ACCF/AHA/HRS/SCAI clinical competence statement on physician knowledge to optimize patient safety and image quality in fluoroscopically guided invasive cardiovascular procedures. A report of the American College of Cardiology Foundation/American Heart Association/American College of Physicians Task Force on Clinical Competence and Training

Ionizing radiation exposure in complex percutaneous coronary intervention: Defining local diagnostic reference levels in the catheterization laboratory

INTRODUCTION AND OBJECTIVES

Concerns regarding the consequences of ionizing radiation (IR) have been increasing in the field of interventional cardiology (IC). There is little information on reported national and local radiation diagnostic reference levels (DRLs) in catheterization laboratories in Portugal. This study was designed to assess the IR dose exposure during complex percutaneous coronary intervention (PCI), and to set the respective DRLs and future achievable doses (ADs).

METHODS

This was a retrospective cohort study which took place between 2019 and 2020, including patients who underwent complex PCI. Complex PCI was defined as all procedures that encompass treatment of chronic total occlusions (CTO) or left main coronary artery. DRLs were defined as the 75th percentile of the distribution of the median values of air kerma area product (PKA) and cumulative air kerma (Ka,r). ADs were set at the 50th percentile of the study dose distribution. Multivariate analysis was performed using linear regression to identify predictors significantly associated with radiation dose (Ka,r).

RESULTS

A total of 242 patients were included in the analysis. Most patients underwent a CTO procedure (146, 60.3%). Patients were aged 67.9±11.2 years and mostly male (81.4%). DRLs were set in Ka,r (3012 mGy) and PKA (162 Gy cm2) for complex PCI. ADs were also set in Ka,r (1917 mGy) and PKA (101 Gy cm2). Independent predictors of Ka,r with a positive correlation were PKA (0.893, p<0.001), fluoroscopy time (0.520, p<0.001) and PCI time (0.521, p<0.001).

CONCLUSIONS

This study reports the results of IR in complex PCI. DRLs were set for IR dose exposure measured in Ka,r (3012 mGy) and PKA (162 Gy cm2). ADs, values to be achieved in future assessment, were set to Ka,r (1917 mGy) and PKA (101 Gy cm2).

Evaluation of the reduction of radiation dose received by pediatric patients in new-generation biplane angiocardiography: Randomized controlled study

Objective

We aimed to evaluate the safety and efficacy of radiation dose reduction with a new-generation biplane angiocardiography system in patients undergoing transcatheter isolated patent ductus arteriosus (PDA) closure.

Materials and methods

Fifty pediatric patients who underwent transcatheter PDA closure were randomly divided into two groups as normal radiation dose and low dose. Patients who required additional procedures other than PDA closure were excluded. PDA closure was performed according to the angiographic measurement of the defect. After the procedure, age, weight, sex, PDA measurements, and radiation measurements such as dose-area product (DAP, Gy.cm2) and air kerma (AK, mGy) were compared between the groups.

Results

There was no statistically significant difference between the groups in age, sex, weight, PDA diameter, PDA type, device used, and device diameter (p > 0.05). While there was no statistically significant difference between the groups in terms of cine recording, number of recorded images, and fluoroscopy time (p > 0.05), there was a statistically significant difference between the total DAP, cine and fluoroscopy DAP, total AK, frontal and lateral tube AK, and DAP/kg (mGy.m2/kg) measurements (p < 0.05).

Conclusion

Transcatheter PDA closure with a low radiation dose is as effective as that with a normal radiation dose. The radiation dose received by the patient during the procedure was significantly reduced. With the vision provided by this study, it seems possible to work with a low radiation dose in other groups of patients.

A report on a survey among Portuguese Association of Interventional Cardiology associates regarding ionizing radiation protection practices in national interventional cath-labs

INTRODUCTION AND OBJECTIVES

Concerns surrounding the consequences of ionizing radiation (IR) have increased in interventional cardiology (IC). Despite this, the ever-growing complexity of diseases as well as procedures can lead to greater exposure to radiation. The aim of this survey, led by Portuguese Association of Interventional Cardiology (APIC), was to evaluate the level of awareness and current practices on IR protection among its members.

METHODS

An online survey was emailed to all APIC members, between August and November 2021. The questionnaire consisted of 50 questions focusing on knowledge and measures of IR protection in the catheterization laboratory. Results were analyzed using descriptive statistics.

RESULTS

From a response rate of 46.9%, the study obtained a total sample of 159 responses (156 selected for analysis). Most survey respondents (66.0%) were unaware of the radiation exposure category, and only 60.4% reported systematically using a dosimeter. A large majority (90.4%) employed techniques to minimize exposure to radiation. All participants used personal protective equipment, despite eyewear protection only being used frequently by 49.2% of main operators. Ceiling suspended shields and table protectors were often used. Only two-thirds were familiar with the legally established limit on radiation doses for workers or the dose that should trigger patient follow-up. Most of the survey respondents had a non-certified training in IR procedures and only 32.0% had attended their yearly occupational health consultation.

CONCLUSIONS

Safety methods and protective equipment are largely adopted among interventional cardiologists, who have shown some IR awareness. Despite this, there is room for improvement, especially concerning the use of eyewear protection, monitoring, and certification.

Zero fluoroscopy ablation for atrioventricular nodal reentrant tachycardia and typical atrial flutter is equally safe and effective with EnSite NavX, Carto3, and Rhythmia mapping systems

PURPOSE

Our purpose was to compare the procedural characteristics, success rate, and complication rate of the conventional fluoroscopic (CF) and the zero-fluoroscopic (ZF) approach in patients undergoing catheter ablation of AVNRT or typical atrial flutter (Aflu).

METHODS

186 consecutive patients with an indication for AVNRT or Aflu ablation were enrolled. Based on the operator's preference, the patients were assigned to either CF or ZF group. In the ZF group EnSite NavX, Carto3, or Rhythmia EAMS were used for catheter guidance.

