Estimation of children's radiation dose from cardiac catheterisations, performed for the diagnosis or the treatment of a congenital heart disease using TLD dosimetry and Monte Carlo simulation

Use of ionizing radiation in a Norwegian cohort of children with congenital heart disease: imaging frequency and radiation dose for the Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) study

BACKGROUND

The European-funded Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Pediatrics (HARMONIC) project is a multicenter cohort study assessing the long-term effects of ionizing radiation in patients with congenital heart disease. Knowledge is lacking regarding the use of ionizing radiation from sources other than cardiac catheterization in this cohort.

OBJECTIVE

This study aims to assess imaging frequency and radiation dose (excluding cardiac catheterization) to patients from a single center participating in the Norwegian HARMONIC project.

MATERIALS AND METHODS

Between 2000 and 2020, we recruited 3,609 patients treated for congenital heart disease (age < 18 years), with 33,768 examinations categorized by modality and body region. Data were retrieved from the radiology information system. Effective doses were estimated using International Commission on Radiological Protection Publication 60 conversion factors, and the analysis was stratified into six age categories: newborn; 1 year, 5 years, 10 years, 15 years, and late adolescence.

RESULTS

The examination distribution was as follows: 91.0% conventional radiography, 4.0% computed tomography (CT), 3.6% diagnostic fluoroscopy, 1.2% nuclear medicine, and 0.3% noncardiac intervention. In the newborn to 15 years age categories, 4-12% had ≥ ten conventional radiography studies, 1-8% underwent CT, and 0.3-2.5% received nuclear medicine examinations. The median effective dose ranged from 0.008-0.02 mSv and from 0.76-3.47 mSv for thoracic conventional radiography and thoracic CT, respectively. The total effective dose burden from thoracic conventional radiography ranged between 28-65% of the dose burden from thoracic CT in various age categories (40% for all ages combined). The median effective dose for nuclear medicine lung perfusion was 0.6-0.86 mSv and for gastrointestinal fluoroscopy 0.17-0.27 mSv. Because of their low frequency, these procedures contributed less to the total effective dose than thoracic radiography.

CONCLUSION

This study shows that CT made the largest contribution to the radiation dose from imaging (excluding cardiac intervention). However, although the dose per conventional radiograph was low, the large number of examinations resulted in a substantial total effective dose. Therefore, it is important to consider the frequency of conventional radiography while calculating cumulative dose for individuals. The findings of this study will help the HARMONIC project to improve risk assessment by minimizing the uncertainty associated with cumulative dose calculations.

RADIATION DOSE FOR PATIENTS WITH KAWASAKI DISEASE UNDERGOING FLUOROSCOPICALLY GUIDED CARDIAC CATHETERIZATION

The goal of the present study was to estimate the radiation dose for a group of 45 Kawasaki disease (KD) patients undergoing fluoroscopically guided cardiac catheterization. The sample of procedures corresponds to a single hospital and was collected in 10 years. Anthropometric characteristics and the quantities of air kerma-area product (PKA) among others were recorded for each procedure. Monte Carlo PCXMC 2.0 software was used to estimate organ and effective doses. The PKA value of 7.2 Gy cm2 was proposed as the local Diagnostic Reference Level for KD. For organ absorbed doses, median values for thyroid, heart, lungs, esophagus, skin, active bone and breast were 1.2; 2.2; 4.6; 2.7; 1.1; 1.2 and 2.7 mGy, respectively. For effective dose, the mean value was 2.7 ± 2.5 mSv. This paper presents the first patient dose values for the KD using catheterization techniques, in Latin America and the Caribbean Region.

Transcatheter and intraoperative device closure of atrial septal defect in infants under three years of age

Background

Transcatheter and intraoperative device closures have been widely used in the treatment of secundum atrial septal defect (ASD). However, for young infants with ASD, device closure remains controversial, and such treatment features limited data. We compared the clinical data and follow-up results of percutaneous and intraoperative device closure for ASD to evaluate the feasibility, safety, and efficacy of both treatments in infants under 3 years of age.

Methods

From September 2010 to September 2018, 186 children under 3 years of age with significant secundum ASD were included in this study. A total of 88 and 98 patients were divided into groups A (transcatheter device closure) and B (intraoperative device closure), respectively. The clinical data and follow-up results of the two groups were analyzed retrospectively.

