Cost-effectiveness analysis of stents, balloon angioplasty, and surgery for the treatment of branch pulmonary artery stenosis

Ultra-high pressure balloon angioplasty for pulmonary artery stenosis in children with congenital heart defects: Short- to mid-term follow-up results from a retrospective cohort in a single tertiary center

Objective

Balloon angioplasty (BA) has been the treatment of choice for pulmonary artery stenosis (PAS) in children. There remains, however, a significant proportion of resistant lesions. The ultra-high pressure (UHP) balloons might be effective in a subset of these lesions. In this study, we analyzed the safety and efficacy with short- to mid-term follow-up results of UHP BA for PAS in children with congenital heart defects (CHD) in our center.

Methods

This is a retrospective cohort study in a single tertiary heart center. Children diagnosed with PAS associated with CHD were referred for UHP BA. All data with these children were collected for analysis with updated follow-up.

Results

A total of 37 UHP BAs were performed consecutively in 28 children. The success rate was 78.4%. A significantly (P = 0.005) larger ratio of the balloon to the minimal luminal diameter at the stenotic waist (balloon/waist ratio) was present in the success group (median 3.00, 1.64-8.33) compared to that in the failure group (median 1.94, 1.41 ± 4.00). Stepwise logistic regression analysis further identified that the balloon/waist ratio and the presence of therapeutic tears were two independent predictors of procedural success. The receiver operating characteristic curve revealed a cut-off value of 2.57 for the balloon/waist ratio to best differentiate success from failure cases. Signs of therapeutic tears were present in eight cases, all of whom were in the success group. Perioperative acute adverse events were recorded in 16 patients, including 11 pulmonary artery injuries, three pulmonary hemorrhages, and two pulmonary artery aneurysms. During a median follow-up period of 10.4 (0.1-21.0) months, nine cases experienced restenosis at a median time of 40 (4-325) days after angioplasty.

Conclusions

The UHP BA is safe and effective for the primary treatment of PAS in infants and children with CHD. The success rate is high with a low incidence of severe complications. The predictors of success are a larger balloon/waist ratio and the presence of therapeutic tears. The occurrence of restenosis during follow-up, however, remains a problem. A larger number of cases and longer periods of follow-up are needed for further study.

Initial status and 3-month results relating to the use of biodegradable nitride iron stents in children and the evaluation of right ventricular function

Background

Pulmonary artery stenosis is often associated with congenital heart disease. The aim of the study was to evaluate the efficacy and safety of stenting for branch pulmonary artery stenosis using a biodegradable nitride iron stent (IBS^® Angel™) and right ventricular systolic and diastolic function.

Methods

From July 2021 to February 2022, a total of 11 cases (ages ranged from 36 to 86 months old) were included in this pre and post-intervention, prospective, cohort and preclinical study. All cases underwent transthoracic echocardiographic (TTE), chest radiography, along with computed tomography (256-slice scanner, multiple-detector) and right heart catheterization. Different types of biodegradable nitride iron stents were implanted. TTE was performed serially 1 day, 1 month and 3 months after the procedure to evaluate the rate of restenosis and right ventricular function.

Results

Stenting was successful in 11 patients. There were no major adverse cardiovascular events related to the device or to the procedure. Blood perfusion in the branch pulmonary artery was improved immediately. At follow-up, there was no significant restenosis that required re-intervention. None of the patients suffered from in-stent thrombosis, vascular embolism, stent displacement or heart failure. Compared with normal values, there were statistical with regards to FAC, E/A and E′/A′. Furthermore, we found that TAPSE correlated significantly with pulsed Doppler S wave (p = 0.008) and left ventricular ejection fraction (p < 0.01). The early trans-tricuspid inflow velocities E/E′ (tissue doppler at the lateral tricuspid annulus) correlated significantly with E′/A′ (p = 0.009). FAC and E′/A′ were statistically different from those prior to stenting (p = 0.041 and p = 0.035) when tested one month postoperatively. At three months postoperatively, only E/A showed a statistical difference (p = 0.015).

Conclusion

Our analysis suggests that biodegradable nitride iron stents are feasible, safe, and effective in children. Some small improvements were observed in right ventricular systolic and diastolic function after successful transcatheter intervention, although change was not statistically significant due to the small sample number. (A clinical Trial to Evaluate the Safety and Efficacy of IBS Angel in Patients With Pulmonary Artery Stenosis (IRIS); NCT04973540).

Pulmonary artery pathologies in Alagille syndrome: a meta-analysis

Alagille syndrome, caused by mutations in the gene encoding Jagged1 (JAG1), a ligand in the Notch signaling pathway, is an autosomal dominant disorder with developmental abnormalities affecting the liver, heart, eyes, face and skeleton. The aim of the present study is try to disclose the clinical features, management and outcomes of pulmonary artery stenosis associated with Alagille syndrome. By comprehensive literature retrieval, 38 articles involving 401 patients were recruited for this study. The pertinent variables closely related to pulmonary artery stenosis in patients with Alagille syndrome were comprehensively analyzed by following the PRISMA guidelines. The management of pulmonary artery pathologies, especially a severe type of pulmonary artery stenosis in Alagille syndrome, is a concerned matter. Publications of literature retrieval of recent 3 decades were the study material of this article. The pulmonary artery pathologies, especially the severe type of pulmonary artery stenosis in Alagille syndrome, warrant surgical or interventional treatments. After the procedures, the right ventricular to left ventricular pressure ratio was reduced by 25%. There were no intergroup differences in terms of recovery, reintervention and mortality rates between interventionally and surgically treated patients. Transcatheter treatment is preferable due to less trauma. Surgical treatment of pulmonary artery stenosis can be performed currently with intracardiac defect repair.

