Echocardiogram-Guided Balloon Valvuloplasty of the Aortic Valve in Neonates and Infants Reduces Contrast Exposure with Maintained Efficacy and Less Aortic Regurgitation.

Balloon aortic valvuloplasty (BAV) is performed in children with significant aortic stenosis (AS). Traditionally, contrast angiography measures the annulus and assesses aortic regurgitation (AR) after each dilation. Echocardiographic guidance is hypothesized to reduce contrast and radiation exposure, without compromising efficacy or safety. Patients < 10 kg undergoing BAV from 2013 to 2022 were retrospectively investigated. Agreement between echocardiographic and angiographic annulus measurements was assessed. Echocardiogram-guided (eBAV) and traditional angiogram-guided (tBAV) outcomes were compared controlling for weight, critical AS, and other congenital heart disease (CHD). Twelve eBAV and 19 tBAV procedures were performed. The median age was 33 days, median weight was 4.3 kg, 7 patients (23%) had critical AS, and 9 patients (29%) had other CHD. Annulus measurements by intraprocedural echocardiography and angiography displayed excellent correlation (ICC 0.95, p < 0.001). eBAV patients received less contrast (0.5 vs 3.5 ml/kg, p < 0.01). Five recent eBAV procedures were performed contrast free. Radiation exposure was not statistically different between the eBAV and tBAV groups (155 vs 313 µGy·M2, p = 0.12). One eBAV patient (8%) and 3 tBAV patients (16%, p = 0.62) experienced serious adverse events. Technical success (gradient < 35 mmHg and increase in AR by ≤ 1 grade) occurred in 11 eBAV patients (92%) and 16 tBAV patients (84%, p = 0.22). AR increased in 2 eBAV patients (17%) and 8 tBAV patients (44%, p = 0.02). eBAV was associated with similar efficacy and significantly lower contrast exposure and risk of aortic regurgitation. There was strong agreement between aortic valve annulus measurements by intraprocedural echocardiography and angiography, ultimately permitting contrast free BAV.

Left Atrial Hypertension and Respiratory Failure Requiring Venoarterial ECMO After Transcatheter Pulmonary Valve Replacement.

A 33-year-old woman with aortic valve stenosis status-post Ross at age 6 years developed symptomatic right heart failure from right ventricle to pulmonary artery conduit stenosis. Conduit rehabilitation and transcatheter pulmonary valve replacement resulted in acute left atrial hypertension and respiratory failure requiring venoarterial extracorporeal membrane oxygenation and atrial septal defect creation as a bridge to recovery.

Combined Echo and Fluoroscopy-Guided Pulmonary Valvuloplasty in Neonates and Infants: Efficacy and Safety.

Percutaneous balloon pulmonary valvuloplasty (PBPV) is the treatment of choice for isolated pulmonary valve stenosis. While this procedure is highly efficacious and has an excellent safety profile, as currently practiced, patients are obligatorily exposed to the secondary risks of ionizing radiation and contrast media. To mitigate these risks, we developed a protocol which utilized echo guidance for portions of the procedure which typically require fluoroscopy and/or angiography. Ten cases of echo-guided pulmonary valvuloplasty (EG-PBPV) for isolated pulmonary stenosis in children less than a year of age were compared to a historical cohort of nineteen standard cases using fluoroscopy/angiography alone, which demonstrated equivalent procedural outcomes and safety, while achieving a median reduction in radiation (total dose area product) and contrast load of 80% and 84%, respectively. Our early experience demonstrates that EG-PBPV in neonates and infants has results equivalent to standard valvuloplasty but with less radiation and contrast.

Anatomical Classification and Posttreatment Remodeling Characteristics to Guide Management and Follow-Up of Neonates and Infants With Coronary Artery Fistula: A Multicenter Study From the Coronary Artery Fistula Registry.