Result

The mean age and weight of patients in group A were significantly higher than those in group B. The proportion of complex ASDs (multiples or rims deficiency) and the device/weight ratio in group B were significantly higher than those in group A. Successful closure was obtained in 86 (97.7%) and 96 (98.0%) infants in groups A and B, respectively, with two failed cases in each group (2.3% vs 2%). The rate of periprocedural complications reached 13.6 and 26.5% for groups A and B (P = 0.058), respectively. The durations of the procedure and postoperative hospital stay in group A were significantly shorter than those in group B (P < 0.05). Excellent follow-up results were observed in both groups. At present, no death nor major complications have occurred. Symptoms either resolved completely or improved significantly for all symptomatic infants. No residual shunts at the 6th month of follow-up evaluation were observed. Patients with failure to thrive gained weight appropriately for age, and the structure and hemodynamic parameters significantly improved during follow-up.

Conclusion

Transcatheter and intraoperative device closure are feasible, effective, and safe methods for the treatment of ASDs in infants under 3 years of age. Considering improved cosmetic effect and the short duration of the procedure and postoperative hospital stay, transcatheter is preferred for patients with appropriate conditions. Intraoperative device closure can be performed as an alternative to percutaneous closure, particularly for infants with large, complex ASDs, young age, or low-body weight.

Diagnostic Reference Levels, Deterministic and Stochastic Risks in Pediatric Interventional Cardiology Procedures

To establish diagnostic reference levels (DRLs) and investigate deterministic and stochastic risks in pediatric interventional cardiology (IC) procedures. Exposure parameters were retrospectively reviewed for 373 patients treated between May 2016 and November 2018 at a single specialized hospital. Weight specific DRLs were derived for pediatric IC procedures. Additionally, peak skin dose (Dskin,max) was measured using thermoluminescent dosimeters for a sample of 7 diagnostic and 43 therapeutic procedures. Finally, using PCXMC software, organ doses were computed and the risk of exposure-induced cancer death (REID) was estimated using the risk models of the Biological Effects of Ionizing Radiation VII committee. DRLs for ventricular septal defect (VSD) occlusions, lacking in the literature, in terms of air kerma at patient entrance reference point (388 and 629 mGy) and total air kerma-area product (28 and 61 Gycm) were proposed for patients weight-groups 5 - < 15 kg and 15 - < 30 kg, respectively. The mean (range) Dskin,max was 15 (1-30) mGy and 94 (1-491) mGy for diagnostic and therapeutic procedures, respectively. Meanwhile, VSD occlusion involved the highest organ doses where the lungs, liver, stomach, and breasts mean doses were 57, 37, 6, and 10 mGy, respectively, and the associated REID were 0.5% and 0.3% in female and male patients, respectively. DRLs were proposed for pediatric IC procedures; these will help optimize patient exposure. Dskin,max values were lower than the 2 Gy threshold for skin injuries. Pediatric organ doses and the REID were the highest during VSD occlusion and may be critical for repetitive procedures.

Retrospective study of patients radiation dose during cardiac catheterization procedures

OBJECTIVE

Cardiac catheterization procedures provide tremendous benefits to modern healthcare and the benefit derived by the patient should far outweigh the radiation risk associated with a properly optimized procedure. With increasing utilization of such procedures, there is growing concern regarding the magnitude and variations of dose to patients associated with procedure complexity and techniques parameters. Therefore, this study investigated radiation dose to patients from six cardiac catheterization procedures at our facility and suggest possible initial dose values for benchmark for patient radiation dose from these procedures. This initial benchmark data will be used for clinical radiation dose management which is essential for assessing the impact of any quality improvement initiatives in the cardiac catheterization laboratory.

METHODS

We retrospectively analyzed the dose parameters of 1000 patients who underwent various cardiac catheterization procedures: left heart catheterization (LH), percutaneous coronary intervention (PCI), complex PCI, LH with complex PCI, LH with PCI and cardiac resynchronization therapy (CRT) pacemaker in our cardiac catheterization laboratories. Patient's clinical radiation dose data [kerma-area-product (KAP) and air-kerma at the interventional reference point (Ka,r)] and technique parameters (fluoroscopy time, tube potential, current, pulse width and number of cine images) along with demographic information (age, height and weight) were collected from the hospital's RIS (Synapse), Sensis/Syngo Dynamics and Siemens Sensis Stats Manager electronic database. Statistical analysis was performed with the IBM SPSS Modeler v. 18.1 software.

