Strategies and techniques for percutaneous Veno-Arterial ECMO cannulation and decannulation in children.

OBJECTIVES: To describe the techniques used for percutaneous veno-arterial extracorporeal membrane oxygenation (VA-ECMO) cannulation and decannulation in children with the pediatric interventional cardiologist (PIC) as the primary operator, and present outcomes of this initial clinical experience. BACKGROUND: Percutaneous VA-ECMO during cardiopulmonary resuscitation (CPR) has been successfully performed in adults, but currently, not much data exists on children. METHODS: This is a single-center study including VA-ECMO cannulations performed by the PIC between 2019 and 2021. Efficacy was defined as the successful initiation of VA-ECMO without surgical cutdown. Safety was defined as the absence of additional procedures related to cannulation. RESULTS: Twenty-three percutaneous VA-ECMO cannulations were performed by PIC on 20 children with 100% success. Fourteen (61%) were performed during ongoing CPR, and nine for cardiogenic shock. The Median age was 15 (0.15-18) years, and the median weight was 65 (3.3-180) kg. All arterial cannulations were via the femoral artery except in one, 8-week-old infant who was cannulated in the carotid artery. A distal perfusion cannula was placed in the ipsilateral limb in 17 (78%). The median time from initiating cannulation to ECMO flow was 35 (13-112) minutes. Two patients required arterial graft placement at the time of decannulation and one needed below-knee amputation. ECMO support was maintained for a median of 4 (0.3-38) days. Thirty-day survival was 74%. CONCLUSION: Percutaneous VA-ECMO cannulations can be effectively performed, even during CPR with the Pediatric Interventional Cardiologist being the primary operator. This is an initial clinical experience. Future outcome studies compared with standard surgical cannulations are necessary to advocate routine percutaneous VA-ECMO in children.

Feasibility and Safety of Percutaneous Cardiac Interventions for Congenital and Acquired Heart Defects in Infants ≤1000 g.

The transcatheter closure of patent ductus arteriosus (TCPC) has been demonstrated to be feasible even in infants weighing ≤1000 g. However, other percutaneous cardiac interventions (PCI) for such small infants born with congenital heart defects (CHD) or acquired heart defects (AHD) have not been well described. The purpose of this study was to describe the feasibility and safety of PCI in infants ≤1000 g. A retrospective review was conducted between June 2015 and May 2021, looking at 148 consecutive PCIs performed on infants weighing ≤1000 g at the time of the procedure. The procedural success rate was 100%. The major adverse event (AE) rate for TCPC was 3%, while there were no major AEs for other PCI. It is feasible to perform PCIs in infants weighing ≤1000 g with CHD and AHD using currently available technologies.

Echocardiographic versus Angiographic Measurement of the Patent Ductus Arteriosus in Extremely Low Birth Weight Infants and the Utility of Echo Guidance for Transcatheter Closure.

BACKGROUND: Transthoracic echocardiography (TTE) is increasingly utilized for guiding transcatheter closure of patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants. The objectives of this study were to compare PDA size measurements by TTE with angiographic measurements and to describe TTE techniques used in guiding transcatheter PDA closure (TCPC) in ELBW infants. METHODS: One hundred twenty-five consecutive ELBW infants (gestational age < 27 weeks, birth weight < 1 kg) who underwent TCPC before 8 weeks of age under TTE guidance were included. Patent ductus arteriosus sizes were measured from the procedural TTE and angiograms retrospectively by blinded observers. The TTE PDA diameters at the aortic (ED1) and pulmonary end (ED2) were compared with the corresponding angiographic diameters (CD1 and CD2). The TTE PDA lengths, obtained by two techniques (EL1, a straight line between ED1 and ED2; and EL2, a curvilinear line along the PDA), were compared with the PDA length by angiography (CL). Transthoracic echocardiography was used to guide accurate device positioning within the PDA. RESULTS: The procedure weight was 600-1,460 g. The TTE and angiographic PDA diameters were comparable (mean ED1 vs CD1 = 4.5 ± 0.68 vs 4.4 ± 0.85 mm, P = .26; and mean ED2 vs CD2 = 3.1 ± 0.72 vs 3.2 ± 0.94 mm, P = .14). The angiographic length was underestimated by EL1 by 2.6 ± 1.6 mm (P < .0001), while EL2 estimated it better (mean EL2 vs CL = 11.0 ± 1.83 vs 10.8 ± 2.15 mm; P = .40). Transcatheter PDA closure was successful in 100% of the cases using TTE guidance. There were no intraprocedural complications. CONCLUSIONS: Transthoracic echocardiography guidance during TCPC in ELBW infants eliminates the need for aortograms via femoral arterial access, preventing the complications associated with it. Transthoracic echocardiography PDA measurements are comparable to angiographic measurements, thereby assisting in appropriate device size selection.

