Assessing the State of Training in Congenital Interventional Cardiology: A Global Survey of Program Directors.

This study aimed to evaluate the current state of congenital interventional cardiology training worldwide, with a focus on case volumes, competency assessment, and the need for ongoing mentorship during early career stages. A survey was conducted among program directors (PDs) of congenital interventional training programs across the globe. The survey gathered data on training pathways, case volumes, types of procedures performed, trainee competency assessment, and the role of ongoing mentorship. Of the 79 PDs who completed the survey, it was observed that training pathways and case volumes varied significantly, particularly between the United States and other countries. Most PDs reported an annual laboratory case volume of >500 congenital cardiac cases, with most cases being interventional. While trainees demonstrated competency in simple procedures (diagnostic cases, simple ASD closure), complex interventions (such as patent ductus arteriosus closure in premature infants) require ongoing mentorship for graduates. PDs recommended a minimum case volume of 400 total cases for trainees, including 250 interventional cases. In addition to case volumes, assessing trainee competency was deemed important, with clinical reasoning, judgment, skillset, teamwork, and complication management being key areas of evaluation. The study highlights the variability in congenital interventional cardiology training and the need for ongoing mentorship during the early career years. External mentorship programs, facilitated by national and international societies, are proposed to provide critical support for early career interventionalists thus enhancing patient care for congenital heart disease. Ultimately, the findings of this survey may serve as a framework for future training standards and guidelines in this specialized field.

Meta-analysis: Incidence of cirrhosis and hepatocellular carcinoma in patients with Fontan palliation.

BACKGROUND AND AIMS: The Fontan palliation is the final stage of surgery for many children born with univentricular physiology. Almost all Fontan patients develop liver fibrosis which may eventually lead to cirrhosis and hepatocellular carcinoma (HCC). These are important causes of morbidity and mortality in these patients. We performed a systematic review and meta-analysis to assess the incidence of cirrhosis and HCC in Fontan patients and stratify it based on time since surgery. METHODS: A literature search of seven databases identified 1158 records. Studies reporting the number of cirrhosis and HCC cases in Fontan patients and time since Fontan surgery were included. In the cirrhosis cohort, we included only those studies where all patients underwent liver biopsy. RESULTS: A total of 23 studies were included: 12 and 13 studies in the cirrhosis and HCC cohorts, respectively, with two studies included in both cohorts. The incidence of cirrhosis was 0.97 per 100 patient-years (95% CI 0.57-1.63), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 1.61 per 100 patient-years (95% CI 1.24-2.08) and 32.2% (95% CI 25.8%-39.4%), respectively. The incidence of HCC was 0.12 per 100 patient-years (95% CI 0.07-0.21), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 0.20 per 100 patient-years (95% CI 0.12-0.35) and 3.9% (95% CI 2.2%-6.8%), respectively. Only about 70% of patients with HCC (20/28) had underlying cirrhosis. CONCLUSION: The incidence of cirrhosis and HCC increases over time, especially at ≥20 years post Fontan surgery. Studies are needed to further identify at-risk patients in order to streamline surveillance for these highly morbid conditions.

Cardiac magnetic resonance haemodynamics in paediatric heart transplant patients: fick oximetry versus cardiac magnetic resonance phase contrast.