BACKGROUND: Coronary artery fistulas (CAFs) presenting in infancy are rare, and data regarding postclosure sequelae and follow-up are limited. METHODS: A retrospective review of all the neonates and infants (<1 year) was conducted from the CAF registry for CAF treatment. The CAF type (proximal or distal), size, treatment method, and follow-up angiography were reviewed to assess outcomes and coronary remodeling. RESULTS: Forty-eight patients were included from 20 centers. Of these, 30 were proximal and 18 had distal CAF; 39 were large, 7 medium, and 2 had small CAF. The median age and weight was 0.16 years (0.01-1) and 4.2 kg (1.7-10.6). Heart failure was noted in 28 of 48 (58%) patients. Transcatheter closure was performed in 24, surgical closure in 18, and 6 were observed medically. Procedural success was 92% and 94 % for transcatheter closure and surgical closure, respectively. Follow-up data were obtained in 34 of 48 (70%) at a median of 2.9 (0.1-18) years. Angiography to assess remodeling was available in 20 of 48 (41%). I. Optimal remodeling (n=10, 7 proximal and 3 distal CAF). II. Suboptimal remodeling (n=7) included (A) symptomatic coronary thrombosis (n=2, distal CAF), (B) asymptomatic coronary thrombosis (n=3, 1 proximal and 2 distal CAF), and (C) partial thrombosis with residual cul-de-sac (n=1, proximal CAF) and vessel irregularity with stenosis (n=1, distal CAF). Finally, (III) persistent coronary artery dilation (n=4). Antiplatelets and anticoagulation were used in 31 and 7 patients post-closure, respectively. Overall, 7 of 10 (70%) with proximal CAF had optimal remodeling, but 5 of 11 (45%) with distal CAF had suboptimal remodeling. Only 1 of 7 patients with suboptimal remodeling were on anticoagulation. CONCLUSIONS: Neonates/infants with hemodynamically significant CAF can be treated by transcatheter or surgical closure with excellent procedural success. Patients with distal CAF are at higher risk for suboptimal remodeling. Postclosure anticoagulation and follow-up coronary anatomic evaluation are warranted.

Pre-procedural CT imaging aids neonatal PDA stenting for ductal-dependent pulmonary blood flow with reduction in overall procedural morbidity.

Patent ductus arteriosus stenting for ductal-dependent pulmonary blood flow is a technically challenging neonatal procedure to maintain a stable pulmonary circulation. Pre-procedural computed tomography imaging aids in outlining ductal origin, insertion, size, course and curvature. Computed tomography imaging may add value to procedural outcomes and reduce overall procedural morbidity in neonatal patent ductus arteriosus stenting. We conducted a single centre retrospective chart review of neonates with ductal-dependent pulmonary blood flow who underwent patent ductus arteriosus stenting between January 1, 2014 and June 31, 2020. We compared patients variables between patients who underwent pre-procedural computed tomography imaging to those who did not. A total of 64 patients were referred for patent ductus arteriosus stenting with 33 (52%) obtaining pre-procedural computed tomography imaging. Average age [19 days; range 1-242 days (p = 0.85)] and weight [3.3 kg (range 2.2-6.0 kg; p = 0.19)] was not significantly different between the groups. A diagnosis of pulmonary atresia was made in 42 out of 64 (66%) patients prior to patent ductus arteriosus stenting. The cohort with pre-intervention computed tomography imaging had a significant reduction in the total number of access sites (1.2 versus 1.5; p = 0.03), contrast needed (5.9 versus 8.2 ml/kg; p = 0.008), fluoroscopy (20.7 versus 38.8 minutes; p = 0.02) and procedural time (83.4-128.4 minutes; p = 0.002) for the intervention. There was no significant difference in radiation burden between the groups (p = 0.35). Pre-procedural computed tomography imaging adds value by aiding interventional planning for neonatal patent ductus arteriosus stenting. A statistically significant reduction in the number of access sites, contrast exposure, as well as fluoroscopic and procedural time was noted without significantly increasing the cumulative radiation burden.

Deployed Dimensions of the GORE® CARDIOFORM ASD Occluder as Function of Defect Size.