RESULTS

The median age was 56 (IQR = 42-68) years, 144 patients had AVNRT, and 42 had Aflu ablation. CF approach was chosen in 123 cases, while ZF in 63 cases. ZF approach was used more often in case of AVNRT patients [56 (39%) vs. 7 (17%), p = 0.006] and in the case of female patients [43 (68%) vs. 20 (32%), p = 0.008]. Acute procedural success was obtained in all cases. There was no difference in the complication rate (1 vs. 1, p > 0.99) between the two groups. No difference was found regarding the procedure time between the CF and ZF groups [CF: 55 (46-60) min, ZF 60 (47-65) min; p = 0.487] or in the procedure time for the different EAMS [EnSite NavX: 58 (50-63) min, Carto3: 60 (44.5-66.3) min, Rhythmia: 55 (35-69) min; p = 0.887]. A similar success rate was seen at the 3-month follow-up in the two groups [41 (100%) vs. 96 (97%); p = 0.55].

DISCUSSION

The ZF approach demonstrated non-inferiority in safety and efficacy compared with CF for the AVNRT and Aflu ablations.

Efficacy of Catheter Ablation Using the Electroanatomical System without the Use of Fluoroscopy in Patients with Ventricular Extrasystolic Beats

BACKGROUND

Catheter ablation (CA) has become safe and efficient for the treatment of patients with ventricular extrasystolic beats (VEBs). The three-dimensional electroanatomic mapping (EAM) system allows the elimination of fluoroscopy time during CA procedures. Non-fluoroscopy CA is a challenging procedure requiring intimate knowledge of cardiac anatomy in patients with VEBs. The study aimed to evaluate the efficacy and safety of the non-fluoroscopy CA using the EAM system in patients with VEBs.

METHODS

Completely fluoroless CA of VEBs guided by EAM was performed in 86% (94 out of 109) of consecutive patients with VEBs. The remaining 15 patients underwent conventional fluoroscopy-guided CA. Demographic and clinical baseline characteristics, procedure parameters, and following complications were obtained from the medical records. Primary outcomes were the acute procedural success rate, the permanent success rate (6-month follow-up), complications, and procedure time.

RESULTS

There were no significant differences between groups regarding baseline characteristics. Acute procedural success was achieved in 85 patients (90%) in the non-fluoroscopy group and in 14 patients (93%) in the fluoroscopy group (ns). A long-term success rate was achieved in 82 patients (87%) in the non-fluoroscopy group and in 14 (82%) patients in the fluoroscopy group (ns). The median procedure time was 85 min in the non-fluoroscopy group and 120 min in the fluoroscopy group (p = 0.029). There was only one major complication in the non-fluoroscopy group (ns).

CONCLUSIONS

Completely fluoroless CA of VEBs guided by EAM is a feasible, safe, and efficient procedure.

Radiation Risks and Interventional Cardiology: The Value of Radiation Reduction Exposure

Fluoroscopically guided cardiac procedures are an essential component of care in the practice of cardiology, and are, in most cases, lifesaving [...]

Risk of ionizing radiation in pregnancy: just a myth or a real concern?

There are natural concerns regarding the risks posed to the foetus by ionizing radiation exposure during pregnancy. Therefore, many female physicians select to avoid working in an environment associated with ionizing radiation exposure like the catheterization laboratory and even exclude training as electrophysiology, interventional cardiologists, or radiologists. For those already working in this field, pregnancy involves usually a 1-year interruption (pregnancy and maternity leave) to their careers, leading at times to delays in the decision to become pregnant. This review describes the low added risk of malformation/cancer in the offspring, highlight gaps in our understanding, discuss several common wrong beliefs, and recommend how to further decrease radiation dose, especially during pregnancy.

Trends and predictors of radiation exposure in percutaneous coronary intervention: the PROTECTION VIII study

BACKGROUND

Percutaneous coronary intervention (PCI) is indispensable in cardiology; however, exposure to potentially harmful ionising radiation remains a concern.

AIMS

This study was designed to assess the PCI-related radiation dose over the last decade and to identify predictors of increased dose exposure.

METHODS

The PROcedural radiaTion dose Exposure in percutaneous Coronary intervenTION (PROTECTION VIII) study included all PCIs reported to a German quality assurance programme between 2008 and 2018. Dose area product (DAP) and radiation time were analysed. Effective dose (ED) was estimated (ED=DAP*k; conversion coefficient k=0.0022 mSv/cGy*cm²). Multivariate linear regression analysis was used to identify predictors associated with a clinically relevant increase of radiation dose (ED ≥1 mSv).

RESULTS

We enrolled 3,704,986 patients undergoing PCI (median age 70 years, 30% female). Indications were chronic coronary syndrome (37.5%), unstable angina pectoris and non-ST-segment elevation myocardial infarction (non-STEMI; 33.2%) and STEMI (18.5%). Median DAP was 4,203 (interquartile range [IQR] 2,313-7,300) cGy*cm, ED was 9.2 mSv and median radiation time was 9.2 (IQR 5.8-15.0) min. Within the 10-year period, radiation exposure was reduced by 36% (p<0.001) and resulted in a median DAP of 3,070 cGy*cm (ED 6.8 mSv) in 2018. A significant 5.3-fold variability of median DAP was observed between catheterisation laboratories (p<0.001). We identified patient-related (gender, coronary artery bypass graft surgery, heart failure) and procedure-related (coronary occlusion PCI, ostial lesion PCI, left main PCI, multivessel PCI) predictors of increased radiation dose (all p<0.001).

CONCLUSIONS

This radiation dose survey demonstrates a considerable reduction of PCI radiation exposure during the last decade. However, large variability between catheterisation laboratories underlines the need for further radiation dose reduction.

Rhythmia zero-fluoroscopy workflow with high-power, short-duration ablation: retrospective analysis of procedural data

Background

Fluoroscopy is commonly used during atrial fibrillation (AF) ablation to guide catheter navigation and placement. Technology improvements have significantly reduced fluoroscopy time, and subsequent radiation dose, necessary to perform successful ablations. However, there is still no amount of radiation exposure known to be completely safe. The aim of this manuscript is to describe a detailed zero-fluoroscopy RHYTHMIA HDx workflow for AF ablation.

Methods

This was an observational, single-center experience to describe the technique, acute procedural success, and safety using a novel zero-fluoroscopy workflow with the RHYTHMIA HDx mapping system and intracardiac echocardiography (ICE). Seventy-two consecutive patients undergoing de novo or redo AF ablation were retrospectively analyzed. Venous access was guided with ultrasound. ICE combined with the mapping system’s magnetic tracking and sheath detection was used for precise catheter placement in the coronary sinus, at the transseptal puncture, and in the left atrium. A high-power, short-duration ablation strategy guided by local impedance was used. Pulmonary vein isolation was performed or touched up for all patients with additional lines added at the operator’s discretion.