BACKGROUND: Lifetime radiation exposure for paediatric orthotopic heart transplant (OHT) patients is significant with cardiac catheterisation as the dominant source. Interventional cardiac magnetic resonance is utilised to obtain simultaneous, radiation-free haemodynamics and flow/function measurements. We sought to compare invasive haemodynamic measurements and radiation exposure in traditional cardiac catheterisation, to comprehensive interventional cardiac magnetic resonance. METHODS: Twenty-eight OHT patients who underwent 67 interventional cardiac magnetic resonance procedures at Children's National Hospital were identified. Both invasive oximetry with peripheral oxygen saturation (Fick) and cardiac magnetic resonance phase contrast measurements of pulmonary and systemic blood flow were performed. Systemic and pulmonary blood flow from the two modalities was compared using Bland-Altman, concordance analysis, and inter-reader correlation. A mixed model was implemented to account for confounding variables and repeat encounters. Radiation dosage data were collected for a contemporaneous cohort of orthotopic heart transplant patients undergoing standard, X-ray-guided catheterisation. RESULTS: Simultaneous cardiac magnetic resonance and Fick have poor agreement in our study based on Lin's correlation coefficient of 0.68 and 0.73 for pulmonary and systemic blood flow, respectively. Bland-Altman analysis demonstrated a consistent over estimation of cardiac magnetic resonance cardiac output by Fick. The average indexed dose area product for patients undergoing haemodynamics with endomyocardial biopsy was 0.73 (SD ±0.6) Gy*m2/kg. With coronary angiography added, the indexed dose area product was 14.6 (SD ± 7.8) Gy*m2/kg. CONCLUSIONS: Cardiac magnetic resonancemeasurements of cardiac output/index in paediatric orthotopic heart transplant patients have poor concordance with Fick estimates; however, cardiac magnetic resonance has good internal validity and inter-reader reliability. Radiation doses are small for haemodynamics with biopsy and increase exponentially with angiography, identifying a new target for cardiac magnetic resonance imaging.

Accuracy of free-breathing multi-parametric SASHA in identifying T1 and T2 elevations in pediatric orthotopic heart transplant patients.

T1/T2 parametric mapping may reveal patterns of elevation ("hotspots") in myocardial diseases, such as rejection in orthotopic heart transplant (OHT) patients. This study aimed to evaluate the diagnostic accuracy of free-breathing (FB) multi-parametric SAturation recovery single-SHot Acquisition (mSASHA) T1/T2 mapping in identifying hotspots present on conventional Breath-held Modified Look-Locker Inversion recovery (BH MOLLI) T1 and T2-prepared balanced steady-state free-precession (BH T2p-bSSFP) maps in pediatric OHT patients. Pediatric OHT patients underwent noncontrast 1.5T CMR with BH MOLLI T1 and T2p-bSSFP and prototype FB mSASHA T1/T2 mapping in 8 short-axis slices. FB and BH T1/T2 hotspots were segmented using semi-automated thresholding (ITK-SNAP) and their 3D coordinate locations were collected (3-Matic, Materialise, Leuven, Belgium). Receiver operator characteristic curve analysis and measures of central tendency were utilized. 40 imaging datasets from 23 pediatric OHT patients were obtained. FB mSASHA yielded a sensitivity of 82.8% for T1 and 80% for T2 maps when compared to the standard BH MOLLI, as well as 100% specificity for both T1 and T2 maps. When identified on both FB and BH maps, hotspots overlapped in all cases, with an average long axis offset between FB and BH hotspot centers of 5.8 mm (IQR 3.5-8.2) on T1 and 5.9 mm (IQR 3.5-8.2) on T2 maps. FB mSASHA T1/T2 maps can identify hotspots present on conventional BH T1/T2 maps in pediatric patients with OHT, with high sensitivity, specificity, and overlap in 3D space. Free-breathing mapping may improve patient comfort and facilitate OHT assessment in younger patient populations.

The Effect of Udenafil on Heart Rate and Blood Pressure in Adolescents With the Fontan Circulation.

