is possible that the effects of anterograde pulmonary blood flow on pulmonary artery growth in early life continue long after the Fontan completion.

Surgical management of pediatric renovascular hypertension and midaortic syndrome at a single-center multidisciplinary program

ObjectiveTo evaluate the outcomes of various surgical approaches in the treatment of renovascular hypertension and midaortic syndrome (MAS) in children. MethodsWe performed a retrospective medical record review of patients who had undergone surgery for renovascular hypertension from 2010 to 2018 at our center under the care of a multidisciplinary team. The operative interventions included mesenteric artery growth improves circulation (MAGIC), tissue expander-stimulated lengthening of arteries (TESLA), aortic bypass using polytetrafluorethylene, renal artery reimplantation, and autotransplantation. The MAGIC procedure uses the meandering mesenteric artery as a free conduit for aortic bypass. The TESLA procedure is based on lengthening the normal distal aorta and iliac arteries by gradual filling of a retroaortic tissue expander for several weeks, followed by resection of the stenotic aorta and subsequent primary reconstruction. ResultsA total of 39 patients were identified, 10 with isolated renal artery stenosis, 26 with MAS, and 3 with systemic inflammatory vasculitis. The median age at presentation and surgery was 6.4 years (range, 0-16.3 years) and 9.3 years (range, 0-9.2 years), respectively. The MAS-associated syndromes included neurofibromatosis type 1 (15.4%) and Williams syndrome (5.1%), although most cases were idiopathic. At surgery, 33.3% had had stage 1 hypertension (HTN), 53.8% stage 2 HTN, and 12.8% normal blood pressure with a median of three antihypertensive medications. Follow-up of 37 patients at a median of 2.5 years demonstrated normal blood pressure in 86.1%, stage 1 HTN in 8.3%, and stage 2 HTN in 5.6%, with a median of one antihypertensive medication for the entire cohort. ConclusionsThe patterns of vascular involvement leading to renovascular hypertension in children are variable and complex, requiring thoughtful multidisciplinary planning and surgical decision-making. The MAGIC and TESLA procedures provide feasible approaches for aortic bypass and reconstruction using autologous tissues and will result in normalization of blood pressure in 85% of children 2.5 years after surgery.

Stenting of the right ventricular outflow tract as an initial intervention in Tetralogy of Fallot with pulmonary stenosis and major aortopulmonary collateral arteries.

To assess the role of right ventricular outflow tract stenting as the primary intervention in Tetralogy of Fallot with pulmonary stenosis and major aortopulmonary collateral arteries. The management of a subset of infants with Tetralogy of Fallot with pulmonary stenosis and major aortopulmonary collateral arteries requires a staged approach including rehabilitation of diminutive native pulmonary arteries, conventionally using an aortopulmonary shunt. We share our experience of pulmonary artery rehabilitation with right ventricular outflow tract stenting. Retrospective review of all patients with Tetralogy of Fallot with pulmonary stenosis who underwent right ventricular outflow tract stenting as primary intervention over an 8-year period. Ten patients underwent right ventricular outflow tract stent insertion at a median age of 61 days (interquartile range (IQR) 8.3-155 days). Median weight at stent deployment was 4.2 kg (IQR 3.2-5.7 kg). Oxygen saturations improved from a median of 79% (IQR 76-80%) to 92% (IQR 90-95%), p = 0.012. The median right and left pulmonary artery z score increased from -3.51 (IQR -4.59 to -2.80) and -2.07 (IQR -3.72 to 0.15) to a median of -1.17 (IQR -2.26 to 0.16) p < 0.05, and 0.24 (IQR -1.09 to 1.84) p < 0.05, respectively, at subsequent angiogram. Nine patients underwent further catheterisation. Four patients underwent complete anatomical repair. Only one patient required unifocalisation, as most patients had a native supply to all-important lung segments. Right ventricular outflow tract stenting is a useful procedure in the subset of patients with Tetralogy of Fallot with pulmonary stenosis and major aortopulmonary collateral arteries, where native pulmonary arterial growth is required to facilitate repair.

Outcomes of management of major aortopulmonary collaterals for pulmonary atresia and ventricular septal defect.