Results

Using this zero-fluoroscopy workflow, all patients achieved acute isolation with no significant procedure-related complications. Average procedure time was 73.7 ± 16.2 min, which included persistent (58%) and paroxysmal (42%) AF cases, and no procedures required conversion to fluoroscopy.

Conclusions

In this experience, a zero-fluoroscopy workflow using the RHYTHMIA HDx mapping system combined with ICE was feasible and safe for ablation in a heterogenous AF population. This approach, in the appropriate patient population, can eliminate radiation exposure to patients and staff.

Generative learning approach for radiation dose reduction in X-ray guided cardiac interventions

BACKGROUND

Navigation guidance in cardiac interventions is provided by X-ray angiography. Cumulative radiation exposure is a serious concern for pediatric cardiac interventions.

PURPOSE

A generative learning-based approach is proposed to predict X-ray angiography frames to reduce the radiation exposure for pediatric cardiac interventions while preserving the image quality.

METHODS

Frame predictions are based on a model-free motion estimation approach using a Long Short Term Memory (LSTM) architecture and a content predictor using a Convolutional Neural Network (CNN) structure. The presented model thus estimates contrast-enhanced vascular structures such as the coronary arteries and their motion in X-ray sequences in an end-to-end system. This work was validated with 56 simulated and 52 patients' X-ray angiography sequences.

RESULTS

Using the predicted images can reduce the number of pulses by up to 3 new frames without affecting the image quality. The average required acquisition can drop by 30% per second for a 15 frame per second acquisition. The average Structural Similarity Index Measurement (SSIM) was 97% for the simulated dataset and 82% for the patients' dataset.

CONCLUSIONS

Frame prediction using a learning-based method is promising for minimizing radiation dose exposure. The required pulse rate is reduced while preserving the frame rate and the image quality. With proper integration in X-ray angiography systems, this method can pave the way for improved dose management. This article is protected by copyright. All rights reserved.

Impact of Different Measures of Body Size on the Radiation Dose During Coronary Angiography and Percutaneous Coronary Intervention: Results from a Large Single Center Cohort

Efforts to reduce and optimize the radiation exposure during coronary angiography and intervention have pointed at patients' body size as a major determinant of irradiation for the patients and operators. We aimed at comparing body weight and body mass index (BMI) among consecutive patients undergoing angiographic procedures (coronary angiography and/or interventions) in a single center. Patients were divided in normal weight (NW, BMI <25 Kg/m²) and overweight (OW, BMI ≥25 Kg/m²). Patients' dose exposure was evaluated as dose area product (DAP), time of exposure (fluoroscopy duration), and relative DAP (DAP/minutes of exposure). We included 748 patients, 61.6% undergoing percutaneous coronary interventions and 56.8% classified as OW. OW patients were more often men (P < .001), with history of hypertension (P < .001) and diabetes (P = .001). Mean DAP and relative DAP were significantly higher among OW compared with NW patients (P < .001). DAP and relative DAP were directly related with body weight (both r = .22, P < .001); a similar linear association was also described for BMI (r = .18, P < .001 and r = .19, P < .001, respectively). At multivariate analysis, however, body weight, but not BMI, independently predicted the DAP. Therefore, body weight should be considered as the preferred indicator of body size in the setting and optimization of radiation exposure during coronary diagnostic and intervention procedures.

Manual der Arbeitsgruppe Interventionelle Kardiologie (AGIK) der Deutschen Gesellschaft für Kardiologie – Herz- und Kreislaufforschung e. V. (DGK)

Dieses Manual zur diagnostischen Herzkatheteruntersuchung (Teil 1) ist eine Anwendungsempfehlung für interventionell tätige Ärzte, die den gegenwärtigen Kenntnisstand unter Berücksichtigung neuester Studienergebnisse wiedergibt. Hierzu wurde in den einzelnen Kapiteln speziell auf die Alltagstauglichkeit der Empfehlungen geachtet, sodass dieses Manual jedem interventionell tätigen Kardiologen als Entscheidungshilfe im Herzkatheterlabor dienen soll. Trotz der von vielen Experten eingebrachten praktischen Hinweise kann dieses Manual dennoch nicht die ärztliche Evaluation des individuellen Patienten ersetzen und damit eine Anpassung der Diagnostik bzw. Therapie ersetzen.

Safety and effectiveness of strategies to reduce radiation exposure to proceduralists performing cardiac catheterization procedures: a systematic review

OBJECTIVE

The objective of this systematic review was to synthesize the best available evidence on the effect of various radiation protection strategies on radiation dose received by proceduralists performing cardiac catheterization procedures involving fluoroscopy.

INTRODUCTION

Cardiac catheterization procedures under fluoroscopy are the gold standard diagnostic and treatment method for patients with coronary artery disease. The growing demand of procedures means that proceduralists are being exposed to increasing amounts of radiation, resulting in an increased risk of deterministic and stochastic effects. Standard protective strategies and equipment such as lead garments reduce radiation exposure; however, the evidence surrounding additional equipment is contradictory.

INCLUSION CRITERIA

Randomized controlled trials that compared the use of an additional radiation protection strategy with conventional radiation protection methods were considered for inclusion. The primary outcome of interest was the radiation dose received by the proceduralist during cardiac catheterization procedures.

METHODS

A three-step search was conducted in MEDLINE, CINAHL, Embase, and the Cochrane Library (CENTRAL). Trials published in the English language with adult participants were included. Trials published from database inception until July 2019 were eligible for inclusion. The methodological quality of the included studies was assessed using the JBI critical appraisal checklist for randomized controlled trials. Quantitative data were extracted from the included papers using the JBI data extraction tool. Results that could not be pooled in meta-analysis were reported in a narrative form.