RESULTS

The overall patient median age was 67.0 (range: 26.0-97.0) years and the median body mass index (BMI) was 28.8 (range: 15.9-61.7) kg/m2 . The median KAP for the LH, PCI, LH with complex PCI, complex PCI, LH with PCI and CRT-pacemaker procedures are 44.4 (4.1-203.2), 80.2 (18.9-208.5), 83.7 (48.0-246.1), 113.8 (60.9-284.5), 91.7 (6.0-426.0) and 51.1 (7.0-175.9) Gy-cm2 . The median Ka,r for the LH, PCI, LH with complex PCI, complex PCI, LH with PCI and CRT-pacemaker procedures are 701.0 (35.3-3794.0), 1384.7 (291.7-4021.8), 1607.0 (883.5-4448.3), 2260.2 (867.4-5311.9), 1589.3 (100.2-7237.4) and 463.8 (67.7-1695.9) mGy respectively.

CONCLUSION

We have analyzed patient radiation doses from six commonly used procedures in our cardiac catheterization laboratories and suggested possible initial values for benchmark from these procedures for the fluoroscopy time, KAP and air-kerma at the interventional reference point based on our current practices. Our data compare well with published values reported in the literature by investigators who have also studied patient doses and established benchmark dose levels for their facilities. Procedure-specific benchmark dose data for various groups of patients can provide the motivation for monitoring practices to promote improvements in patient radiation dose optimization in the cardiac catheterization laboratories.

ADVANCES IN KNOWLEDGE

We have investigated local patients' radiation doses and established benchmark radiation data which are essential for assessing the impact of any quality improvement initiatives for radiation dose optimization.

Effect of metallic tools on scattered radiation dose during the use of C-arm fluoroscopy in orthopaedic surgery

This study investigated the effect of metallic tools on the scattered radiation dose delivered to surgeons' radiosensitive organs while simulating hip surgery using C-arm fluoroscopy. Two phantoms, a pelvis and a Rando phantom, were used to simulate a patient and a surgeon in this study. Photoluminescence dosimeters were inserted into the Rando phantom in the positions of the eye, thyroid and gonad. A drill was positioned above the hip of the pelvis phantom or beside the pelvis phantom of the same height. For each drill location, the scattered radiation dose was measured when the angle to the operator phantom was 45°; this was repeated when the angle was 90°. The scattered radiation doses to the eye, thyroid and gonad when the drill was placed beside the pelvis phantom with 90° angulation to the operator phantom were significantly lower than the reference values and those when the drill was placed beside the pelvis phantom at a 45° angulation to the operator phantom. The scattered radiation doses to the eye and thyroid when the drill was placed above the hip were significantly lower than the references values. Of the four different scenarios, the scattered radiation doses to the eye, thyroid and gonad were lowest when the drill was placed beside the pelvis phantom with 90° angulation. This study showed that the scattered radiation doses to radiosensitive organs were affected by the location and angle of the metallic tools in relation to the operator. Therefore, orthopedic surgeons should consider the effect of metallic tools on the scattered radiation dose during intraoperative use of C-arm fluoroscopy.

Transesophageal echocardiography and fluoroscopy for percutaneous closure of atrial septal defects: A comparative study

The aim of the study was to compare transesophageal echocardiography (TEE) and fluoroscopy for percutaneous atrial septal defect (ASD) closure.This was a retrospective analysis of children who underwent percutaneous ASD closure. The procedure was guided by TEE without fluoroscopy in 130 patients (TEE group) and by fluoroscopy in 163 patients (fluoroscopy group). Baseline demographic/clinical characteristics were recorded. Patients were followed until hospital discharge. Outcomes were procedure duration, peri/postoperative complications, hospital stay, and costs.The TEE and fluoroscopy groups showed no significant differences in age (71.7 ± 40.7 vs 62.5 ± 38.8 months), male/female ratio (54/76 vs 66/97), weight (22.0 ± 12.0 vs 20.1 ± 9.0 kg), ASD diameter (9.9 ± 4.2 vs 9.3 ± 3.9 cm), distances to the superior vena cava (13.4 ± 4.6 vs 13.3 ± 4.2 cm), inferior vena cava (13.4 ± 4.3 vs 13.9 ± 4.1 cm) and atrial septal roof (12.1 ± 4.0 vs 12.3 ± 3.2 cm), or atrial septal size (38.2 ± 6.2 vs 39.4 ± 26.6 cm); distance to the mitral valve was greater in the TEE group (13.2 ± 4.4 vs 11.3 ± 3.9 cm; P < .001). The TEE and fluoroscopy groups showed no significant differences in occlusion device size (14.3 ± 4.6 vs 13.8 ± 4.0 cm) or sheath size (8.7 ± 1.8 vs 8.7 ± 0.9 cm), but procedure duration was shorter in the TEE group (21.5 ± 14.6 vs 28.6 ± 10.9 minutes; P < .001). Postoperative fever (>38°C) occurred less frequently in the TEE group than in the fluoroscopy group (0.8% vs 9.2%; P < .001); there were no significant differences for the other complications. No patient had postoperative residual shunt, occlusion device shedding/displacement, or pericardial effusion. The TEE group had longer hospital stay (3.2 ± 0.6 vs 2.9 ± 0.6 days; P < .001) and higher procedure cost (29,687 ± 4218 vs 28,530 ± 1668 CNY (China Yuan); P = .002) than the fluoroscopy group.TEE-guided percutaneous ASD closure can be used as an alternative to fluoroscopy-guided procedures and avoids the use of radiation or contrast agents.