Partially open stent after balloon catheter iatrogenic perforation. How to solve this complication using a novel technique? The Mij-Her technique

Complications related to pulmonary artery stenting are potentially life-threatening. We reported a novel technique of how to achieve the introduction of a partial dilated stent into a long sheath using a snare in the event of a iatrogenic perforation of a balloon catheter.There are no publications of similar techniques describing successful resolution of this type of complication.

Transcatheter Device Therapy and the Integration of Advanced Imaging in Congenital Heart Disease

Transcatheter device intervention is now offered as first line therapy for many congenital heart defects (CHD) which were traditionally treated with cardiac surgery. While off-label use of devices is common and appropriate, a growing number of devices are now specifically designed and approved for use in CHD. Advanced imaging is now an integral part of interventional procedures including pre-procedure planning, intra-procedural guidance, and post-procedure monitoring. There is robust societal and industrial support for research and development of CHD-specific devices, and the regulatory framework at the national and international level is patient friendly. It is against this backdrop that we review transcatheter implantable devices for CHD, the role and integration of advanced imaging, and explore the current regulatory framework for device approval.

Multimodality Imaging of Transposition of the Great Arteries

Transposition of the great arteries (TGA) is a congenital conotruncal abnormality characterized by discordant connections between the ventricles and great arteries, with the aorta originating from the right ventricle (RV), and the pulmonary artery (PA) originating from the left ventricle (LV). The two main types of TGA are complete transposition or dextro-transposition of the great arteries (D-TGA), commonly referred to as d-loop, and congenitally corrected transposition (CCTGA), commonly referred to as l-loop or L-TGA. In D-TGA, the connections between the ventricles and atria are concordant, whereas in CCTGA they are discordant, with the left atrium connected to the RV, and the right atrium connected to the LV. D-TGA manifests during the neonatal period and can be surgically managed by atrial switch operation (AtrSO), arterial switch operation (ASO), Rastelli procedure, or Nikaidoh procedure. Arrhythmia, systemic ventricular dysfunction, baffle stenosis, and baffle leak are the common complications of AtrSO, whereas supravalvular pulmonary or branch PA stenosis, neoaortic dilatation, and coronary artery narrowing are the common complications of ASO. CCTGA may manifest late in life, even in adulthood. Surgeries for associated lesions such as tricuspid regurgitation, subpulmonic stenosis, and ventricular septal defect may be performed. A double-switch operation that includes both the atrial and arterial switch operations constitutes anatomic correction for CCTGA. Imaging plays an important role in the evaluation of TGA, both before and after surgery, for helping define the anatomy, quantify hemodynamics, and evaluate complications. Transthoracic echocardiography is the first-line imaging modality for presurgical planning in children with TGA. MRI provides comprehensive morphologic and functional information, particularly in adults after surgery. CT is performed when MRI is contraindicated or expected to generate artifacts. The authors review the imaging appearances of TGA, with a focus on pre- and postsurgical imaging. Online supplemental material is available for this article. ^©RSNA, 2021.

Long-term evolution of stents implanted in branch pulmonary arteries

BACKGROUND

Branch pulmonary artery stenosis complicates the management of congenital heart diseases. Surgical branch pulmonary artery angioplasty is associated with a high reintervention rate. As an alternative, percutaneous or intraoperative branch pulmonary artery stents have been implanted to improve efficiency, but long-term evaluations are limited.

AIM

To describe the long-term evolution of branch pulmonary artery stents.

METHODS

We conducted a retrospective cohort study at Tours University Hospital. All stents implanted by surgery or catheterization in branch pulmonary arteries with a minimum follow-up of 12 months and at least one catheterization control were included. The primary endpoint combined cardiovascular mortality, surgical or percutaneous reintervention for stent complication or new stent implantation.

RESULTS

Between 2007 and 2017, 76 stents in 51 patients were included (62 stents implanted by surgery, 14 by catheterization). At implantation, the patients' mean age and weight were 4.7years (interquartile range 4.2years) and 17.3kg (interquartile range 11.0kg), respectively. Mean branch pulmonary artery minimum diameter was 4.1±2.1mm (mean Z-score-4.9±2.9), and mean initial stent diameter was 9.1±3.1mm. During a follow-up of 5.3years (range 0-11.2 years), freedom from primary endpoint was 86.8% (95% confidence interval 79.6-94.8%) at 1 year, 71.5% (95% confidence interval 61.9-82.7%) at 5years and 69.6% (95% confidence interval 59.6-81.2%) at 10 years. We did not identify any factors associated with major adverse cardiovascular events. Among stents without major adverse cardiovascular events, the mean branch pulmonary artery diameter Z-score at last evaluation had increased by +4.8±3.2 compared with the initial diameter (P<0.001). After stent implantation, a median of 2 re-expansions were performed for each stent (range 0-7).