Percutaneous Stage 1 Palliation for Hypoplastic Left Heart Syndrome.

Surgical palliation for hypoplastic left heart syndrome still carries significant morbidity and mortality in neonates. We previously described a percutaneous stage 1 palliation (PS1P) in a swine experiment. Here we report the human application of the PS1P for hypoplastic left heart syndrome in the United States. The procedure is performed through a 4F sheath in the femoral vein. Bilateral pulmonary flow restrictors are implanted in the proximal branch pulmonary arteries and a stent within the ductus arteriosus. PS1P could postpone surgical repair beyond the neonatal period. It offers a simple, less invasive alternative to currently available operations for newborns with HLHS.

Hemodynamic and clinical consequences of early versus delayed closure of patent ductus arteriosus in extremely low birth weight infants.

OBJECTIVES: To describe changes in hemodynamics, respiratory support, and growth associated with transcatheter PDA closure (TCPC) in ELBW infants, stratified by postnatal age at treatment. STUDY DESIGN: This is an observational study of ELBW infants who underwent TCPC at ≤4 weeks (Group-1; n = 34), 4-8 weeks (Group-2; n = 33), and >8 weeks of age (Group-3; n = 33). Hemodynamic assessment was performed during TCPC. Multivariate Cox-proportionate-hazard modeling was used to identify factors associated with respiratory severity score (RSS) > 2 for >30 days following TCPC. RESULTS: In comparison with Group-1, Group-3 infants had higher pulmonary vascular resistance (PVRi = 3.3 vs. 1.6 WU*m2; P = 0.01), less weight gain between 4 and 8 weeks of age (16 vs. 25 g/day) and took longer to achieve RSS < 2 (median 81 vs. 20 days; P = 0.001). RSS > 2 for >30 days was associated with TCPC > 8 weeks (OR = 3.2, 95% CI: 1.75-5.8; p = 0.03) and PVRi ≥ 3 (OR = 4.5, 95% CI: 2.7-8.9; p < 0.01). CONCLUSION: ELBW infants may benefit from PDA closure within the first 4 weeks of life in order to prevent early onset pulmonary vascular disease, promote faster growth, and for quicker weaning of ventilator and oxygen support.

Construction of Femoral Vessel Nomograms for Planning Cardiac Interventional Procedures in Children 0-4 Years Old.

The objectives of this study were to construct femoral artery (FA) and femoral vein (FV) nomograms in children aged 0-4 years and to construct probability curves for the occurrence of arterial access complications based on the size of the FA. The FV and FA are commonly accessed during cardiac catheterizations in children with congenital heart diseases (CHD). However, nomograms for vessel dimensions based on child's age or size are not available. This knowledge may be helpful for interventional planning. A prospective study was performed on 400 children (age 0-4 years) with CHD undergoing cardiac catheterizations over a 3-year period. Ultrasound evaluation of the right and left FA and FV was performed under anesthesia prior to vascular access. Regression modeling was applied to derive nomograms based on quantile polynomial regression, which yielded good fit to the data judged by R-squared. GAMLSS transformation method was used to formulate smoothed percentiles. A separate prospective evaluation of FA to determine the size below which loss of pulse (LOP) are likely to occur was performed. Nomograms for FA and FV diameter and cross-sectional area against age and body surface area and probability curves for FA LOP were constructed. It is now possible to examine ultrasound-based normal sizes of femoral vein and artery in children 0-4 years of age. Femoral vessel nomograms and LOP probability curves may help with interventional planning. Future studies with larger sample size, including children of other ages may be useful.

Accessing Femoral Arteries Less than 3 mm in Diameter is Associated with Increased Incidence of Loss of Pulse Following Cardiac Catheterization in Infants.

