Radiation Exposure of Operators Performing Transesophageal Echocardiography During Percutaneous Structural Cardiac Interventions

Addressing the Occupational Risk of Radiation Exposure in the Evolving Field of Interventional Echocardiography

Interventional echocardiography (IE) is a relatively new subspecialty in the field of cardiology that has rapidly evolved to occupy a critical role in the treatment of structural heart disease. Despite this, clear competency guidelines are only now being issued, and, of pressing importance, the health risks associated with the profession, particularly occupational radiation exposure, still need to be recognized and appropriately addressed for both specialists and trainees in IE as well as for supporting sonographers. This review will briefly discuss the extensive training interventional echocardiographers need in advanced imaging modalities and will then present standard measures as well as possible innovative devices that can be implemented to reduce ionizing radiation exposure for those working in the field of IE.

Trends in female representation in cardiology and its subspecialties: The current state and the desired state

INTRODUCTION

Women have been historically underrepresented in Cardiology and its subspecialties. However, limited research has been done to examine the trends of representation of women in cardiology and its subspecialties over time. Our study aims to examine these trends and compare them to other internal medicine subspecialties.

METHODS

We used data from the Accreditation Council for Graduate Medical Education (ACGME) to conduct a retrospective analysis of the gender trends of cardiology and its subspecialties over a decade from 2013 to 2023. Chi-square statistical testing was used to compare representation percentages across groups. A p-value <0.05 was considered statistically significant.

RESULTS

Compared to all internal medicine subspecialties, cardiology and its subspecialties continues to remain the least represented by women. We found a statistically significant increase in women's representation in cardiovascular disease and interventional cardiology. However, there was no statistically significant changes in the representation of women in electrophysiology and advanced heart failure. We have found over the last decade that there was a positive trend in overall women fellows choosing cardiology and its subspecialties, especially since 2018.

CONCLUSION

While strides have been made in increasing the number of female fellows in cardiology, it still lags compared to other internal medicine subspecialties. As we celebrate this minor milestone, it is crucial to emphasize the importance of persistently overcoming obstacles and fostering a supportive environment throughout all training phases to attract, retain, and mentor female trainees.

Radiation Exposure to the Interventional Echocardiographers and Sonographers: A Call to Action

Interventional echocardiography is a rapidly growing field within the disciplines of cardiology and anesthesiology, with the rise of advanced transcatheter procedures making skilled imagers more important than ever. However, these procedures also involve frequent manipulation of the transesophageal echocardiography probe, which means interventional echocardiographers (IEs) are at risk of long-term occupational radiation exposure. Studies have shown that radiation exposure is linked to various health issues, including cancer, cataracts, hypertension, hyperlipidemia, endothelial dysfunction, vascular aging, and early atherosclerosis. While there is increasing awareness of the occupational radiation dose limits and the need for better shielding methods, the importance of radiation safety for the IE is still not sufficiently prioritized in most cardiac catheterization laboratories/hybrid operating rooms. This is partly due to a paucity of studies looking at long-term radiation exposure to the IE, as this field is newer than that of interventional cardiologists.

Transcatheter Mitral Valve Intervention: Current and Future Role of Multimodality Imaging for Device Selection and Periprocedural Guidance

Mitral regurgitation (MR) is a broadly diffuse valvular heart disease (VHD) with a significant impact on the healthcare system and patient prognosis. Transcatheter mitral valve interventions (TMVI) are now well-established techniques included in the therapeutic armamentarium for managing patients with mitral regurgitation, either primary or functional MR. Even if the guidelines give indications regarding the correct management of this VHD, the wide heterogeneity of patients' clinical backgrounds and valvular and heart anatomies make each patient a unique case, in which the appropriate device's selection requires a multimodal imaging evaluation and a multidisciplinary discussion. Proper pre-procedural evaluation plays a pivotal role in judging the feasibility of TMVI, while a cooperative work between imagers and interventionalist is also crucial for procedural success. This manuscript aims to provide an exhaustive overview of the main parameters that need to be evaluated for appropriate device selection, pre-procedural planning, intra-procedural guidance and post-operative assessment in the setting of TMVI. In addition, it tries to give some insights about future perspectives for structural cardiovascular imaging.

