Usefulness of PREDIC3T Case Type Risk Category in the CRISP Registry.

Procedural risk in Congenital Cardiac Catheterization (PREDIC3T) was recently reported as the contemporary procedure-type risk metric by the Congenital Cardiac Catheterization Project on Outcomes (C3PO) registry. The usefulness of this metric has not been evaluated elsewhere. The CRISP registry of Congenital Cardiovascular Interventional Study Consortium (CCISC) data set was analyzed. The study period was 14 years (2009 to 2022). The primary outcome was significant adverse event (SAE). Cases were assigned to the 6 PREDIC3T risk categories. Univariate and multivariable logistic regression models were used to evaluate the association between PREDIC3T and the primary outcome. The model discriminative performance was evaluated by the c-statistic. In a total of 64,419 enrolled cases, PREDIC3T case types were assigned in 59,822 cases (93%). The frequency for PREDIC3T category was 0 = 7,494 (12.5%), 1 = 16,932 (28.3%), 2 = 17,023 (28.5%), 3 = 9,885 (16.5%), 4 = 4,403 (7.4%), and 5 = 4,085 (6.8%). SAE was observed in 2,474 cases (4.1%). The SAE rates for category were 0 = 1.0%, 1 = 2.3%, 2 = 4.0%, 3 = 6.2%, 4 = 8.2%, and 5 = 9.0%. In a multivariable model, PREDIC3T case type risk category (odds ratios for category: 0 = 0.49, 1 = 1.00, 2 = 1.40, 3 = 2.06, 4 = 2.79, and 5 = 3.15; p <0.001) were significantly associated with SAE (c-statistic of 0.707) after adjusting for age, preprocedural inotropic support and systemic illness, low systemic saturation, high pulmonary vascular resistance, and the use of general anesthesia. The PREDIC3T case type risk category was associated with the risk of SAE in the CRISP registry data set and appeared to be a useful procedural risk classification tool.

Hybrid approach to pulmonary vein stenting after Fontan palliation.

Pulmonary vein stenosis is poorly tolerated in patients who have undergone Fontan palliation and typically requires surgical or transcatheter intervention. Percutaneous transcatheter approaches to intervention can be technically difficult due to challenging anatomy. A hybrid per-atrial transcatheter approach for stenting pulmonary veins provides a direct approach to the pulmonary veins and has the potential to improve safety and efficacy of this complex intervention. We describe our experience with hybrid per-atrial pulmonary vein stenting in three patients with pulmonary vein stenosis following Fontan palliation.

Update on Transcatheter Device Closure of Congenital Septal Defects.

PURPOSE OF REVIEW: The goal of this paper is to review currently available devices for closure of atrial septal defects (ASDs) and ventricular septal defects (VSDs). RECENT FINDINGS: Favorable results from the ASSURED trial resulted in FDA approval for the most recently developed device for transcatheter ASD closure in the United States. Further studies are required to assist in the development or approval of safe devices for transcatheter perimembranous VSD closure in pediatric patients. Device closure is the less invasive and preferred management option for many ASDs, with multiple studies demonstrating lower complication rates, shorter hospital stays, and lower mortality than surgical repair. Complex ASDs that make device closure more difficult include large defects, rim deficiencies, fenestrated defects, multiple defects, and the presence of pulmonary arterial hypertension. Device closure has also become an accepted alternative to surgery for some types of ventricular septal defects VSDs, though challenges and limitations remain. Future innovations including novel devices and techniques are needed to further expand on the types of defects that can be safely closed via transcatheter approach.

Impact of Ventricular Dominance on Long-Term Fontan Outcomes: A 25-year Single-institution Study.