Doubly committed ventricular septal defect closure using eccentric occluder via ultraminimal incision

OBJECTIVES

This study aimed to investigate the safety, feasibility and availability of doubly committed ventricular septal defect (DCVSD) closure via an ultraminimal intercostal incision under the guidance of transoesophageal echocardiography in children.

METHODS

From August 2014 to August 2016, 35 children with DCVSDs (≤5 mm in diameter) were enrolled in this study. A left parasternal ultraminimal intercostal incision (≤1 cm) and a pericardium hanging technique were employed without sternal incision. DCVSDs were closed through a short delivery sheath assembled with an eccentric occluder device. Transoesophageal echocardiography was used to guide and monitor the entire procedure. All patients were followed up.

RESULTS

All 35 children had complete closures with an operation success rate of 100%. The average size of DCVSDs was 3.50 ± 0.79 (range 2.2-5.0) mm, and the average device size was 5 ± 2 (range 4-9) mm. The average operation duration was 45.42 ± 11.77 (range 25-70) min, and the average hospital stay was 8 ± 2 (range 7-16) days. The median follow-up period was 17 months (range 6 months-2.5 years). Pre-existing aortic regurgitation disappeared after surgery in 1 patient and remained the same in 4 patients. No other complications were found during the operation or during follow-up.

CONCLUSIONS

Under transoesophageal echocardiography guidance, DCVSD closure using an eccentric occluder via an ultraminimal intercostal incision is feasible, safe and effective in children. The use of this approach is recommended.

THE IMPACT OF DIGITAL TECHNOLOGY ON DOSE REDUCTION IN PAEDIATRIC CARDIAC CATHETERISATION WITHIN A LARGE METROPOLITAN CHILDREN'S HOSPITAL

This study examines the kerma-area product (PKA) levels from paediatric cardiac catheterisations at a major Children's Hospital over three different time periods in order to gain an understanding of the causation of dose variations over time and to present a model for dose reduction. A retrospective review of 1245 paediatric procedural records was undertaken. This cohort consisted of patients that were catheterised over a period from November 2007 to July 2009, October 2009 to November 2011 and January 2016 to December 2016. The age distribution was from newborn to 18 years. Archived (PKA) readings were retrieved and analysed. The 75th percentile PKA values for the specific age categories over time periods (1, 2, 3) were 0-30 days-(5.47, 1.37, 1.37) Gy cm2; 1-12 months-(6.42, 2.03, 1.06) Gy cm2; 1-3 years-(11.25, 3.20, 1.25) Gy cm2; 3-5 years-(12.65, 3.72, 2.88) Gy cm2; 5-10 years-(12.80, 8.53, 3.52) Gy cm2; 10-15 years-(27.92, 10.85, 2.97) Gy cm2; >15 years-(29.09, 27.81, 11.65) Gy cm2. Using newer imaging technologies, optimising dose reduction strategies and regular dose auditing can transform radiation dose delivery for paediatric x-ray examinations. Our centre provides a template for dose reduction success worldwide.

Non-fluoroscopic percutaneous transcatheter closure of atrial septal defects in children under transesophageal echocardiographic guidance

BACKGROUND

This study sought to investigate the feasibility, safety and effectiveness of transcatheter closure of atrial septal defects (ASDs) under the guidance of transesophageal echocardiography (TEE) in children.

METHODS

We reviewed the medical records of patients who underwent percutaneous ASD closure at our center from August 2016 to December 2017. For a total of 88 patients who were identified as having a single-hole defect and were undergoing percutaneous transcatheter ASD closure, a procedure completely guided by TEE was performed. There were 31 male patients and 57 female patients. The patients' mean age was 60.09 ± 36.42 months (13-182 months), and their mean body weight was 20.16 ± 10.04 kg (9-77 kg). Patients were followed up by performing transthoracic echocardiography and obtaining chest X-rays and electrocardiograms.