EACVI survey on radiation exposure in interventional echocardiography

AIMS

The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey on radiation exposure in interventional echocardiography. The survey aimed to collect data on local practices for radioprotection in interventional echocardiography and to assess the awareness of echocardiography operators about radiation-related risks.

METHODS AND RESULTS

A total of 258 interventional echocardiographers from 52 different countries (48% European) responded to the survey. One hundred twenty-two (47%) participants were women. Two-thirds (76%) of interventional echocardiographers worked in tertiary care/university hospitals. Interventional echocardiography was the main clinical activity for 34% of the survey participants. The median time spent in the cath-lab for the echocardiographic monitoring of structural heart procedures was 10 (5-20) hours/month. Despite this, only 28% of interventional echocardiographers received periodic training and certification in radioprotection and 72% of them did not know their annual radiation dose. The main adopted personal protection devices were lead aprons and thyroid collars (95% and 92% of use, respectively). Dedicated architectural protective shielding was not available for 33% of interventional echocardiographers. Nearly two-thirds of responders thought that the radiation exposure of interventional echocardiographers was higher than that of interventional cardiologists and 72% claimed for an improvement in the radioprotection measures.

CONCLUSION

Radioprotection measures for interventional echocardiographers are widely variable across centres. Radioprotection devices are often underused by interventional echocardiographers, portending an increased radiation-related risk. International scientific societies working in the field should collaborate to endorse radioprotection training, promote reliable radiation dose assessment, and support the adoption of radioprotection shielding dedicated to interventional echocardiographers.

Radiation Exposure, Training, and Safety in Cardiology

Exposure to ionizing radiation is an inherent occupational health hazard in clinical cardiology. Health risks have been reported previously, including predilection to cancer. In addition, orthopedic injury due to prolonged wearing of heavy protective lead aprons, which are mandatory to reduce radiation risk, have been extensively documented. Cardiology as a specialty has grown with rising volumes of increasingly complex procedures. This includes electrophysiological, coronary, and structural intervention, advanced heart failure/transplant management, and diagnostic imaging. Both the operator as well imaging specialists are exposed to radiation, particularly in structural interventions where interventional cardiologists and structural imagers work closely. Increasingly, women interested in cardiology may deselect the field due to radiation concerns. This expert document highlights the risks of radiation exposure in cardiology, including practical tips within various subspecialty fields such as interventional/structural cardiology, electrophysiology, imaging, advanced heart failure, and pediatric cardiology.

Comprehensive Shielding System Enhances Radiation Protection for Structural Heart Procedures

Background

This study of radiation exposure (RE) to physicians performing structural heart procedures evaluated the efficacy of a novel comprehensive radiation shield compared to those of traditional shielding methods. A novel comprehensive shielding system (Protego, Image Diagnostics Inc) has been documented to provide superior RE protection during coronary procedures compared to that provided by a standard "drop down" shield. The purpose of this study was to assess the efficacy of this shield in transcatheter aortic valve replacement (TAVR) procedures, which are associated with disproportionate RE to operators.

Methods

This single-center, 2-group cohort, observational analysis compared RE to the primary physician operator performing TAVR using the Protego shield (n = 25) with that using a standard drop-down shield with personal leaded apparel (n = 25). RE was measured at both thyroid and waist levels with a real-time dosimetry system (RaySafe i3, RaySafe) and was calculated on a mean per case basis. Data were collected on additional procedural parameters, including access site(s) for device implantation, per case fluoroscopy time, air kerma, and patient factors, including body mass index. Between-group comparisons were conducted to evaluate RE by group and measurement sites.

Results

The Protego system reduced operator RE by 99% compared to that using standard protection. RE was significantly lower at both the thyroid level (0.08 ± 0.27 vs 79.2 ± 62.4 μSv; P < .001) and the waist level (0.70 ± 1.50 vs 162.0 ± 91.0 μSv, P < .001). "Zero" total RE was documented by RaySafe in 60% (n = 15) of TAVR cases using Protego. In contrast, standard protection did not achieve zero exposure in a single case.