BACKGROUND: The long-term impact of ventricular dominance on Fontan outcomes is controversial. This study examined this issue in a 25-year cohort. METHODS: Patients undergoing the Fontan operation at a single institution (Duke University Medical Center, Durham, NC) from October 1998 to February 2022 were reviewed. Primary outcomes were transplant-free survival and Fontan failure (death, heart transplantation, takedown, protein-losing enteropathy, or plastic bronchitis). Secondary outcomes included hospital and intensive care lengths of stay. Kaplan-Meier methodology compared outcomes by ventricular dominance. Multiphase parametric risk hazard analysis identified risk factors for primary outcomes. RESULTS: There were 195 patients (104 right ventricular dominant) included in the study. Baseline characteristics were comparable. Perioperative survival was similar (right ventricular dominant, 98%; non-right ventricular dominant, 100%; P = .51). The proportion of patients experiencing death or heart transplantation was 8.7%, and the rate of Fontan failure was 11.8% during a median follow-up of 4.5 years (interquartile range, 0.3-9.8 years). Right ventricular-dominant patients had reduced transplant-free survival (10-year estimates: 80% [95% CI, 70%-91%] vs 92% [95% CI, 83%-100%]; P = .04) and freedom from Fontan failure (73% [95% CI, 62%-86%] vs 92% [95% CI, 83%-100%]; P = .04). Multiphase hazard modeling resolved 2 risk phases. The early phase spanned from surgery to approximately 6 months afterward. The late phase spanned from approximately 6 months after surgery onward. In multivariable analysis, right ventricular dominance was an independent risk factor for death or heart transplantation (parameter estimate, 1.3 ± 0.6; P = .04) and Fontan failure (1.1 ± 0.5; P = .04) during the second phase, with no significant first-phase risk factors. CONCLUSIONS: Right ventricular dominance was associated with long-term complications after Fontan procedures, including mortality, heart transplantation, and Fontan failure. This cohort may benefit from heightened surveillance in a multidisciplinary Fontan clinic after the perioperative period.

Whole-Chest Three-Dimensional Modeling Aids Hybrid Pulmonary Valve Replacement Following Double Switch Operation.

The double switch operation for congenitally corrected transposition of the great arteries (CC-TGA) has been associated with high rates of reintervention, including the need for pulmonary valve replacement. Hybrid interventional approaches can avoid bypass when complex anatomy complicates traditional catheter-based approaches. We present a case of successful transcatheter pulmonary valve replacement via hybrid per-ventricular approach with pre-procedural planning aided by 3D segmentation of skeletal and cardiac anatomy in a patient with surgically corrected CC-GTA.

Transition to Ductal Stenting for Single Ventricle Patients Led to Improved Survival: An Institutional Case Series.

BACKGROUND: The use of systemic-to-pulmonary shunts (SPS) in neonates with single ventricle heart defects and ductal-dependent pulmonary blood flow (ddPBF) was historically associated with high morbidity and mortality at our center. As a result, we transitioned to the preferential use of ductus arteriosus stents (DS) when feasible. This report describes our initial results with this strategy. METHODS: A single-center study of single ventricle patients that received DS or SPS from 2015 to 2019 was performed to assess whether DS was associated with decreased in-hospital morbidity and increased survival to stage II palliation. RESULTS: A total of 34 patients were included (DS = 11; SPS = 23). Underlying cardiac anomalies were similar between groups and included pulmonary atresia, unbalanced atrioventricular septal defect, and tricuspid atresia. Procedure success was similar between groups (82% vs 83%). Two DS patients were converted to SPS, due to ductal vasospasm or pulmonary artery obstruction, and four SPS patients required surgical shunt revision. In DS patients, postprocedure mechanical ventilation duration was shorter (one vs three days, P = .009) and fewer required postprocedure extracorporeal membrane oxygenation (9% vs 39%, P = .11). A higher proportion of DS patients survived to stage II palliation (100% vs 64%, P = .035), and the probability of one-year survival was higher in DS patients (100% vs 61%, P = .02). CONCLUSIONS: At our center, patients with single ventricle heart defects and ddPBF that received DS experienced reduced in-hospital morbidity and increased survival to stage II palliation compared to SPS.

