Development of pulmonary arteries after central aortopulmonary shunt in newborns

The Hemodynamics of Patent Ductus Arteriosus in Patients after Central Shunt Operation

A central shunt (CS) was an important surgery of systemic-to-pulmonary shunt (SPS) for the treatment of complex congenital heart diseases with decreased pulmonary blood flow (CCHDs-DPBF). There was no clear conclusion on how to deal with unclosed patent ductus arteriosus (PDA) during CS surgery. This study expanded the knowledge base on PDA by exploring the influence of the closing process of the PDA on the hemodynamic parameters for the CS model. The initial three-dimensional (3D) geometry was reconstructed based on the patient's computed tomography (CT) data. Then, a CS configuration with three typical pulmonary artery (PA) dysplasia structures and different sizes of PDA was established. The three-element windkessel (3WK) multiscale coupling model was used to define boundary conditions for transient simulation through computational fluid dynamics (CFD). The results showed that the larger size of PDA led to a greater systemic-to-pulmonary shunt ratio (Q _S/A), and the flow ratio of the left pulmonary artery (LPA) to right pulmonary artery (RPA) (Q _L/R) was more close to 1, while both the proportion of high wall shear stress (WSS) areas and power loss decreased. The case of PDA nonclosure demonstrates that the aortic oxygen saturation (Sao₂) increased, while the systemic oxygen delivery (Do₂) decreased. In general, for the CS model with three typical PA dysplasia, the changing trends of hemodynamic parameters during the spontaneous closing process of PDA were roughly identical, and nonclosure of PDA had a series of hemodynamic advantages, but a larger PDA may cause excessive PA perfusion and was not conducive to reducing cyanosis symptoms.

Evaluation of the Growth of Central Pulmonary Arteries Following Patent Ductus Arteriosus Stenting in Patients with Duct Dependent Pulmonary Circulation

Pulmonary arteries' (PAs) growth can be promoted by stenting of patent ductus arteriosus (PDA). This may result in better angle between the PDA and the PAs, allowing improved growth. In this study, we sought to evaluate the effect of PDA stenting on the growth of the pulmonary arteries by comparing their dimensions pre-stenting to their dimensions in the pre-second stage operations in patients with congenital heart diseases-duct-dependent pulmonary (CHD-DDP) circulation. Between January 2015 and December 2016, 58 neonates with CHD-DDP circulation underwent transcatheter PDA stenting and had evaluation of PAs growth before the second stage. Various parameters [Pre-branching right and left pulmonary artery (RPA, LPA) diameters, their Z scores, LPA/RPA ratio, McGoon's ratio and Nakata index] were recorded and compared pre-stenting and pre-second stage. The evaluation was done using catheterization or multislice computed tomography (MSCT). PDA stenting was successful in 49 patients out of 58 (84.5%) patients with an age of 13.5 ± 10.4 days and a weight of 2.9 ± 0.5 kg. Twenty-two (44.9%) patients had complex CHD-DDP, 14 (28.6%) patients had PA/IVS and 13 (26.5%) patients had PA/VSD. Pre-second stage RPA, LPA diameters and their Z scores increased significantly (RPA increased from 0.36 ± 0.05 cm to 0.60 ± 0.11 cm, P < 0.001, RPA Z-score increased from - 1.29 ± 0.91 to 0.81 ± 0.18, P < 0.001; LPA increased from 0.34 ± 0.06 cm to 0.58 ± 0.10 cm, P < 0.001, LPA Z-score increased from - 1.17 ± 0.86 to 0.97 ± 0.48, P < 0.001). McGoon's ratio increased significantly from 1.20 ± 0.11 to 1.61 ± 0.15 (P < 0.001). Nakata index increased from 105.94 ± 33.53 to 183.48 ± 40.58 mm²/m² (P < 0.001). However, LPA/RPA ratio did not change (0.96 ± 0.05 and 0.98 ± 0.16, P = 0.288). PDA stenting is effective in promoting the global and the individual pulmonary artery growth in congenital heart diseases with duct-dependent pulmonary circulation. In this study, we presented our experience with this approach in 2 tertiary care centers in the DELTA region of Egypt. PDA stenting, generally, showed symmetric growth of the pulmonary arteries with comparable results to the international figures.

