Pediatric Cardiac Catheterization Research Articles

Elective Extracorporeal Membrane Oxygenation Support for High-Risk Pediatric Cardiac Catheterization

The utility of extracorporeal membrane oxygenation (ECMO) as an elective support modality for high-risk cardiac procedures is extensively described in adults, but its use in children is limited to isolated reports. The objective of this study was to analyze the outcomes of patients who underwent elective cannulation to ECMO for this purpose. Single-center, retrospective chart review. Free-standing pediatric tertiary care center. Patients who underwent elective cannulation to ECMO for cardiorespiratory support during a high-risk cardiac catheterization procedure. Elective ECMO cannulation for high-risk percutaneous cardiac interventions or electrophysiology procedures. Survival to discharge was 71.4% compared with 30% for patients who required extracorporeal cardiopulmonary resuscitation in the cardiac catheterization laboratory. The mean duration of cannulation was 137.43 hours (range 27-615 h, median 55 h). There were no major neurologic sequelae, but ECMO circuit thrombosis (57%) was relatively common. The use of elective ECMO support for high-risk pediatric cardiac catheterizations can be accomplished safely and may allow for an improved rate of survival with lower rates of severe adverse events compared with extracorporeal cardiopulmonary resuscitation as rescue therapy.

The current practice and care of paediatric patients post cardiac catheterisation.

Literature is lacking to guide standardised care and assessment practices for paediatric patients post cardiac catheterisation. In response to this gap, we sought to describe the current state of practice in cardiology programmes performing paediatric cardiac catheterisations procedures in the United States of America.Materials and methodsA web-based survey was distributed to the Congenital Cardiovascular Interventional Study Consortium Listserv, with representation from 113 identified institutions. A 36-question survey, including fixed-choice and open-ended questions, was developed and piloted for reliability and validity before distribution. Data were summarised descriptively with count and frequency or median and range. Of the 113 identified institutions, 52% (n=59) responded to the survey. Manual pressure is used to achieve haemostasis by 94.9% of the respondents. Pressure dressings are used by a majority of the facilities and the length of time for bed rest is variable, with the majority using 6 hours for arterial access and 4 hours for venous access. Predominantly, respondents use the time of haemostasis as the start time of bed rest while a third of respondents reported using the time the sheath was removed. In this study, variation in a number of post catheterisation care and assessment practices for paediatric patients was noted across cardiology programmes. Information from this assessment identifies key opportunities to collaborate in developing standardised practices for the care and assessment of the paediatric patients post catheterisation.

Reducing radiation exposure by lowering frame rate in children undergoing cardiac catheterization: A quality improvement study.

Reduction of radiation dosage in the pediatric cardiac catheterization laboratory (PCL) is important to reduce the risk of its stochastic effect in children with congenital heart disease. Lowering the frame rate would reduce radiation dosage possibly at the expense of image quality, potentially resulting in higher fluoroscopic time and procedural complication rate. The data were retrospectively analyzed in three eras: era 1 (n=234), cineangiography 30frames/sec (f/s) and fluoroscopy 15pulse/sec (p/s); era 2 (n=381), cineangiography 30f/s and fluoroscopy 6p/s; and era 3 (n=328), cineangiography 15f/s and fluoroscopy 6p/s. Also, three operators blinded to the frame rate setting evaluated cineangiography image quality. In this study, the impact of lowering the default frame rates on radiation dosage, fluoroscopic time, contrast volume, diagnostic image quality, and complication rates in the PCL was assessed. Overall radiation dosage progressively declined during these eras (70.0 vs 64.1 vs 36.6 µGym2 /kg, P<.001) without a difference in significant adverse event rates. There was no significant increase in either fluoroscopy time or contrast volume. There was no difference in the diagnostic image quality between cineangiography 30 and 15f/s. Lowering the default frame/pulse rates of both fluoroscopy and cineangiography significantly decreased the overall radiation dosage in the PCL. Importantly, fluoroscopy time, contrast volume, and complication rates did not increase while maintaining diagnostic image quality. This quality improvement project proved successful in lowering radiation dosage without compromising the efficacy and safety of catheterizations.