Mustard Baffle Revision With Systemic Ventricular Assist Device Placement.

Systemic right ventricle failure often develops in patients with dextro-transposition of the great arteries who have undergone atrial-level switch procedures. An adult with dextro-transposition of the great arteries with Mustard repair in childhood presented with end-stage heart failure due to systemic right ventricle failure, Mustard baffle leak, and unrepaired partial anomalous pulmonary venous return. She underwent device closure of the baffle leak by catheterization, followed by baffle revision and concomitant systemic ventricular assist device placement by adult and pediatric heart surgeons. This case demonstrates the importance of multidisciplinary collaboration between pediatric and adult heart failure specialists in caring for complex adult congenital heart patients.

Palliating Premature Infants With Obstructed Total Anomalous Pulmonary Venous Connection via Catheterization.

Obstructed total anomalous pulmonary venous connection (TAPVC) involves anomalous drainage of all pulmonary veins to a location other than the left atrium and typically causes significant respiratory symptoms requiring urgent surgical repair. Premature infants born with obstructed TAPVC are often not considered to be suitable surgical candidates due to their size and therefore pose a significant treatment dilemma. Catheter-based interventions provide a temporizing option for infants with obstructed TAPVC, allowing for hemodynamic stabilization and growth until surgical intervention is feasible. We describe the course of two premature infants with obstructed TAPVC who were palliated with stenting of their anomalous pulmonary veins. Both infants required repeat catheter-based intervention for recurrent stenosis and ultimately underwent successful surgical repair at an acceptable weight and corrected gestational age. We propose that a novel catheter-based approach to initial management may be a beneficial option in the premature and low-weight patient population.

Preprocedural three-dimensional planning aids in transcatheter ductal stent placement: A single-center experience.

OBJECTIVES: Describe the use of three-dimensional (3D) patent ductus arteriosus (PDA) modeling to better define ductal anatomy to improve preprocedural planning for ductal stent placement. BACKGROUND: Ductal stenting is an alternative to surgical shunting in patients with ductal dependent pulmonary blood flow. Ductal anatomy is often complex with extreme tortuosity and risk of pulmonary artery isolation, thus increasing procedural risks. METHODS: CT angiograms were segmented to produce 3D PDA models. Ductal morphology was characterized with attention to access approach, degree of pulmonary artery offset/risk of isolation and ductal tortuosity. 3D models were retrospectively compared with biplane angiography. RESULTS: 3D modeling was performed in 12 patients with adequate image quality for complete analysis in 11; median (interquartile range) age/weight 17 days (8-20 days) and 3.1 kg (2.4-3.9 kg). The PDA was reverse oriented in nine with average length of 17.2 ± 2.5 mm and high tortuosity (mean tortuosity index 52, range 3-108). From 3D modeling, two patients were excluded from ductal stenting-extreme ductal tortuosity and threatened pulmonary artery discontinuity, respectively. Ductal stenting was successful in the remaining nine with no major procedural complications. 3D modeling predicted a successful access approach based on the aortic orientation of the ductus in all patients (five carotid, two axillary, two femoral). When comparing 2D angiography with 3D models, angiography consistently underestimated ductal length (-3.2 mm ± 1.6 mm) and tortuosity (-14.8 ± 7.2). CONCLUSIONS: 3D modeling prior to ductal stent placement for ductal dependent pulmonary blood flow is useful in procedural planning, specifically for eligibility, access approach, and accurate ductal measurements. Further studies are needed to determine if 3D planning improves procedural outcomes.

Hybrid transcatheter pulmonary valve replacement with a SAPIEN S3 valve after pulmonary artery banding via left lateral thoracotomy.

