Randomized Trial of Cutting Balloon Compared With High-Pressure Angioplasty for the Treatment of Resistant Pulmonary Artery Stenosis

Pulmonary Hypertension Induced by Right Pulmonary Artery Occlusion: Hemodynamic Consequences of Bmpr2 Mutation

BACKGROUND

The primary genetic risk factor for heritable pulmonary arterial hypertension is the presence of monoallelic mutations in the BMPR2 gene. The incomplete penetrance of BMPR2 mutations implies that additional triggers are necessary for pulmonary arterial hypertension occurrence. Pulmonary artery stenosis directly raises pulmonary artery pressure, and the redirection of blood flow to unobstructed arteries leads to endothelial dysfunction and vascular remodeling. We hypothesized that right pulmonary artery occlusion (RPAO) triggers pulmonary hypertension (PH) in rats with Bmpr2 mutations.

METHODS AND RESULTS

Male and female rats with a 71 bp monoallelic deletion in exon 1 of Bmpr2 and their wild-type siblings underwent acute and chronic RPAO. They were subjected to full high-fidelity hemodynamic characterization. We also examined how chronic RPAO can mimic the pulmonary gene expression pattern associated with installed PH in unobstructed territories. RPAO induced precapillary PH in male and female rats, both acutely and chronically. Bmpr2 mutant and male rats manifested more severe PH compared with their counterparts. Although wild-type rats adapted to RPAO, Bmpr2 mutant rats experienced heightened mortality. RPAO induced a decline in cardiac contractility index, particularly pronounced in male Bmpr2 rats. Chronic RPAO resulted in elevated pulmonary IL-6 (interleukin-6) expression and decreased Gdf2 expression (corrected P value<0.05 and log2 fold change>1). In this context, male rats expressed higher pulmonary levels of endothelin-1 and IL-6 than females.

CONCLUSIONS

Our novel 2-hit rat model presents a promising avenue to explore the adaptation of the right ventricle and pulmonary vasculature to PH, shedding light on pertinent sex- and gene-related effects.

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.

Exercise feature and predictor of prognosis in patients with pulmonary artery stenosis-associated pulmonary hypertension

AIMS

The prognosis is poor for patients with pulmonary artery stenosis-associated pulmonary hypertension (PAS-PH). Identifying predictors of prognosis in PAS-PH is crucial to preventing premature death, which has rarely been investigated. We aimed to explore the cardiopulmonary exercise testing (CPET) parameters to predict the prognosis of these patients.

METHODS

We prospectively included all patients with PAS-PH who underwent CPET between September 2014 and June 2021 in Fuwai Hospital (ClinicalTrials.gov ID: NCT02061787). The primary outcome was clinical worsening, including death, rehospitalization for heart failure, or deterioration of PH.

RESULTS

Seventy-two patients were included in this study. A median of 2-year follow-up revealed that 18 (25%) patients experienced clinical worsening. The 1-year, 3-year, and 5-year event-free survival rates were 92.5%, 81.7%, and 62.7%, respectively. Patients with clinical worsening demonstrated significantly worse baseline haemodynamics and poorer exercise capacity than their counterparts. Multivariable Cox regression identified that peak O₂ pulse could independently predict clinical worsening [hazard ratio: 0.344, 95% confidence interval (CI) 0.188-0.631, P < 0.001], outperforming other parameters. Peak O₂ pulse correlated with PH severity. Incorporating peak O₂ pulse into the simplified 2015 European Society of Cardiology/European Respiratory Society risk stratification improved the accuracy for predicting clinical worsening (pre vs. post area under the curve: 0.727 vs. 0.846, P < 0.001; net reclassification index: 0.852, 95% CI 0.372-1.332, P < 0.001; integrated discrimination index 0.133, 95% CI 0.031-0.235, P = 0.011).

CONCLUSIONS

The prognosis is poor for PAS-PH, and exercise intolerance and ventilation inefficiency are commonly observed. Peak O₂ pulse independently predicted the prognosis of these patients. A low peak O₂ pulse identified patients at high risk of clinical deterioration and served for risk stratification of PAS-PH.