RESULTS

The transcatheter closure of ASDs was successful in all patients. The mean ASD size was 11.58 ± 5.31 mm (3-28 mm), and the mean size of the occlusion device was 16.07 ± 5.29 mm (6-36 mm). The mean procedural times were 13.33 ± 2.82 minutes (6-16 minutes). The mean hospitalization costs were 27,259.66 ± 2507.04 RMB (25,200.00-33,911.45 RMB). The mean postoperative hospital stay was 3.22 ± 0.53 days (3-5 days). Residual shunt, occlusion device shedding or displacement, and pericardial effusion were not observed during or after the operation.

CONCLUSION

Percutaneous transcatheter ASD closure completely guided by TEE is a feasible, safe, non-invasive and easy procedure.

Radiation dose in paediatric cardiac catheterisation: A systematic literature review

OBJECTIVES

It is believed that children are more sensitive to ionising radiation than adults. This work reviewed the reported radiation dose estimates for paediatric cardiac catheterisation. A systematic literature review was performed by searching healthcare databases for studies reporting radiation dose using predetermined key words relating to children having cardiac catheterisation. The quality of publications was assessed using relevant Critical Appraisal Skills Programme questions and their reported radiation exposures were evaluated.

KEY FINDINGS

It is only in recent years that larger cohort observations have been undertaken. Although radiation dose from paediatric cardiac catheterisation has decreased in recent years, the literature indicated that it remains varied and potentially substantial.

CONCLUSION

Standardisation of weight categories and procedure types such as those recommended by the PiDRL project could help compare current and future radiation dose estimates.

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.

Organ and effective doses from paediatric interventional cardiology procedures in Chile

The aim of this study was to present the results of organ and effective doses for paediatric patients for different types of interventional cardiology procedures for age and weight groups, derived from a patient dosimetry pilot programme carried out in Chile, under the auspices of the International Atomic Energy Agency. Over seven years, a retrospective collection of demographic and patient dose data was obtained: age, gender, weight, height, number of cine series, total number of cine frames, fluoroscopy time, dose-area product (DAP) and cumulative dose at patient entrance reference point. Monte Carlo software was used to calculate organ and effective doses. 1506 procedures were divided into four age and seven weight groups. Organ doses (median values) for diagnostic and therapeutic procedures were: active bone marrow 0.90 and 0.64mGy; heart 1.99 and 1.46mGy; lungs 3.56 and 2.59mGy; thyroid 1.27 and 0.83; and breast (in the case of females) 1.78 and 1.36mGy. The ranges for effective doses (median values) and weight bands were 1.2-3.9mSv for diagnostic procedures and 1.0-2.5mSv for therapeutic procedures. The resulting conversion factors (median values) to estimate effective dose from DAP (in mSv/Gy.cm2) were: 1.70; 0.89; 0.58; and 0.40, for age groups of <1year, 1-<5years, 5-<10years and 10-<16years, respectively. The obtained set of dose values will enable comparisons with other imaging procedures (comparing the same age bands) for justification and optimization purposes.

Patient radiation doses in paediatric interventional cardiology procedures: a review

A large number of investigations into the radiation doses from x-ray guided interventional cardiology procedures in children have been carried out in recent years. A review was conducted of these studies, gathering data on kerma area product (P KA), fluoroscopic screening time (FT), air kerma, and estimates of effective dose and organ doses. The majority of studies focus on P KA and FT with no estimation of dose to the patient. A greater than ten-fold variation in average P KA was found between different studies, even where data were stratified by patient age or weight. Typical values of P KA were 0.6-10 Gy · cm2 (<1 year/10 kg), 1.5-30 Gy · cm2 (1-5 years), 2-40 Gy · cm2 (5-10 years), 5-100 Gy · cm2 (10-16 years) and 10-200 Gy · cm2 (>16 years). P KA was lowest for heart biopsy (0.3-10 Gy · cm2 for all ages combined) and atrial septostomy (0.4-4.0 Gy · cm2), and highest for pulmonary artery angioplasty (1.5-35 Gy · cm2) and right ventricular outflow tract dilatation (139 Gy · cm2). Most estimates of patient dose were in the form of effective dose (typically 3-15 mSv) which is of limited usefulness in individualised risk assessment. Few studies estimated organ doses. Despite advances in radiation protection, recent publications have reported surprisingly large doses, as represented by P KA and air kerma. There is little indication of a fall in these dose indicators over the last 15 years. Nor is there much suggestion of a fall in doses associated with the use of flat panel detectors, as opposed to image intensifiers. An assessment of the impact of radiation dose in the context of overall patient outcome is required.