For many patients with repaired congenital heart disease, the need for reintervention on dysfunctional right ventricular outflow tracts is pervasive. Many such patients are poor candidates for both transcatheter pulmonary valve replacement and cardiopulmonary bypass, and hybrid surgical and transcatheter procedures have evolved to meet this need. We present two cases of hybrid pulmonary valve replacement involving pulmonary artery band placement via left anterior thoracotomy followed by transvenous placement of a SAPIEN S3 valve without prestenting. This approach avoids cardiopulmonary bypass as well as redo sternotomy and will likely see an increase in utilization in the future.

Estimating radiation exposure during paediatric cardiac catheterisation: a potential for radiation reduction with air gap technique.

INTRODUCTION: The air gap technique (AGT) is an approach to radiation dose optimisation during fluoroscopy where an "air gap" is used in place of an anti-scatter grid to reduce scatter irradiation. The AGT is effective in adults but remains largely untested in children. Effects are expected to vary depending on patient size and the amount of scatter irradiation produced. METHODS: Fluoroscopy and cineangiography were performed using a Phillips Allura Fluoroscope on tissue simulation anthropomorphic phantoms representing a neonate, 5-year-old, and teenager. Monte Carlo simulations were then used to estimate effective radiation dose first using a standard recommended imaging approach and then repeated using the AGT. Objective image quality assessments were performed using an image quality phantom. RESULTS: Effective radiation doses for the neonate and 5-year-old phantom increased consistently (2-92%) when the AGT was used compared to the standard recommended imaging approaches in which the anti-scatter grid is removed at baseline. In the teenage phantom, the AGT reduced effective doses by 5-59%, with greater dose reductions for imaging across the greater thoracic dimension of lateral projection. The AGT increased geometric magnification but with no detectable change in image blur or contrast differentiation. CONCLUSIONS: The AGT is an effective approach for dose reduction in larger patients, particularly for lateral imaging. Compared to the current dose optimisation guidelines, the technique may be harmful in smaller children where scatter irradiation is minimal.

Postoperative Transcatheter Interventions in Children Undergoing Congenital Heart Surgery.

Background Postoperative transcatheter interventions (TCIs) are performed after congenital heart surgery to treat residual or recurrent anatomic lesions. We used the Society of Thoracic Surgeons Congenital Heart Surgery Database to evaluate rates of postoperative TCIs, center variability, and to determine whether center approaches to postoperative TCI might be associated with outcomes. Methods and Results Patients <18 years undergoing an index operation (2010-2016) were included. We determined predischarge postoperative TCI rates and used multivariable modeling, adjusting for patient factors and case complexity, to evaluate the association between center risk-adjusted postoperative TCI rates and risk-adjusted outcomes (operative mortality, post-TCI mortality, and failure-to-rescue). Postoperative TCI was performed after 2615/105 742 (2.5%) index operations and after 1443/25 416 (5.7%) highest complexity operations (STAT [Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Mortality Score] Mortality Category 4 and 5). Median (interquartile range) age of patients undergoing TCI was 2.7 (0.2-8.0) months with 43% performed in neonates. There was a wide center variability across the 107 included centers with risk-adjusted rates of postoperative TCI ranging from 0.0% to 8.0% overall and 0.0% to 20.7% for STAT 4 and 5 cases. Postoperative TCI was associated with higher risk-adjusted odds of operative mortality (odds ratio, 4.06; 95% CI, 3.60-4.58). Centers with higher postoperative TCI rates had higher overall operative mortality ( R2=0.23; P=0.02) but did not have higher post-TCI mortality ( P=0.10). There was no correlation between center TCI rates and failure-to-rescue ( P=0.19). Conclusions Patients undergoing postoperative TCI represent a high-risk cohort. Wide center variability suggests the potential for improving outcomes, but further study is necessary to better understand optimal approaches.

Routine postprocedure ultrasound increases rate of detection of femoral arterial thrombosis in infants after cardiac catheterization.

