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Standardizing Radiation Exposure during Cardiac Catheterization in Children with Congenital Heart Disease: Data from a Multicenter Brazilian Registry

Abstract

Background

In recent years the increasing number of interventional procedures has resulted in growing concerns regarding radiation exposure for patients and staff. The evaluation of radiation exposure in children is difficult due to the great variability in body weight. Therefore, reference levels of radiation are not well defined for this population.

Objectives

To study and validate the ratio of dose-area product (DAP) to patient weight as a reference measurement of radiation for hemodynamic congenital heart disease procedures in children.

Methods

This observational multicenter study uses data obtained from a Brazilian registry of cardiac catheterization for congenital heart disease from March 2013 to June 2014. Inclusion criteria were all patients aged <18 years old undergoing hemodynamic procedures for congenital heart disease, with recorded DAP doses. P-value < 0.05 was considered as statistically significant.

Results

This study evaluated 429 patients with median age and weight of 50 (10, 103) months and 15 (7, 28) kg, respectively. Median DAP was 742.2 (288.8, 1,791.5) μGy.m2. There was a good correlation between DAP and weight-fluoroscopic time product(rs=0.66). No statistically significant difference was observed in DAP/weight ratio between therapeutic and diagnostic procedures. There was a wide variation in the DAP/weight ratio among the therapeutic procedures (p<0.001).

Conclusions

The DAP/weight ratio is the simplest and most applicable measurement to evaluate radiation exposure in a pediatric population. Although there is limited literature available, the doses obtained in the present study were similar to those previously found. Ongoing research is important to evaluate the impact of strategies to reduce radiation exposure in this population (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Diagnostic,Imaging/methods; Radiation Exposure Pathways; Heart Defects, Congenital; Cardiac Catheterization/methods; Child

Resumo

Fundamento

Nos últimos anos, o recente aumento no número de procedimentos intervencionistas tem resultado em crescente preocupação em relação à exposição radiológica por pacientes e equipe médica. A avaliação da exposição dos níveis de radiação em crianças é difícil devido à grande variabilidade no peso corporal. Portanto, os valores de referência de radiação não estão bem definidos para essa população.

Objetivos

Avaliar e validar a razão do produto dose-área (DAP) em relação ao peso corporal como uma medida de referência de radiação em cateterismos cardíacos em crianças.

Métodos

Estudo multicêntrico observacional com dados do Registro Brasileiro de Cateterismo Cardíaco em Cardiopatias Congênitas (CHAIN) de março de 2013 a junho de 2014. Os critérios de inclusão foram: pacientes <18 anos submetidos a procedimentos hemodinâmicos para cardiopatia congênita, com DAP devidamente registrado. Foram considerados diferenças estatísticas significativas os valores de p < 0,05.

Resultados

Este estudo avaliou 429 pacientes com idade e peso medianos de 50 (10, 103) meses e 15 (7, 28) kg, respectivamente. O DAP mediano foi de 742,2 (288,8, 1.791,5) μGy.m2. Houve uma boa correlação entre o DAP e o produto peso/tempo de fluoroscopia (rs=0,66). Não foi observada diferença estatisticamente significativa na relação DAP/peso entre procedimentos terapêuticos e diagnósticos. Houve ampla variação da relação DAP/peso entre os procedimentos terapêuticos (p<0.001).

Conclusões

A proporção DAP/peso é a medida mais simples e aplicável para avaliar a exposição radiológica em uma população pediátrica. Apesar da escassa literatura disponível, as doses obtidas no presente estudo foram semelhantes àquelas encontradas anteriormente. Estudos de validação e comparação são importantes na avaliação do impacto de estratégias para redução da exposição radiológica nessa população. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)

Diagnóstico por Imagem/métodos; Vias de Exposição de Radiação; Cardiopatias Congênitas; Cateterismo Cardíaco/métodos; Criança

Introduction

Over the last 20 years, cardiac catheterization has not only been used as a diagnostic examination for congenital heart diseases, but has also played an important role in palliative and definitive treatments of more than 50% of patients with congenital heart diseases.11. Feltes TF, Bacha E, Beekman RH, Cheatham JP, Feinstein JA, Gomes AS, et al. Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association. Circulation. 2011;123(22):2607-52. During this period, the complexity, duration, and number of percutaneous procedures have increased, along with a consequent increase in the exposure of patients to ionizing radiation.22. Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9.