This study aimed to investigate the association between long-term survival and different management of major aortopulmonary collateral arteries in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries. From November, 2009 to October, 2018, a total of 98 consecutive patients with pulmonary atresia, ventricular septal defect, major aortopulmonary collateral arteries, and hypoplastic pulmonary arteries treated with modified Blalock-Taussig shunt or right ventricle-pulmonary artery connection were included. Fifty-five patients who received occlusion or ligation of major aortopulmonary collateral arteries during or after palliative procedure were occlusion group, and the other 43 patients were no occlusion group. The early and late outcomes were compared. The mean duration of follow-up was 30.9 months in no occlusion group and 49.8 months in the occlusion group (p < 0.001). Multivariate analysis showed that only no occlusion of major aortopulmonary collateral arteries was predictive of total mortality (Hazard Ratio: 4.42, 95% CI: 1.27 to 15.42, p = 0.02). The Kaplan-Meier survival curves confirmed that patients without occlusion of major aortopulmonary collateral arteries demonstrated worse survival as compared with the occlusion group (p = 0.013). The Kaplan-Meier survival curves of patients who underwent different palliative procedures showed no differences. For patients with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries when a primary repair is not feasible, those without occlusion of major aortopulmonary collateral arteries have a higher risk of death following an initial palliative procedure compared with patients who underwent occlusion of major aortopulmonary collateral arteries. The occlusion of major aortopulmonary collateral arteries is not associated with a higher rate of complete repair or better improvement of pulmonary artery growth.

Abstract 15665: Can Pulmonary Vasodilators Grow Pulmonary Vasculature in Cases With Bidirectional Glenn for Fontan Candidates?

Background: The condition of pulmonary vasculature is a key to determine the outcome of Fontan candidates. The previous reports described no significant growth of pulmonary arteries (PA) after having bi-directional Glenn shunt (BDG), which may influence peri- and post-operative management of Fontan procedure. Aim: We hypothesized the pulmonary vasodilators (PVDs) facilitate to grow small PA even after BDG in Fontan Candidates. Method: The twenty-one cases after BDG, whose PA index (Nakata index) were less than 140 mm 2 /m 2 , were enrolled. The enrolled cases were divided into two group: 15 with PVDs treatment ( PV+) and 6 without (PV-). PVDs used in this study were PDE5 inhibitor, Endothelin-receptor-blocker, oral prostacyclines , and their combination. In addition to measure the hemodynamic parameters ( mean PA pressure(mPAp), indexed pulmonary vascular resistance (Rp), Pulmonary flow (Qp) ), PA index and PA branch index ( a sum of cross-sectional area of first PA branches at both side indexed by body surface area) were measured and compared at the timing of after BDG and at after Fontan completion, respectively. Result: PA index and PA branch index after BDG of (PV+) and (PV-)were 104±33 vs 104±17 mm 2 /m 2 : 151±33 vs 194±45 mm 2 /m 2 . PA index in both groups after Fontan procedure was increased up to 153±42 vs 152±56 mm 2 /m 2 in same fashion, while PA branch index of (PV+) was significantly increased up to 199±60 than that of (PV-) 226±65 mm 2 /m 2 (% increase was 131% vs 116%). Rp and mPAp in both groups were not changed , while Qp in (PV+) was significantly more increased (140%) than that in (PV-)(107%). In conclusion, PVDs facilitates the growth of PA branches by increasing Qp, which brings a favor outcome of Fontan patients.

Abstract 16907: Relationship Between 3 rd Trimester Umbilical Arterial Blood Flow and Neurodevelopmental Outcomes at 2 Years in Major Fetal Heart Disease

Introduction: Congenital heart disease (CHD) requiring surgical intervention in infancy is associated with impaired neurodevelopmental (ND) outcomes which may be due in part to prenatal insults. Supporting this, we recently found an inverse relationship between 3 rd trimester umbilical artery Doppler-based (UA) pulsatility index (PI=systolic velocity-diastolic velocity/mean velocity) and growth and ND outcomes at 2 years in hypoplastic left heart syndrome and d-transposition of great arteries. In the present study we explore associations between 2 nd and 3 rd trimester UA-PI in all major fetal CHD and 2-year ND outcomes. Methods: We identified all patients with major structural CHD and fetal echocardiography who underwent cardiac surgery and 2-year ND and biometric assessments (Western Canadian Complex Pediatric Therapies Follow-up Program) from 2007-2017 in our program. Eligible surgeries were: bypass &lt; 6 weeks, shunts at &lt; 6 months or isomerisms with surgery at &lt; 12 months. Patients with genetic syndromes were excluded. 2 nd and 3 rd trimester UA-PI z scores were examined for relationships with 2 year Bayley III ND scales. Data is presented as mean (SD). Results: Data from 147 children was analysed (see Table). 2 nd and 3 rd trimester fetal echo was performed at 22.4(3.7) and 34.7(2.9) weeks, with UA-PI z scores of 0.18 (0.3), and 0.51(1.4) and respectively. The Bayley III cognitive, language and motor scores were 93(13), 89(15) and 89(14) for the entire group. Multivariable regression analysis of the entire group and specific subgroups showed an inverse relationship between 3 rd trimester UA-PI and ND domains (see Table). No association was found for 2 nd trimester UA-PI and ND for the whole group and subgroups. Conclusions: Increased 3 rd trimester UA-PI, which could reflect an altered late gestation placental circulation, inversely relates to abnormal 2 year ND. These relationships are most notably observed in SVs and in CHD associated with AOTO.