Managing confounding and effect modification in pediatric/congenital interventional cardiology research

Measuring the effect of a treatment on outcomes is an important goal for research in pediatric/congenital interventional cardiology. The breadth of anatomic and physiologic variations, patient ages, and genetic syndromes and noncardiac comorbid conditions all represent sources of potential confounding and effect modification that are major obstacles to this goal. If not accounted for, these factors can obscure the "true" treatment effect and lead to spurious conclusions about the relative efficacy and/or safety of therapies. In this review, we discuss the importance of confounding and effect modification in pediatric/congenital interventional cardiology research. We define these terms and discuss strategies (both in study design and data analysis) to mitigate error introduced by confounding and effect modification. The importance of confounding by indication in pediatric/congenital cardiology is discussed along with specific methods to address it.

Pediatric/Congenital Cardiac Catheterization Quality: An Analysis of Existing Metrics

OBJECTIVES

The aim of this study was to enumerate and categorize quality metrics relevant to the pediatric/congenital cardiac catheterization laboratory (PCCL).

BACKGROUND

Diagnostic and interventional catheterization procedures are an increasingly important part of the care of young patients with cardiac disease. Measurement of the performance of PCCL programs in a stringent and consistent fashion is a crucial step toward improving outcomes. To the best of our knowledge, a systematic evaluation of current quality metrics in PCCL has not been performed previously.

METHODS

Potential metrics were evaluated by: 1) a systematic review of peer-reviewed research; 2) a review of metrics from organizations interested in quality improvement, patient safety, and/or PCCL programs; and 3) a survey of U.S. PCCL cardiologists. Collected metrics were grouped on 2 dimensions: 1) Institute of Medicine domains; and 2) the Donabedian structure/process/outcome framework. Survey responses were dichotomized between favorable and unfavorable responses and then compared within and between categories.

RESULTS

In the systematic review, 6 metrics were identified (from 9 publications), all focused on safety either as an outcome (adverse events [AEs], mortality, and failure to rescue along with radiation exposure) or as a structure (procedure volume or operator experience). Four organizations measure quality metrics of PCCL programs, of which only 1 publicly reports data. For the survey, 229 cardiologists from 118 hospital programs responded (66% of individuals and 72% of hospital programs). The highest favorable ratings were for safety metrics (p < 0.001), of which major AEs, failure to rescue, and procedure-specific AEs had the highest ratings. Of respondents, 67% stated that current risk adjustment were not effective. Favorability ratings for hospital characteristics, PCCL characteristics, and quality improvement processes were significantly lower than for safety and less consistent within categories.

CONCLUSIONS

There is a limited number of PCCL quality metrics, primarily focused on safety. Confidence in current risk adjustment methodology is low. The knowledge gaps identified should guide future research in the development of new quality metrics.

Transcatheter Intervention for Congenital Defects Involving the Great Vessels: JACC Review Topic of the Week

Since the development of balloon angioplasty and balloon-expandable endovascular stent technology in the 1970s and 1980s, percutaneous transcatheter intervention has emerged as a mainstay of therapy for congenital heart disease (CHD) lesions throughout the systemic and pulmonary vascular beds. Congenital lesions of the great vessels, including the aorta, pulmonary arteries, and patent ductus arteriosus, are each amenable to transcatheter intervention throughout the lifespan, from neonate to adult. In many cases, on-label devices now exist to facilitate these therapies. In this review, we seek to describe the contemporary approach to and outcomes from transcatheter management of major CHD lesions of the great vessels, with a focus on coarctation of the aorta, single- or multiple-branch pulmonary artery stenoses, and persistent patent ductus arteriosus. We further comment on the future of transcatheter therapies for these CHD lesions.

Cutting balloon angioplasty on branch pulmonary artery stenosis in pediatric patients

OBJECTIVES

To identify medium-term results following cutting balloon angioplasty (CBA) for branch pulmonary artery stenosis (PAS) and predictors of successful intervention.