OBJECTIVES: To examine the effect of implementing postcatheterization ultrasound (US) on femoral arterial thrombosis detection rates and factors associated with thrombosis in infants. BACKGROUND: Although femoral arterial thrombosis is an uncommon complication of cardiac catheterization, it can cause limb threatening complications. Previous studies assessing the utility of postprocedure US to detect thrombosis in infants have utilized US as an adjunct to standard clinical detection methods, are small scale, or include small cohorts of infants within older populations. METHODS: We reviewed institutional records of patients 0-12 months undergoing catheterization from 2007 to 2016. Demographics and procedural data were compared between the thrombosis and non-thrombosis group. Pre- and post-US groups were compared for detected thrombosis rate. Using univariate and multivariable analyses, we identified factors associated with thrombosis. RESULTS: In total, 270 patients underwent 509 catheterizations, with 40 (7.9%) documented thromboses. The rate of thrombus detection in patients younger than 6 months increased from 8.3% to 23.4% (P = 0.006) after implementing routine US. On multivariable analysis, lower weight (P < 0.001), larger arterial sheath size (P < 0.001), and longer procedure duration (P = 0.003) were independently associated with higher odds of thrombosis. CONCLUSIONS: Higher rates of femoral arterial thrombosis detection were observed since implementing an US screening program. Further studies are needed to evaluate age-related changes in hemostasis in this population and how advanced screening methods and anticoagulation protocols may help improve short-term and long-term sequelae of femoral arterial thrombosis.

Validation and refinement of the catheterization RISk score for pediatrics (CRISP score): An analysis from the congenital cardiac interventional study consortium.

OBJECTIVES: To externally validate the CRISP score, and determine if refinements might improve clinical utility. BACKGROUND: The CRISP score estimates risk of serious adverse events (SAEs) for pediatric catheterization. METHODS: Pediatric (age < 18) procedures reported to the Congenital Cardiovascular Interventional Study Consortium registry from 05/08 to 09/17 (n = 29,830, 27 centers) were divided into a development dataset of 14,784 earlier procedures, and a validation dataset of 15,046 more recent procedures. The development dataset was used to refit the original CRISP model, and to develop a revised(r) CRISP score, consisting of entirely pre-procedurally collected data. The validation dataset was then used to compare model fit and risk prediction between CRISP, rCRISP and two existing risk scores using Akaike's (AIC), Schwarz's (BIC) Bayes Information Criteria, -log Likelihood (N2LL), area under the receiver operator curve and chi-square goodness-of-fit statistic (across 5 risk categories). RESULTS: Overall 4.31% of patients experienced at least one SAE with frequency increasing from 1.08% in CRISP category 1 to 27.34% in category 5. Both CRISP and rCRISP (entirely pre-procedural) predicted risk of SAEs well, with observed to predicted ratios ranging from 0.71 to 1.18 across the 5 risk categories. Compared to the original CRISP score, rCRISP demonstrated less optimal model fit (higher AIC, BIC, and N2LL) but similar risk prediction (C-statistic = 0.71 vs. 0.70; chi-squared statistic = 6.77 vs. 6.85). CONCLUSION: The CRISP score accurately predicts procedural risk. With minor modifications, the revised version (rCRISP) performed well with arguably greater clinical utility as an entirely preprocedural risk model.

3-Year Outcomes of the Edwards SAPIEN Transcatheter Heart Valve for Conduit Failure in the Pulmonary Position From the COMPASSION Multicenter Clinical Trial.