The Fontan Udenafil Exercise Longitudinal (FUEL) trial showed that treatment with udenafil was associated with improved exercise performance at the ventilatory anaerobic threshold in children with Fontan physiology. However, it is not known how the initiation of phosphodiesterase 5 inhibitor therapy affects heart rate and blood pressure in this population. These data may help inform patient selection and monitoring after the initiation of udenafil therapy. The purpose of this study is to evaluate the effects of udenafil on vital signs in the cohort of patients enrolled in the FUEL trial. This international, multicenter, randomized, double-blind, placebo-controlled trial of udenafil included adolescents with single ventricle congenital heart disease who had undergone Fontan palliation. Changes in vital signs (heart rate [HR], systolic [SBP] and diastolic blood pressure [DBP]) were compared both to subject baseline and between the treatment and the placebo groups. Additional exploratory analyses were performed to evaluate changes in vital signs for prespecified subpopulations believed to be most sensitive to udenafil initiation. Baseline characteristics were similar between the treatment and placebo cohorts (n = 200 for each). The groups demonstrated a decrease in HR, SBP, and DBP 2 hours after drug/placebo administration, except SBP in the placebo group. There was an increase in SBP from baseline to after 6-min walk test in the treatment and placebo groups, and the treatment group showed an increase in HR (87.4 ± 15.0 to 93.1 ± 19.4 beats/min, p <0.01) after exercise. When comparing changes from baseline to the 26-week study visit, small decreases in both SBP (-1.9 ± 12.3 mm Hg, p = 0.03) and DBP (-3.0 ± 9.6 mm Hg, p <0.01) were seen in the treatment group. There were no clinically significant differences between treatment and placebo group in change in HR or blood pressure in the youngest age quartile, lightest weight quartile, or those on afterload-reducing agents. In conclusion, initiation of treatment with udenafil in patients with Fontan circulation was not associated with clinically significant changes in vital signs, implying that for patients similar to those enrolled in the FUEL trial, udenafil can be started without the requirement for additional monitoring after initial administration.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

BACKGROUND: The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool. METHODS: PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried. RESULTS: A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions. CONCLUSIONS: Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

Measured Oxygen Consumption During Pediatric Cardiac Catheterization is More Accurate than Assumed Oxygen Consumption.

When calculating cardiac index (C.I.) by the Fick method, oxygen consumption (VO2) is often unknown, so assumed values are typically used. This practice introduces a known source of inaccuracy into the calculation. Using a measured VO2 (mVO2) from the CARESCAPE E-sCAiOVX module provides an alternative that may improve accuracy of C.I. calculations. Our aim is to validate this measurement in a general pediatric catheterization population and compare its accuracy with assumed VO2 (aVO2). mVO2 was recorded for all patients undergoing cardiac catheterization with general anesthesia and controlled ventilation during the study period. mVO2 was compared to the reference VO2 (refVO2) determined by the reverse Fick method using cardiac MRI (cMRI) or thermodilution (TD) as a reference standard for measurement of C.I. when available. 193 VO2 measurements were obtained, including 71 with a corresponding cMRI or TD measure of cardiac index for validation. mVO2 demonstrated satisfactory concordance and correlation with the TD- or cMRI-derived refVO2 (ρc = 0.73, r2 = 0.63) with a mean bias of - 3.2% (SD ± 17.3%). Assumed VO2 demonstrated much weaker concordance and correlation with refVO2 (ρc = 0.28, r2 = 0.31) with a mean bias of + 27.5% (SD ± 30.0%). Subgroup analysis of patients < 36 months of age demonstrated that error in mVO2 was not significantly different from that observed in older patients. Many previously reported prediction models for assuming VO2 performed poorly in this younger age range. Measured oxygen consumption using the E-sCAiOVX module is significantly more accurate than assumed VO2 when compared to TD- or cMRI-derived VO2 in a pediatric catheterization lab.

Hybrid strategy in neonates with ductal-dependent systemic circulation and multiple risk factors.

OBJECTIVE: The study objective was to analyze outcomes of the hybrid strategy for ductal-dependent systemic circulation consisting of bilateral pulmonary artery banding with or without ductal stenting followed by delayed Norwood-type palliation or comprehensive stage II operation in high-risk neonates. METHODS: A retrospective analysis was performed between December 2017 and March 2021. Thirty high-risk neonates underwent palliation with bilateral pulmonary artery banding: 11 with prostaglandin therapy and 19 with ductal stenting. Median (range) age and body weight of patients at hybrid stage I were 3 days (0-43) and 2.9 kg (1.1-4.2), respectively. Operative and interstage mortality, morbidity, and reintervention rates were assessed. RESULTS: Overall survival was 70% (21/30) at a median follow-up time of 9 months (range, 0-37) from hybrid stage I. Operative survival for hybrid stage I was 90% (27/30), of which 2 patients received palliative care, and there was 1 interstage death (4%, 1/27). After hybrid stage I, 37% of patients had a reintervention, and 3% (n = 1) used extracorporeal membrane oxygenation before the next stage of repair. Five patients are awaiting second-stage operation, and 9 patients are awaiting Fontan completion. CONCLUSIONS: High-risk neonates with hypoplastic left heart syndrome or its variants can be successfully palliated using the hybrid strategy and bridged to a delayed Norwood or comprehensive stage II operation with satisfactory survival. This operative approach is a promising alternative pathway for neonates deemed to be high risk due to multiple preoperative risk factors.