3. Smith BG, Tibby SM, Qureshi SA, Rosenthal E, Krasemann T. Quantification of temporal, procedural, and hardware-related factors influencing radiation exposure during pediatric cardiac catheterization. Catheter Cardiovasc Interv. 2012;80(6):931-6.
- 44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9.

Children are highly sensitive to ionizing radiation, due to their higher proportion of actively dividing cells and the large fraction of exposed body area.22. Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9. Thus, there is a great concern about the cumulative effects, particularly the high risk of malignancy caused by long-term chromosomal damage, with reports demonstrating that children are up to ten times more susceptible to the development of cancer by radiation exposure than adults.55. Strauss KJ, Kaste SC. ALARA in pediatric interventional and fluoroscopic imaging: striving to keep radiation doses as low as possible during fluoroscopy of pediatric patients—a white paper executive summary. J Am Coll Radiol. 2006;3(9):686-8. , 66. Chambers CE, Fetterly KA, Holzer R, Lin PJ, Blankenship JC, Balter S, et al. Radiation safety program for the cardiac catheterization laboratory. Catheter Cardiovasc Interv. 2011;77(4):546-56. In addition, the effective radiation dose is higher for children, resulting in a higher radiation dose for surrounding organs when an area of interest is being assessed.

There are limited studies on radiation doses emitted during interventions in children with congenital heart disease.33. Smith BG, Tibby SM, Qureshi SA, Rosenthal E, Krasemann T. Quantification of temporal, procedural, and hardware-related factors influencing radiation exposure during pediatric cardiac catheterization. Catheter Cardiovasc Interv. 2012;80(6):931-6. , 77. Verghese GR, McElhinney DB, Strauss KJ, Bergersen L. Characterization of radiation exposure and effect of a radiation monitoring policy in a large volume pediatric cardiac catheterization lab. Catheter CardiovascInterv. 2012;79(2):294-301. To achieve a reduction in the radiation dose, it is essential to establish reference doses that allow comparisons between procedures.44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. However, it is difficult to evaluate the radiation exposure in a pediatric population due to the differences in the complexity of procedures, age and weight of the patients, as well as in the types of equipment used.88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. Moreover, the calculation of the estimated effective radiation dose is complex. Currently, the total radiation dose (total air kerma) and total dose-area product (DAP; air kerma-area product), which is a better estimator of stochastic (long-term radiation effects and risk of malignancy) and cumulative effects of exposure, are used as indicators of a cumulative radiation dose to the skin.

Recently, Chida et al.22. Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9. and Kobayashi et al.88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. observed a correlation between DAP and weight as a reference radiation dose in children. They concluded that the radiation dose tends to vary proportionally to patient size. In this context, the present study aims to evaluate the DAP/weight ratio as a reference for radiation exposure in pediatric cardiac catheterization procedures performed in Brazil.

Materials and Methods

Study Design and Population

This is a cross-sectional observational study in which patients aged <18 years old and participating in the Congenital Heart Disease Intervention and Angiography (CHAIN) registry, a Brazilian registry of cardiac catheterization for congenital heart disease, were evaluated after undergoing a diagnostic or interventional procedure between March 5th, 2013 and June 30th, 2014.

The CHAIN registry is a national multicenter prospective study, coordinated by the Teaching and Research Institute of Hospital do Coração , together with the Ministry of Health and the Brazilian Society of Hemodynamics and Interventional Cardiology. The main objective was to gather prospective data and create a national registry of catheterization of patients with congenital heart diseases, as well as to propose a comprehensive analysis of the current status and devise effective action measures for public health in Brazil.

Patients who underwent electrophysiological procedures or those in whom vascular access was achieved using hybrid procedures were excluded from the study. Patients who underwent more than one catheterization on different dates were considered as distinct patients in each procedure and were included in the overall statistics as well as in the group of each specific procedure. Patients who underwent more than one intervention using the same procedure were classified according to the most complex procedure.

Analyzed Variables

Demographic characteristics of patients, such as age, gender, weight, body surface, type of heart disease, and residual lesions, were obtained from the CHAIN registry, in addition to data regarding the hemodynamic procedure performed, including fluoroscopic time and radiation exposure dose. DAP, which represents the radiation dose measured in the air in relation to the distance from the X-ray tube multiplied by the X-ray beam area at this distance, was expressed in μGy.m2. Radiation measurements expressed in units of Gy.cm2, cGy.cm2, and mGy.cm2were converted and recorded in μGy.m2. Moreover, the DAP/weight ratio (μGy.m2/kg) was analyzed among the catheterization categories for possible comparisons and standardization of radiation doses. Procedures lacking data related to radiation dose, or radiation dose recorded in different units, were excluded from the study.