Radiation dose and mortality risk to children undergoing therapeutic interventional cardiology

BACKGROUND

Children undergoing interventional cardiology procedures deserve special concern due to the greater radiation sensitivity of their tissues and more remaining years of life during which a radiation-induced cancer may develop.

PURPOSE

To determine the patient radiation dose for pediatric therapeutic interventional cardiology and to estimate the patient effective dose and lifetime mortality risk to children associated with five common procedures.

MATERIAL AND METHODS

Ninety children with congenital heart defects undergoing interventional therapy were enrolled in this study. Data regarding fluoroscopy and radiography time, dose-area product (DAP) and peak skin dose (PSD) for each case were measured. Patients were divided into five groups. The patient effective dose (E) was calculated using a multiplicative model of ICRP 60. The overall lifetime mortality risk was evaluated using appropriate risk coefficients.

RESULTS

The mean, median, standard deviation, and range of time, PSD, DAP, and E were presented for the five study groups. When these metrics were considered, there were wide variations for different cases within the same group and statistically significant differences between the five groups. The PSD correlated significantly with DAP (Pearson r = 0.70; P < 0.01), but the correlation in individual cases was poor. For all cases, the range of E was found to be between 0.44 and 66.7 mSv. The corresponding risk of lifetime mortality was 1.16 per thousand.

CONCLUSION

The current study provides overall data on the time, PSD, E, and lifetime mortality risk for pediatric therapeutic interventional cardiology. Radio frequency ablation showed the highest radiation risk.

Radiation safety protocol using real-time dose reporting reduces patient exposure in pediatric electrophysiology procedures

Radiation exposure during pediatric catheterization is significant. We sought to describe radiation exposure and the effectiveness of radiation safety protocols in reducing exposure during catheter ablations with electrophysiology studies in children and patients with congenital heart disease. We additionally sought to identify at-risk patients. We retrospectively reviewed all interventional electrophysiology procedures performed from April 2009 to September 2011 (6 months preceding intervention, 12 months following implementation of initial radiation safety protocol, and 8 months following implementation of modified protocol). The protocols consisted of low pulse rate fluoroscopy settings, operator notification of skin entrance dose every 1,000 mGy, adjusting cameras by >5 at every 1,000 mGy, and appropriate collimation. The cohort consisted of 291 patients (70 pre-intervention, 137 after initial protocol implementation, 84 after modified protocol implementation) at a median age of 14.9 years with congenital heart disease present in 11 %. Diagnoses included atrioventricular nodal reentrant tachycardia (25 %), atrioventricular reentrant tachycardia (61 %), atrial tachycardias (12 %), and ventricular tachycardia (2 %). There were no differences between groups based on patient, arrhythmia, and procedural characteristics. Following implementation of the protocols, there were significant reductions in all measures of radiation exposure: fluoroscopy time (17.8 %), dose area product (80.2 %), skin entry dose (81.0 %), and effective dose (76.9 %), p = 0.0001. Independent predictors of increased radiation exposure included larger patient weight, longer fluoroscopy time, and lack of radiation safety protocol. Implementation of a radiation safety protocol for pediatric and congenital catheter ablations can drastically reduce radiation exposure to patients without affecting procedural success.

Local reference levels and organ doses from pediatric cardiac interventional procedures

Interventional cardiology (IC) procedures can be responsible for relatively high radiation doses compared to conventional radiology especially for young patients. The aim of this study was to assess current exposure levels in a French reference centre of pediatric IC. Dosimetric data including dose area product (DAP), fluoroscopy time (FT) and number of cine frame (NF) were analysed taking into account patient weight. Doses to the lungs, esophagus, breast and thyroid were evaluated using anthropomorphic phantoms and thermoluminescent dosimeters. Finally, effective doses (E) were calculated using DAP and conversion factors calculated with PCXMC 2.0 software. 801 IC procedures performed between 2010 and 2011 were analysed. Large variations were observed for DAP, FT and NF values for a given procedure and a given weight group. The assessment of organ doses showed high levels of dose to the lungs and esophagus especially in new-born babies. For diagnostic procedures, E varied from 0.3 to 23 mSv with a mean value of 4.8 mSv and for therapeutic procedures, values ranged from 0.1 to 48.4 mSv with a mean value of 7.3 mSv. The highest values were recorded for angioplasty procedures (mean 13 mSv, range 0.6-48.4 mSv). The increasing use of IC in pediatric population stresses the need of setting up reference levels and keeping doses to children as low as possible.

Computed tomographic versus catheterization angiography in tetralogy of Fallot

AIM

To compare multidetector computed tomographic angiography with the gold standard cardiac catheterization and angiography in tetralogy of Fallot.