RESULTS

Fifteen randomized controlled trials were included in the review. Six radiation protection strategies were assessed: leaded and unleaded pelvic or arm drapes, transradial protection board, remotely controlled mechanical contrast injector, extension tubing for contrast injection, real-time radiation monitor, and a reduction in frame rate to 7.5 frames per second. Pooled data from two trials demonstrated a statistically significant decrease in the mean radiation dose (P < 0.00001) received by proceduralists performing transfemoral cardiac catheterization on patients who received a leaded pelvic drape compared to standard protection. One trial that compared the use of unleaded pelvic drapes placed on patients compared to standard protection reported a statistically significant decrease (P = 0.004) in the mean radiation dose received by proceduralists.Compared to standard protection, two trials that used unleaded arm drapes for patients, one trial that used a remotely controlled mechanical contrast injector, and one trial that used a transradial protection board demonstrated a statistically significant reduction in the radiation dose received by proceduralists.Similarly, using a frame rate of 7.5 versus 15 frames per second and monitoring radiation dose in real-time radiation significantly lowered the radiation dose received by the proceduralist. One trial demonstrated no statistically significant difference in proceduralist radiation dose among those who used the extension tubing compared to standard protection (P = 1).

CONCLUSIONS

This review provides evidence to support the use of leaded pelvic drapes for patients as an additional radiation protection strategy for proceduralists performing transradial or transfemoral cardiac catheterization. Further studies on the effectiveness of using a lower fluoroscopy frame rate, real-time radiation monitor, and transradial protection board are needed.

The radioprotective effect of the Cathpax® AIR cabin during interventional cardiology procedures

BACKGROUND

The use of ionizing radiation during cardiac catheterization interventions adversely impacts the medical staff. Traditional radiation protection equipment is only partially effective. The Cathpax® radiation protection cabin (RPC) has proven to significantly reduce radiation exposure in electrophysiological and neuroradiology interventions. Our objective was to analyze whether the Cathpax® RPC reduces radiation dose in coronary and cardiac structural interventions in unselected real-world procedures.

METHODS AND RESULTS

In this nonrandomized all-comers prospective study, 119 consecutive cardiac interventional procedures were alternatively divided into two groups: the RPC group (n = 59) and the non-RPC group (n = 60). No significant changes in the characteristics of patients and procedures, average contrast volume, air kerma (AK), dose area-product (DAP) and fluoroscopy time between both groups were apparent. In the RPC group, the first-operator relative radiation exposure was reduced by 78% at the chest and by 70% at the wrist. This effect was consistent during different types of procedures including complex percutaneous interventions and structural procedures.

CONCLUSIONS

Our study demonstrates, for the first time, that the Cathpax® cabin significantly and efficiently reduces relative operator radiation exposure during different types of interventional procedures, confirming its feasibility in a real-world setting.

Fluoroscopy time and scattered radiation during electrophysiology procedures: analysis of one-year data of a laboratory providing electrophysiology training

OBJECTIVES

Patients and medical staff expose to significant radiation during electro-physiological (EP) procedures. There are few data regarding the leading factors of longer fluoroscopy time and higher scattered radiation in a laboratory giving EP training during those interventions.

MATERIAL AND METHODS

The patients' recordings that underwent EP procedure in a single centre arrhythmia unit from February 2019 to January 2020 were examined. Prospectively collected data regarding procedure duration, fluoroscopy time and total air kerma, demographic characteristics of the patients, type of procedure, success of ablation and the use of electro anatomic mapping were retrospectively evaluated. Predictors of total air kerma were analysed with linear regression analysis.

RESULTS

Study population consisted of 437 patients with a median age of 47 (39-56); 184 (42.1%) were male. Median fluoroscopy time was 768 (420-1320) seconds and median cumulative air kerma was 369 (191-750) mGy. Fluoroscopy time and cumulative air kerma were significantly lower in diagnostic EP studies compared to other procedures. There was no difference in terms of total air kerma between the procedures other than the diagnostic EP study. In multivariable linear regression analysis; body surface area, fluoroscopy time, not using the electro-anatomical mapping, unsuccessful ablation and atrial flutter ablation were predictors of total air kerma in EP studies performed by trainees.

CONCLUSION

Scattered radiation during EP procedures performed by in-training operators is related with some factors. Awareness about those may help to effort reducing the harmful effect of ionising radiation.

Radiation and the Pregnant IR: Myth versus Fact

The article is part of the series of articles on radiation protection. You can find further articles in the special section of the CVIR issue. Radiation exposure during pregnancy is a source of concern for many women interventional radiologists. There are misconceptions about the actual risks and what is safe. This article will address the myths surrounding occupational radiation exposure and clarify the facts.

Reduction of radiation exposure using low pulse rate fluoroscopy during neuroendovascular surgery

INTRODUCTION

Endovascular surgery is minimally invasive, but the radiation exposure can be problematic. There is no report assessing whether radiation exposure can be reduced by using a low pulse rate during carotid artery stenting (CAS). The aim of this study was to evaluate whether reducing the pulse rate from 7.5 to 4 frames per second (f/s) can reduce the radiation exposure while maintaining safety during CAS procedure.

METHODS

We retrospectively reviewed the radiation data and clinical features of all 100 patients who underwent CAS between 2014 and 2019. We changed the pulse rate from 7.5 to 4 f/s in 2017. The fluoroscopic time (FT), dose area product (DAP), and total air kerma (AK) were collected. Statistical analyses were performed between the pulse rate and clinical outcomes, including radiation exposure.

Radiation doses during cardiac catheterisation procedures in India: a multicentre study: Radiation dose study

AIMS

Established, evidence-based measures of radiation are required to minimise its hazards, while maintaining adequate image quality. The aim of this study is to evaluate radiation data and generate reference radiation levels for commonly performed coronary catheterisation procedures in India.

METHODS AND RESULTS

In this prospective, observational study, all procedures were performed in accordance with the established standards using Innova IGS 520/2100-IQ catheterisation laboratories. Demographic, procedural and radiation data were collected. Dose reference limits (DRL) were established as the 75th percentile of the total distribution. There were 2,906 coronary angiograms (CAG), 750 percutaneous coronary interventions (PCI) and 715 CAG+PCI. DRLs for dose area product were: 19.6 Gy·cm2 for CAG, 49.8 Gy·cm2 for PCI and 72.0 Gy·cm2 for CAG+PCI, respectively. Median cumulative air kerma levels were: 185 mGy for CAG, 533mGy for PCI, and 891 mGy for CAG+PCI. Male gender, higher BMI, combining CAG+PCI, fluoroscopy time, number of cine frames, and image acquisition settings were significant contributors to increased radiation dose.