To evaluate whether avoidance of a risk factor associated with loss of pulse (LOP) following femoral artery (FA) catheterization in infants identified from previous study, was associated with decreased incidence of LOP during a prospective evaluation. Since initiation of routine ultrasound guided femoral arterial access (UGFAA) for infants undergoing catheterization in Jan 2003-Dec 2011 (Period-1), our incidence of LOP had stayed steady. Prospective evaluation between Jan 2012-Dec 2014 (Period-2), identified FA-diameter < 3 mm as risk factor for LOP. Between Jan 2015-Dec 2018 (Period-3), an initiative to avoid UGFAA for FA-diameter < 3 mm was implemented to determine whether that led to a decreased incidence of LOP. FA-diameter was measured prior to USGFAA and ratio of outer diameter of arterial sheath to luminal diameter of cannulated artery (OD/AD ratio) was calculated during Periods-2 and 3. The incidence and risk factors for LOP were assessed during the three periods. FA-access rates dropped significantly during Period-3 (56.7% vs. 93.8% and 90.4% during Periods-1 and 2, respectively, p < 0.001). Incidence of LOP in Period-3 decreased to 2.7% compared to 12.5% (Period-1) and 17.4% (Period-2) (p < 0.001). By multivariate analysis, FA size < 3 mm and an OD/AD ratio > 40% were the only significant independent predictors for LOP (OR 6.48, 95% CI 2.3-11.42, p < 0.001 and OR 4.16, 95% CI 1.79-8.65, p < 0.01, respectively). Access of femoral artery < 3 mm and OD/AD ratio > 50% are associated with increased incidence of LOP. Avoidance of these factors may help decrease complications in infants undergoing cardiac catheterizations.

Diagnostic and Therapeutic Approach to Arrhythmias in Adult Congenital Heart Disease.

PURPOSE OF REVIEW: Adult survivors of congenital heart disease (CHD) are at increased risk of arrhythmia. The goal of this review is to outline diagnostic and therapeutic approaches to arrhythmia in adult CHD patients. RECENT FINDINGS: Macro-reentrant atrial tachyarrhythmia is the most common arrhythmia encountered in adults with CHD. Approximately 25% of hospitalizations associated with arrhythmia. The risk of ventricular arrhythmia is estimated as high as 25-100 times that for the general population and increased after two decades. Routine ambulatory monitoring is important for arrhythmia risk assessment in adults with CHD. There are limitations, potential adverse effects, and risk of recurrence with antiarrhythmic drugs, catheter ablation, and surgical approaches. Adults with CHD suffer various forms of arrhythmia, are at increased risk of sudden death, and require special consideration for medical and interventional therapy.

Utility of the Medtronic microvascular plug™ as a transcatheter implantable and explantable pulmonary artery flow restrictor in a swine model.

BACKGROUND: A surgical pulmonary artery band (PAB) is used to control excessive pulmonary blood flow for certain congenital heart diseases. Previous attempts have been made to develop a transcatheter, implantable pulmonary flow restrictor (PFR) without great success. We modified a microvascular plug (MVP) to be used as a PFR. The objectives of this study were to demonstrate feasibility of transcatheter implantation and retrieval of the modified MVP as a PFR, and compare PA growth while using the PFR versus PAB. METHODS AND RESULTS: The PFR was implanted in eight newborn piglets in bilateral branch pulmonary arteries (PAs). Immediately post-PFR implantation, the right ventricular systolic pressure increased from a median of 20-51 mmHg. Transcatheter retrieval of PFR was 100% successful at 3, 6, and 9 weeks and 50% at 12-weeks post-implant. A left PAB was placed via thoracotomy in four other newborn piglets. Debanding was performed 6-weeks later via balloon angioplasty. On follow-up, the proximal left PA diameters in the PFR and the PAB groups were similar (median 8 vs. 7.1 mm; p = 0.11); albeit the surgical band sites required repeat balloon angioplasty secondary to recurrent stenosis. By histopathology, there was grade II vessel injury in two pigs immediately post-retrieval of PFR that healed by 12 weeks. CONCLUSIONS: Transcatheter implantation and retrieval of the MVP as a PFR is feasible. PA growth is comparable to surgical PAB, which is likely to require reinterventions. The use of the MVP as a PFR in humans has to be trialed before recommending its routine use.

Live broadcast of transcatheter PDA closure in a 700 grams ELBW infant during the International PDA Symposium.