Feasibility, Safety and Accuracy of Echocardiography-Fluoroscopy Imaging Fusion During Percutaneous Atrial Septal Defect Closure in Children

Imaging fusion between echocardiography and fluoroscopy was recently developed. The aim of this study was to assess its feasibility and accuracy during pediatric cardiac catheterization. Thirty-one patients (median weight, 26kg; interquartile range [IQR], 21-37kg) who underwent percutaneous atrial septal defect closure were prospectively included. The feasibility and accuracy of various imaging fusion modalities (live two-dimensional, live color two-dimensional, live three-dimensional and markers) with EchoNavigator software were assessed. To assess the accuracy of spatial registration of the echocardiogram on the fluoroscopic image, the occluder screw, an object that appeared on each image, was used as a reference tool, and the distance between the two when fused was measured. A distance was measured on the fusion screen between a marker positioned on the screw from the echocardiography screen and from the fluoroscopy screen (distance 1). Another distance was measured on the fusion screen between the screw visualized by three-dimensional echocardiography and by fluoroscopy (distance 2). The two distances were measured on four C-arm orientations in end-systolic and end-diastolic frames. Fusion and marker positioning were feasible in real time in all cases. On the fusion screen, median systolic and diastolic distance 1 were 0.5mm (IQR, 0.3-1mm) and 2mm (IQR, 1.5-2.5mm; P<.0001), respectively. The marker positioned from the echocardiography screen was fixed on the fusion screen anddid not follow the movement of the screw. Median systolic and diastolic distance 2 were 0.5mm (IQR, 0-0.5mm) and 2mm (IQR, 1.5-2.5mm; P<.0001), respectively. Echocardiographic fluoroscopic imaging fusion is feasible, safe, and accurate in children weighting >20kg. This technique offers a new method of imaging guidance in the catheterization laboratory for complex procedures and training.

Audit on Preparations for Pediatric Cardiac Catheterization

Audit on Preparations for Pediatric Cardiac Catheterization

Simulation for Safety in the Pediatric Cardiac Catheterization Laboratory

AbstractTreating congenital heart disease is a high-risk, high-benefit scenario, be it in the operating rooms or in cardiac catheterization labs. Inherent to the high-risk nature of the disease, adverse events of varying severity can happen during cath or surgical intervention. These have been traditionally the ‘real’ clinical teaching for the physician. Simulation technology helps physicians to be trained stress-free in zero-risk environments, especially for the low-frequency, high-risk events. But as always, introduction of new technology faces barriers, so is the case with simulators. Anesthesiology proudly compares itself to the aviation industry, which had also ridiculed aviation simulators in the 1970s. Now they are mandated by all worldwide aviation training authorities. Maybe its time for the anesthesiologists to take the lead in simulation in the health care sector too.

Effect of Nursing Guidelines for Nurses on Occurrence of Selected Post Therapeutic Cardiac Catheterization Complications Among Children

Abstract Background: Pediatric cardiac catheterization has shifted from a diagnostic tool to a therapeutic one and now more applicable for therapeutic reasons.Aim of Study: The aim of the current study was to evaluate the effect of guidelines for nurses on occurrence of selected post therapeutic cardiac catheterization complications among children.Subjects and Methods: Quasi-experimental design (Pre-Posttest) was used to achieve the aim of the current study. A convenient sample of 30 nurses and 60 children having cardiac defects undergoing cardiac catheterization were participated in the current study; children were divided into two equal groups: 30 as a control group and 30 as a study group and nurses were the same for the study and control group of children. The current study was conducted at post cardiac catheterization Intensive Care Unit at Cairo University Spe-cialized Pediatric Hospital (CUSPH). The required data was collected through: 1- Structured interview (questionnaire); 2- Nurses's knowledge and observed practice assessment sheet (pre-posttest) and 3- Post cardiac catheterization assessment sheet. Results: The study's results revealed that, children in the study group exposed to less post cardiac catheterization complications such as weak or absent pulse, hypotension and hypothermia; than children in the control group. There was statistically significance difference between the total mean score of nurses' knowledge before and after implementation of the nursing guidelines.Conclusion: The study concluded that nurses who received nursing guidelines sessions had improved outcomes in relation to less complications on children they were caring. Recom-mendation: It was recommended that provision of nursing guidelines of children undergoing cardiac catheterization is mandatory for fewer occurrences of complications. Simple Arabic illustrated booklet about cardiac catheterization care for children undergoing CC should be available in every post CC unit.