CONCLUSIONS

This study established reference radiation dose levels for diagnostic and interventional coronary procedures in India, which were comparable to and in the lower range of international standards.

[Update on radiation exposure in catheter ablation of atrial fibrillation]

The rising number of catheter ablations of atrial fibrillation increases radiation exposure for both patients and surgeons. Fortunately, this trend is counteracted by the development of measures to reduce total fluoroscopy time using non-fluoroscopic catheter visualization. Since even low-dose radiation can cause serious injury, all options to reduce radiation burden must be utilized (ALARA, "as low as reasonably achievable"). Dose reduction protocols with low-dose settings, which include reduced framerates, pulse duration, detector entrance dose and increased beam hardening, play a decisive role in this regard. This review provides a state-of-the-art summary of non-fluoroscopic catheter visualization and dose reduction protocols for catheter ablation of atrial fibrillation.

Effective Reduction of Radiation Exposure during Cardiac Catheterization

Exposure to ionizing radiation during cardiac catheterization can have harmful consequences for patients and for the medical staff involved in the procedures. Minimizing radiation doses during the procedures is essential. We investigated whether fine-tuning the radiation protocol reduces radiation doses in the cardiac catheterization laboratory. In January 2016, we implemented a new protocol with reduced radiation doses in the Hospital de Jerez catheterization laboratory. We analyzed 170 consecutive coronary interventional procedures (85 of which were performed after the new protocol was implemented) and the personal dosimeters of the interventional cardiologists who performed the procedures. Overall, the low-radiation protocol reduced air kerma (dose of radiation) by 44.9% (95% CI, 18.4%-70.8%; P=0.001). The dose-area product decreased by 61% (95% CI, 30.2%-90.1%; P <0.001) during percutaneous coronary interventions. We also found that the annual deep (79%, P=0.026) and shallow (62.2%, P=0.035) radiation doses to which primary operators were exposed decreased significantly under the low-radiation protocol. These dose reductions were achieved without increasing the volume of contrast media, fluoroscopy time, or rates of procedural complications, and without reducing the productivity of the laboratory. Optimizing the radiation safety protocol effectively reduced radiation exposure in patients and operators during cardiac catheterization procedures.

Effectiveness of protection strategies for reducing radiation exposure in proceduralists during cardiac catheterization procedures: a systematic review protocol

REVIEW QUESTION

What is the effectiveness of radiation protection strategies for reducing the radiation dose received by the proceduralist during cardiac catheterization procedures?

2018 ACC/HRS/NASCI/SCAI/SCCT Expert Consensus Document on Optimal Use of Ionizing Radiation in Cardiovascular Imaging: Best Practices for Safety and Effectiveness-A Review for the Cardiac Anesthesiologist

The American College of Cardiology, in collaboration with the American Society of Nuclear Cardiology, Heart Rhythm Society, Mended Hearts, North American Society for Cardiovascular Imaging, Society for Cardiovascular Angiography and Interventions, Society for Cardiovascular Computed Tomography, and Society of Nuclear Medicine and Molecular Imaging, recently published a consensus document recommending best practices for the use of ionizing radiation in cardiovascular medicine. With the increase in number and complexity of catheter-based cardiovascular interventions, cardiothoracic anesthesiologists are being requested to consult and provide care for these patients. This review summarizes the salient portions of the consensus document as it pertains to the anesthesiologist. Radiation exposure for both patients and providers should be minimized to be as low as reasonably achievable. For the anesthesiologist involved in the procedure, the authors recommend wearing protective garments including apron, vest, neck collar, and glasses of at least 0.25-mm lead or lead equivalent. The addition of a portable shield also is strongly recommended. The anesthesiologist should maintain the maximum distance allowable from the x-ray source, remembering that radiation intensity is inversely proportional to the square of the distance from the x-ray source. Monitoring radiation exposure is done best by both collar and under-apron film badge. A 0.5-mm lead-equivalent apron is expected to shield approximately 95% of the radiation. By using these recommendations, the anesthesiologist should be able to keep radiation exposure under 20 mSv per year as recommended by the International Commission on Radiation Protection.

Reducing Radiation Exposure in Cardiac Catheterizations for Congenital Heart Disease

Ionizing radiation exposure is a necessary risk entailed during congenital cardiac catheterizations. The congenital catheterization lab at Yale New Haven Children's Hospital employed quality improvement strategies to minimize radiation exposure in this vulnerable population. In two phases, we implemented six interventions, which included adding and utilizing lower fluoroscopy and digital angiography (DA) doses, increasing staff and physician radiation awareness, focusing on tighter collimation, and changing the default fluoroscopy and DA doses to lower settings. Post-intervention data were collected prospectively for all procedures in the congenital catheterization lab and compared to pre-intervention radiation data collected retrospectively. Radiation exposure was measured in total air kerma (mGy), dose area product per body weight (DAP/kg) (µGy m²/kg), and fluoroscopy time (min). Data were collected for a total of 312 cases. In considering all procedures, the DAP/kg decreased by 67.6% and air kerma decreased by 63%. Fluoroscopy time did not change over the study period. Significant decreases in radiation exposure (DAP/kg) by procedure type were seen for atrial septal defect, patent ductus arteriosus, and transcatheter pulmonary valve procedures with a 45%, 42% and 83% decrease, respectively. Air kerma decreased significantly for ASD and PDA procedures with an 80% and 72% decrease, respectively. When compared to national benchmarks, the median DAP/kg and air kerma for these procedures are lower at our institution. The decreases continue to be sustained 2 years post-interventions. Systems-based interventions can be readily implemented in the congenital cardiac catheterization lab with dramatic and sustainable radiation dose reduction for patients.

[Multicenter Survey of the Display Air Kerma and Actual Measured Values in IVR X-ray Apparatus]

PURPOSE

We conducted a multicenter study to investigate the current status of difference between the actual values at the patient entrance reference point (PERP) and display air kerma.