The GORE® CARDIOFORM ASD occluder (ASDO) is approved for closure of ASDs up to 35 mm diameter. With an adaptable central waist, each device size is suitable over a range of defect diameters. Understanding deployed dimensions across various defect sizes will assist operators. Therefore, this study investigates the deployed dimensions of the ASDO as a function of defect size. A 2-mm-thick ASD model with circular defects ranging from 5 to 35 mm was 3D printed. Diameter, width, and left-right disc diameter were measured by fluoroscopy after ASDO devices were deployed in applicable defects. Linear regression evaluated relationships between device size, defect size, and deployed dimensions. Six ASDOs of each size (27, 32, 37, 44, and 48 mm) were deployed in all applicable defects. There was significant ASDO size-defect size interaction in determining deployed ASDO diameter. Diameter was positively associated with defect size for 48-mm (B = 0.13, p < 0.001) and 44-mm (B = 0.11, p < 0.001) ASDOs, while no association was seen for 27-mm, 32-mm, or 37-mm ASDOs. No such interaction existed for deployed width or left-right disc difference. Controlling for ASDO size, width (B = - 0.12, p < 0.001) and left-right disc difference (B = - 0.06, p < 0.001) were negatively associated with defect size. In smaller defects, the 44-mm and 48-mm ASDOs display progressive diameter foreshortening, and all devices display progressive increase in width and left-right disc asymmetry. Anticipating the degree of diameter foreshortening may be critical when attempting closure of fenestrated lesions and/or in patients with limited total atrial septal length.

3D advanced imaging overlay with rapid registration in CHD to reduce radiation and assist cardiac catheterisation interventions.

Novel commercially available software has enabled registration of both CT and MRI images to rapidly fuse with X-ray fluoroscopic imaging. We describe our initial experience performing cardiac catheterisations with the guidance of 3D imaging overlay using the VesselNavigator system (Philips Healthcare, Best, NL). A total of 33 patients with CHD were included in our study. Demographic, advanced imaging, and catheterisation data were collected between 1 December, 2016 and 31 January, 2019. We report successful use of this technology in both diagnostic and interventional cases such as placing stents and percutaneous valves, performing angioplasties, occlusion of collaterals, and guidance for lymphatic interventions. In addition, radiation exposure was markedly decreased when comparing our 10-15-year-old coarctation of the aorta stent angioplasty cohort to cases without the use of overlay technology and the most recently published national radiation dose benchmarks. No complications were encountered due to the application of overlay technology. 3D CT or MRI overlay for CHD intervention with rapid registration is feasible and aids decisions regarding access and planned angiographic angles. Operators found intraprocedural overlay fusion registration using placed vessel guidewires to be more accurate than attempts using bony structures.

Invasive cardiovascular magnetic resonance (iCMR) for diagnostic right and left heart catheterization using an MR-conditional guidewire and passive visualization in congenital heart disease.