CONCLUSIONS

Stent implantation should offer a good long-term solution for branch pulmonary artery stenosis, although iterative re-expansions are required.

Successful angioplasties using high pressure large balloons in a patient with severe anastomotic pulmonary artery stenosis soon after single-lung transplantation

A 59-year-old man received a single-lung transplantation due to interstitial pneumonitis. Severe anastomotic pulmonary artery stenosis (PAS) resulting in hypoxia and respiratory symptoms was found in the immediate postoperative period. A scintigraphy showed severe hypoperfusion of the left transplanted lung with 7% of the total pulmonary blood flow. On postoperative days (POD) 29 and 64, the patient underwent serial balloon angioplasties without any complications. Based on the balloon selection criteria for PAS after heart surgery in children, a high-pressure large balloon was used with resultant improvement in respiratory signs and symptoms without any complications. The patient was discharged on POD 92. A follow-up scintigraphy on POD 169 revealed 58% of blood distribution to the left lung. The patient has been doing clinically well and remained asymptomatic one year after the transplantation. Balloon angioplasty with a high-pressure large balloon without stent implantation during an early postoperative period may be a safe and effective strategy. The balloon selecting criteria used in pediatric patients may be applied in the adult lung transplant recipients. <Learning objective: Anastomotic pulmonary artery stenosis (PAS) in a single-lung transplant recipient is a critical complication. A balloon angioplasty with a high-pressure large balloon should be a first choice for anastomotic PAS, because it is safer than stent implantation especially for transplant recipients. And the balloon selecting criteria used in children with congenital heart disease may be applied in the adult lung transplant recipients.>.

Treatment of Peripheral Pulmonary Artery Stenosis

Peripheral pulmonary artery stenosis (PAS) is an abnormal narrowing of the pulmonary vasculature and can form anywhere within the pulmonary artery tree. PAS is a congenital or an acquired disease, and its severity depends on the etiology, location, and number of stenoses. Most often seen in infants and young children, some symptoms include shortness of breath, fatigue, and tachycardia. Symptoms can progressively worsen over time as right ventricular pressure increases, leading to further complications including pulmonary artery hypertension and systolic and diastolic dysfunctions. The current treatment options for PAS include simple balloon angioplasty, cutting balloon angioplasty, and stent placement. Simple balloon angioplasty is the most basic therapeutic option for proximally located PAS. Cutting balloon angioplasty is utilized for more dilation-resistant PAS vessels and for more distally located PAS. Stent placement is the most effective option seen to treat the majority of PAS; however, it requires multiple re-interventions for serial dilations and is generally reserved for PAS vessels that are resistant to angioplasty.

Treatment approach to unilateral branch pulmonary artery stenosis

Unilateral proximal pulmonary artery stenosis is often seen in the setting of postoperative congenital heart disease. Accurate assessment of the hemodynamic significance of such a lesion is important so as to determine "When to intervene?" A thorough evaluation should include symptom assessment, anatomical assessment through detailed imaging, functional assessment using differential pulmonary blood flow measurement and cardiopulmonary exercise testing. Symptoms of exertional dyspnea or intolerance, decreased pulmonary blood flow to stenosed lung, and abnormal exertional performance would be factors to pursue therapy in the setting of significant anatomical narrowing. Safe and effective therapy can be offered through transcatheter or surgical techniques and has been shown to improve exertional performance.

A review: Percutaneous pulmonary artery stenosis therapy: state-of-the-art and look to the future

Stenosis, or narrowing, of the branches of the pulmonary artery is a type of CHD that, if left untreated, may lead to significant complications. Ideally, interventions to treat stenosis occur before significant complications or long-term sequelae take place, often within the first 2 years of life. Treatment depends on specifics of the condition, the presence of other malformations, and age of the child. Research and recent innovation to address these shortcomings have provided physicians with safer and more effective methods of treatment. This has further continued to push the ceiling of pulmonary arterial stenosis treatment available for patients. Despite continuous advancement in angioplasty - such as conventional and cutting balloon - and stenting, each treatment method is not without its unique limitations. New technological developments such as bioresorbable stents can accommodate patient growth and pulmonary artery stenosis treatment. As more than a decade has passed since the review by Bergersen and Lock, this article aims to provide a contemporary summary and investigation into the effectiveness of various therapeutic tools currently available, such as bare metal stents and potential innovations including bioresorbable stents.

Pulmonary Artery Stenting

Stent implantation for pulmonary artery stenosis has advanced. Newer generations of stents allow confidence in long-term results, even in pediatric interventions. Primary intravascular stent implantation is recommended in significant branch pulmonary artery stenosis when the vessel or patient is large enough to accommodate a stent that can be dilated to an adult diameter. A variety of specialized stents are now available, improving applicability despite complex vessel size characteristics. Developments in bioresorbable stents and patient-specific rapid prototyping are anticipated.

The Y-stenting technique for pulmonary artery bifurcation stenosis: Initial results and mid-term outcomes

BACKGROUND

Treatment for main or peripheral PBS is challenging. An interventional approach is generally preferred as surgical angioplasty often results in residual stenosis. However, there is limited data on the mid- and long-term results of the different interventional approaches. The aim of this study is to report on initial and mid-term results of the Y-stenting technique for pulmonary artery bifurcation stenosis (PBS).