OBJECTIVES: This study provides the 3-year follow-up results of the COMPASSION (Congenital Multicenter Trial of Pulmonic Valve Regurgitation Studying the SAPIEN Transcatheter Heart Valve) trial. Patients with moderate to severe pulmonary regurgitation and/or right ventricular outflow tract conduit obstruction were implanted with the SAPIEN transcatheter heart valve (THV). BACKGROUND: Early safety and efficacy of the Edwards SAPIEN THV in the pulmonary position have been established through a multicenter clinical trial. METHODS: Eligible patients were included if body weight was >35 kg and in situ conduit diameter was ≥16 and ≤24 mm. Adverse events were adjudicated by an independent clinical events committee. Three-year clinical and echocardiographic outcomes were evaluated in these patients. RESULTS: Fifty-seven of the 63 eligible patients were accounted for at the 3-year follow-up visit from a total of 69 implantations in 81 enrolled patients. THV implantation was indicated for pulmonary stenosis (7.6%), regurgitation (12.7%), or both (79.7%). Twenty-two patients (27.8%) underwent implantation of 26-mm valves, and 47 patients received 23-mm valves. Functional improvement in New York Heart Association functional class was observed in 93.5% of patients. Mean peak conduit gradient decreased from 37.5 ± 25.4 to 17.8 ± 12.4 mm Hg (p < 0.001), and mean right ventricular systolic pressure decreased from 59.6 ± 17.7 to 42.9 ± 13.4 mm Hg (p < 0.001). Pulmonary regurgitation was mild or less in 91.1% of patients. Freedom from all-cause mortality at 3 years was 98.4%. Freedom from reintervention was 93.7% and from endocarditis was 97.1% at 3 years. There were no observed stent fractures. CONCLUSIONS: Transcatheter pulmonary valve replacement using the Edwards SAPIEN THV demonstrates excellent valve function and clinical outcomes at 3-year follow-up.

Transcatheter Valve Replacement for Right-sided Valve Disease in Congenital Heart Patients.

Pulmonary and/or tricuspid valve dysfunction is common among individuals with congenital heart disease, and surgical intervention often carries prohibitive risks. Transcatheter valve replacement (TVR) of the right-sided cardiac valves has become a viable treatment option over the past two decades, while continued technological development aims to broaden its applicability to an even larger portion of those with repaired congenital heart disease. To date, two transcatheter valves have been approved for use in patients with dysfunctional right ventricular to pulmonary artery conduits as well as those with failing pulmonic bioprosthetic valves, and are also used off-label in the "native" RVOT and within surgically repaired/replaced but failing tricuspid valves. TVR has demonstrated comparable safety and short-term outcomes to that of surgical valve replacement. This article aims to review current available devices, focusing on their safety, efficacy and on and off label usage, while briefly describing some of the emerging devices and novel procedural techniques that will likely lead to significant expansion of transcatheter treatment of right sided valve disease in the future.

Correlation between minute carbon dioxide elimination and pulmonary blood flow in single-ventricle patients after stage 1 palliation and 2-ventricle patients with intracardiac shunts: A pilot study.

BACKGROUND: Assessment of pulmonary blood flow and cardiac output is critical in the postoperative management of patients with single-ventricle physiology or 2-ventricle physiology with intracardiac shunting. Currently, such hemodynamic data are only obtainable by invasive procedures, such as cardiac catheterization or the use of a pulmonary artery catheter. Ready availability of such information, especially if attainable noninvasively, could be a valuable addition to postoperative management. AIMS: The aim of this study was to assess the correlation between volume of CO2 elimination obtained by volumetric capnography and pulmonary blood flow in pediatric patients with single-ventricle physiology after stage 1 palliation as well as in patients with other cardiac lesions associated with intracardiac shunting. METHODS: This prospective cohort study included children with congenital or acquired heart disease who underwent cardiac catheterization as part of clinical care. Cardiac output, pulmonary blood flow, and volume of CO2 elimination were simultaneously collected. Spearman's rank correlation coefficients were used to assess correlation between measurements after controlling for minute ventilation. RESULTS: Thirty-five patients were enrolled and divided into 3 groups. Group 1 (n = 8) included single-ventricle patients after stage 1 palliation. Group 2 (n = 10) patients had structural heart disease with 2 ventricles and intracardiac shunting. Group 3 (n = 17) had structurally normal hearts. Among Group 1 patients, the correlation coefficients (R2 ) between volume of CO2 elimination and pulmonary blood flow and volume of CO2 elimination and cardiac output were 0.60 (P = .02) 95% CI [0.01-0.79] and 0.29 (P = .74) 95% CI [-0.91 - 0.86], respectively. In patients with 2 ventricles associated with intracardiac shunts (Group 2), the correlation coefficients between volume of CO2 elimination and pulmonary blood flow and volume of CO2 elimination and cardiac output were 0.86 (P = .001) 95% CI [0.53 - 0.97] and 0.73 (P = .001) 95% CI [0.29 - 0.95], respectively. Among Group 3 patients, the correlation coefficient between volume of CO2 elimination and pulmonary blood flow was 0.66 (P = .038) 95% CI [0.29 - 0.87]. CONCLUSION: Volume of CO2 elimination may be a surrogate marker of pulmonary blood flow in single-ventricle patients and patients with biventricular physiology with intracardiac shunting. Also, among patients with normal cardiac anatomy, volume of CO2 elimination may be a marker of cardiac output.