METHODS

In 40 consecutive patients over 5 years of age with tetralogy of Fallot, multidetector computed tomographic angiography and catheterization angiography studies were compared for intracardiac anatomy, pulmonary anatomy and indices, coronaries and collaterals. Safety parameters, relative advantages and limitations were also analyzed.

RESULTS

All catheterization studies required hospitalization whereas all tomographic studies were performed as outpatient procedures. The need for sedation and amount of contrast used were significantly greater in catheterization than in tomographic studies. Complications noted during catheterization were access site complications in 4 patients, cyanotic spells in 2, transient complete heart block requiring temporary pacing in 2, and air embolism in one. No complication was observed during tomographic studies. All tomographic studies were adequate, but 2 catheterization studies were inadequate. Ventricular septal defects, aortic override, level of right ventricular outflow tract obstruction, and pulmonary artery anatomy were equally assessed by both imaging modalities. However, tomographic studies missed additional small muscular ventricular septal defects. There was a linear correlation between tomographic and catheterization studies for pulmonary annulus size, artery sizes, Z-score, and Nakata index. There was complete concordance with respect to side of aortic arch and detection of collaterals. Coronary anatomy was better delineated in tomographic studies.

CONCLUSIONS

For preoperative evaluation of tetralogy of Fallot patients, multidetector computed tomographic angiography can be used as a reliable noninvasive alternative to cardiac catheterization angiography.

Catheterization therapy vs surgical closure in pediatric patients with patent ductus arteriosus: a meta-analysis

BACKGROUND

Patent ductus arteriosus (PDA) remains a common congenital heart disease in pediatric patients, and the new trend of catheterization therapy is still associated with some potential risks and complications.

HYPOTHESIS

Compared with surgical closure, the clinical effect of catheterization therapy in pediatric PDA patients requires meta-analysis.

METHODS

A systematic literature search of PubMed, Cochrane Library, Embase, Science Citation Index, Web of Science, and the Chinese Biomedicine literature database was conducted. Eligible studies included controlled trials of pediatric PDA patients receiving catheterization therapy vs surgical closure. Relative risks (RRs), standard mean differences, and 95% confidence intervals (CIs) were calculated and heterogeneity was assessed with the I(2) test.

RESULTS

Seven studies with a total of 810 patients met the inclusion criteria. Catheterization therapy neither significantly increased the primary success rate (RR: 0.92, 95% CI: 0.82-1.03, P = 0.16) nor reduced the total postprocedure complications (RR: 0.74, 95% CI: 0.44-1.25, P = 0.26) and blood transfusion (RR: 1.10, 95% CI: 0.16-7.67, P = 0.93). Catheterization was associated with a statistically significant increase in residual shunts (RR: 5.19, 95% CI: 1.41-19.20, P = 0.01) and reduction in length of hospital stay (standard mean difference: -1.66, 95% CI: -2.65 to -0.67, P = 0.001).

CONCLUSIONS

Catheterization therapy in pediatric PDA patients did not show a significant advantage in primary success rate, total complications, or blood transfusion, but it was associated with increase in residual shunts and reduction in length of hospital stay.

Risk of cancer associated with cardiac catheterization procedures during childhood: a cohort study in France

BACKGROUND

Radiation can be used effectively for diagnosis and medical treatment, but it can also cause cancers later on. Children with congenital heart disease frequently undergo cardiac catheterization procedures for diagnostic or treatment purposes. Despite the clear clinical benefit to the patient, the complexity of these procedures may result in high cumulative radiation exposure. Given children's greater sensitivity to radiation and the longer life span during which radiation health effects can develop, an epidemiological cohort study is being launched in France to evaluate the risks of leukaemia and solid cancers in this specific population.

METHODS/DESIGN

The study population will include all children who have undergone at least one cardiac catheterization procedure since 2000 and were under 10 years old and permanent residents of France at the time of the procedure. Electronically stored patient records from the departments of paediatric cardiology of the French national network for complex congenital heart diseases (M3C) are being searched to identify the children to be included. The minimum dataset will comprise: identification of the subject (file number in the centre or department, full name, sex, date and place of birth), and characteristics of the intervention (date, underlying disease, type of procedure, technical details, such as fluoroscopy time and dose area product, (DAP), which are needed to reconstruct the doses received by each child). The cohort will be followed up through linkage with the two French paediatric cancer registries, which have recorded all cases of childhood leukaemia and solid cancers in France since 1990 and 2000, respectively. Radiation exposure will be estimated retrospectively for each child. 4500 children with catherizations between 2000 and 2011 have been already included in the cohort, and recruitment is ongoing at the national level. The study is expected to finally include a total of 8000 children.