BACKGROUND

CBA has emerged as a successful alternative therapy for PAS resistant to conventional balloon angioplasty techniques but there is little information on medium and long-term outcomes.

METHODS

This is a descriptive, single center, retrospective chart review of pediatric patients who underwent CBA for PAS at Arkansas Children's Hospital between May 2005 and December 2020. We reviewed demographics, procedural specifics, and 30-day complications.

RESULTS

Forty-four patients underwent pulmonary artery CBA on 114 pulmonary artery segments through 126 catheterization cases, totaling 148 CBA events. Thirty-three individual pulmonary arteries underwent repeat intervention. Average minimal luminal diameter increase from pre-CBA to end of follow-up was 57% (CI, 38%-75%). Absence of Tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries (TOF/PA/MAPCAs) and the absence of Alagille Syndrome, Williams Syndrome, or Arterial Tortuosity Syndrome (ATS) were associated with increased odds of sustained success by 70% (CI, 0.11-0.79) and 91% (CI, 0.02-0.56), respectively. Increasing the cutting balloon diameter-to-minimal luminal diameter ratio by 0.5 increased odds of successful intervention by 2.37-fold (CI, 1.7-3.3). Seven patients had 30-day complications including one death.

CONCLUSIONS

In the longest follow-up to date of children and adolescents who underwent CBA for branch PAS, we found that there was moderate medium-term success. Additionally, absence of TOF/PA/MAPCAs, absence of Alagille Syndrome, Williams Syndrome, or ATS, and high cutting balloon diameter-to-minimal luminal diameter ratio are predictors of sustained results.

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.

Modular Catheter Systems in Minimally Invasive Interventional Medical Procedures: Case Study

Background

Medical device catheters that are used in minimally invasive interventional medical procedures all follow the same integrated design and use paradigm. The features and elements of any catheter device are combined in a single unitary construction. A modular approach to the design, construction, and use of these types of interventional catheters may provide significant advantages and benefits not available with an integrated design paradigm.

Objective

This paper aimed to present the design of a modular catheter system and the findings from an initial veterinary use as a case study for the potential of modular catheter systems in general.

Methods

A modular catheter system was designed using commercially available angioplasty balloon dilatation catheters as one module in the system and a custom designed scoring adapter as the other module. The scoring adapter incorporates wires to add scoring features to the angioplasty balloon catheter to improve the dilatation performance during a pulmonary valvuloplasty procedure. The scoring adapter also includes a novel attachment mechanism to couple the scoring adapter to any 0.035-inch guidewire–compatible angioplasty balloon catheter.

Results

The modular catheter system was successfully designed, manufactured, and used in an initial minimally invasive veterinary cardiovascular intervention to treat a case of canine subvalvular pulmonary stenosis. The scoring adapter and angioplasty balloon catheter were successfully combined tableside in the operating room at the time of the procedure and used to successfully dilate the subvalvular obstruction.

Conclusions

The successful design and use of the presented modular catheter system demonstrates the feasibility and potential advantages of this type of paradigm to enable physicians to create interventional catheter devices at the time of a procedure guided by the procedural needs.

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.

Current Status and Future Potential of Transcatheter Interventions in Congenital Heart Disease

Percutaneous therapies for congenital heart disease have evolved rapidly in the past 3 decades. This has occurred despite limited investment from industry and support from regulatory bodies resulting in a lack of specific device development. Indeed, many devices remain off-label with a best-fit approach often required, spurning an innovative culture within the subspecialty, which had arguably laid the foundation for many of the current and evolving structural heart interventions. Challenges remain, not least encouraging device design focused on smaller infants and the inevitable consequences of somatic growth. Data collection tools are emerging but remain behind adult cardiology and cardiac surgery and leading to partial blindness as to the longer-term consequences of our interventions. Tail coating on the back of developments in other fields of adult intervention will soon fail to meet the expanding needs for more precise interventions and biological materials. Increasing collaboration with surgical colleagues will require development of dedicated equipment for hybrid interventions aimed at minimizing the longer-term consequences of scar to the heart. Therefore, great challenges remain to ensure that children and adults with congenital heart disease continue to benefit from an exponential growth in minimally invasive interventions and technology. This can only be achieved through a concerted collaborative approach from physicians, industry, academia, and regulatory bodies supporting great innovators to continue the philosophy of thinking beyond the limits that has been the foundation of our specialty for the past 50 years.