METHODS

A single centre retrospective study of all Y-stenting procedures for main or peripheral PBS was conducted. Patient and procedural data as well as mid-term outcomes were analysed.

RESULTS

11 Y-stenting procedures were performed, 9 in the main pulmonary bifurcation and 2 in the PA periphery. In 8 patients the bifurcation stents were connected, in 3 patients there was no connection between the stents. Y-stenting creates a geometry close to the physiological PA bifurcation anatomy with complete alignment to the vessel wall without flow separation. Control angiography showed unrestricted blood flow after all procedures. Median right/left ventricle pressure ratio decreased from 0.9 to 0.5. No immediate or delayed adverse events were seen. During a median follow-up of 33.5 months, 2 patients in the non-connected group and 3 patients in the connected group needed a total of 6 re-interventions. No intima proliferation was seen in patients with connected stents.

CONCLUSIONS

Y-stenting is a safe and effective treatment for PBS. When both bifurcation stents are connected, this may result in lower rates of in-stent intima proliferation in comparison to other PBS stenting techniques.

Balloon Angioplasty as a Modality to Treat Children with Pulmonary Stenosis Secondary to Complex Congenital Heart Diseases

BACKGROUND

Pulmonary stenosis is common in children with complex congenital heart diseases. Proper management of this problem, especially postoperatively, is still controversial. This study was designed to assess the rate and determinants of success or failure of balloon angioplasty for such lesions.

METHODS

Clinical and hemodynamic data from 40 pediatric patients (24 boys and 16 girls) with complex congenital heart diseases who underwent balloon angioplasty were reviewed retrospectively from January 2012 to December 2016. Patients were divided into four groups according to the site of stenosis, which included pulmonary valve stenosis (PVS), valved conduit stenosis, pulmonary artery stenosis (PAS), and supravalvular pulmonary stenosis (SVPS). Success rates were calculated according to defined criteria for initial success and favorable clinical impacts, and comparison between the successful subgroup and the unsuccessful subgroups was analyzed.

RESULTS

Grouped by the site of stenosis, initial success rates varied from 40.0% to 52.4% with the greatest success being seen in the PVS group, followed by the PAS group and SVPS group. In the PVS group and the PAS group, there was no statistical difference among age at dilation, postoperative interval, balloon/stenosis ratio, or pressure gradient predilation between the successful and the unsuccessful subgroups. Favorable clinical impacts included success rates of balloon angioplasty in the SVPS group, which was best (100%), followed by the PVS group (90.9%) and the PAS group (85.7%). There were a total of two transient complications (5.0%).

CONCLUSIONS

Balloon angioplasty was proven to be a safe and useful modality in children with complex congenital heart diseases and postoperative pulmonary stenosis, which should be the initial therapeutic modality in selected patients.

Computational simulation of postoperative pulmonary flow distribution in Alagille patients with peripheral pulmonary artery stenosis

BACKGROUND

Up to 90% of individuals with Alagille syndrome have congenital heart diseases. Peripheral pulmonary artery stenosis (PPS), resulting in right ventricular hypertension and pulmonary flow disparity, is one of the most common abnormalities, yet the hemodynamic effects are ill-defined, and optimal patient management and treatment strategies are not well established. The purpose of this pilot study is to use recently refined computational simulation in the setting of multiple surgical strategies, to examine the influence of pulmonary artery reconstruction on hemodynamics in this population.

MATERIALS AND METHODS

Based on computed tomography angiography and cardiac catheterization data, preoperative pulmonary artery models were constructed for 4 patients with Alagille syndrome with PPS (all male, age range: 0.6-2.9 years), and flow simulations with deformable walls were performed. Surgeon directed virtual surgery, mimicking the surgical procedure, was then performed to derive postoperative models. Postoperative simulation-derived hemodynamics and blood flow distribution were then compared with the clinical results.

RESULTS

Simulations confirmed substantial resistance, resulting from preoperative severe ostial stenoses, and the use of newly developed adaptive outflow boundary conditions led to excellent agreement with in vivo measurements. Relief of PPS decreased pulmonary artery pressures and improved pulmonary flow distribution both in vivo and in silico with good correlation.

CONCLUSIONS

Using adaptive outflow boundary conditions, computational simulations can estimate postoperative overall pulmonary flow distribution in patients with Alagille syndrome after pulmonary artery reconstruction. Obstruction relief along with pulmonary artery vasodilation determines postoperative pulmonary flow distribution and newer methods can incorporate these physiologic changes. Evolving blood flow simulations may be useful in surgical or transcatheter planning and in understanding the complex interplay among various obstructions in patients with peripheral pulmonary stenosis.

Twenty years of experience with intraoperative pulmonary artery stenting

OBJECTIVES

To describe our 20-year experience with intraoperative pulmonary artery (PA) stent placement and evaluate long-term patient outcomes, specifically the need and risk factors for reintervention.

BACKGROUND

Intraoperative PA stent placement is an alternative to surgical patch arterioplasty and percutaneous angioplasty or stent placement to treat branch PA stenosis.

METHODS

We performed a retrospective review of all intraoperative PA stents placed at our institution from 1994-2013. Patient and stent characteristics and outcome data were collected. Risk factors associated with reintervention were identified using univariate cox regression analysis.