METHODS

We exposure dose and fluoroscopy dose were measured by 32 apparatuses at 32 member institutions of the Japanese Society of Circulation Imaging Technology (CITEC) under unified conditions, and the actual measured values and display air kerma were compared. We entrance doses during fluoroscopy and imaging were measured at the PERP, with focus detector distance (FDD) 110 cm, a copper plate of 3.5 mm in thickness adhered to the front face of flat panel detector (FPD) as absorber, field-of-view (FOV) 18 cm, and the frame rate of 15 f/s, excluding the bed. Display air kerma were recorded at the same time. JIS (Z 4751-2-43: 2012) specify "The reference air kerma rate and the cumulative reference air kerma shall not deviate from their respective display air kerma by more than ±35% over the range of 6 mGy/min and 100 mGy to the maximum value." The number of apparatuses display air kerma deviated from this condition and its percentage were obtained.

RESULTS

The mean difference percentage between actual measured values and display air kerma in 32 apparatuses was approximately 15.6%, with some apparatuses showing substantially different display air kerma.

CONCLUSION

In order to estimate patients' skin exposure dose from display air kerma more accurately, it is necessary to perform calibration of the apparatus by regular dose measurement or convert values.

Analysis of intraoperative radiation use in vascular surgery: Catalyst for quality improvement in patient and personnel safety

OBJECTIVES

There is paucity in the literature reporting radiation usage analysis in vascular surgery. In the era of endovascular surgeries, analyzing the surgeons' use of radiation in vascular procedures can help establish quality improvement initiatives.

METHODS

A retrospective review was undertaken of intraoperative fluoroscopic-guided vascular surgery procedures at a single institution from 2010 to 2017. Mobile C-arms were utilized to gather the six radiation usage metrics and cases were categorized into 6 anatomic surgical fields and 10 surgical procedure types.

RESULTS

Three hundred and eighteen vascular surgery cases were analyzed and notable trends in all radiation usage metrics were identified both across the surgical field location and type of surgical procedure. The highest cumulative dose was identified in embolization cases with a mean of 932.5 mGy. The highest fluoroscopic time was seen in atherectomies with a mean of 2629.6 s. In terms of surgical field, the highest cumulative does and fluoroscopic time was identified in abdomen/pelvis procedures with a mean of 352.1 mGy and 1186.8 s, respectively. Analysis of dose reduction techniques also demonstrated notable trends.

CONCLUSIONS

There were notable trends in the analyzed radiation usage variables both across the surgical field location and type of surgical procedure. Specifically, cases that involve the abdomen/pelvis, embolization and atherectomy have the highest radiation use. These types of cases can be targeted for future improved dose reduction techniques or staged procedures. This data can serve as baseline information for future quality improvement initiatives for patient and personnel radiation exposure safety.

Efficacy of radiation dose reduction due to real-time monitoring and visualization of peak skin dose during coronary angiography and percutaneous coronary intervention

OBJECTIVES

This study assessed that the use of real-time monitoring and visualization of peak skin dose could reduce radiation dose during coronary angiography (CAG) and percutaneous coronary intervention (PCI).

BACKGROUND

Exposure to ionizing radiation has dose related effects including skin damage. Reducing the radiation exposure is important during CAG and PCI. The skin dose-tracking system (DTS) has a real-time monitor of radiation peak skin dose.

METHODS

A total of 323 consecutive patients who underwent CAG and PCI between September 2014 and June 2015 were enrolled. Patients were classified into with DTS group (CAG alone in 104 and PCI in 57 patients) or without DTS group (CAG alone in 106 and PCI in 56 patients).

RESULTS

There was no significant difference in reference air kerma between CAG alone with and without DTS groups. Reference air kerma with DTS group during PCI was lower than without DTS group (204.6 ± 141.1 mGy vs. 294.2 ± 237.4 mGy, P = 0.016). Moreover, kerma area product (17.8 ± 13.0 Gycm² vs. 25.2 ± 19.3 Gycm² , P = 0.019) and number of cine runs (12.8 ± 5.0 vs. 15.5 ± 6.5, P = 0.013) with DTS group were lower than without DTS group. Multiple regression analysis showed increased reference air kerma was associated with male gender, body mass index and type B2/C lesion. Conversely, DTS correlated with decreased reference air kerma.

CONCLUSIONS

The use of DTS could reduce radiation dose during PCI. Real-time radiation monitoring and visualization of peak skin dose was effective for the patients with PCI.

The effect of an ultra-low frame rate and antiscatter grid-less radiation protocol for cardiac device implantations

BACKGROUND AND AIMS

Antiscatter grids improve image contrast by absorbing scattered x-ray beams, although by removing the antiscatter grid patient dose can be reduced as more x-ray beams reach the image receptor. Additionally, there is a trend toward ultra-low frame rates for radiation dose reduction during various electrophysiology procedures. As for most cardiac device implantations (CIED) image quality demands are usually modest, the purpose of this study was to assess the safety and efficacy of an ultra-low frame rate and scatter grid-less radiation protocol.

METHODS/RESULTS

A total of 140 patients undergoing CIED implantation between 2014 and 2017 were included in the study. Seventy patients (50%) implanted after implementation of the antiscatter grid-less and ultra-low frame rate protocol were matched to controls before the dose-reduction protocol was established. Forty patients (28.6%) had a one-chamber pacemaker or one-chamber implantable cardioverter defibrillator (ICD) implantation/revision, 60 (42.9%) had a two-chamber pacemaker or two-chamber ICD implantation/revision, and 40 (28.6%) patients had a cardiac resynchronization therapy device implantation/revision. Removing the antiscatter-grid and lowering the frame rate led to a 73% reduction of the overall dose area product (1,206 ± 2,015 vs 324 ± 422 μGym, P < 0.001). Procedural duration (95 ± 51 minutes vs 82 ± 44 minutes, P  =  0.053) and rate of complications were not significantly different between the two groups.

CONCLUSION

The use of an ultra-low frame rate and antiscatter grid-less radiation protocol significantly reduced radiation dose for implantation of CIED and led to very low average patient doses, while procedural duration and complication rates did not increase.

Safety and efficacy of applying a low-dose radiation fluoroscopy protocol in device implantations

Aims

For cardiac implantable electronic device (CIED) implantations, visualization of lead placement is necessary and fluoroscopy remains by far the most commonly used technique. With simple changes in the X-ray system settings, total radiation dose can be reduced significantly. The purpose of this study was to assess the safety and efficacy of various CIED implantations performed after implementation of a new dose reduction protocol (DRP).