Conclusions

The Protego shield system provides superior operator RE protection during TAVR procedures. This shield allows operators to work without the need for personal lead aprons and has potential to reduce catheterization laboratory occupational health hazards.

Comprehensive Training Model for Procedural Guidance of Transcatheter Mitral Valve Edge-to-Edge Repair: Divide and Conquer Approach

Transcatheter edge-to-edge repair (TEER) of the mitral valve is a complex procedure requiring continuous image guidance with 2-dimensional and 3-dimensional transesophageal echocardiography. In this context, the role of the echocardiographer is of paramount importance. Training in interventional echocardiography for procedures such as TEER requires comprehending the complicated workflow of the hybrid operating room and advanced imaging skills that go beyond traditional echocardiography training to guide the procedure. Despite TEER being more commonly performed, the training structure for interventional echocardiographers is lagging, with many practitioners not having any formal training in image guidance for this procedure. In this context, novel training strategies must be developed to increase exposure and aid training. In this review, the authors present a step-wise approach to training for image guidance during TEER of the mitral valve. The authors have deconstructed this complex procedure into modular components and have incremental stages of training based on different steps of the procedure. At each step, trainees must demonstrate proficiency before advancing to the next step, thus ensuring a more structured approach to attaining proficiency in this complex procedure.

Radioprotection for the imaging specialist during structural heart interventions: Not an option!

Structural heart interventions are steadily increasing, and the majority requires echocardiographic guidance. As a result, imaging specialists are exposed to the harmful effects of scattered ionizing radiation. This X-ray exposure must be quantified, its potential consequences should be monitored by occupational medicine and the "as low as reasonably achievable" principles of radioprotection should be optimized (including increasing the distance, decreasing the duration, using shielding radiation and providing safety training for the imaging specialist). The spatial organization of and shielding provision in the procedural rooms should be designed to optimize radioprotection for all team members.

Recommendations for Special Competency in Echocardiographic Guidance of Structural Heart Disease Interventions: From the American Society of Echocardiography

Transcatheter therapies for structural heart disease continue to grow at a rapid pace, and echocardiography is the primary imaging modality used to support such procedures. Transesophageal echocardiographic guidance of structural heart disease procedures must be performed by highly skilled echocardiographers who can provide rapid, accurate, and high-quality image acquisition and interpretation in real time. Training standards are needed to ensure that interventional echocardiographers have the necessary expertise to perform this complex task. This document provides guidance on all critical aspects of training for cardiology and anesthesiology trainees and postgraduate echocardiographers who plan to specialize in interventional echocardiography. Core competencies common to all transcatheter therapies are reviewed in addition to competencies for each specific transcatheter procedure. A core principle is that the length of interventional echocardiography training or achieved procedure volumes are less important than the demonstration of procedure-specific competencies within the milestone domains of knowledge, skill, and communication.

Body Surface Radiation Exposure in Interventional Echocardiographers During Structural Heart Disease Procedures

Background

The distribution of radiation exposure on the body surface of interventional echocardiographers during structural heart disease (SHD) procedures is unclear.

Objectives

This study estimated and visualized radiation exposure on the body surface of interventional echocardiographers performing transesophageal echocardiography by computer simulations and real-life measurements of radiation exposure during SHD procedures.

Methods

A Monte Carlo simulation was performed to clarify the absorbed dose distribution of radiation on the body surface of interventional echocardiographers. The real-life radiation exposure was measured during 79 consecutive procedures (44 transcatheter edge-to-edge repairs of the mitral valve and 35 transcatheter aortic valve replacements [TAVRs]).

Results

The simulation demonstrated high-dose exposure areas (>20 μGy/h) in the right half of the body, especially the waist and lower body, in all fluoroscopic directions caused by scattered radiation from the bottom edge of the patient bed. High-dose exposure occurred when obtaining posterior-anterior and cusp-overlap views. The real-life exposure measurements were consistent with the simulation estimates: interventional echocardiographers were more exposed to radiation at their waist in transcatheter edge-to-edge repair than in TAVR procedures (median 0.334 μSv/mGy vs 0.053 μSv/mGy; P < 0.001) and in TAVR with self-expanding valves than in those with balloon-expandable valves (median 0.067 μSv/mGy vs 0.039 μSv/mGy; P < 0.01) when the posterior-anterior or the right anterior oblique angle fluoroscopic directions were used.