BACKGROUND: Today's standard of care, in the congenital heart disease (CHD) population, involves performing cardiac catheterization under x-ray fluoroscopy and cardiac magnetic resonance (CMR) imaging separately. The unique ability of CMR to provide real-time functional imaging in multiple views without ionizing radiation exposure has the potential to be a powerful tool for diagnostic and interventional procedures. Limiting fluoroscopic radiation exposure remains a challenge for pediatric interventional cardiologists. This pilot study's objective is to establish feasibility of right (RHC) and left heart catheterization (LHC) during invasive CMR (iCMR) procedures at our institution in the CHD population. Furthermore, we aim to improve simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures. METHODS: Subjects with CHD were enrolled in a pilot study for iCMR procedures at 1.5 T with an MR-conditional guidewire. The CMR area is located adjacent to a standard catheterization laboratory. Using the interactive scanning mode for real-time control of the imaging location, a dilute gadolinium-filled balloon-tip catheter was used in combination with an MR-conditional guidewire to obtain cardiac saturations and hemodynamics. A recently developed catheter tracking technique using a real-time single-shot balanced steady-state free precession (bSSFP), flip angle (FA) 35-45°, echo time (TE) 1.3 ms, repetition time (TR) 2.7 ms, 40° partial saturation (pSAT) pre-pulse was used to visualize the gadolinium-filled balloon, MR-conditional guidewire, and cardiac structures simultaneously. MR-conditional guidewire visualization was enabled due to susceptibility artifact created by distal markers. Pre-clinical phantom testing was performed to determine the optimum imaging FA-pSAT combination. RESULTS: The iCMR procedure was successfully performed to completion in 31/34 (91%) subjects between August 1st, 2017 to December 13th, 2018. Median age and weight were 7.7 years and 25.2 kg (range: 3 months - 33 years and 8 - 80 kg). Twenty-one subjects had single ventricle (SV) anatomy: one subject was referred for pre-Glenn evaluation, 11 were pre-Fontan evaluations and 9 post-Fontan evaluations for protein losing enteropathy (PLE) and/or cyanosis. Thirteen subjects had bi-ventricular (BiV) anatomy, 4 were referred for coarctation of the aorta (CoA) evaluations, 3 underwent vaso-reactivity testing with inhaled nitric oxide, 3 investigated RV volume dimensions, two underwent branch PA stenosis evaluation, and the remaining subject was status post heart transplant. No catheter related complications were encountered. Average time taken for first pass RHC, LHC/aortic pull back, and to cross the Fontan fenestration was 5.2, 3.0, and 6.5 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 331/337 (98%). Subjects were transferred to the x-ray fluoroscopy lab if further intervention was required including Fontan fenestration device closure, balloon angioplasty of pulmonary arteries/conduits, CoA stenting, and/or coiling of aortopulmonary (AP) collaterals. Starting with subject #10, an MR-conditional guidewire was used in all subsequent subjects (15 SV and 10 BiV) with a success rate of 96% (24/25). Real-time CMR-guided RHC (25/25 subjects, 100%), retrograde and prograde LHC/aortic pull back (24/25 subjects, 96%), CoA crossing (3/4 subjects, 75%) and Fontan fenestration test occlusion (2/3 subjects, 67%) were successfully performed in the majority of subjects when an MR-conditional guidewire was utilized. CONCLUSION: Feasibility for detailed diagnostic RHC, LHC, and Fontan fenestration test occlusion iCMR procedures in SV and BiV pediatric subjects with complex CHD is demonstrated with the aid of an MR-conditional guidewire. A novel real-time pSAT GRE sequence with optimized FA-pSAT angle has facilitated simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.

Supra-Annular Mitral Implantation of Melody Valve: Minimizing Left Ventricular Outflow Tract Obstruction.

Utilization of the Melody valve for mitral valve replacement has been previously reported; however, left ventricular outflow tract obstruction is a frequent concern. In this report, a technique for supra-annular placement of the Melody valve in the mitral position is described which will minimize the risk of left ventricular outflow tract obstruction.

Biodegradable Stents for Congenital Heart Disease.

The quest for an ideal biodegradable stent for both adult coronary and pediatric congenital heart disease applications continues. Over the past few years, a lot of progress has been made toward development of a dedicated pediatric biodegradable stent that can be used for congenital heart disease applications. At present, there are no biodegradable stents available for use in congenital heart disease. In this article, the authors review the different biodegradable materials and their limitations and provide an overview of the current biodegradable stents being evaluated for congenital heart disease applications.

Long-Term Outcomes of Hypertrophic Cardiomyopathy Diagnosed During Childhood: Results From a National Population-Based Study.

BACKGROUND: Late survival and symptomatic status of children with hypertrophic cardiomyopathy have not been well defined. We examined long-term outcomes for pediatric hypertrophic cardiomyopathy. METHODS: The National Australian Childhood Cardiomyopathy Study is a longitudinal population-based cohort study of children (0-10 years of age) diagnosed with cardiomyopathy between 1987 and 1996. The primary study end point was time to death or cardiac transplantation. RESULTS: There were 80 patients with hypertrophic cardiomyopathy, with a median age at diagnosis of 0.48 (interquartile range, 0.1, 2.5) years. Freedom from death/transplantation was 86% (95% confidence interval [CI], 77.0-92.0) 1 year after presentation, 80% (95% CI, 69.0-87.0) at 10 years, and 78% (95% CI, 67.0-86.0) at 20 years. From multivariable analyses, risk factors for death/transplantation included symmetrical left ventricular hypertrophy at the time of diagnosis (hazard ratio, 4.20; 95% CI, 1.60-11.05; P=0.004), Noonan syndrome (hazard ratio, 2.88; 95% CI, 1.02-8.08; P=0.045), higher posterior wall thickness z score (hazard ratio, 1.45; 95% CI, 1.22-1.73; P<0.001), and lower fractional shortening z score (hazard ratio, 0.84; 95% CI, 0.74-0.95; P=0.005) during follow-up. Nineteen (23%) subjects underwent left ventricular myectomy. At a median of 15.7 years of follow-up, 27 (42%) of 63 survivors were treated with ß-blocker, and 13 (21%) had an implantable cardioverter-defibrillator. CONCLUSIONS: The highest risk of death or transplantation for children with hypertrophic cardiomyopathy is within 1 year after diagnosis, with low attrition rates thereafter. Many subjects receive medical, surgical, or device therapy.