Learning from a case of right ventricular outflow tract stenting in tricuspid atresia with critical pulmonary stenosis

Tricuspid valve atresia with severe pulmonary stenosis is one of the common cyanotic diseases in neonate. Child can succumb due to profound cyanosis and arterial hypoxaemia after closure of patent ductus arteriosus. Evolving procedure of right ventricular outflow tract stenting may be considered as a palliative procedure in such vulnerable group, destined for a later definitive management. The right ventricular outflow tract stenting is described essentially for tetralogy of Fallot physiology with a catheter course across tricuspid valve. We describe a case of successful right ventricular outflow tract stenting in a 5-day-old symptomatic neonate. We discuss the possible routes and the tips to facilitate right ventricular outflow tract stenting in such a case. This happens to be the first reported case description with successful stenting of neonate with tricuspid atresia with critical pulmonic stenosis.

The effects of corrective surgery on endothelial biomarkers and anthropometric data in children with congenital heart disease

Objective To investigate the influence of surgical correction on biomarkers of endothelial dysfunction in children with congenital heart disease and to evaluate anthropometric data. Methods Children with pulmonary hypertension (PH) or Tetralogy of Fallot (TOF) who were scheduled for corrective surgery were enrolled in this prospective study. Age-matched healthy children were included as controls. Demographic, haemodynamic and cardiac ultrasonography data were collected. Blood samples were taken pre-surgery, 24-48 hours post-surgery and again 3-6 months later. Several biomarkers (protein C, soluble platelet selectin [CD62P], soluble endothelium selectin [CD62E], soluble leukocyte selectin [CD62L], plasma von Willebrand Factor [vWF] atrial natriuretic peptide [ANP], brain natriuretic peptide[(BNP] and insulin-like growth factor-1 [IGF-1]) were measured. Results Sixty-three children (32 with PH, 15 with TOF, and 16 controls) were enrolled. No significant differences between the PH and TOF groups were observed in the expression of biomarkers pre- and post-surgery. IGF-1 levels were closely related to anthropometric data, particularly those children with PH. Expression of IGF-1 and weight/height normalized after corrective surgery. Conclusions No significant endothelial dysfunction was observed in children with PH or TOF before or after corrective surgery. Significant retardation of growth, particularly weight, was found before surgery and may be related to IGF-1 suppression.

Pulmonary artery growth after arterial duct stenting in completely duct-dependent pulmonary circulation

OBJECTIVE

Significant and balanced pulmonary artery (PA) growth following arterial duct (AD) stenting has already been reported in literature. However, no data are so far available about the role of this percutaneous approach in promoting PA growth in the case of congenital heart disease (CHD) with completely duct-dependent pulmonary blood flow (CDD-PBF). Aim of this study was to evaluate the effect of AD stenting in this pathophysiological setting.

METHODS

PA growth was evaluated as Nakata index and McGoon ratio as well as individual PA z-score changes in 49 patients submitted to neonatal AD stenting according to their pathophysiology (CDD-PBF (n=15) versus multiple PBF sources (n=34)).

RESULTS

Control angiography was performed 7.2±6.4 months (range 1-8, median 6) after AD stenting. In the whole population, significant and balanced PA growth was recorded (Nakata index+122±117%; left pulmonary artery (LPA) z-score +84±52%; right pulmonary artery (RPA) z-score +92±53% versus preprocedure, p<0.0001 for all comparisons). Percentage increase of global and branch vessel size was not significantly different in patients with CDD-PBF compared with those with multiple PBF sources (Nakata index 89±90% vs 144±124%; LPA z-score 63±40% vs 89±58%; RPA z-score 74±35% vs 100±57%, p=NS for all comparisons) as was final absolute PA size (Nakata index 237±90 vs 289±80 mm(2)/m(2), p=NS).