Myocardial infarction due to thrombosis of native aorta late after Fontan procedure for hypoplastic left heart syndrome.

Patients with single ventricle physiology who have undergone the Fontan procedure are at risk for long-term complications such as thrombus formation. Thrombus formation in the native aortic root (NAR) can be life-threatening if retrograde filling of the coronary arteries (CAs) is impaired. We present three cases of NAR thrombus with embolization to the CA, resulting in myocardial infarction. Thromboembolic events are well-documented complications of Fontan physiology, and optimal prevention and treatment strategies are poorly defined.

Spontaneous rupture of a coronary artery fistula presenting with post-exertional syncope and haemopericardium.

An 8-year-old with a known diagnosis of an asymptomatic coronary artery fistula (CAF) presented with exertional syncope and haemopericardium due to contained rupture of CAF. A transcatheter closure was attempted, but the fistula ruptured again prompting emergency surgical repair. Spontaneous rupture is a catastrophic complication of CAF and warrants a high index of suspicion, timely diagnosis and team management.

Diagnosis and management of the adult patient with a failing Fontan circulation.

Since the original description, the Fontan operation has been widely used for the palliation of children with single ventricle physiology. Although the Fontan operation revolutionized the survival rates of patients with single ventricle physiology, it carries an inevitable risk for long-term morbidity and mortality that impacts clinical outcomes and quality of life. This review will focus on the evaluation and treatment of the patient with the failing Fontan phenotype, with an emphasis on creating an individualized treatment plan.

Reintervention Burden and Vessel Growth After Surgical Reimplantation of a Pulmonary Artery During Childhood.

Children requiring reimplantation of a branch pulmonary artery (PA) are at risk for postoperative stenosis and impaired growth of the reimplanted PA. Outcomes and risk factors for reintervention and impaired growth are incompletely described. We reviewed data on patients who underwent reimplantation of a branch PA between 1/1/99 and 5/1/15 at a single center. The primary outcome was reintervention to treat postoperative stenosis. The secondary outcome was "catch-up" growth (faster diameter growth of the affected PA compared with the unaffected PA from the preoperative to follow-up measurements.). Twenty-six patients were identified with a total follow-up of 102.2 patient-years (median 2.5 years). Diagnoses included LPA sling (n = 12) and isolated PA of ductal origin with (n = 7) or without (n = 7) tetralogy of Fallot (ToF). All had primary repair of the anomalous PA. Seventeen (65%) had reintervention with median time to first reintervention of 69 (range 1-1005) days and median of 1.5 (range 1-6) reinterventions. 94% of reinterventions were transcatheter (53% balloon and 41% stent angioplasty). Patients with reintervention were younger (hazard ratio 0.75 per log-day, p = 0.02) and lower weight (hazard ratio 0.18 per log-kg, p = 0.02) at initial repair. Of the 18 with PA growth data, 8 (44%) had catch-up growth. There were no identified differences between those who did and did not demonstrate catch-up growth. Despite a practice of primary reimplantation and aggressive postoperative reintervention, these results suggest that changes in strategy are needed or that there are intrinsic patient factors that have more influence on longer-term reimplanted PA growth.

Surgical and Catheter-Based Reinterventions Are Common in Long-Term Survivors of the Fontan Operation.