Methods and results

We conducted a retrospective chart review of 584 patients undergoing CIED implantation or revision in our hospital. Of these patients, 280 (48%) underwent the implantation prior to and 304 (52%) after the DRP introduction. The DRP included various changes for optimized image processing and exposure system settings to enable dose reduction, as well as a reduced frame rates (4 FPS for fluoroscopy and 7.5 FPS for cinematographic images). Of the 584 patients, 53 (9.1%) had a one-chamber pacemaker, 232 (39.7%) a two-chamber pacemaker, 133 (22.8%) a one-chamber ICD, 35 (6.0%) a two-chamber ICD, 82 (14.0%) a CRT (de novo) implantation, and 49 (8.3%) had an upgrade to a CRT device. DRP was associated with a 64% reduction of the dose-area product (1372 ± 2659 vs. 3792 ± 5025 cGcm2, P < 0.001), while fluoroscopy duration (13 ± 15 vs. 13 ± 15 min) and procedural duration (93 ± 52 vs. 92 ± 52 min.) did not significantly increase. Complication rates did not differ significantly between the two groups.

Conclusion

The DRP proved to effectively reduce radiation dose for all types of CIED implantations. Fluoroscopy time, total procedure time, and the number of complications did not increase after introducing the DRP.

Radiation reduction during percutaneous coronary intervention: A new protocol with a low frame rate and selective fluoroscopic image storage

The percutaneous coronary intervention (PCI) procedure is associated with potentially high levels of radiation exposure and therefore increased risk of adverse radiation-induced outcomes, ranging from cataract to malignancy. Frame rate reduction and selective fluoroscopy storage may help reduce radiation exposure. In this study, we evaluated the efficacy of a radiation reduction protocol that uses a lower frame rate and selective storage of fluoroscopic images in terms of its effect on reducing the radiation dose during PCI.The new protocol incorporated a lower frame rate as compared with the conventional protocol, and used selective storage of fluoroscopic images. We reviewed the medical records of patients who underwent PCI under the conventional protocol from January 2013 to December 2013, and compared them with those who underwent PCI with the new protocol from January 2015 to December 2015. The primary endpoint was radiation dose reduction expressed as cumulative air kerma and dose-area product (DAP). The image quality was assessed by 3 independent well-trained cardiologists.One hundred fifty-five patients were enrolled in the conventional protocol group, and 152 were enrolled in the radiation reduction protocol group (total, n = 307). There was no statistical significance in terms of the baseline characteristics, including body mass index. Overall, the radiation reduction protocol group showed a significant reduction in both cumulative air kerma (1634.39 ± 717.95 vs 2074.75 ± 1003.72 mGy, P < .001) and DAP (12344.86 ± 5371.75 vs 15312.19 ± 7136.58 μGy m, P < .001). Image quality was acceptable in both groups.The radiation reduction protocol, which uses a lower frame rate and selective storage of fluoroscopic images, may be an alternative approach to reducing PCI radiation dose.

Remote magnetic catheter navigation versus conventional ablation in atrial fibrillation ablation: Fluoroscopy reduction

Background

Percutaneous transcatheter radiofrequency ablation of atrial fibrillation with remote controlled magnetic navigation (RMN) has been shown to reduce radiation exposure to patients and physicians compared with conventional manual (MAN) ablation techniques.

Methods

Catheter ablation for atrial fibrillation was performed utilizing RMN in 214 consecutive patients and MAN ablation techniques in 229 patients. We compared the fluoroscopy and procedural times between RMN and MAN catheter ablation of atrial fibrillation. Secondary objectives included comparing acute procedural success and short-term complication rates between both ablation strategies.

Results

Fluoroscopy time was significantly shorter in the RMN group than the MAN group (53.5±30.1 vs 68.1±27.6 min, respectively; p<0.01); however, the total procedural time was longer in the RMN group (280.2±74.4 min vs 213.1±64.75, respectively; p>0.001). Further subgroup analysis of the most recent 50 ablations each from the RMN and MAN groups, to attenuate the RMN learning curve effect, showed an even greater difference in fluoroscopy time (RMN vs MAN: 53.5±30.1 vs 68.1±27.6 min), though a consistently longer procedure time with RMN (249.5±65.5 vs 186.3±65.6 min, respectively). The acute procedural success rate was comparable between the groups (98.6% vs 95.6%, respectively; p=0.07). The rates of acute complications were similar in both groups (2.3% vs 4.8%, respectively; p=0.16).

Conclusions

In radiofrequency ablation of atrial fibrillation, RMN appears to significantly reduce fluoroscopy time compared with conventional MAN ablation, though at a cost of increased total procedural time, with comparable acute success rates and safety profile. A reduction in procedure and fluoroscopy times is possible with gaining experience.

Reduction in operator radiation exposure during transradial coronary procedures using a simple lead rectangle

Objectives

Transradial access for percutaneous coronary intervention (PCI) reduces procedural complications however, there are concerns regarding the potential for increased exposure to ionizing radiation to the primary operator. We evaluated the efficacy of a lead-attenuator in reducing radiation exposure during transradial PCI.

Methods and results

This was a non-randomized, prospective, observational study in which 52 consecutive patients were assigned to either standard operator protection (n = 26) or the addition of the lead attenuator across their abdomen/pelvis (n = 26). In the attenuator group patients were relatively older with a higher prevalence of peripheral vascular disease (67.9 vs 58.7 p = 0.0292 and 12% vs 7.6% p < 0.001 respectively). Despite similar average fluoroscopy times (12.3 ± 9.8 min vs. 9.3 ± 5.4 min, p = 0.175) and average examination doses (111866 ± 80790 vs. 91,268 ± 47916 Gycm², p = 0.2688), the total radiation exposure to the operator, at the thyroid level, was significantly lower when the lead-attenuator was utilized (20.2% p < 0.0001) as compared to the control group. Amongst the 26 patients assigned to the lead-attenuator, there was a significant reduction in measured radiation of 94.5% (p < 0.0001), above as compared to underneath the lead attenuator.

Conclusions

Additional protection with the use of a lead rectangle-attenuator significantly lowered radiation exposure to the primary operator, which may confer long-term benefits in reducing radiation-induced injury.

Advances in knowledge

This is the first paper to show that a simple lead attenuator almost completely reduced the scattered radiation at very close proximity to the patient and should be considered as part of the standard equipment within catheterization laboratories.