Therapeutic Utilities of Pediatric Cardiac Catheterization

In an era when less invasive techniques are favored, therapeutic cardiac catheterization constantly evolves and widens its spectrum of usage in the pediatric population. The advent of sophisticated devices and well-designed equipment has made the management of many congenital cardiac lesions more efficient and safer, while providing more comfort to the patient. Nowadays, a large variety of heart diseases are managed with transcatheter techniques, such as patent foramen ovale, atrial and ventricular septal defects, valve stenosis, patent ductus arteriosus, aortic coarctation, pulmonary artery and vein stenosis and arteriovenous malformations. Moreover, hybrid procedures and catheter ablation have opened new paths in the treatment of complex cardiac lesions and arrhythmias, respectively. In this article, the main therapeutic utilities of cardiac catheterization in children are discussed.

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.

Balloon Angioplasty for the Treatment of Left Innominate Vein Obstruction Related Chylothorax after Congenital Heart Surgery

OBJECTIVE

Chylothorax complicates the postoperative course of patients after congenital heart surgery. Innominate vein thrombosis and stenosis have been associated with postoperative chylothorax. Revascularization and angioplasty can be accomplished using transcatheter techniques. We report our experience with this procedure for the management of postoperative chylothorax.

DESIGN

This is a retrospective case series of patients who underwent catheter revascularization and/or angioplasty of the innominate vein following cardiac surgery at our institution from January 1, 2008 through April 9, 2014.

SETTING

The cardiovascular intensive care unit and cardiac catheterization laboratory at the University of Alabama at Birmingham and Benjamin Russell Hospital for Children in Birmingham, Alabama were used as settings for the study.

PATIENTS

Out of 112 patients with postoperative chylothorax, 7 (6.3%) underwent transcatheter dilation of the innominate vein for occlusion/stenosis. The median age of the cohort was 1 month (15 days-6 years); median weight was 3 kg (2.7-22.2). Diagnosis was made a median 8 days (2-20) and persisted for a median of 24 days (9-44). Most patients failed medical management (low fat diet, nothing by mouth, and/or octreotide).

RESULTS

Cardiac catheterization occurred at a median 9 days (2-29) after chylothorax diagnosis. Median chest tube output on the day prior to procedure was 63 (12-149) cc/kg/day and decreased to 23 (0-64) cc/kg/day 2 days postprocedure (P = .01). Effusions resolved in a median of 5 days (1-16). There were no clinical complications postcatheterization. All patients who have undergone repeat angiography have maintained patency of the innominate vein. There was no mortality. Complications from chylothorax included prolong hospitalization, hyponatremia, hypoproteinemia, coagulopathy, lymphopenia, and infection.

CONCLUSIONS

Innominate vein occlusion and stenosis associated with chylous effusion are amenable to transcatheter revascularization and/or angioplasty, consistently leading to improvement, if not full resolution of chylothorax.

Iatrogenic left pulmonary artery to left atrium fistula

Trans-catheter balloon angioplasty is a well-established treatment modality for pulmonary artery (PA) stenosis in children with congenital heart disease. We report a case of an unusual complication where a fistula developed between the left PA and the left atrium during balloon angioplasty in a patient with history of tetralogy of Fallot. This was successfully treated with placement of a covered stent.

Impact of Percutaneous Interventions for Pulmonary Artery Stenosis in Alagille Syndrome

OBJECTIVE

The study aims to examine acute and midterm outcomes after percutaneous interventions for treatment of pulmonary artery stenosis (PAS) in patients with Alagille Syndrome (ALGS).