CONCLUSIONS

Percutaneous AD stenting was associated with significant and balanced PA growth in CHD with completely duct-dependent pulmonary circulation over a short-term follow-up. Thus, it may be considered as an alternative to surgical palliation in this subset of patients.

Fate of Hypoplastic Pulmonary Arteries After Arterial Duct Stenting in Congenital Heart Disease With Duct-Dependent Pulmonary Circulation

OBJECTIVES

This study sought to evaluate the impact of arterial duct (AD) stenting in promoting catch-up growth of hypoplastic pulmonary artery (PA) tree in congenital heart disease with duct-dependent pulmonary circulation (CHD-DPC).

BACKGROUND

Significant and balanced PA growth following AD stenting has already been consistently reported in the literature. However, no data are so far available about the role of this approach in severe PA hypoplasia, which significantly impacts the risk of surgical repair.

METHODS

Pre-surgical angiographic PA evaluation was performed in 45 patients with confluent PAs submitted to neonatal AD stenting as palliation of CHD-DPC. PA growth was evaluated as Nakata Index and McGoon ratio as well as individual PA z-score changes, both in the whole population and according to the original vessel size (Nakata Index <100 mm(2)/m(2), Group I [n = 15] vs. Nakata Index >100 mm(2)/m(2), Group II [n = 30]).

RESULTS

Control angiography was performed 7.5 ± 6.5 months (median 6 months) after duct stenting, showing significant and balanced PA growth. The Nakata Index increased from 143 ± 73 mm(2)/m(2) to 270 ± 88 mm(2)/m(2) (124 ± 118%, p < 0.0001); left PA z-score from -0.7 ± 1.7 to 1.0 ± 1.4; right PA z-score from -0.6 ± 1.3 to 1.2 ± 1.3 (p < 0.0001 for both comparisons). Group I showed a greater increase of global PA growth (Nakata Index increase 227 ± 141% vs. 72 ± 57%, p < 0.001) as compared with Group II. Final PA size did not significantly differ between the groups (246 ± 105 mm(2)/m(2) vs. 282 ± 78 mm(2)/m(2), p = NS).

CONCLUSIONS

Percutaneous AD stenting is highly effective in promoting a significant and balanced catch-up growth of diminutive PAs, being therefore advisable in this subset of patients as a reliable alternative to surgical palliation.

Catheter Interventions for Pulmonary Artery Stenosis: Matching the Intervention with the Pathology

Pulmonary artery (PA) stenosis represents a heterogeneous defect with a wide morphology and etiology. Interventions to treat PA stenosis should be based on the location, severity, and cause of stenosis as well as the size of the patient at presentation. Specialized dilation balloons, stents, and delivery techniques have been developed to treat a variety of PA stenoses in small infants through adulthood. Early and intermediate results of angioplasty and stenting are superior to surgical results, while long-term data on angioplasty and stenting are becoming available for these proven safe and effective techniques.

An angiographic predictor of pulmonary artery stenosis after the Norwood-Sano operation for hypoplastic left heart syndrome

The objective of this study was to determine angiographic predictors of future pulmonary artery stenosis (PS) in patients with hypoplastic left heart syndrome (HLHS) at the time of pre-stage 2 cardiac catheterization (PS2C). The Sano modification of the Norwood operation (NSO) for HLHS includes placement of a right ventricle-to-pulmonary artery (RV-PA) conduit. Branch PS is a recognized complication. Data from patients with HLHS who underwent NSO from 2005 to 2009 and who underwent PS2C were reviewed retrospectively. Nakata and McGoon indices were calculated in the traditional fashion, and modified Nakata and McGoon indices were calculated using the narrowest branch PA diameters. Thirty-three patients underwent NSO and 28 patients underwent PS2C. Mean follow-up was 35.8 ± 7.5 months. Ten (36 %) patients had significant left branch PS, with two requiring balloon angioplasty and eight requiring stent placement, a median of 15.2 months after PS2C (interquartile range 1.2, 32.8). The modified Nakata index was predictive of future intervention for left PS (receiver operating characteristic curve area under the curve 0.811), with a cut-off of 135 mm(2)/m(2) and a sensitivity of 100 % and specificity of 72.2 %. A modified Nakata index <135 mm(2)/m(2) at PS2C predicts future need for intervention on left-branch PS in patients with HLHS after the NSO. Surgical pulmonary arterioplasty at the time of stage 2 surgical palliation may obviate the need for future interventions.