Limited fluoroscopy catheter ablation of accessory pathways in children

BACKGROUND

Limited fluoroscopy ablation using 3D electro-anatomical system (3DS) has been used for arrhythmias in children, however it is not a common practice. We aimed to facilitate a fluoroscopy limited approach for ablation of accessory pathways (AP) in children.

METHODS

Following electrophysiologic (EP) catheter placement a single dual-plane fluoroscopic image (right anterior oblique-30° and left anterior oblique-60° views) was acquired and the 3DS views were rotated to be a perfect match to the fluoroscopy. Ninety-four consecutive pediatric patients [mean age 11.8±4.1 (4.2-18) years, 61.7% males] with Wolf-Parkinson-White syndrome underwent ablation of an AP. Fifty-seven had manifest AP, 54 had left-sided AP (LSAP) and 40 had right-sided AP (RSAP).

RESULTS

The acute success rate was 95.7% (90/94), with a recurrence rate of 1.1% (1/90) at a mean follow-up of 13±5.5 (4.4-22.9) months. Mean procedure and fluoroscopy times were 144±45 (55-262)min and 1.8±1.4 (0.1-5.6)min, respectively. Comparison of the first 20 procedures to the next 74 procedures demonstrated an extended procedure time (171±53min vs 135±38min, p<0.005), however the fluoroscopy time, the number of long applications, the time to effect, and the acute success rate were similar. There were no permanent ablation-related complications.

CONCLUSIONS

A limited fluoroscopy approach for ablation of AP in children using 3DS is easily acquired, adapted, reduces the fluoroscopy time, and has an excellent efficacy and safety profile.

RADIATION PROTECTION IN AN INTERVENTIONAL LABORATORY: A COMPARATIVE STUDY OF AUSTRALIAN AND SAUDI ARABIAN HOSPITALS

This study aimed to investigate whether the use of protection devices and attitudes of interventional professionals (including radiologists, cardiologists, vascular surgeons, medical imaging technicians and nurses) towards radiation protection will differ between Saudi Arabian and Australian hospitals. Hard copies of an anonymous survey were distributed to 10 and 6 clinical departments in the Eastern province of Saudi Arabia and metropolitan hospitals in Western Australia, respectively. The overall response rate was 43 % comprising 110 Australian participants and 63 % comprising 147 Saudi participants. Analysis showed that Australian respondents differed significantly from Saudi respondents with respect to their usages of leaded glasses (p < 0.001), ceiling-suspended lead screen (p < 0.001) and lead drape suspended from the table (p < 0.001). This study indicates that the trained interventional professionals in Australia tend to adhere to benefit from having an array of tools for personal radiation protection than the corresponding group in Saudi Arabia.

Fluoroscopy pulse rate reduction during diagnostic and therapeutic imaging in the cardiac catheterization laboratory: An evaluation of radiation dose, procedure complications and outcomes

OBJECTIVES

To evaluate radiation reduction by reducing fluoroscopy pulse rate in diagnostic cardiac catheterizations and percutaneous coronary interventions (PCI) as well as outcomes at 30 days and six months.

BACKGROUND

Radiation exposure to the public at large has increased dramatically over the past three decades, and the cardiac catheterization laboratory is a large contributor. Fluoroscopy pulse rate is one way to decrease radiation exposure.

METHODS

Fluoroscopy pulse rate was reduced from 10 pulses/sec (p/s) to 7.5 p/s as part of an internal quality improvement project. A retrospective analysis of all cardiac catheterizations was performed, evaluating Air KERMA at the interventional reference point (K_{a, r} ), Air KERMA area product (P_KA ), procedural complications and major adverse cardiac events at 30 days and 6 months.

RESULTS

In diagnostic catheterization median P_KA (µGy·m² ) and K_a,r (mGy) were significantly reduced (P_KA - 5,613.3 vs. 4,400, P < 0.001; K_a,r - 703.0 vs. 621.0, P = 0.041). In PCI, median P_KA and K_a,r were further reduced (P_KA - 13,481.6 vs. 10,648.0, P < 0.001; K_a,r - 1787.0 vs. 1,459.0, P = 0.002). There was no difference in complications, fluoroscopy time or number of stents placed. There was no difference in MACE after adjustment for number of STEMIs.

CONCLUSIONS

Reducing fluoroscopy pulse rates to 7.5 from 10 is an effective way to reduce patient radiation exposure across meaningful dose indices. A pulse rate of 7.5 p/s is safe, with no difference in complications or outcomes. A fluoroscopy pulse rate of 7.5 p/s should be given strong consideration for a new standard. © 2016 Wiley Periodicals, Inc.

Effectiveness of the implementation of a simple radiation reduction protocol in the catheterization laboratory

BACKGROUND AND PURPOSE

A reduction in radiation doses at the catheterization laboratory, maintaining the quality of procedures is essential. Our objective was to analyze the results of a simple radiation reduction protocol at a high-volume interventional cardiology unit.

METHODS

We analyzed 1160 consecutive procedures: 580 performed before the implementation of the protocol and 580 after it. The protocol consisted in: the reduction of the number of ventriculographies and aortographies, the optimization of the collimation and the geometry of the X ray tube-patient-receptor, the use of low dose-rate fluoroscopy and the reduction of the number of cine sequences using the software "last fluoroscopy hold".

RESULTS

There were no significant differences in clinical baseline features or in the procedural characteristics with the exception of a higher percentage of radial approach (30.7% vs 69.6%; p<0.001) and of percutaneous coronary interventions of chronic total occlusions after the implementation of the protocol (2.1% vs 6.7%; p=0,001). Angiographic success was similar during both periods (98.3% vs 99.2%; p=0.2). There were no significant differences between both periods regarding the overall duration of the procedures (26.9 vs 29.6min; p=0.14), or the fluoroscopy time (13.3 vs 13.2min; p=0.8). We observed a reduction in the percentage of procedures with ventriculography (80.9% vs 7.1%; p<0.0001) or aortography (15.4% vs 4.4%; p<0.0001), the cine runs (21.8 vs 6.9; p<0.0001) and the dose-area product (165 vs 71 Gyxcm(2); p<0.0001).

CONCLUSIONS

With the implementation of a simple radiation reduction protocol, a 57% reduction of dose-area product was observed without a reduction in the quality or the complexity of procedures.