OBJECTIVE: The objective of this article is to describe a live case transmission of transcatheter closure of a patent ductus arteriosus (PDA) in an extremely low birth weight (ELBW) infant during the first International PDA Symposium conducted in Memphis, Tennessee. SETTING: A multidisciplinary team approach including audiovisual specialists, information technology specialists, physicians, nurses, and other health care specialists was required to perform the transcatheter PDA closure (TCPC) in an ELBW infant at LeBonheur Children's Hospital and the procedure was broadcast live to the attendees at the International PDA Symposium allowing for a two-way audiovisual discussion during the procedure. PATIENT: The patient was a 14 days old 24-week premature ELBW infant, who weighed 700 g at the time of the procedure. The patient was requiring mechanical ventilation secondary to pulmonary hemorrhage. The PDA measured 4 mm in diameter and 12 mm in length. INTERVENTIONS: TCPC was performed safely without any procedural complications using a specialized minimally invasive technique. OUTCOME MEASURES: The patient was weaned off the ventilator in < 7 days after the procedure. The child was discharged 9 weeks after the procedure (35 weeks' corrected gestation) weighing 2.2 kg, on full oral feeds and no supplemental oxygen. RESULTS: The successful TCPC allowed for this child to have an uneventful hospital course. The case also highlights the technical nuances involved in setting up the live transmission. CONCLUSIONS: This case demonstrated to the audience in the International PDA Symposium the feasibility and safety of performing TCPC in an ELBW infant. Live cases are useful in exhibiting the nuances involved in any new technique and allows for best learning experience.

Practice variation in the management of patent ductus arteriosus in extremely low birth weight infants in the United States: Survey results among cardiologists and neonatologists.

BACKGROUND: Patent ductus arteriosus (PDA) is highly prevalent in extremely low birth weight (ELBW), preterm infants. There are diverse management approaches for the PDA in ELBW infants. The objectives of this research were to identify current PDA management practices among cardiologists and neonatologists in the United States, describe any significant differences in management, and describe areas where practices align. METHODS: A survey of 10 questions based on the management of PDA in ELBW infants was conducted among 100 prominent neonatologists from 74 centers and 103 prominent cardiologists from 75 centers. Among the cardiologists, approximately 50% were interventionists who perform transcatheter PDA closures (TCPC). Fisher's exact test was performed to compare practice variations among neonatologists and cardiologists. A potentially biased audience including a combination of health care providers belonging to cardiology, neonatology, and surgery were also surveyed during the International PDA Symposium. The results of this survey were not included for statistical comparison, due to this audience being potentially influenced by the Symposium. RESULTS: Statistically significant differences were identified between neonatologists and cardiologists regarding the impact of PDA closure on morbidity and mortality, with 80% cardiologists responding that it does vs 54% of neonatologists (P < 0.001), the need for PDA closure (P < .001), and the preferred method of PDA closure if indicated (P < .001). There was agreement between neonatologists and cardiologists on symptomatic therapy; however more neonatologists favored watchful waiting over intervention in contrast to more cardiologists favoring intervention over observation (77% vs 95%, P < .001). Survey responses also identified a need for further training and research on TCPC. CONCLUSION: Neonatologists and cardiologists have notable differences in managing PDA, and continued discussion across cardiology and neonatology has the potential to facilitate more of a consensus on best management practices. Further investigation is needed to identify outcomes in transcatheter PDA closure, particularly in ELBW infants.

Use of 3-D digital subtraction rotational angiography during cardiac catheterization of infants and adults with congenital heart diseases.

OBJECTIVE: To compare image quality, radiation and contrast doses required to obtain 3D-Digital subtraction rotational angiography (3D-DSRA) with 3D-Digital rotational angiography (3D-DRA) in infants (children ≤ 2 years of age) and adults with congenital heart diseases (ACHD). BACKGROUND: 3D-DRA can be performed with radiation doses comparable to bi-plane cine-angiography. However, 3D-DRA in infants requires a large contrast volume. The resolution of 3D-DRA performed in ACHD patients is limited by their soft tissue density. We hypothesized that the use of 3D-DSRA could help alleviate these concerns. METHODS: Radiation (DAP) and contrast doses required to obtain 3D-DSRA was compared with 3D-DRA in 15 age-, size-, and intervention-matched infants and 15 ACHD patients. The diagnostic quality and utility of these two modalities were scored by 4 qualified independent observers. RESULTS: Both in infants and adults, the median contrast volume for 3D-DSRA was lower than 3D-DRA (0.98 vs. 1.81 mL/kg; P < 0.001 and 0.92 vs. 1.4 mL/kg; P < 0.001, respectively) with an increased DAP (median: 188 vs. 128 cGy cm2 ; P = 0.068 and 659 vs. 427 cGy cm2 ; P = 0.045, respectively). The diagnostic quality and utility scores for rotational-angiography, and 3D-reconstruction were superior for 3D-DSRA (score = 94 vs. 80%, P = 0.03 and 90 vs.79%, P = 0.01, respectively) and equivalent for multi-planar-reformation and 3D-roadmapping in ACHD patients compared with 3D-DRA. All scores for both modalities were equivalent for infants. CONCLUSIONS: 3D-DSRA can be acquired using lower contrast volume with a mildly higher radiation dose than 3D-DRA in infants and ACHD patients. The diagnostic quality and utility scores for 3D-DSRA were higher in ACHD patients and equivalent for infants compared with 3D-DRA.