Long-Term Outcomes of Childhood Left Ventricular Noncompaction Cardiomyopathy: Results From a National Population-Based Study.

BACKGROUND: Long-term outcomes for childhood left ventricular noncompaction (LVNC) are uncertain. We examined late outcomes for children with LVNC enrolled in a national population-based study. METHODS: The National Australian Childhood Cardiomyopathy Study includes all children in Australia with primary cardiomyopathy diagnosed before 10 years of age between 1987 and 1996. Outcomes for subjects with LVNC with a dilated phenotype (LVNC-D) were compared with outcomes for those with dilated cardiomyopathy. Propensity-score analysis was used for risk factor adjustment. RESULTS: There were 29 subjects with LVNC (9.2% of all cardiomyopathy subjects), with a mean annual incidence of newly diagnosed cases of 0.11 per 100 000 at-risk individuals. Congestive heart failure was the initial symptom in 24 of 29 subjects (83%), and 27 (93%) had LVNC-D. The median age at diagnosis was 0.3 (interquartile interval, 0.08-1.3) years. The median duration of follow-up was 6.8 (interquartile interval, 0.7-24.0) years for all subjects and 24.7 (interquartile interval, 23.3 - 27.7) years for surviving subjects. Freedom from death or transplantation was 48% (95% confidence interval [CI], 30-65) at 10 years after diagnosis and 45% (95% CI, 27-63) at 15 years. In competing-risk analysis, 21% of subjects with LVNC were alive with normal left ventricular systolic function, and 31% were alive with abnormal function at 15 years. Propensity-score matching between subjects with LVNC-D and those with dilated cardiomyopathy suggested a lower freedom from death/transplantation at 15 years after diagnosis in the subjects with LVNC-D (LVNC-D, 46% [95% CI, 26-66] versus dilated cardiomyopathy, 70% [95% CI, 42-97]; P=0.08). Using propensity-score inverse probability of treatment-weighted Cox regression, we found evidence that LVNC-D was associated with a greater risk of death or transplantation (hazard ratio, 2.3; 95% CI, 1.4-3.8; P=0.0012). CONCLUSIONS: Symptomatic children with LVNC usually present in early infancy with a predominant dilated phenotype. Long-term outcomes are worse than for matched children with dilated cardiomyopathy.

Mechanical and microstructural analysis of a radially expandable vascular conduit for neonatal and pediatric cardiovascular surgery.

In pediatric cardiovascular surgery, there is a significant need for vascular prostheses that have the potential to grow with the patient following implantation. Current clinical options consist of nonexpanding conduits, requiring repeat surgeries as the patient outgrows the device. To address this issue, PECA Labs has developed a novel ePTFE vascular conduit with the capability of being radially expanded via balloon catheterization. In the described study, a systematic characterization and comparison of two proprietary ePTFE expandable conduits was conducted. Conduit sizes of 8 and 16 mm inner diameters for both conduits were evaluated before and after expansion with a 26 mm balloon. Comprehensive mechanical testing was completed, including quantification of circumferential, and longitudinal tensile strength, suture retention strength, burst strength, water entry pressure, dynamic compliance, and kink radius. Scanning electron microscopy was used to investigate the microstructural properties. Automated extraction of the fiber architectural features for each scanning electron micrograph was achieved with an algorithm for each conduit before and after expansion. Results showed that both conduits were able to expand significantly, to as much as 2.5× their original inner diameter. All mechanical properties were within clinically acceptable values following expansion. Analysis of the microstructure properties of the conduits revealed that the circumferential main angle of orientation, orientation index, and spatial periodicity did not significantly change following expansion, whereas the node area fraction decreased post expansion. Successful proof-of-concept of this novel product represents a critical step toward clinical translation and provides hope for newborns and growing children with congenital heart disease. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 659-671, 2018.