Arterial duct stenting: Do we still need surgical shunt in congenital heart malformations with duct-dependent pulmonary circulation?

BACKGROUND

Despite current trends toward primary repair, surgical systemic-to-pulmonary shunt is still an invaluable palliative option in some patients with congenital heart defects and duct-dependent pulmonary circulation. However, arterial duct stabilization with a high-flexibility coronary stent could be an effective alternative in high-risk surgical candidates or whenever short-term pulmonary blood flow support is anticipated.

METHODS AND RESULTS

On the basis of ductal origin and morphology, the stenting procedure can be performed from an arterial or venous route. Following arterial duct angiographic imaging, the stabilizing stent is chosen to completely cover the entire ductal length and dilated slightly less than the proposed surgical shunt. Procedural failure depends mainly on ductal tortuosity and ranges around 10% of cases. Morbidity and mortality are 8-11% and less than 1%, respectively. Mid-term fate of the stented duct is spontaneous, slow and progressive closure within a few months. Compared with a Blalock-Taussig shunt, stented ducts result in similar but more uniform pulmonary artery growth over a mid-term follow-up.

CONCLUSION

Arterial duct stenting is a technically feasible, well tolerated and effective palliation in congenital heart disease with duct-dependent pulmonary circulation. It is advisable either in high-risk neonates or whenever a short-term pulmonary blood flow support is anticipated. The stented duct appears less durable than a conventional surgical shunt although it is highly effective in promoting a global and uniform pulmonary artery growth.

The Impact of Shunt Type on Palliative Outcomes in Neonates and Infants With Diminished Pulmonary Blood Flow

We analyzed early and intermediate outcomes in cyanotic neonates (n = 43) and infants (n = 26) requiring palliation with either a modified Blalock-Taussig shunt (MBT) or a central aortopulmonary shunt (CAP). Between 1995 and 2009, 69 consecutive patients underwent an MBT (n = 42) or CAP (n = 27) for tetralogy of Fallot (n = 21), pulmonary atresia (n = 25), severe pulmonary valve stenosis (n = 22), and 2-stage repair of transposition of the great arteries (n = 1). The groups were similar with regard to age, weight, pulmonary artery diameter, and preoperative saturations. Postoperative mortality was 3 after CAP (11.1%) versus 1 after MBT (2.4%; P = .0203). Shunt size/weight index was comparable for both groups. MBTs had shorter surgical times ( P = .002), required less inotropes (inotropic index, 103 ± 18 vs 889 ± 199; P = .0069), less blood product transfusions ( P = .01), and had shorter duration of ventilation ( P = .026) and intensive care unit (ICU) stay ( P = .042). Children with MBTs had higher saturations at hospital discharge ( P = .018). Prior to complete repair, 2 patients with a CAP and 10 patients after an MBT needed pulmonary artery dilation or stent implantation ( P = .23). At the time of complete repair and shunt takedown, 3 MBT patients needed surgical patch augmentation of the pulmonary artery. The MBT is a safer and more expeditious operation and more frequently avoids cardiopulmonary bypass. Patients require less inotropes, blood products, and ICU time but may require more interventional therapy to treat pulmonary artery stenosis in the interval to complete repair. Surgical treatment of shunt-related pulmonary artery distortion may be addressed at the time of complete repair.