The Medtronic Micro Vascular Plug™ for Vascular Embolization in Children With Congenital Heart Diseases.

OBJECTIVES: To describe the early multi-center, clinical experience with the Medtronic Micro Vascular Plug™ (MVP) in children with congenital heart disease (CHD) undergoing vascular embolization. BACKGROUND: The MVP is a large diameter vascular occlusion device that can be delivered through a microcatheter for embolization of abnormal blood vessels. METHODS: A retrospective review of embolization procedures using the MVP in children with CHD was performed in 3-centers. Occlusion of patent ductus arteriosus using the MVP was not included. RESULTS: Ten children underwent attempted occlusion using the MVP. The most common indication to use the MVP was failed attempted occlusion using other embolic devices. Five, single ventricle patients (median age 3-years, median weight 14.9 kg) underwent occlusion of veno-venous collaterals following bidirectional Glenn operation. Three patients (Median age 8 years) underwent occlusion of coronary artery fistulae (CAF). Two patients (age 7 months and 1 year) underwent occlusion of large aorto-pulmonary collaterals. A 7-day-old child with a large CAF required 2 MVPs and an Amplatzer Vascular Plug (AVP-II) for complete occlusion. Occlusion of all other blood vessels was achieved using a single MVP. One MVP embolized distally in an 8-years-old child with a large CAF. There were no other procedural complications or during follow-up (median 9 months). CONCLUSIONS: The MVP is a new, large-diameter vascular embolization device that can be delivered through a microcatheter. It may play an important role in providing highly effective occlusion of abnormal vessels in children.

Initial clinical experience with the Medtronic Micro Vascular Plug™ in transcatheter occlusion of PDAs in extremely premature infants.

OBJECTIVES: To describe the early multicenter, clinical experience with the Medtronic Micro Vascular Plug™ (MVP) for the occlusion of patent ductus arteriosus (PDA) in premature infants. BACKGROUND: The MVP is a large diameter plug that can be delivered through a microcatheter for occlusion of abnormal blood vessels. METHODS: A Retrospective review of PDA embolization procedures performed in two centers using the MVP was performed. RESULTS: Fifteen premature infants underwent attempted PDA occlusion using the MVP. The gestational age and birth weight were 25.6 ± 2.5 weeks and 735 ± 251 g, respectively. The median weight and age at the time of the procedure were 1,210 g (700-3,500 g) and 4.5 weeks (2-12 weeks), respectively. Median procedure and fluoroscopy times were 45 and 6.5 min, respectively. The median radiation and contrast doses were 19.7 mGy and 2.4 mL/kg, respectively. Antegrade occlusion was successfully achieved in 13 patients <2 kg with only femoral venous access aided by echo guidance. The two patients >2 kg had arterial access and attempted retrograde occlusion; one of which was unsuccessful due to the PDA being short and wide. Complete closure was observed in 13 of 14 successful procedures (93%), with one patient having a small residual shunt that was not seen on follow-up. There were no complications related to the procedure or noted during follow-up (Median 11 months). CONCLUSIONS: The MVP is a new, large-diameter vascular embolization device that may be useful for the occlusion of PDA in extremely small, premature infants. © 2016 Wiley Periodicals, Inc.