BACKGROUND: There are limited follow-up studies examining surgical and catheter-based reinterventions in long-term survivors of the Fontan operation. METHODS AND RESULTS: All 773 patients who underwent Fontan at our institution between 1992 and 2009 were retrospectively reviewed. Current information regarding post-Fontan intervention was available for 70%. By 20 years after Fontan, 65% of patients had experienced either surgical or transcatheter intervention. The median time to first reintervention was 9.8 years. Freedom from reoperation was 69% at 15 years and 63% at 20 years. The most common operations were pacemaker placement and Fontan revision. Risk factors for pacemaker placement included systemic left ventricle (hazard ratio [HR], 2.2; P=0.006) and lateral tunnel Fontan (HR, 4.3; P=0.001). Freedom from interventional catheterization was 53% at 15 years and 50% at 20 years. The most common procedures performed were fenestration closure and pulmonary artery intervention. Catheter intervention for anatomic indications was associated with Fontan after 2002 (HR, 2.1; P=0.007), Norwood operation (HR, 2.3; P=0.001), and longer cardiopulmonary bypass time (HR, 1.1 per 10 minutes; P=0.001). Catheter intervention for physiological indications was associated with prolonged post-Fontan pleural drainage (HR, 4.0; P<0.001) and hypoplastic left heart syndrome (HR, 2.0; P=0.01). CONCLUSIONS: In this study of Fontan survivors, two thirds of patients required surgical or catheter-based reintervention by 20 years. Families should be counseled that the Fontan is typically not the final stage of single-ventricle palliation.

Effect of Fontan-Associated Morbidities on Survival With Intact Fontan Circulation.

Although survival after the Fontan operation has improved, little is known about the burden of major medical morbidities associated with the modern total cavopulmonary connection (TCPC). A total of 773 consecutive patients who underwent a first Fontan operation at our institution between 1992 and 2009 were retrospectively reviewed. All subjects underwent TCPC (53% lateral tunnel, 47% extracardiac conduit). Median length of follow-up was 5.3 years (interquartile range 1.4 to 11.2), and 30% had follow-up >10 years. Freedom from a composite medical morbidity outcome (protein-losing enteropathy, plastic bronchitis, serious thromboembolic event, or tachyarrhythmia) was 47% at 20 years (95% confidence interval [CI] 38 to 55). Independent risk factors for morbidity included pre-Fontan atrioventricular valve regurgitation (hazard ratio [HR] 1.7, 95% CI 1.2 to 2.4, p = 0.001), pleural drainage >14 days (HR 1.5, 95% CI 1.01 to 2.2, p = 0.04), and longer cross-clamp time (HR 1.2 per 10 minutes, 95% CI 1.06 to 1.3, p = 0.004) at the time of TCPC. Surgical era, Fontan type, and ventricular morphology were not associated with the composite outcome. Presence of Fontan-associated morbidity was associated with a 36-fold increase in the risk of subsequent Fontan takedown, heart transplantation, or death (95% CI 17 to 76, p <0.001). For patients without any component of the composite outcome, freedom from Fontan failure was 98% at 20 years (95% CI 96 to 99). Medical morbidities after TCPC are common and significantly reduce the longevity of the Fontan circulation. However, for those patients who remain free from the composite morbidity outcome, 20-year survival with intact Fontan circulation is encouraging.

Long-term survival after the Fontan operation: Twenty years of experience at a single center.

OBJECTIVE: Existing studies of patients palliated with the Fontan operation are limited by heterogeneous patient populations and incomplete follow-up. This study aimed to describe long-term post-Fontan survival in a modern patient cohort. METHODS: All 773 patients who underwent a first Fontan operation at our institution between 1992 and 2009 were reviewed. The primary outcome was the composite endpoint of Fontan takedown, heart transplantation, or death before 2013. RESULTS: Follow-up rate was 99.2%. Survival with intact Fontan circulation was 94% at 1 year (95% confidence interval [95% CI], 92%-95%), 90% at 10 years (95% CI, 88%-92%), 85% at 15 years (95% CI, 82%-88%), and 74% at 20 years (95% CI, 67%-80%). Distinct risk factors were identified for early (≤1 year) and late composite outcomes. Independent risk factors for early outcome included prolonged pleural drainage (hazard ratio [HR], 4.4; P < .001), intensive care unit stay >1 week (HR, 2.4; P < .001), Fontan before 1997 (HR, 3.3; P < .001), preoperative atrioventricular valve regurgitation (HR, 2.0; P < .001), and longer crossclamp time (HR, 1.3 per 10 minutes; P < .001). Late outcome was predicted by atrioventricular valve regurgitation prior to Fontan (HR, 2.0; P ≤ .001), and post-Fontan ICU stay >1 week (HR, 2.4; P < .001). CONCLUSIONS: Long-term mortality after Fontan operation remains substantial. Risk factors for death or loss of Fontan circulation differ between the early and late postoperative periods. Long-term survival has not improved appreciably over the last decade, suggesting that alternatives to the Fontan are warranted.