DISCUSSION

This French cohort study is specifically designed to provide further knowledge about the potential cancer risks associated with paediatric cardiac catheterization procedures. It will also provide new information on typical dose levels associated with these procedures in France. Finally, it should help improve awareness of the importance of radiation protection in these procedures.

Estimation of radiation dose and risk to children undergoing cardiac catheterization for the treatment of a congenital heart disease using Monte Carlo simulations

BACKGROUND

Children diagnosed with congenital heart disease often undergo cardiac catheterization for their treatment, which involves the use of ionizing radiation and therefore a risk of radiation-induced cancer.

OBJECTIVE

The purpose of this study was to calculate the effective and equivalent organ doses (H(T)) in those children and estimate the risk of exposure-induced death.

MATERIALS AND METHODS

Fifty-three children were divided into three groups: atrial septal defect (ASD), ventricular septal defect (VSD) and patent ductus arteriosus (PDA). In all procedures, the exposure conditions and the dose-area product meters readings were recorded for each individual acquisition. Monte Carlo simulations were run using the PCXMC 2.0 code and mathematical phantoms simulating a child's anatomy. The H(T) values to all irradiated organs and the resulting E and risk of exposure-induced death values were calculated.

RESULTS

The average dose-area product values were, respectively, 40 ± 12 Gy·cm(2) for the ASD, 17.5 ± 0.7 Gy·cm(2) for the VSD and 9.5 ± 1 Gy·cm(2) for the PDA group. The average E values were 40 ± 12, 22 ± 2.5 and 17 ± 3.6 mSv for ASD, VSD and PDA groups, respectively. The respective estimated risk of exposure-induced death values per procedure were 0.109, 0.106 and 0.067%.

CONCLUSION

Cardiac catheterizations in children involve a considerable risk for radiation-induced cancer that has to be further reduced.

Interventional closure of atrial septal defects without fluoroscopy in adult and pediatric patients

BACKGROUND

Interventional closure of atrial septal defects (ASDs) with a transcatheter device is the preferred strategy in children and adults. This procedure has been proven in numerous studies, but X-ray and contrast agent exposure is still a major side effect. The aim of this study was to clarify whether the interventional closure of ASDs is possible and safe if it is guided by transesophageal echocardiography (TEE) alone.

METHODS AND RESULTS

We retrospectively selected and studied pediatric and adult patients with interventional closure of ASDs at the Deutsches Herzzentrum Berlin (DHZB) without fluoroscopy between 1999 and 2010. We included 330 out of 1,605 patients; 254 had an ASD II, 30 a PFO and 46 multiperforated atrial septum. Median age was 8.92 (0.96-76.3) years and median body weight 32.6 (8.3-156) kg. Median stretched defect size was 13 (5-29) mm. Median procedure time was 50 (20-170) min. Closure was performed in the majority of patients with the Amplatzer(®) septal occluder or Amplatzer(®) PFO occluder. The procedure succeeded in 98.2 % of cases and closure rate was 94.9 % after 48 h. Complication rate was low and procedure time was similar to that necessary with studies using fluoroscopy.

CONCLUSION

Interventional closure of ASDs is safe and effective if guided with TEE alone. The results can compete with those with the use of fluoroscopy. TEE-guided closure of ASD should be considered in more catheter laboratories to avoid unnecessary radiation exposure for the patient and the examiner.

Computed tomographic angiography in tetralogy of Fallot

Echocardiography is often inadequate for imaging tetralogy of Fallot, prompting cineangiography. This study prospectively evaluated multidetector computed tomographic angiography for preoperative evaluation of tetralogy of Fallot in 112 consecutive patients. Forty-eight had nonconfluent or hypoplastic pulmonary arteries (mean z-score, −2; range, −11.1–0.13) permitting only palliative or no surgery; 64 had adequate pulmonary artery anatomy (mean z-score, 0.59; range,−2.53–3.4) allowing total repair. The surgical data of 50 patients who underwent total correction were compared with transthoracic echocardiography and multidetector computed tomographic angiography findings. Multidetector computed tomographic angiography tended to reveal unsuspected collaterals and coronary abnormalities besides outlining the right ventricular outflow tract and pulmonary artery branches. The branch pulmonary artery diameter z-score was the most important determinant of surgical strategy, with the worst figures being associated with no surgical options or palliative surgery, and the best figures leading to corrective surgery. The mean radiation dose was 3.45 mSv. Multidetector computed tomographic angiography is a powerful supplement to echocardiography in the preoperative evaluation of tetralogy of Fallot.