Conclusions

During SHD procedures, the right waist and lower body of interventional echocardiographers were exposed to high radiation doses. Exposure dose varied between different C-arm projections. Interventional echocardiographers, especially young women, should be educated regarding radiation exposure during these procedures. (The development of radiation protection shield for catheter-based treatment of structural heart disease [for echocardiologists and anesthesiologists]; UMIN000046478).

Interventional echocardiography: Opportunities and challenges in an emerging field

The growth of transcatheter structural heart disease interventions has created a subspecialty of interventional imagers who focus on preprocedural planning and the periprocedural guidance of these complex cases. In particular interventional imagers who focus on periprocedural guidance have developed a specific expertise in interventional transesophageal echocardiography (iTEE). This nascent field has challenges in training, reimbursement, and occupational hazards which are unique to this field. This review encompasses the evolution of iTEE, current challenges, and future opportunities.

Comparison of Radiation Exposure Among Interventional Echocardiographers, Interventional Cardiologists, and Sonographers During Percutaneous Structural Heart Interventions

IMPORTANCE

Transesophageal echocardiography during percutaneous left atrial appendage closure (LAAO) and transcatheter edge-to-edge mitral valve repair (TEER) require an interventional echocardiographer to stand near the radiation source and patient, the primary source of scatter radiation. Despite previous work demonstrating high radiation exposure for interventional cardiologists performing percutaneous coronary and structural heart interventions, similar data for interventional echocardiographers are lacking.

OBJECTIVE

To assess whether interventional echocardiographers are exposed to greater radiation doses than interventional cardiologists and sonographers during structural heart procedures.

DESIGN, SETTING, AND PARTICIPANTS

In this single-center cross-sectional study, radiation doses were collected from interventional echocardiographers, interventional cardiologists, and sonographers at a quaternary care center during 30 sequential LAAO and 30 sequential TEER procedures from July 1, 2016, to January 31, 2018. Participants and study personnel were blinded to radiation doses through data analysis (January 1, 2020, to October 12, 2021).

EXPOSURES

Occupation defined as interventional echocardiographers, interventional cardiologists, and sonographers.

MAIN OUTCOMES AND MEASURES

Measured personal dose equivalents per case were recorded using real-time radiation dosimeters.

RESULTS

A total of 60 (30 TEER and 30 LAAO) procedures were performed in 60 patients (mean [SD] age, 79 [8] years; 32 [53.3%] male) with a high cardiovascular risk factor burden. The median radiation dose per case was higher for interventional echocardiographers (10.6 μSv; IQR, 4.2-22.4 μSv) than for interventional cardiologists (2.1 μSv; IQR, 0.2-8.3 μSv; P < .001). During TEER, interventional echocardiographers received a median radiation dose of 10.5 μSv (IQR, 3.1-20.5 μSv), which was higher than the median radiation dose received by interventional cardiologists (0.9 μSv; IQR, 0.1-12.2 μSv; P < .001). During LAAO procedures, the median radiation dose was 10.6 μSv (IQR, 5.8-24.1 μSv) among interventional echocardiographers and 3.5 (IQR, 1.3-6.3 μSv) among interventional cardiologists (P < .001). Compared with interventional echocardiographers, sonographers exhibited low median radiation doses during both LAAO (0.2 μSv; IQR, 0.0-1.6 μSv; P < .001) and TEER (0.0 μSv; IQR, 0.0-0.1 μSv; P < .001).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, interventional echocardiographers were exposed to higher radiation doses than interventional cardiologists during LAAO and TEER procedures, whereas sonographers demonstrated comparatively lower radiation doses. Higher radiation doses indicate a previously underappreciated occupational risk faced by interventional echocardiographers, which has implications for the rapidly expanding structural heart team.