RESULTS

Eighty-one PA stents were placed in 68 patients. The procedural complication rate was 4.4%. During a median follow-up period of 6 years (interquartile range [IQR] 0.9-12.7), 30 patients (44%) underwent reintervention on the stented PA with a median time to first reintervention of 2.6 years (IQR 0.7-4.4 years). The first reintervention was surgical in 30% and catheter-based in 70%. Risk factors for reintervention included age < 18 months (Hazard ratio [HR] 2.97, P = 0.005) and body surface area < 0.47 m² (HR 3.20, P = 0.003) at the time of stent implantation, and the presence of multiple aortopulmonary collaterals in patients with tetralogy of Fallot (HR 4.61, P = 0.003).

CONCLUSIONS

Intraoperative PA stent implantation is a safe and effective alternative to percutaneous stent implantation and offers several advantages, including the ability to implant adult-size stents in small patients while avoiding injury to peripheral vessels, to position stents to facilitate future percutaneous stent redilation, and to access the PAs directly, which eliminates radiation exposure. © 2017 Wiley Periodicals, Inc.

What Interventional Cardiologists Are Still Leaving to the Surgeons?

Nowadays, development of new technologies is still ongoing with the ultimate goal of maximizing treatment outcomes with less invasiveness and reduced procedural risk. This review is intended to update on when interventionalists need surgical support in common or emerging problems in congenital heart disease.

Intervention for Supravalvar Pulmonary Stenosis After the Arterial Switch Operation

BACKGROUND

The arterial switch operation is standard of care for infants born with dextrotransposition of the great arteries. Supravalvar pulmonary stenosis is a common complication that may require reintervention-balloon angioplasty, stenting, or surgical augmentation. A subset of patients requires more than one reintervention.

METHODS

We performed a retrospective review of patients who underwent the arterial switch operation for dextrotransposition of the great arteries at a single institution between August 1990 and January 2014. Anatomic, perioperative and follow-up data were collected. Reinterventions were stratified in a site-specific manner. Statistical analysis was performed using IBM SPSS version 21 (IBM Corp, Armonk, NY).

RESULTS

Of the 103 patients who met inclusion criteria, 28% (29) required reintervention for supravalvar pulmonary stenosis; 41% of those receiving primary reintervention required an additional 21 reinterventions. Balloon angioplasty of the main pulmonary artery and left pulmonary artery was associated with the need for multiple reinterventions (odds ratio 4.9, p = 0.051, and odds ratio 5.1, p = 0.029, respectively). Freedom from future reintervention at the main pulmonary artery and left pulmonary artery was significantly shorter after balloon angioplasty relative to alternative reintervention options (hazard ratio 10, p = 0.005, and hazard ratio 3.2, p = 0.02, respectively). Balloon angioplasty of the right pulmonary artery was not associated with an increased risk of reintervention (p = 0.42).

CONCLUSIONS

Supravalvar pulmonary stenosis after the arterial switch operation for dextrotransposition of the great arteries is common and more than one reintervention are required in a subset of patients. The benefit of balloon angioplasty of the main pulmonary artery and left pulmonary artery was shown to be temporary. Attempting balloon angioplasties at these locations remain reasonable, although families should be counseled about the increased incidence of, and decreased time to, subsequent reintervention that is associated with this treatment option.

Quality assessment of economic evaluation studies in pediatric surgery: a systematic review

PURPOSE

To assess economic evaluation studies (EES) in pediatric surgery and to identify potential factors associated with high-quality studies.

METHODS

A systematic review of the literature using PubMed and Cochrane databases was conducted to identify EES in pediatric surgery published between 1 June 1993 and 30 June 2013. Assessment criteria are derived from the Drummond checklist. A high quality study was defined as a Drummond score ≥7. Logistic regression analysis was used to determine factors associated with high quality studies.

RESULTS

119 studies were included. 43.7% (n=52) of studies were full EES. Cost-effectiveness analysis was the most frequent (61.5%) type of full EES. Only 31.6% of studies had a Drummond score ≥7 and 73% of these were full EES. The factors associated with high quality were identification of costs (OR: 14.08; 95% CI: 3.38-100; p<0.001), estimation of utility value (OR: 8.13; 95% CI: 2.02-43.47; p=0.005) and study funding (OR: 3.50; 95% CI: 1.27-10.10; p=0.02).

CONCLUSION

This review shows that the number and the quality of EES are low despite the increasing number of studies published in recent years. In the current context of budget constraints, our results should encourage pediatric surgeons to focus more on EES.

Stents in paediatric and adult congenital interventional cardiac catheterization

A 'stent' is a tubular meshed endoprosthesis that has contributed to the development of interventional catheterization over the past 30 years. In congenital heart diseases, stents have offered new solutions to the treatment of congenital vessel stenosis or postsurgical lesions, to maintain or close shunt patency, and to allow transcatheter valve replacement. First, stents were made of bare metal. Then, stent frameworks evolved to achieve a better compromise between radial strength and flexibility. However, almost all stents used currently in children have not been approved for vascular lesions in children and are therefore used 'off-label'. Furthermore, the inability of stents to follow natural vessel growth still limits their use in low-weight children and infants. Recently, bioresorbable stents have been manufactured and may overcome this issue; they are made from materials that may dissolve or be absorbed in the body. In this review, we aim to describe the history of stent development, the technical characteristics of stents used currently, the clinical applications and results, and the latest technological developments and perspectives in paediatric and adult congenital cardiac catheterization.