Abstract 227: Inter-hospital Variation in Costs of Pediatric Cardiac Catheterization: An Analysis of the PHIS Database

Background: No previous studies have studied the variation in costs between hospitals for catheterization procedures performed in children. Variation in cost not explained by differences in case-mix can indicate opportunities to improve efficiency and quality of care. Methods: A multicenter observational study was performed, studying total hospital costs of 9 common transcatheter procedures (diagnostic procedures in 2 populations and 7 interventional procedures) performed between 2007-2015 at hospitals contributing data to the Pediatric Health Information Systems database. Mixed effects models were used to adjust costs for case mix and to assess inter-hospital variation. Bayesian methods were used to calculate risk-standardized costs for each hospital. Results: The study included 35,637 procedures from 43 hospitals. Median costs (US 2015 dollars) increased roughly with technical complexity, from $8,249 (heart transplant diagnostic catheterization) to $38,909 (transcatheter pulmonary valve replacement). There was significant inter-hospital variation in cost for each procedure ( p &lt;0.0001). After case mix-adjustment, the range of standardized costs remained broad (Table). These differences were not explained by differences in hospital catheterization volume. Conclusion: There is significant inter-hospital variation in costs of transcatheter procedures after case-mix adjustment. Exploring the etiology of these differences is an opportunity to improve care of children with heart disease.

Recent advances in cardiac catheterization for congenital heart disease.

The field of pediatric and adult congenital cardiac catheterization has evolved rapidly in recent years. This review will focus on some of the newer endovascular technological and management strategies now being applied in the pediatric interventional laboratory. Emerging imaging techniques such as three-dimensional (3D) rotational angiography, multi-modal image fusion, 3D printing, and holographic imaging have the potential to enhance our understanding of complex congenital heart lesions for diagnostic or interventional purposes. While fluoroscopy and standard angiography remain procedural cornerstones, improved equipment design has allowed for effective radiation exposure reduction strategies. Innovations in device design and implantation techniques have enabled the application of percutaneous therapies in a wider range of patients, especially those with prohibitive surgical risk. For example, there is growing experience in transcatheter duct occlusion in symptomatic low-weight or premature infants and stent implantation into the right ventricular outflow tract or arterial duct in cyanotic neonates with duct-dependent pulmonary circulations. The application of percutaneous pulmonary valve implantation has been extended to a broader patient population with dysfunctional ‘native’ right ventricular outflow tracts and has spurred the development of novel techniques and devices to solve associated anatomic challenges. Finally, hybrid strategies, combining cardiosurgical and interventional approaches, have enhanced our capabilities to provide care for those with the most complex of lesions while optimizing efficacy and safety.

Complications of cardiac catheterization in children with congenital heart disease.

Tokel K, Gümüş A, Ayabakan C, Varan B, Erdoğan İ. Complications of cardiac catheterization in children with congenital heart disease. Turk J Pediatr 2018; 60: 675-683. Catheterization procedures for congenital heart disease include a broad range of procedures with a large spectrum of potential adverse outcomes. We aimed to determine the incidence of various complications during pediatric cardiac catheterizations and to designate the relative risk factors for such complications. All pediatric patients undergoing cardiac catheterizations between January 2005-December 2010 were included. Data are collected prospectively by filling out computerized catheterization reports. Patient records were scanned for potential risk factors retrospectively. Groups were divided based on cardiac diagnosis; type of procedure. Adverse events were categorized into major or minor events. A total of 2662 cardiac catheterizations were performed during this period. The mean age of patients was 53.2±64.3 months. Diagnostic catheterizations were done for 1797 (67.5%) patients, and interventional procedures were done in 865 (32.5%) cases. Adverse events were observed in 688 patients (26%) during 941 procedures. Minor and major events were seen in 21.4% and 7.1% of the procedures respectively. Most frequent major complications were anesthesia related (6%), most frequent minor complications were vascular complications (45.2%). Complications were more frequent in younger patients (p=0.0001), during interventional procedures (p=0.0001). Thirteen patients died after a cardiac catheterization; they were younger and had longer procedures compared to those who survived (p=0.0001). Vascular complications were frequent among younger patients, with prolonged procedure time and vessel access (p < 0.0001). Cyanotic patients had more complications (p < 0.05; OR for major and minor complications: 3.5 and 2 respectively). Minor complications were 2.7 times more likely in ventricular outflow obstructions (p < 0.05). The complication rates of cardiac catheterization in children are low, but not negligible. Defining risk factors will help anticipate adverse events, which will guide in preparation for rescue procedures and improvement of patient safety systems in catheterization laboratories.

The role of diagnostic cardiac catheterization for children with congenital heart diseases: local experience.