Reduction of radiation exposure during transcatheter edge-to-edge mitral valve repair

BACKGROUND

Transcatheter mitral valve repair is an increasingly used therapy for mitral regurgitation which requires fluoroscopic guidance. Limiting radiation exposure during lengthy procedures is important for both patient and operator safety. This study aimed to investigate radiation dose during contemporary use of MitraClip implantation and the effects of a dose reduction program.

METHODS

A total of 115 patients who underwent MitraClip implantation were prospectively enrolled in a single-center observational study. During the inclusion period, our institution adopted a radiation dose reduction program, comprising lowering of fluoroscopy pulse rate and image target dose. The first 58 patients were treated with conventional fluoroscopy settings, while the following 57 patients underwent the procedure with the newly implemented low dose protocol.

RESULTS

Radiation dose area product significantly decreased after introduction of the low dose protocol (693 [366-1231] vs. 2265 [1517-3914] cGy·cm² , p < 0.001). After correcting for fluoroscopy time, gender and body mass index, the low dose protocol emerged as a strong negative predictor of radiation dose (p < 0.001), reducing dose area product by 64% (95% confidence interval [57-70]). Device time, device success, and procedural safety did not differ between the normal dose and low dose group. Furthermore, the low dose protocol was not associated with an increased incidence of a combined endpoint consisting of death, repeat intervention, or heart surgery during 12 months follow-up.

CONCLUSION

Reduction of radiation exposure during transcatheter mitral valve repair by 64% is feasible without affecting procedural success or safety.

Impact of Patient BMI on Patient and Operator Radiation Dose During Percutaneous Coronary Intervention

AIMS

This study sought to investigate patient and operator radiation dose in patients undergoing percutaneous coronary intervention (PCI) and the impact of body mass index (BMI) on patient and operator dose.

METHODS

In patients undergoing PCI, radiation dose parameters, baseline characteristics and procedural data were collected in a tertiary centre for 3.5 years. Operators wore real time dosimeters. Patients were grouped by BMI. Dose area product (DAP) and operator radiation dose were compared across patient BMI categories. Multivariable analysis was performed to investigate the impact of patient BMI and other procedural variables on patient and operator dose.

RESULTS

2,043 patients underwent 2,197 PCI procedures. Each five-unit increase in BMI increased patient dose (expressed as DAP) by an average 31% (95% CI: 29-33%) and operator dose by 27% (95% CI: 20-33%). Patient dose was 2.3 times higher and operator dose was 2.4 times higher in patients with a BMI>40 than for normal BMI patients. Multivariable analysis indicated that there were many procedural factors that were predictors for increasing operator dose and patient dose but that patient BMI was a major contributor for both operator dose and patient dose.

CONCLUSION

Increasing BMI increases the DAP and operator dose for PCI procedures and BMI is demonstrated to be a major factor that contributes to both patient and operator radiation dose.

Intravascular Ultrasound-Guided Contrast-Free Transcatheter Aortic Valve Implantation: A Porcine Feasibility Study

OBJECTIVE

Patients undergoing transcatheter aortic valve implantation (TAVI) frequently present with chronic kidney disease and are therefore particularly susceptible to nephrotoxic influences like iodinated contrast media. Acute kidney injury after TAVI is a severe complication that independently predicts short- and long-term mortality. The present study investigates the feasibility of a contrast-free approach by using intravascular ultrasound (IVUS) in conjunction with fluoroscopy.

METHODS

Six domestic pigs (60 ± 5 kg) were anesthetized and underwent transapical implantation of a balloon-expandable transcatheter heart valve. In the control group (n = 3), the procedures were guided by fluoroscopy/angiography. In the study group (n = 3), the procedures were guided by IVUS for preimplantation evaluation, intra-procedural guidance, and post-implantation evaluation, in conjunction with fluoroscopy without contrast. The procedures were evaluated by IVUS, fluoroscopy, aortic root angiography, and explantation and dissection of the hearts.

RESULTS

Relevant anatomical landmarks for correct implantation were assessed by IVUS. The following annulus measurements were obtained: area (359.67 ± 29.58 mm²), perimeter (68.28 ± 2.63 mm), maximum diameter (22.20 ± 1.22 mm), minimum diameter (20.43 ± 1.12 mm), mean diameter (21.32 ± 0.70 mm), ellipticity index (1.09 ± 0.10), and area-derived diameter (21.39 ± 0.87 mm). IVUS-guided valve deployment resulted in correct expansion within the aortic annulus without signs of paravalvular leak, compromised mitral valve, or coronary obstruction. IVUS-guided post-implantation assessment confirmed circular expansion (25.88 ± 0.30 mm) of the valves.