Clinical evaluation of a radio-protective cream for the hands of the pediatric interventional cardiologist.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of UltraBLOX™ radiation attenuating hand cream during lengthy cardiac catheterization procedures in children. BACKGROUND: The hands of interventional cardiologists receive high doses of radiation due to their proximity to the X-ray beam. Radiation attenuating gloves have about a 26% attenuation rate, but reduce dexterity and tactile sensation. The UltraBLOX™ cream is a new FDA-approved X-ray attenuating cream that can be applied to the operator's hands for radio-protection. METHODS: Two nanoDot™ dosimeters were secured side by side on the dorsum of the operator's (n = 2) left hand close to the wrist. One dosimeter and the rest of the hand were covered with 0.2 mm layer of the cream. The other dosimeter was unshielded. Procedures were performed using 110 kVp fluoroscopy at 15 pulses/sec. The measurements were categorized into four groups dependent on the duration of the procedure. The patients in all four groups were well matched for age and size. RESULTS: Procedural and cumulative hand radiation doses were higher with longer procedural duration. The overall % attenuation by the cream was 39.7% (28.6-51.5) and was unaffected by the length of the procedure (median: 40.9% at 30 min and 41.4% at 180 min; P = 0.66) or the dose of radiation. The kappa statistic for interobserver agreement for good tactile sensitivity was 0.82. CONCLUSIONS: UltraBLOX™ cream provides a new option for radio-protection for the hands of interventional cardiologists without impairing tactile sensitivity. There was no decrease in attenuation up to 180 min. © 2016 Wiley Periodicals, Inc.

Ultrasound-guided femoral arterial access in pediatric cardiac catheterizations: A prospective evaluation of the prevalence, risk factors, and mechanism for acute loss of arterial pulse.

OBJECTIVES: The objectives of this study were to describe the prevalence, mechanisms, and identify risk factors for acute loss of arterial pulse (LOP) in children who had ultrasound-guided femoral arterial access (UGFAA) during cardiac catheterization. BACKGROUND: LOP is a known complication in children following femoral arterial (FA) access for cardiac catheterization. The prevalence of LOP requiring treatment ranges between 4% and 8%. METHODS: A prospective study was performed including 486 cardiac catheterizations using UGFAA in children ≤18 years over a 3 years period. Ultrasound and Doppler evaluations were performed prior to and at the end of the procedure. RESULTS: LOP was identified in 33 cases (6.8%) with 23 (4.7%) requiring treatment. For children ≤6 months, the prevalence of LOP requiring treatment was 13.6%. FA diameter <3 mm was the only significant independent predictor for LOP (OR: 8.44, 95% CI: 2.07-34.5, P < 0.001). Smaller patient size, number of access attempts, time required for access, operator experience, sheath size, and length of procedure were not found to be significant predictors. Children with LOP had a greater percentage decrease in vessel diameter (median 62% vs 18%, P < 0.001) compared to those without LOP. FA thrombus was diagnosed only in 9 patients (27% of those with LOP). CONCLUSIONS: The prevalence of LOP requiring treatment is 4.7% when UGFAA is used during pediatric cardiac catheterizations. Arterial spasm was more common than thrombus as a cause of LOP. FA diameter <3 mm was the only independent predictor for LOP in this carefully designed prospective study. © 2016 Wiley Periodicals, Inc.

Near Catastrophic Accelerated Structural Degeneration of the Perimount Magna Pericardial Bioprosthesis in Children.

Experience with pericardial bioprostheses in young patients is limited. Accelerated degeneration of the Mitroflow valve has recently been reported. We report early accelerated structural valve degeneration with the Perimount Magna bioprosthesis, which has not been previously reported. Young patients with the Magna bioprosthesis are at high risk for rapid progression to severe stenosis, which underscores their need for more vigilant surveillance. The benefits and risks of these bioprosthetic valves must be weighed carefully when options for replacement in these young patients are discussed.

Feasibility and Safety of Unzipping Small Diameter Stents in the Blood Vessels of Piglets.

OBJECTIVES: This study sought to determine the feasibility and safety of unzipping small-diameter stents (SDS) in a growing animal model. BACKGROUND: SDS implanted to relieve stenosis of blood vessels in infants may result in refractory stenosis as the child grows. If stents can be longitudinally fractured-unzipped-then the target vessel can potentially be redilated to the eventual adult vessel diameter. METHODS: Fifty stents (diameter 4 to 7 mm) were implanted in 5 neonatal piglets (mean age and weight = 1.5 weeks and 3.4 kg). Pre-mounted coronary (CS) (n = 24), biliary (BS) (n = 14), nitinol (NS) (n = 3), and renal stents (RS) (n = 9) were implanted in pulmonary arteries (n = 13), systemic arteries (n = 25), and systemic veins (n = 12). Three months later (median weight = 32 kg), unzipping was attempted by dilating the stents. RESULTS: All CS and RS unzipped at twice their nominal diameter with <20% shortening. None of the NS unzipped. The BS shortened the most (∼40%), with only 69% of the stents unzipping. Stainless steel CS and RS with an open cell design were significant predictors (p ≤ 0.01) for unzipping. On histopathology, unzipping of the BS caused the most medial dissection and vessel wall injury, while unzipping of the CS caused the least. CONCLUSIONS: Unzipping of small-diameter CS and RS implanted in systemic and pulmonary vessels is more feasible than the BS and NS. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