Therapeutic catheterization procedures were divided into 10 categories. Radiation exposure was evaluated after the patients were categorized into age (<1 year; 1–4 years; 5–9 years; 10–14 years, and ≥15 years) and weight (up to7 kg; up to15 kg; up to 28 kg; >28 kg) subgroups. Data regarding DAP, DAP/weight ratio, age, weight, fluoroscopic time, and weight–fluoroscopic time product were not normally distributed, and were, therefore, described as medians (interquartile range).

Statistical Analysis

All data were analyzed using SPSS (IBM, SPSS Statistics, Version 22.0. Armonk, NY: IBM Corp).

The Kolmogorov Smirnov method was the statistical test used to verify the normality of the data. Continuous variables did not present normal distribution after the Kolmogorov-Smirnov test was applied. Non-normally distributed quantitative variables are presented as medians (interquartile range). Categorical variables are presented as absolute frequencies (n). Associations between continuous variables were evaluated using the Spearman correlation coefficient test (rs). The relationship between non-parametric continuous quantitative and two categorical variables were assessed using the Mann-Whitney U test. The relationship between non-parametric continuous quantitative and more than two categorical variables was assessed using the Kruskal-Wallis test. P-value < 0.05 was considered as statistically significant.

Results

A total of 1,311 patients aged <18 years old from 16 participating centers participating in the CHAIN study were included in the analysis. Among those, 206 patients had no records on radiation doses and were excluded. Of the remaining 1,026 patients with recorded radiation doses, 597 were excluded as their doses were not recorded as DAP. This resulted in a total of 429 participating patients (56.4% male) from six centers. After these exclusion criteria were applied, three out of the six centers contributed 90% of patient data.

Demographic data and the characteristics of the population and procedure groups are described in Table 1 .

Table 1
– Demographic data and characteristics of the procedures

The median DAP in the studied population was 742.2 (288.8, 1,791.5) μGy.m2. Interventional procedures had higher median DAP than diagnostic ones: 751 (315, 2,095) versus 715 (230, 1,535) μGy.m2, respectively. No differences were observed in the DAP/weight ratio between diagnostic and therapeutic procedures: 57 (23, 110) versus 57 (30, 139) respectively.

DAP was found to have a good correlation with the weight–fluoroscopic time product (rs= 0.66), and this correlation pattern was also observed when diagnostic and therapeutic procedures were separately analyzed (rs= 0.56 and rs= 0.72, respectively) ( Figures 1 and 2 ). Patients categorized into weight subgroups demonstrated higher radiation doses (DAP) in therapeutic than in diagnostic procedures (p= 0.001). When patients were categorized into age subgroups, a significant difference in radiation doses was observed between diagnostic and therapeutic procedures, but only in patients aged >15 years (p=0.004; Table 2 ).

Figure 1
Scatterplot shows relationship between dose–area product (DAP) and weight– fluoroscopic time product in pediatric patients who underwent diagnostic cardiac catheterization (r = 0.75).

Figure 2
Scatterplot shows relationship between dose–area product (DAP) and weight– fluoroscopic time product in pediatric patients who underwent diagnostic cardiac catheterization (r = 0.75).

Table 2
– Dose-area product (DAP; uGy.m2) of diagnostic and therapeutic catheterizations stratified by age groups

Table 3 highlights the different procedures, fluoroscopic times, and corresponding DAP/weight ratios. The highest DAP/weight ratios were observed for percutaneous pulmonary valve implantation (Melody), closure of ventricular septal defects (VSD), and balloon or stent angioplasty in the right ventricular outflow tract (RVOT) or pulmonary artery (PA), with means of 273.8, 169.2, and 155.9, respectively. In addition, there was a significant difference between intervention procedure subgroups and DAP/weight ratios (p<0.001).