Pulmonary artery stents in the recent era: Immediate and intermediate follow-up

BACKGROUND

Long-term follow-up after stent dilation of native and acquired pulmonary artery stenosis is scarce in the pediatric population. Most cohorts include a myriad of anatomies and associated conditions.

METHOD

In order to establish objective performance criteria, we performed a retrospective review of all patients who underwent unilateral pulmonary artery stenting in biventricular physiology at three centers from June 2006 to June 2011.

RESULTS

Fifty-eight patients received 60 stents with Palmaz Genesis stent used most commonly (78%). Average age at implantation was 10.4 ± 10.3 years and weight 31.6 ± 21.8 kg. The immediate success rate was 98%, with improvement in minimal diameter from 5.1 ± 2 cm to 10.6 ± 3 cm (P < 0.01). There were 10 complications (7 major and 3 minor) and no acute mortality. One-year follow-up studies were available in 48 patients (83%), including echocardiogram (60%), catheterization (28%), MRI (29%), and lung perfusion (31%). Follow-up echocardiogram showed mild increase in stent gradient, from 5.7 ± 6.7 mm Hg post-procedure to 17.1 ± 11.7 mm Hg. Follow-up catheterization showed no significant change in minimal stent diameter (8.8 ± 2.6 to 7.8 ± 2.3 mm), gradient (7.7 ± 8.4 to 12.6 ± 12.2 mm Hg), or right ventricular pressures (43.7 ± 9 to 47.7 ± 10.5 mm Hg). Nine patients (16%) underwent scheduled stent redilation over a period of 12 days to 25 months.

CONCLUSION

In conclusion, stent implantation shows excellent immediate and 1-year follow-up results with maintenance of improved caliber of the stented vessel and lowered right ventricular systolic pressures.

Single-center outcome analysis comparing reintervention rates of surgical arterioplasty with stenting for branch pulmonary artery stenosis in a pediatric population

Although catheter-based intervention is generally accepted as the treatment of choice for branch pulmonary artery (PA) stenosis, there are no data directly comparing both the need for reintervention and time to reintervention in patients undergoing transcatheter stenting versus surgical arterioplasty. We compared children who underwent surgical branch pulmonary arterioplasty and branch PA stent placement between January 2008 and May 2012 at a single tertiary center. Need for reintervention and mean time to reintervention were assessed using chi-square and independent sample Student t test. Thirty-seven patients were included (surgery n = 18, stent n = 19). Mean weight at initial intervention was 11.3 ± 8.8 kg for surgical and 20.1 ± 15.5 kg for stent (p = 0.041). Intervention was performed on the left PA in 17 patients, the right PA in 12 patients, and both PAs in 8 patients. Five patients had undergone previous intervention. On mean follow-up of 807 ± 415 days, 50% (9 of 18) of the surgery cohort and 5.3% (1 of 19) of the stent cohort required reintervention (p = 0.002). In all but one case reintervention was catheter-based. Mean time to reintervention for the surgery cohort was 272 ± 162 days and for the single stent cohort it was 150 days. When comparable age and weight groups were analyzed, reintervention was still more common in the surgery cohort (p = 0.007). Children undergoing surgical branch pulmonary arterioplasty are more likely to require reintervention than those undergoing stent placement.

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.

Cheatham-Platinum stent implantation for pulmonary artery stenosis in children and adolescents: immediate and mid-term outcome

BACKGROUND

NuMED Cheatham-Platinum (CP) stent implantation for pulmonary artery stenosis in children and adolescents has been rarely reported. This study aimed to evaluate the immediate and mid-term results of CP stent implantation for the treatment of pulmonary artery stenosis associated with congenital heart disease (CHD) in children and adolescents.

METHODS

From August 2005 to May 2007, four consecutive pediatric patients with pulmonary artery stenosis associated with CHD underwent CP stent implantation. They were followed up, and transthoracic echocardiography was done for outcome evaluation.

RESULTS

In the four patients, 5 stent placement procedures were performed and 7 CP stents were implanted (8-zig, 22-39 mm in length). All stents except one were successfully placed in the target lesions without displacement during the procedures. After the procedure, the systolic pressure gradient across the stenosis decreased from 36.67 ± 20.08 to 3.67 ± 3.20 mmHg (P=0.005), and the narrowest diameter of the stenotic segment increased from 6.97 ± 2.22 to 13.40 ± 4.40 mm (P=0.013). Two stents implanted in the left and right pulmonary arteries in patient 4 developed intrastent restenosis 6 months after the procedure, and the distal end of the main pulmonary artery also developed restenosis 26 months later. The results of the remaining stents have been stable without complications during a median follow-up of 34 months (range, 26-48 months).

CONCLUSIONS

Our experience indicates that CP stent implantation is suitable for the treatment of pulmonary artery stenosis in children and adolescents with CHD. The immediate and mid-term results are encouraging, but long-term results demand further follow-up in more cases.