IntroductionDespite the development of non-invasive tools of investigations for congenital heart diseases (CHDs), still the role of diagnostic cardiac catheterization (DCC) cannot be undermined. The study aimed to analyze the clinical profile of indicated CHDs cases at our center for DCC to evaluate the contribution of DCC in patients’ management plans.Material and methodsThe study checked files of cases performed DCC between 2011 and 2012 at the pediatric catheterization unit of Alexandria University Children’s Hospital by the same operator. Demographic, laboratory and hemodynamic data were collected and analyzed.ResultsFiles of 61 children were included in the study. They were grouped into: group I (GI) (n = 25) with pulmonary hypertension (PH), and group II (GII) (n = 36) cases with obstructive pulmonary artery diseases. For the PH group, ventricular septal defect (VSD) was the most common (55%), and patients’ outcome plans were based on angiography – operable subgroup GI-A: (84%) (n = 21) and non-operable (16%) GI-B: (4% inoperable, 12% recommended for sildenafil). GI-B cases were significantly older, with higher PVRI and PVRI/SVRI (3.62, 0.68, p = 0.002) compared to GI-A (0.89, 0.23, p = 0.002, respectively). For group II, tetralogy of Fallot (TOF) was predominant (60%) among the disease spectrum, and the McGoon ratio ranged from 0.7 to 3.2 (median: 1.8). Outcome for GII: 63% operable, 25% shunt, 12% stent. Only pulmonary atresia cases showed a significant difference in the unmatched plans between echocardiography and catheterization reports (χ2 = 7.438, p = 0.023).ConclusionsDiagnostic cardiac catheterization had a positive contribution for determination of the management plans for more than 84% of cases. The utility of pediatric cardiac catheterization in diagnosis should be adjusted according to the local needs of every cardiac center.

Anesthesia Management for Pediatric Cardiac Catheterization

Anesthesia Management for Pediatric Cardiac Catheterization

Letter to the editor regarding Cevallos PC et al. Radiation dose benchmarks in pediatric cardiac catheterization: A prospective multi-center C3P0-QI study. Catheter Cardiovasc Interv. 2017 Aug;90(2):269-280

Letter to the editor regarding Cevallos PC et al. Radiation dose benchmarks in pediatric cardiac catheterization: A prospective multi-center C3P0-QI study. Catheter Cardiovasc Interv. 2017 Aug;90(2):269-280

Removal of scatter radiation in paediatric cardiac catheterisation: a randomised controlled clinical trial

Objective. This study sought to determine if DNA integrity was compromised by ionising radiation from paediatric cardiac catheterisations and if dose optimisation techniques allowed DNA integrity to be maintained. Materials and methods. Children were imaged using either: (i) an anti-scatter grid (current departmental protocol), (ii) no anti-scatter grid or, (iii) no anti-scatter grid and a 15 cm air-gap between the child and the x-ray detector. Dose area product and image quality were assessed, lifetime attributable cancer risk estimates were calculated and DNA double-strand breakages quantified using the γH2AX assay. Results. Consent was obtained from 70 parents/guardians/children. Image quality was sufficient for each procedure performed. Removal of the anti-scatter grid resulted in dose reductions of 20% (no anti-scatter grid) and 30% (15 cm air-gap), DNA double-strand break reductions of 30% (no anti-scatter grid) and 20% (15 cm air-gap) and a reduction of radiation-induced cancer mortality risk of up to 45%. Conclusion. Radiation doses received during paediatric cardiac catheterisation procedures resulted in a significant increase in DNA damage while maintaining acceptable image quality and diagnostic efficacy. It is feasible to remove the anti-scatter grid resulting in a reduction in DNA damage to the patient. The γH2AX assay may be used for assessment of dose optimisation strategies in children.

Reduction in Radiation Dose in a Pediatric Cardiac Catheterization Lab Using the Philips AlluraClarity X-ray System.