Table 3
– Fluoroscopic time and normalized dose–area product indexed to body weight(DAP/weight; uGy.m2/kg) stratified by procedure types

Discussion

In recent years, the complexity and number of transcatheter procedures have increased.44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. Thus, methods to protect patients and staff from cumulative exposure to ionizing radiation and its potential effects are important and, therefore, establishing reference data is crucial.88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. Currently, the major limitations for setting reference values with interventional procedures for congenital heart diseases are the lack of standardization of dosage and measurement units,99. Dragusin O, Gewillig M, Desmet W, Smans K, Struelens L, Bosmans H. Radiation dose survey in a paediatric cardiac catheterisation laboratory equipped with flat-panel detectors. Radiat Prot Dosimetry. 2008;129(1-3):91-5. as well as the existence of a wide variety of procedures and complexities, weight and age variations, types of equipment and medical abilities. All these factors contribute to a great heterogeneity, which makes comparisons difficult.44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. , 88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. The Food and Drug Administration and the World Health Organization recommend recording DAP and calculating effective doses for all patients undergoing procedures utilizing radiation.1010. Al-Haj AN, Lobriguito AM, Rafeh W. Variation in radiation doses in paediatric cardiac catheterisation procedures. Radiat Prot Dosimetry. 2008;129(1-3):173-8. Based on this proposal, a total of 429 patients aged <18 years and registered in the CHAIN study were evaluated in the present study. Although relatively smaller than the number of patients reported in previous studies,44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. , 77. Verghese GR, McElhinney DB, Strauss KJ, Bergersen L. Characterization of radiation exposure and effect of a radiation monitoring policy in a large volume pediatric cardiac catheterization lab. Catheter CardiovascInterv. 2012;79(2):294-301. , 88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. , 1111. Borik S, Devadas S, Mroczek D, Lee KJ, Chaturvedi R, Benson LN. Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheter Cardiovasc Interv. 2015;86(5):841-8. , 1212. Cevallos PC, Armstrong AK, Glatz AC, Goldstein BH, Gudausky TM, Leahy RA, et al. Radiation Dose Benchmarks in Pediatric Cardiac Catheterization: A Prospective Multi-Center C3PO-QI Study. Catheter Cardiovasc Interv. 2017;90(2):269–80. the results from the present analysis reveal the potential of using the DAP/weight ratio as a reference for comparison.

The absence of a statistical difference in DAP between diagnostic and therapeutic procedures in the present study can be explained by recent advances in low-complexity interventional procedures, such as the percutaneous closure of atrial septal defects (ASD), patent foramen ovale (PFO), and patent arterial duct (PDA), in addition to pulmonary valvuloplasty, which use relatively low radiation doses. Furthermore, diagnostic procedures often involve patients with complex cardiac diseases without a defined diagnosis, requiring high fluoroscopy times.

During the analysis of diagnostic and therapeutic catheterization, it was observed that DAP increased as age increased. When the two procedures were compared with age subgroups, no statistical differences were observed, except in the group aged >15 years, in which the radiation dose was significantly higher in therapeutic procedures, similar to that reported by Ubedaet al.,1313. Ubeda C, Vano E, Miranda P, Leyton F. Pilot program on patient dosimetry in pediatric interventional cardiology in Chile. Med Phys. 2012;39(5):2424-30. This was likely a result of a higher number of complex procedures, such as percutaneous valve implantation and angioplasty in older patients.

The main interventional procedures analyzed in the present study had dose medians comparable to those reported in recent studies33. Smith BG, Tibby SM, Qureshi SA, Rosenthal E, Krasemann T. Quantification of temporal, procedural, and hardware-related factors influencing radiation exposure during pediatric cardiac catheterization. Catheter Cardiovasc Interv. 2012;80(6):931-6.

4. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9.

5. Strauss KJ, Kaste SC. ALARA in pediatric interventional and fluoroscopic imaging: striving to keep radiation doses as low as possible during fluoroscopy of pediatric patients—a white paper executive summary. J Am Coll Radiol. 2006;3(9):686-8.

6. Chambers CE, Fetterly KA, Holzer R, Lin PJ, Blankenship JC, Balter S, et al. Radiation safety program for the cardiac catheterization laboratory. Catheter Cardiovasc Interv. 2011;77(4):546-56.