How we approach peripheral pulmonary stenosis in Williams-Beuren syndrome

Williams-Beuren syndrome is associated with supravalvar aortic stenosis and peripheral pulmonary artery stenosis in the majority of affected individuals. Among patients in whom surgery for supravalvar aortic stenosis is contemplated, stenosis of the branch pulmonary arteries is common. For asymptomatic patients with subsystemic right ventricular pressure, the natural history is favorable and no intervention is necessary. For patients with important proximal branch pulmonary artery, stenoses patch arterioplasty can be accomplished at the time of surgery for supravalvar aortic stenosis. For patients with important peripheral pulmonary stenosis, preoperative catheter-based therapy is indicated. Surgical repair of peripheral pulmonary stenosis is indicated when preoperative intervention is unsuccessful and can include a combination of patch arterioplasty as well as intraoperative application of catheter-based techniques. This report will address the approach to this lesion with catheter-based approaches, surgical approaches, and their combination.

Percutaneous stent placement in children weighing less than 10 kilograms

The objectives of this study were to evaluate the safety, efficacy, and outcomes of palliative percutaneous stent placement in infants with congenital heart disease (CHD). There is interest in improving outcomes of infants with CHD through interventional/surgical collaboration. Small, high-risk patients may benefit from delayed open operations, and endovascular stents may provide a means to defer surgery to more advantageous times in select infants. Patients weighing < or =10 kg in whom stent placement was attempted during 2003-2006 were identified. Diagnoses, indications, angiographic and hemodynamic data, complications, and outcomes were reviewed. Seventeen stents were successfully placed in 15 patients. The mean age was 10.21 months; the mean weight was 6.08 kg. Indications were branch pulmonary artery stenosis, coarctation, total anomalous pulmonary venous return with obstructed venous egress, right ventricle-pulmonary artery conduit, and shunt stenosis. Premounted Palmaz Genesis and Driver Mx stents were used. Average vessel diameter increased from 3.65 to 6.72 mm (p < 0.001). The pressure gradient fell from 24 to 15 mm Hg (p < 0.01). Two stents migrated. One was recaptured and implanted at the target site and one implanted away from the target site. None needed surgical intervention. Mean follow-up was 270 days. Five patients have had additional surgery; seven patients underwent 10 additional stent dilations. There was no procedural-related mortality. Five patients (33%) died during the follow-up period, none attributable to the stent placement. We conclude that stent placement can be successfully accomplished in select, small, high-risk patients. A collaborative interventional/surgical paradigm is important to ensure that the risk-benefit ratio is properly evaluated during the patient selection.

Total Cavopulmonary Connection Flow With Functional Left Pulmonary Artery Stenosis

BACKGROUND

In our multicenter study of the total cavopulmonary connection (TCPC), a cohort of patients with long-segment left pulmonary artery (LPA) stenosis was observed (35%). The clinically recognized detrimental effects of LPA stenosis motivated a computational fluid dynamic simulation study within 3-dimensional patient-specific and idealized TCPC pathways. The goal of this study was to quantify and evaluate the hemodynamic impact of LPA stenosis and to judge interventional strategies aimed at treating it.

METHODS AND RESULTS

Simulations were conducted at equal vascular lung resistance, modeling both discrete stenosis (DS) and diffuse long-segment hypoplasia with varying degrees of obstruction (0% to 80%). Models having fenestrations of 2 to 6 mm and atrium pressures of 4 to 14 mm Hg were explored. A patient-specific, extracardiac TCPC with 85% DS was studied in its original configuration and after virtual surgery that dilated the LPA to 0% stenosis in the computer medium. Performance indices improved exponentially (R2>0.99) with decreasing obstruction. Diffuse long-segment hypoplasia was approximately 50% more severe with regard to lung perfusion and cardiac energy loss than DS. Virtual angioplasty performed on the 3-dimensional Fontan anatomy exhibiting an 85% DS stenosis produced a 61% increase in left lung perfusion and a 50% decrease in cardiac energy dissipation. After 4-mm fenestration, TCPC baffle pressure dropped by approximately 10% and left lung perfusion decreased by approximately 8% compared with the 80% DS case.

CONCLUSIONS

DS <60% and diffuse long-segment hypoplasia <40% could be considered tolerable because both resulted in only a 12% decrease in left lung perfusion. In contrast to angioplasty, a fenestration (right-to-left shunt) reduced TCPC pressure at the cost of decreased left and right lung perfusion. These results suggest that pre-Fontan computational fluid dynamic simulation may be valuable for determining both the hemodynamic significance of LPA stenosis and the potential benefits of intervention.

Interventional strategies in the management of peripheral pulmonary artery stenosis

Peripheral pulmonary artery stenosis challenges therapeutic algorithms for the management of congenital heart malformations. Surgical repair of the proximal pulmonary artery lesion remains with a high recurrence rate while the distal lesions are difficult to access. With the development of transcatheter interventional strategies in the early 1980s, a number of transcatheter treatment options became available. In this review, we summarize the current state of the art for interventional strategies in the management of peripheral pulmonary artery stenosis.