The objective of this study was to compare radiation doses and imaging quality using Philips AlluraClarity (Philips Healthcare, Best, The Netherlands) X-ray system and an older generation reference system. AlluraClarity is a new generation fluoroscopy system designed to reduce radiation without compromising image quality, but reports of its use in pediatric patients are limited. Dose area products (DAP, mGycm2) and DAP/kg were compared in patients catheterized using Allura Xper and AlluraClarity systems over a year of use for each. Randomly selected studies from each system were assessed for image quality. The 430 patients imaged with Clarity were larger than the 332 imaged with Xper (median BSA: 0.74 vs. 0.64m2, p=0.06), and median total fluoroscopic times (TFT) were similar (15.8 vs. 16.1min, p=0.37). Median DAPs were 8661mGycm2(IQR: 18,300mGycm2) and 4523mGycm2(IQR: 11,596mGycm2) with Xper and Clarity, respectively (p<0.001). There was a reduction in median DAP in all procedure categories. After adjustment for BSA, TFT, and procedure type, using Clarity was associated with a 57.5% (95% CI 51.5-62.8%, p<0.001) reduction in DAP for all procedures. Reductions did not significantly differ by weight (<10kg, 10-40kg, ≥40kg). There was an adjusted percent reduction in DAP for each procedure category ranging from 39.0% (95% CI 25.6-50.1%, p<0.001) for cardiac biopsies with or without coronary angiography to 67.6% (95% CI 61.2-72.8%, p<0.001) for device occlusions. Mean overall imaging quality scores (4.3±0.8 with Clarity vs. 4.4±0.6 with Xper, p=0.62) and scores based on specific quality parameters were similar in the two groups. Use of AlluraClarity substantially reduced radiation doses compared to the older generation reference system without compromising imaging quality in a pediatric cardiac catheterization lab.

Comparative study between Dexmedetomidine-Ketamine and Propofol-Ketamine Combinations for Anesthesia in Spontaneously Breathing Pediatric Patients Undergoing Cardiac Catheterization

Introduction: Sedation for pediatric cardiac catheterization is a common requirement in many institutions. The goals of the anesthetic management during cardiac catheterization are adequate analgesia, sedation, immobility, and cardiovascular stability(Cravero et al, 2006). Ketamine has potential advantages includeexcellent sedation and analgesia and maintenance of airwayreflexes and respiratory drive. Also, it preserves cardiac function(Williams et al, 2007). Propofol has a predictable onset of action, a short half-life with a rapid recovery time, and is easily titratable. However, propofol is associated with profound respiratory depression, and no analgesic effect(Ewen et al, 1995). Dexmedetomidine is a highly selevtive α2 adrenoceptor agonist with more specificity for the receptor compared to clonidine, approved by FDA in 1999. It provides excellent sedation and analgesia with minimal respiratory depression (Bhana et al, 2000). Aim of work: This study aimed to compare between dexmedetomidine-ketamine and propofol-ketamine combinations in pediatric patients undergoing cardiac catheterization. Patients and methods: After local ethical committee approval an obtained consent from the parents, 44 acyanotic pediatric patients, aged 4 months to 16 years with ASA II and III, analyzed with the chi-square test.

Utility and Clinical Profile of Dexmedetomidine in Pediatric Cardiac Catheterization Procedures: A Matched Controlled Analysis.

Dexmedetomidine is increasingly used in children undergoing cardiac catheterization procedures. We compared the percentage of surgical time with hemodynamic instability and the incidence of postoperative agitation between pediatric cardiac catheterization patients who received dexmedetomidine infusion and those who did not and the incidence of postoperative agitation. We matched 653 pediatric patients scheduled for cardiac catheterization. Two separate multivariable linear mixed models were used to assess the association between dexmedetomidine use and intraoperative blood pressure and heart rate instability. A multivariate logistic regression was used for relationship between dexmedetomidine and postoperative agitation. No difference between the study groups was found in the duration of MAP ( P = .867) or heart rate (HR) instabilities ( P = .224). The relationship between dexmedetomidine use and the duration of negative hemodynamic effects does not depend on any of the considered CHD types (all P > .001) or intervention ( P = .453 for MAP and P = .023 for HR). No difference in postoperative agitation was found between the study groups ( P = .590). Our study demonstrated no benefit in using dexmedetomidine infusion compared with other general anesthesia techniques to maintain hemodynamic stability or decrease agitation in pediatric patients undergoing cardiac catheterization procedures.

Paediatric cardiac catheterisation in Norway: rates and types of complications in new terms.