First-stage angioplasty for a single ventricle with pulmonary artery coarctation

We report first-stage palliation consisting of pulmonary artery angioplasty and a systemic-to-pulmonary shunt using a minimized cardiopulmonary bypass technique performed with modified ultrafiltration for two patients with a single ventricle, pulmonary atresia, patent ductus arteriosus, and pulmonary coarctation during early infancy. Postoperative early extubation (15 and 18 h) and bilateral pulmonary artery growth before the second stage (Nakata indexes, in mm2/m2: right 94, left 53; and right 209, left 70) were experienced. Less-invasive pulmonary artery continuity reconstruction at an early stage is advantageous for low-weight patients with a single ventricle and pulmonary coarctation.

Criterions for selection of patients for, and results of, a new technique for construction of the modified Blalock-Taussig shunt

BACKGROUND

We describe alternative surgical techniques for construction of systemic-to-pulmonary arterial shunts, and propose criterions for their application in selected patients.

PATIENTS AND METHODS

We constructed a variety of modified systemic-to-pulmonary arterial shunts, using polytetrafluoroethylene grafts, in 92 selected patients with cyanotic congenital heart disease and anomalies of the aortic arch and systemic veins. Their age ranged from 7 days to 3.6 years, with a mean of 7.08 months. We performed 88 operations through a thoracotomy. Of this cohort, 60 patients underwent a second-stage operation, with 15 receiving a superior cavopulmonary connection, 16 a total cavopulmonary connection, and 29 proceeding to biventricular repair after a mean interval of 15.6 months. We have 21 patients awaiting their second or final stage of palliation.

RESULTS

There were five early (5.4%) and six late deaths (6.8%), two of which were related to construction of the shunts. At a mean follow-up of 45.29 months, the increase in diameter of pulmonary trunk and its right and left branches was uniform and significant (p value less than 0.001). Pulmonary arterial distortion requiring correction at the time of second-stage operation was observed in 5 patients (6.1%). Adequate overall palliation was achieved in 98% of the cohort at 8 months, 91% at 12 months, and 58% at 18 months.

CONCLUSIONS

Patients with a right- or left-sided aortic arch and right-sided descending thoracic aorta, those with anomalies of systemic venous drainage masking the origin of great arterial branches, and those with disproportionately small subclavian arteries, constitute the ideal candidates for our suggested modification of the construction of a modified Blalock-Taussig shunt. The palliation provided by these shunts was satisfactory, with predictable growth of pulmonary arteries, insignificant distortion in the great majority, and easy take-down.

Pulmonary Segmental Artery Ratio An Alternative to the Pulmonary Artery Index in Patients With Tetralogy of Fallot

The objective of this study was to determine a reliable, alternative ratio to the pulmonary artery (PA) index, which will help to estimate the adequacy of postoperative pulmonary blood flow in patients with tetralogy of Fallot. We propose the pulmonary segmental artery ratio (PSAR), which is an angiographic measure for the quantitative standardization of the total number of pulmonary segmental arteries in a patient. The expected value of the PSAR is 1 and it is constant after the 16(th) week of intrauterine life. Retrospective analysis of the PSAR and PA index calculations in patients with tetralogy of Fallot was conducted. Sixty-one patients were assigned to a moderate or low risk group according to their PSAR; the low risk group included 31 patients whose PSAR was between 0.75-1 (group 1) while the moderate risk group included 30 patients whose PSAR was between 0.50-0.75 (group 2). High risk patients whose PSAR was less than 0.50 were excluded from the study. Postoperative peak right ventricular pressure, the pulmonary artery to systemic pressure ratio, and peripheral arterial oxygen saturation preoperatively after cardiopulmonary bypass were analyzed separately in groups 1 and 2. Postoperative peak right ventricular pressure was lower in group 1 than group 2, while the pulmonary artery to systemic pressure ratio and peripheral arterial oxygen saturation were higher in group 1 than group 2 (P < 0.01). Based on the present findings, it is concluded that PSAR is not as reliable as the Nakata index. However, in cases in which the PSAR and PA index are not correlated, PSAR may be helpful for determining the adequacy of postoperative pulmonary blood flow and postoperative outcomes of patients with hypoplastic pulmonary arteries.