Invasive Hemodynamics of Adult Congenital Heart Disease: From Shunts to Coarctation.

Adults with congenital heart disease are a growing population with increasingly more complex disease, in large part due to improvements in delivery of care to the pediatric population. Cardiac catheterization is an integral component of diagnosis and management in these patients. Careful attention to detail and a thorough understanding of intracardiac hemodynamics are critical to performing complete diagnostic evaluations. This article outlines the most commonly encountered lesions with guidelines for invasive assessment to help guide further therapy.

Bench and initial preclinical results of a novel 8 mm diameter double opposed helical biodegradable stent.

BACKGROUND: Metallic endovascular stents are utilized off-label in congenital heart disease. Biodegradable stents (BDS) offer potential advantages in a growing child. We have previously reported double opposed helical (DH) BDS up to 6 mm diameter (DH-6). The objectives are to investigate the bench characteristics of larger 8 mm diameter BDS (DH-8) manufactured with increasing strut thicknesses and the inflammatory profile in a porcine model. METHODS: DH-8 were manufactured with strut thicknesses 0.10, 0.12, and 0.18 mm and mechanical testing performed. Stents were deployed into the infrarenal descending aorta (DAO) of nine minipigs. At insertion (nonsurvival = 2), 1 week (n = 2), 1 month (n = 2), and 9 months (n = 3) follow-up angiography, intravascular ultrasound and histopathology were performed. RESULTS: There was superior recoil and collapse pressure with increasing strut thickness, with 0.18 mm having 1.0% elastic recoil and collapse pressure 0.75 Atmospheres. There was good wall apposition at insertion with 5 BDS (4 DH-8 and 1 DH-6) but suboptimal in 4 as the minipigs infrarenal DAO were >8 mm (deployed at iliac bifurcation). Structural integrity was maintained in 8 BDS with 1 DH-8 collapsed at 9 months, secondary to strut damage at insertion. No thrombosis was seen. There was mild inflammation and neointimal proliferation at 1 week and 1 month, but a moderate inflammatory response at 9 months. CONCLUSIONS: DH-8 with increased strut thickness had acceptable mechanical properties at the cost of an increased inflammatory response. Miniaturization to improve delivery and further investigation on the long-term inflammatory profile of thicker struts, including through degradation, is needed. © 2016 Wiley Periodicals, Inc.

Sudden death in childhood cardiomyopathy: results from a long-term national population-based study.

BACKGROUND: Children with cardiomyopathy (CM) are at risk of sudden cardiac death (SCD), but the incidence and risk factors for this outcome are not clear. OBJECTIVES: This study sought to determine the incidence and risk factors for SCD in children with varying CM phenotypes from a long-term population-based study of childhood CM. METHODS: The NACCS (National Australian Childhood Cardiomyopathy Study) is an ongoing longitudinal cohort study including all children in Australia with primary CM who were diagnosed between January 1, 1987, and December 31, 1996, and were <10 years of age. The cumulative incidence and risk factors for SCD within individual CM phenotypes were explored using survival analysis. RESULTS: Of 289 eligible patients, 16 (5.5%) experienced SCD over a median follow-up of 11.9 years (interquartile range: 1.7 to 15.4). The risk of SCD varied according to CM phenotype (p=0.007). The cumulative incidence of SCD at 15 years was 5% for dilated cardiomyopathy (DCM), 6% for hypertrophic cardiomyopathy (HCM), 12% for restrictive cardiomyopathy, and 23% for left ventricular (LV) noncompaction. Older age at diagnosis, positive family history of CM, and severity of LV dysfunction were related to increased risk of SCD in patients with DCM, and a higher posterior wall thickness Z-score was the sole risk factor identified for patients with HCM. CONCLUSIONS: Predictors of SCD include CM phenotype, family history of CM (DCM), severity of systolic dysfunction (DCM), and extent of LV hypertrophy (HCM). Continuing follow-up of this cohort into adulthood is likely to reveal an ongoing risk of SCD.