7. Verghese GR, McElhinney DB, Strauss KJ, Bergersen L. Characterization of radiation exposure and effect of a radiation monitoring policy in a large volume pediatric cardiac catheterization lab. Catheter CardiovascInterv. 2012;79(2):294-301.
- 88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. , 1111. Borik S, Devadas S, Mroczek D, Lee KJ, Chaturvedi R, Benson LN. Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheter Cardiovasc Interv. 2015;86(5):841-8. , 1313. Ubeda C, Vano E, Miranda P, Leyton F. Pilot program on patient dosimetry in pediatric interventional cardiology in Chile. Med Phys. 2012;39(5):2424-30. , 1414. Onnasch DG, Schröder FK, Fischer G, Kramer HH. Diagnostic reference levels and effective dose in paediatric cardiac catheterization. Br J Radiol. 2007;80(951):177-85. ( Table 3 ), particularly when values were compared using the DAP/weight ratio, which standardizes increasing values of DAP related to weight differences in the same procedure. The variation of the DAP/weight ratio between the different types of interventional catheterization was statistically significant, as demonstrated in other studies.22. Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9. , 88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. , 1111. Borik S, Devadas S, Mroczek D, Lee KJ, Chaturvedi R, Benson LN. Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheter Cardiovasc Interv. 2015;86(5):841-8. , 1212. Cevallos PC, Armstrong AK, Glatz AC, Goldstein BH, Gudausky TM, Leahy RA, et al. Radiation Dose Benchmarks in Pediatric Cardiac Catheterization: A Prospective Multi-Center C3PO-QI Study. Catheter Cardiovasc Interv. 2017;90(2):269–80. , 1414. Onnasch DG, Schröder FK, Fischer G, Kramer HH. Diagnostic reference levels and effective dose in paediatric cardiac catheterization. Br J Radiol. 2007;80(951):177-85. The highest doses of radiation were observed in percutaneous pulmonary valve implantations (Melody), closures of VSD, and balloon or stent angioplasties in RVOT or PA, as reported previously.88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. , 1111. Borik S, Devadas S, Mroczek D, Lee KJ, Chaturvedi R, Benson LN. Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheter Cardiovasc Interv. 2015;86(5):841-8. The medians of the DAP/weight ratio in pulmonary valvuloplasties, closures of VSD, and balloon or stent angioplasties of RVOT or PA were similar to those obtained by Kobayashi and Borik et al.,88. Kobayashi D, Meadows J, Forbes TJ, Moore P, Javois AJ, Pedra CA, et al. Standardizing radiation dose reporting in the pediatric cardiac catheterization laboratory-A multicenter study by the CCISC (Congenital Cardiovascular Interventional Study Consortium). Catheter CardiovascInterv. 2014;84(5):785-93. , 1111. Borik S, Devadas S, Mroczek D, Lee KJ, Chaturvedi R, Benson LN. Achievable radiation reduction during pediatric cardiac catheterization: How low can we go? Catheter Cardiovasc Interv. 2015;86(5):841-8.

In many procedures in the present study, DAP medians were lower than those observed in previous studies.33. Smith BG, Tibby SM, Qureshi SA, Rosenthal E, Krasemann T. Quantification of temporal, procedural, and hardware-related factors influencing radiation exposure during pediatric cardiac catheterization. Catheter Cardiovasc Interv. 2012;80(6):931-6. , 44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. , 1515. Glatz AC, Patel A, Zhu X, Dori Y, Hanna BD, Gillespie MJ, et al. Patient radiation exposure in a modern, large-volume, pediatric cardiac catheterization laboratory. Pediatr Cardiol. 2014;35(5):870-8. Glatz et al.,1515. Glatz AC, Patel A, Zhu X, Dori Y, Hanna BD, Gillespie MJ, et al. Patient radiation exposure in a modern, large-volume, pediatric cardiac catheterization laboratory. Pediatr Cardiol. 2014;35(5):870-8. evaluated 2,265 patients in a single-center study and obtained a median DAP significantly higher than in most procedures studied, including adults and patients who weighed >65 kg (maximum, 128 kg). In contrast, the CHAIN study presented a median weight of 21 kg. The only procedure reported by Glatz et al. with a lower dose than those of the present study was the balloon/stent aortoplasty (DAP of 484 versus 1,904 μGy.m22. Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9. , respectively). Ghelani et al. published a study conducted from 2009 to 2011 with 2,713 patients in which the DAP of some interventional procedures was evaluated. The reported DAP medians were higher than those of other studies, including the CHAIN study. These results can also be partially justified by the inclusion of patients aged >15 years and adults, representing approximately 20% of the evaluated population. However, in this study, DAP/Kg was not evaluated. All these data corroborate the concept that the use of the DAP/weight ratio is a rational measure to standardize the evaluation of radiation dose in a heterogeneous pediatric population. In accordance with this line of thought, Cevallos and the C3PO group recently published new benchmarks for radiation dosage in the pediatric population. Differently from the previous study by the same group44. Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9. , they assessed DAP/Kg stratified by age groups and procedure types, which allows for comparison with the current literature.1212. Cevallos PC, Armstrong AK, Glatz AC, Goldstein BH, Gudausky TM, Leahy RA, et al. Radiation Dose Benchmarks in Pediatric Cardiac Catheterization: A Prospective Multi-Center C3PO-QI Study. Catheter Cardiovasc Interv. 2017;90(2):269–80. This study was performed after radiation quality improvements (QI) efforts in the different centers involved. Interestingly, the mean doses found by our group in the present were very similar to those reported by Cevallos et al. after a QI program ( Table 4 ).