Radiation Protocol for Three-Dimensional Rotational Angiography to Limit Procedural Radiation Exposure in the Pediatric Cardiac Catheterization Lab.

BACKGROUND: Three-dimensional rotational angiography (3DRA) offers more detailed anatomic information than 2D digital acquisition (2DDA). Concerns over potentially higher contrast and radiation doses have limited its routine use. OBJECTIVE: The primary objective of this study was to compare radiation doses required to obtain 3DRA using a customized low dose radiation protocol with 2DDA. The secondary objective was to compare total procedural radiation in pediatric cardiac catheterization procedures utilizing 3DRA to those that do not. STUDY DESIGN: Phantom studies were conducted to establish customized 3DRA protocols for radiation reduction. Comparison of 3DRA and non-3DRA procedures in age-, size- and diagnosis-matched controls was performed. Radiation doses were indexed to body surface area (BSA) to account for differing body habitus as validated from the phantom study. RESULTS: Study (n = 100) and control (n = 100) groups were matched for age (10.2 vs. 9.98 years; P = .239) and BSA (1.23 vs. 1.09 m2 ; P = .103). The dose area product (DAP) to acquire a 3DRA was similar to a 5 s, 15 frames/second 2DDA (278 vs. 241 cGy/cm2 ; P = .14). Despite the 3DRA group consisting of more complex interventions, no difference was found in the total procedural Air Kerma and DAP indexed to BSA (244 vs. 249 mGy/m2 ; P = .79 and 3348 vs. 3176 cGy/cm2 /m2 ; P = .48, respectively). The contrast volume to acquire a 3DRA compared to a 2DDA was greater (1.59 vs. 1.01 mL/kg; P < .001). However, no difference was found for the entire procedure (3.8 vs. 4 mL/kg, P = .494). This could have resulted from the need to obtain multiple 2DDAs to achieve the detail of a single 3DRA (11 vs. 7 per study; P < .001). CONCLUSIONS: When 3DRA, using the proposed protocols is employed, total procedural contrast and radiation doses are comparable with the sole use of biplane cine-angiograms. These protocols may allow for routine use of 3DRA for congenital cardiac catheterizations.

Morphologic characterization of the patent ductus arteriosus in the premature infant and the choice of transcatheter occlusion device.

OBJECTIVES: The aim of this study was to describe and differentiate the morphology of patent ductus arteriosus (PDA) seen in children born prematurely from other PDA types. BACKGROUND: PDAs are currently classified as types A-E using the Krichenko's classification. Children born prematurely with a PDA morphology that did not fit this classification were described as Type F PDA. METHODS: A review of 100 consecutive children who underwent transcatheter device closure of PDA was performed. The diameter and length (L) of the PDA and the device diameter (D) were indexed to the descending aorta (DA) diameter. RESULTS: Comparison of 26 Type F PDAs was performed against, 29 Type A, 7 Type C and 32 Type E PDAs. Children with Type F PDAs (median 27.5 weeks gestation) were younger during the device occlusion compared with types A, C, and E (median age: 6 vs. 32, 11, and 42 months; P = 0.002). Type F PDAs were longer and larger, requiring a relatively large device for occlusion than types A, C, and E (Mean L/DA: 1.88 vs. 0.9, 1.21, and 0.89, P ≤ 0.01 and Mean D/DA: 1.04 vs. 0.46, 0.87, and 0.34, P ≤0.01). The Amplatzer vascular plug-II (AVP-II) was preferred for occlusion of Type F PDAs (85%; P <0.001). CONCLUSIONS: Children born prematurely have relatively larger and longer PDAs. These "fetal type PDAs" are best classified separately. We propose to classify them as Type F PDAs to add to types A-E currently in use. The AVP-II was effective in occluding Type F PDAs.