Transcatheter removal of atrial septal stent placed to decompress left atrium with VA ECMO.

Left atrial (LA) decompression in infants with thick atrial septum placed on veno-arterial extracorporeal membrane oxygenation (ECMO) can be reliably achieved with transcatheter atrial septal (AS) stent placement. However, with myocardial recovery and ECMO decannulation the stent causes a permanent left to right shunt and surgical removal of the AS stent is usually accomplished. Transcatheter removal of AS stent is an attractive option as the advantages of LA decompression would then be coupled with the advantage of avoiding a sternotomy for surgical removal of the stent. To our knowledge, this is the first reported case of successful transcatheter retrieval of AS stent used for LA decompression in a 13-month-old child.

A novel design biodegradable stent for use in congenital heart disease: mid-term results in rabbit descending aorta.

OBJECTIVES: This study evaluates the feasibility of delivery and deployment of low and medium molecular weight (LMW and MMW, respectively) double-opposing helical (DH) poly-l-lactic acid biodegradable stent (BDS) in rabbit descending aorta (DAO). Secondary objectives were to assess patency and inflammation of stented vessels at 9 months and to investigate safety following intentional embolization of stent fragments in DAO. BACKGROUND: A BDS that will relieve aortic obstruction and disappears as the child grows older allowing for preservation of aortic wall elasticity and natural growth of aorta will be ideal to treat Coarctation (CoA). BDS have never been evaluated in the DAO. METHODS: Seven New Zealand white rabbits underwent implantation of DH-LMW (n = 7), DH-MMW (n = 3), and metal stents (n = 7) in DAO. BDS fragments were intentionally embolized into DAO in two rabbits. RESULTS: All stents were deployed via a 6-French sheath. Five BDS covered the origin of major DAO side branches. Angiography and intravascular ultrasound showed good stent apposition to the wall of DAO with minimal luminal loss at 9 months follow-up. All stents had minimal neointimal hyperplasia on histopathology. Adverse events included 1 death, 1 aortic aneurysm, and lower extremity ulceration due to self-mutilation in an embolization rabbit. CONCLUSIONS: Pilot study confirms the feasibility of delivery and deployment of up to 6-millimeter diameter DH BDS in rabbit DAO. Stent integrity with DH design was maintained at 9 months with minimal vessel inflammation. Potential morbidity due to embolized BD fragments cannot be ruled out and needs further evaluation.

A novel biodegradable stent applicable for use in congenital heart disease: bench testing and feasibility results in a rabbit model.

OBJECTIVES: A novel double opposed helical (DH) biodegradable stent was designed and fabricated for CHD applications. The primary objective was to evaluate the feasibility of DH stent delivery and deployment in rabbit external iliac arteries (EIA). Secondary objectives were to assess stent patency, thrombosis and inflammation at 1-week and 1-month follow-up. BACKGROUND: Biodegradable stents have largely been designed for adult cardiovascular indications, to avoid long term complications of permanent implants. A growing child with congenital heart disease (CHD) would especially derive substantial benefit from this technology. METHODS: DH stents were manufactured to 3, 4, 5, and 6-mm diameter with poly-l-lactic acid (PLLA) fibers. Bench test analysis was performed. Six DH stents were implanted in rabbit EIA. Vessel patency was assessed at 1-week and 1-month follow-up with repeat angiography, intravascular ultrasound (IVUS). Histopathological evaluation was performed. RESULTS: The elastic recoil and collapse pressure of DH stents were comparable to conventional metal stents. All DH stents were successfully delivered and implanted with good apposition to the vessel wall and no collapse of the proximal, mid or distal ends. All stented vessels remained patent. No acute or early stent thrombosis was noted. Histopathology showed minimal inflammatory response and mild neointimal proliferation at 1 month follow-up. CONCLUSIONS: In vitro results of DH PLLA biodegradable stents are comparable to conventional metal stents. The pilot animal study confirms the delivery and deployment of the DH stents to the desired location. The DH design can be used to fabricate larger diameter stents needed for CHD.