We determined the incidence, type, and severity of complications after cardiac catheterisation in children with heart disease in Norway, and we present the results in terms of the International Paediatric and Congenital Cardiac Code (IPCCC) nomenclature for complications. All paediatric cardiac catheterisations in Norway are performed in one clinical centre. All procedures performed during a 5-year period beginning in 2010 were prospectively registered, and medical records for cases with complications were reviewed to confirm the event and to re-classify the type, severity, and attributability of the complication according to the IPCCC nomenclature. Univariate and multivariate analyses were performed to identify possible risk predictors. A total of 1318 catheterisations performed on 941 patients were included in the present study, of which 68% were interventional. The complication and major complication rates were 5.5 and 1.4%, respectively. Trauma to the vessels or the myocardium, haemodynamic adverse events, and arrhythmias were the most common types of complications. In the multivariate model, weight <4 kg (odds ratios, 3.0; 95% confidence intervals: 1.6-5.8) and risk category 5 (odds ratios, 5.1; 95% confidence intervals: 2.1-12.3) were significant risk predictors for any complication. In spite of a high rate of interventions, the complication rates in this study were similar to older studies, but diverging methods and terminology limit the comparability. We strongly suggest general use of the proposed IPCCC classification system for registration and reports of complications for paediatric cardiac catheterisations.

Radiation dose benchmarks in pediatric cardiac catheterization: A prospective multi-center C3PO-QI study.

This study sought to update benchmark values to use a quality measure prospectively. Congenital Cardiac Catheterization Outcomes Project - Quality Improvement (C3PO-QI), a multi-center registry, defined initial radiation dose benchmarks retrospectively across common interventional procedures. These data facilitated a dose metric endorsed by the American College of Cardiology in 2014. Data was collected prospectively by 9 C3PO-QI institutions with complete case capture between 1/1/2014 and 6/30/2015. Radiation was measured in total air kerma (mGy), dose area product (DAP) (µGy*M2 ), DAP per body weight, and fluoroscopy time (min), and reported by age group as median, 75th and 95th %ile for the following six interventional procedures: (1) atrial septal defect closure; (2) aortic valvuloplasty; (3) treatment of coarctation of the aorta; (4) patent ductus arteriosus closure; (5) pulmonary valvuloplasty; and (6) transcatheter pulmonary valve implantation. The study was comprised of 1,680 unique cases meeting inclusion criteria. Radiation doses were lowest for pulmonary valvuloplasty (age <1 yrs, median mGy: 59, DAP: 249) and highest in transcatheter pulmonary valve implantation (age >15 yrs, median mGy: 1835, DAP: 17990). DAP/kg standardized outcome measures across weights within an age group and procedure type significantly more than DAP alone. Radiation doses decreased for all procedures compared to those reported previously by both median and median weight-based percentile curves. These differences in radiation exposure were observed without changes in median fluoroscopy time. This study updates previously established benchmarks to reflect QI efforts over time. These thresholds can be applied for quality measurement and comparison. © 2017 Wiley Periodicals, Inc.

Cerebral High-Intensity Transient Signals during Pediatric Cardiac Catheterization: A Pilot Study Using Transcranial Doppler Ultrasonography.

Cerebral emboli are one potential cause of acute brain injury in children with congenital heart disease (CHD) undergoing cardiac catheterization. In this pilot study using transcranial Doppler (TCD) ultrasonography, we sought to evaluate the incidence, burden, and circumstances of cerebral high-intensity transient signals (HITS), presumably representing emboli, during pediatric cardiac catheterization. Emboli monitoring of the right middle cerebral artery was performed in five children. HITS, counted offline, were defined as unidirectional signals associated with audible "chirp" and sinusoidal correlation. HITS were grouped as single, >10 HITS ("cluster"), or HITS "with curtain effect" per 3-5 cardiac cycles. Cerebral blood flow velocity (CBFV) and pulsatility index (PI) were recorded after anesthetic induction (baseline). Total HITS in the cohort was 1,697 (790 single HITS, 606 HITS within clusters, and 301 HITS within curtains). HITS in clusters and curtains comprised 53% (907/1,697) of total HITS, and occurred in 44 clusters/curtains. Events associated with clusters/curtains included left ventricular angiography (39%; 17/44), right ventricular angiography (16%; 7/44), device placement (16%; 7/44), heparin bolus (9%; 4/44), pulmonary artery angiography (9%; 4/44), venous access (5%; 2/44), right atrial angiography (2%; 1/44), arterial access (2%; 1/44), and hemodynamic measurements (2%; 1/44). No patient had clinically detectable neurologic injury. HITS are common during pediatric cardiac catheterization, and associated with procedural factors. Whether curtains/clusters are worse than single, repetitive HITS is unknown. Larger studies are needed to determine whether HITS are a marker of risk of neurologic injury from emboli during pediatric cardiac catheterization.