Tetralogy of Fallot: General Principles of Management.

Repaired tetralogy of Fallot (TOF) is one of the most common diagnoses encountered when caring for adults with congenital heart disease. Although long-term survival after childhood TOF repair is excellent, morbidity is common and most patients require reintervention in adulthood. This review provides an overview of key surveillance and management issues for adults with TOF, including residual right ventricular outflow tract disease and timing of pulmonary valve replacement, arrhythmias and risk stratification, left-sided heart disease and heart failure, and pregnancy management.

Cumulative medical radiation exposure throughout staged palliation of single ventricle congenital heart disease.

Patients with single ventricle heart disease undergoing staged palliation are exposed to ionizing radiation from multiple medical sources. We sought to quantify typical radiation burden in this population and identify risk factors for increased exposure. A retrospective review was performed of single ventricle patients surgically palliated at our institution, in which all studies utilizing ionizing radiation occurring from birth through Fontan completion were compiled. Thirty-eight patients were followed for a median of 33 months. A median of 59 radiation events occurred during follow-up, with a median cumulative effective dose of 25.7 milliSieverts (mSv). On average, cardiac catheterization accounted for 4% of radiation encounters but comprised 78% of total radiation exposure. In a multivariate model, factors associated with increased total radiation exposure included pulmonary artery (PA) stenosis requiring intervention (p = 0.005) and systemic right ventricle (p = 0.02). Risk factors for increased exposure from catheterization included heterotaxy syndrome (p = 0.007), re-coarctation (p = 0.003), and PA stenosis (p = 0.02). At our institution, many single ventricle patients are exposed to substantial radiation throughout staged palliation, most of which derives from cardiac catheterization. PA stenosis was identified as a risk factor for increased total and catheterization-based exposure. As patient survival improves, awareness of this scale of radiation exposure at a vulnerable period is imperative.

Cumulative exposure to medical sources of ionizing radiation in the first year after pediatric heart transplantation.

BACKGROUND: Pediatric heart transplant recipients undergo a variety of radiologic tests with the attendant risk of exposure to ionizing radiation. We sought to quantify and describe the cumulative exposure to all forms of medical radiation during the first year after pediatric heart transplantation and identify factors associated with higher exposure. METHODS: Pediatric patients who received a heart transplant between January 2009 and May 2012 with follow-up at our institution were retrospectively reviewed. Patients were included if they survived through 1 year and the first coronary angiography. All medical testing using ionizing radiation performed during follow-up was compiled, and exposures were converted to effective dose (mSv). RESULTS: Included were 31 patients who underwent heart transplantation at a median age of 13.6 years (range, 0.3-18.3 years). The median number of radiologic tests performed was 38 (range, 18-154), including 8 catheterizations (range, 2-12), and 28 X-ray images (range, 11-135). Median cumulative effective dose was 53.5 mSv (range, 10.6-153.5 mSv), of which 91% (range, 34%-98%) derived from catheterizations, 31% (range, 8%-89%) of the exposure occurred during the transplant admission, 59% (range, 11%-88%) during planned follow-up, and 3% (0%-56%) during unplanned follow-up. Older age at transplant was a risk factor for increased exposure (p = 0.006). When adjusted for age, a trend toward increased exposure was shown for congenital heart disease as the indication for transplant (p = 0.08), pre-sensitization (p = 0.12), and positive crossmatch (p = 0.09). CONCLUSIONS: Pediatric heart transplant patients are exposed to significant amounts of ionizing radiation during the first post-transplant year, most during scheduled catheterization. As survival improves, considering the long-term risks associated with these levels of exposure is important.