Utilizing Hybrid Techniques to Maximize Clinical Outcomes in Congenital Heart Disease.

PURPOSE OF REVIEW: The past couple of decades have brought tremendous advances to the field of pediatric and adult congenital cardiology. Recent collaborations between interventional cardiologists and cardiac surgeons have sparked novel innovative hybrid procedures that provide potentially safer, faster, and less invasive alternatives to the management of many diseases. This paper will review the most recent advances in hybrid interventions in the field of pediatric and adult congenital cardiology. RECENT FINDINGS: The earliest experiences with hybrid interventions included intraoperative stenting of pulmonary arteries and perventricular device closure of ventricular septal defects. Newer hybrid interventions have focused on a hybrid approach to stage 1 palliation for infants with hypoplastic left heart syndrome and hybrid approaches to transcatheter pulmonary valve replacement in patients of all ages. Hybrid approaches to complex congenital heart disease are important in the management of congenital heart disease offering a less invasive approach, and novel hybrid procedures will likely be a focus of future research in this field.

Impact of imaging approach on radiation dose and associated cancer risk in children undergoing cardiac catheterization.

OBJECTIVES: To quantify the impact of image optimization on absorbed radiation dose and associated risk in children undergoing cardiac catheterization. BACKGROUND: Various imaging and fluoroscopy system technical parameters including camera magnification, source-to-image distance, collimation, antiscatter grids, beam quality, and pulse rates, all affect radiation dose but have not been well studied in younger children. METHODS: We used anthropomorphic phantoms (ages: newborn and 5 years old) to measure surface radiation exposure from various imaging approaches and estimated absorbed organ doses and effective doses (ED) using Monte Carlo simulations. Models developed in the National Academies' Biological Effects of Ionizing Radiation VII report were used to compare an imaging protocol optimized for dose reduction versus suboptimal imaging (+20 cm source-to-image-distance, +1 magnification setting, no collimation) on lifetime attributable risk (LAR) of cancer. RESULTS: For the newborn and 5-year-old phantoms, respectively ED changes were as follows: +157% and +232% for an increase from 6-inch to 10-inch camera magnification; +61% and +59% for a 20 cm increase in source-to-image-distance; -42% and -48% with addition of 1-inch periphery collimation; -31% and -46% with removal of the antiscatter grid. Compared with an optimized protocol, suboptimal imaging increased ED by 2.75-fold (newborn) and fourfold (5 years old). Estimated cancer LAR from 30-min of posteroanterior fluoroscopy using optimized versus suboptimal imaging, respectively was 0.42% versus 1.23% (newborn female), 0.20% versus 0.53% (newborn male), 0.47% versus 1.70% (5-year-old female) and 0.16% versus 0.69% (5-year-old male). CONCLUSIONS: Radiation-related risks to children undergoing cardiac catheterization can be substantial but are markedly reduced with an optimized imaging approach. © 2016 Wiley Periodicals, Inc.