Table 4
– Comparison of our data stratified by procedures type procedures radiation data (CHAIN) with previously published radiation dose databases

The main limitation of the present study was the lack of data from some participating centers, probably due to the absence of standardization of the collected data. As a consequence, the studied sample was smaller and possibly less heterogeneous. At the same time, this corroborates the hypothesis of a lack of standardization of radiation exposure measurements in pediatric populations and demonstrates that a number of Brazilian centers do not yet properly report the radiation dose used in their procedures. This reinforces the need for awareness of institutions with regard to an appropriate control and a well-developed quality assurance program for radiation safety. Moreover, in some analyses, the number of patients evaluated was small and thus a statistical analysis was not possible, for example, percutaneous pulmonary valve implantation. Nevertheless, the radiation doses these patients received were similar to those cited in the literature.

Conclusions

Radiation dose increases with patient age and the complexity of the procedure. In the present study, the radiation doses observed were similar to those from other reported studies. The radiation doses in these procedures should serve as a benchmark for other institutions for appropriate control of radiation exposure of patients and staff.

The DAP/weight ratio appears to be the most useful and applicable measurement of radiation for the establishment of a reference dose for the pediatric population, given that it allows the elimination of age categories and encompasses the broad spectrum of body sizes. As such, new studies using the DAP/weight ratio are important for the development of reference doses in hemodynamic procedures and for the evaluation of strategies aiming to reduce radiation exposure of patients and staff.

Referências

  • 1
    Feltes TF, Bacha E, Beekman RH, Cheatham JP, Feinstein JA, Gomes AS, et al. Indications for cardiac catheterization and intervention in pediatric cardiac disease: a scientific statement from the American Heart Association. Circulation. 2011;123(22):2607-52.
  • 2
    Chida K, Ohno T, Kakizaki S, Takegawa M, Yuuki H, Nakada M, et al. Radiation dose to the pediatric cardiac catheterization and intervention patient. Am J Roentgenol. 2010;195(5):1175-9.
  • 3
    Smith BG, Tibby SM, Qureshi SA, Rosenthal E, Krasemann T. Quantification of temporal, procedural, and hardware-related factors influencing radiation exposure during pediatric cardiac catheterization. Catheter Cardiovasc Interv. 2012;80(6):931-6.
  • 4
    Ghelani SJ, Glatz AC, David S, Leahy R, Hirsch R, Armsby LB, et al. Radiation dose benchmarks during cardiac catheterization for congenital heart disease in the United States. JACC Cardiovasc Interv. 2014;7(9):1060-9.
  • 5
    Strauss KJ, Kaste SC. ALARA in pediatric interventional and fluoroscopic imaging: striving to keep radiation doses as low as possible during fluoroscopy of pediatric patients—a white paper executive summary. J Am Coll Radiol. 2006;3(9):686-8.
  • 6
    Chambers CE, Fetterly KA, Holzer R, Lin PJ, Blankenship JC, Balter S, et al. Radiation safety program for the cardiac catheterization laboratory. Catheter Cardiovasc Interv. 2011;77(4):546-56.
  • 7
    Verghese GR, McElhinney DB, Strauss KJ, Bergersen L. Characterization of radiation exposure and effect of a radiation monitoring policy in a large volume pediatric cardiac catheterization lab. Catheter CardiovascInterv. 2012;79(2):294-301.
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  • Study Association
    This study is not associated with any thesis or dissertation work.
  • Ethics Approval and Consent to Participate
    This study was approved by the Ethics Committee of the Instituto de Cardiologia/Fundação Universitária de Cardiologia (IC/FUC) under the protocol number 2.919.655. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study.
  • Sources of Funding
    There were no external funding sources for this study.

Publication Dates

  • Publication in this collection
    19 Oct 2020
  • Date of issue
    Dec 2020

History

  • Received
    07 Jan 2019
  • Reviewed
    07 Nov 2019
  • Accepted
    27 Dec 2019
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