Interventional catheterization management of perioperative peripheral pulmonary stenosis: balloon angioplasty or endovascular stenting

There is limited reported experience of catheterization therapy for peripheral pulmonary stenosis (PPS) at a surgical site in the early postoperative period. We reviewed the clinical course of patients undergoing interventional catheterization for PPS at a surgical site < 7 weeks after surgery. Successful dilation (SD) was defined as > 50% increase in predilation diameter. From 1984 to 2000, 17 patients had 19 proximal pulmonary arteries dilated 1 to 46 (median 8) days postoperatively. Median age and weight were 3.1 year and 12.7 kg. Three arteries were initially occluded. Seventeen arteries had initial BD with postintervention imaging available in 15; 8 arteries had SD. The arterial diameter increased from 3.9 +/- 2.6 to 5.5 +/- 2.8 mm (P < 0.001). Nine of these arteries had stents placed with diameter increasing to 8.7 +/- 3.7 mm (P < 0.001 compared with post-BD diameter). Stents increased the diameter in all arteries and made four of four failed BD successful. In the two most recent procedures, stents were placed without prior BD with diameter increasing from 1.3 to 9 mm and 8.2 to 14 mm. A stent was placed in 1 of 7 arteries prior to 1993 and in 10 of 12 arteries thereafter (P < 0.004). Three patients prior to 1995 had catheterization-related deaths secondary to vessel rupture after BD. BD produces SD in approximately one-half of the procedures but is associated with mortality. Stent placement increases vessel diameter substantially more than BD alone. Stents reduce the acute complication rate and avoid early reoperation in this patient group.

Comprehensive management of branch pulmonary artery stenosis

Branch pulmonary artery stenosis may occur as an isolated finding or in conjunction with other cardiac malformations; it may be congenital or acquired postoperatively. Transcatheter management with balloon pulmonary angioplasty (BPA) and/or endovascular stenting is generally considered the procedure of choice for most patients. With the introduction of high-pressure balloons, the results of BPA have improved significantly (75%). Stent implantation has increased the success rate to over 90%. However, BPA continues to be the initial procedure of choice for distal stenoses, or those associated with branching points, and in small children or infants. Stent implantation is preferred over BPA for central or proximal stenoses, and those due to kinking or tenting, external compression, intimal flaps, failed balloon dilation, and early postoperative procedures. Certain lesions, such as supravalvar pulmonary stenosis, or stenosis at the branch pulmonary arteries bifurcation, are better dealt with at surgery. High-risk situations for the development of postoperative pulmonary artery (PA) stenosis exist in small infants with hypoplastic branch PAs after a conotruncal procedure, after duct ligation, after shunt insertion, after PA band placement, or after pulmonary arteriotomies or anastomoses of any kind. A combined collaborative transcatheter and surgical approach is essential for many patients with PA stenosis, particularly in complex forms of tetralogy of Fallot.

Balloon dilation angioplasty of peripheral pulmonary stenosis associated with Williams syndrome

BACKGROUND

Experience of balloon dilation of peripheral pulmonary stenosis (PPS) in Williams syndrome (WS) is limited.

METHODS AND RESULTS

Catheterizations in all patients with WS undergoing therapy for PPS from 1984 to 1999 were reviewed. Criteria for successful dilation included an increase >50% in predilation diameter and a decrease >20% in ratio of right ventricular (RV) to aortic (Ao) systolic pressure. Median age and weight were 1.5 years and 9.5 kg. There were 134 dilations during 39 procedures in 25 patients. The success rate for initial dilations was 51%. In multivariate analysis, successful dilation was more likely (1) in distal than in central pulmonary arteries (P=0.02), (2) if the balloon waist resolved with inflation (P=0.001), and (3) with larger balloon/stenosis ratio (P<0.001). RV pressure was unchanged after dilation (96+/-30 versus 97+/-31 mm Hg), primarily because of failure to enlarge central pulmonary arteries. The Ao pressure increased (102+/-14 versus 109+/-19 mm Hg, P=0.03), and the RV/Ao pressure ratio decreased (0.97+/-0.34 versus 0.91+/-0.30, P=0.05). Aneurysms developed after 24 dilations (18%) and were not related to balloon/stenosis ratio. Balloon rupture in 12 dilations produced an aneurysm in all 7 cases when rupture was in a hypoplastic segment. Three patients died, none from pulmonary artery trauma, and all before 1994.

CONCLUSIONS

Mortality occurred early in our experience. Despite successful dilation of distal pulmonary arteries, there was modest initial hemodynamic improvement, mainly because of persistent central pulmonary artery obstruction. A serial approach of distal dilations followed by surgical repair of proximal obstruction may be a rational and successful therapy.

Treatment of pulmonary artery stenosis after arterial switch operation: stent implantation vs. balloon angioplasty

The development of pulmonary artery stenosis is a potential complication during the mid- to long-term follow-up after arterial switch operation (ASO) for transposition of the great arteries. Surgical results have been disappointing and conventional balloon dilation yields a fairly important incidence of failures and recurrences. We evaluated our results with implantation of balloon-expandable stents in 5 out of 13 patients with a previously attempted unsuccessful conventional balloon dilation of pulmonary artery branch stenosis after ASO. In two more cases, stents were used as a primary procedure. Balloon angioplasty achieved a 15% increase in mean diameter of the stenosis vs. 124% with the use of stents (P< 0.01), a 10% decrease of the pressure gradient across the stenosis vs. 71% of stents (P<0.01), and a 10% drop in RV/aorta pressure ratio vs. 43% of stents (P<0.01). Compared to conventional balloon angioplasty in our series, stents were more effective in the treatment of patients with peripheral pulmonary artery stenosis after ASO. Balloon dilation should be considered in selected cases unsuitable for treatment with endovascular stents.

Interventional cardiac catheterization

Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.