BACKGROUND

PAS affects up to two thirds of ALGS patients. Responsiveness to transcatheter therapies may differ from other causes of PAS. To date, there has been no study to evaluate outcomes of transcatheter interventions on PAS exclusively in ALGS.

METHODS

In this single-center series, we reviewed procedural, hemodynamic, and angiographic data from patients with ALGS and PAS from 2007 to 2011 who underwent an interventional catheterization. Minimal luminal diameter (MLD) was assessed pre- and postintervention, and at follow-up catheterization(s) when available. Acute and midterm response to high-pressure balloon angioplasty (HBA), bare metal stent (BMS) placement, and cutting balloon angioplasty (CBA) were assessed.

RESULTS

Nine patients (median age 9.1 years) underwent 16 cardiac catheterizations with 34 interventions performed (20 HBA, 11 BMS, 3 CBA). There was a significant acute increase in MLD for all three modalities (42% HBA, P < .01; 91% BMS, P < .01; 58% CBA, P = .04). Follow-up data were available for 19 treated lesions at a median of 11 months. There was no significant difference in the improvement of MLD from baseline between the HBA and BMS groups, although in contrast to the BMS group, the HBA group showed continued interval vessel growth.

CONCLUSIONS

Transcatheter intervention for PAS in ALGS is generally safe and acutely effective. Although BMS implantation was associated with the greatest immediate improvement in MLD, HBA-treated vessels demonstrate interval growth, whereas BMS-treated lesions do not.

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.

Outcomes After Primary Transcatheter Therapy in Infants and Young Children With Severe Bilateral Peripheral Pulmonary Artery Stenosis

Background—

Angioplasty and stent implantation have become accepted therapies for isolated peripheral pulmonary stenosis, and have been shown to increase vessel diameter and reduce right ventricular (RV) pressure acutely in patients with pulmonary artery (PA) stenosis. The purpose of this study was to assess long-term outcomes after primary transcatheter therapy for peripheral pulmonary stenosis.

Methods and Results—

We studied 69 patients who underwent primary transcatheter intervention for severe isolated peripheral pulmonary stenosis at ≤5 years of age. Genetic/syndromic diagnoses included Williams syndrome (n=23), non-Williams familial arteriopathy (n=12), and Alagille syndrome (n=3). At the initial PA intervention, median RV:aortic pressure ratio decreased from 1.00 to 0.88 (median decrease, 0.18; P <0.001). Patients with a higher preintervention RV:aortic pressure ratio had a greater reduction ( P <0.001). During follow-up (median, 8.5 years), 10 patients died, 5 from complications of PA catheterization (all before 1998). Thirteen patients underwent surgical PA intervention, most within 1 year and along with repair of supravalvar aortic stenosis. Freedom from any PA reintervention was 38±6% at 1 year and 22±6% at 5 years. The median RV:aortic pressure ratio decreased from 1.0 at baseline to 0.53 at the most recent catheterization ( P <0.001), and 82% of patients with available clinical follow-up were asymptomatic.

Conclusions—

Transcatheter therapy for infants with severe peripheral pulmonary stenosis has become safer, regardless of genetic condition. Coupled with reintervention and surgical relief in selected cases, RV:aortic pressure ratios decrease substantially and most patients are asymptomatic at late follow-up.

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.

The FDA Review Process for Cardiac Medical Devices in Children: A Review for the Clinician

Pediatric medical devices play a vital role in the treatment of children with cardiovascular disease. Most cardiac medical devices used in children today are used off-label where the risk-benefit of devices has not been well characterized. Pediatric medical devices face a variety of challenges to FDA approval related in large part to the small target population, heterogeneity of the patient population and ethical considerations of device testing in children. While relatively few cardiac devices have received FDA approval in children, the number of devices navigating the approval process successfully is growing. Most pediatric device approvals are being granted through the humanitarian device exemption (HDE) pathway, which is designed for rare diseases making it suitable for devices treating congenital heart disease. This review summarizes the FDA review process for pediatric medical devices as it continues to evolve in response to the unique challenges of understanding device performance in the pediatric population.