CONCLUSIONS

IVUS-guided, contrast-free transapical TAVI is feasible in a porcine model.

The structural heart disease interventional imager rationale, skills and training: a position paper of the European Association of Cardiovascular Imaging

Percutaneous therapeutic options for an increasing variety of structural heart diseases (SHD) have grown dramatically. Within this context of continuous expansion of devices and procedures, there has been increased demand for physicians with specific knowledge, skills, and advanced training in multimodality cardiac imaging. As a consequence, a new subspecialty of ‘Interventional Imaging’ for SHD interventions and a new dedicated professional figure, the ‘Interventional Imager’ with specific competencies has emerged. The interventional imager is an integral part of the heart team and plays a central role in decision-making throughout the patient pathway, including the appropriateness and feasibility of a procedure, pre-procedural planning, intra-procedural guidance, and post-procedural follow-up. However, inherent challenges exist to develop a training programme for SHD imaging that differs from traditional cardiovascular imaging pathways. The purpose of this document is to provide the standard requirements for the training in SHD imaging, as well as a starting point for an official certification process for SHD interventional imager.

Effectiveness of a radiation protective device for anesthesiologists and transesophageal echocardiography operators in structural heart disease interventions

In structural heart disease (SHD) interventions, the exposure of staff other than the first operator such as anesthesiologists and transesophageal echocardiography (TEE) operators to the radiation can also pose the risks of cancer and cataracts in the long term. This study was conducted to test our new radiation protective device (RPD) for anesthesiologists and TEE operators in SHD interventions. The RPD, which consists of a head side shield and a cradle shield, was mounted on a 0.25 mm Pb-equivalent unleaded radiation protection sheet on a self-made J-shaped acrylic table, and it was placed on the head side and cradle on the operating table. A CT human body phantom was placed on the operating table, and the C-arm was set in five directions: posteroanterior, right anterior oblique 30°, left anterior oblique 30°, caudal 30°, and cranial 30°. The ambient dose equivalent rate at the usual positions of the anesthesiologist and TEE operator were measured under a fluoroscopic sequence with and without the RPD, and the dose reduction rate was obtained. The height of each measurement point was set to 100, 130 or 160 cm. The reduction rates at the positions of the anesthesiologist and the TEE operator were 82.6-86.4% and 77.9-89.5% at the height of 100 cm, 48.5-68.4% and 83.3-91.0% at 130 cm, and 23.6-62.9% and 72.9-86.1% at 160 cm, respectively. The newly developed RPD can thus effectively reduce the radiation exposure of anesthesiologists and TEE operators during SHD interventions.

Primary operator radiation dose in the cardiac catheter laboratory

OBJECTIVES

Radiation from cardiac angiography procedures is harmful to patients and the staff performing them. This study sought to investigate operator radiation dose for a range of procedures and different operators in order to investigate trends and optimise dose.

METHODS

Real-time dosemeters (RTDs) were worn by operators for angiography procedures for 3 years. Dose-area product (DAP) and RTD were collected. RTD was normalised to DAP (RTD/DAP) to compare radiation dose and radiation protection measures. Comparisons were made across procedure categories and individual operators.

RESULTS

In 7626 procedures, median and 75th percentile levels were established for operator dose for 8 procedure categories. There was a significant difference in all operator dose measures and DAP across procedure categories (p<0.001). DAP, RTD, and RTD/DAP were significantly different across 22 individual operators (p<0.001).

CONCLUSION

DAP was significantly different across procedure categories and a higher RTD was seen with higher DAP. RTD/DAP can demonstrate radiation protection effectiveness and identified differences between procedures and individual operators with this measure. Procedures and individuals were identified where further optimisation of radiation protection measures may be beneficial. A reference level for operator dose can be created and audited against on a regular basis.

ADVANCES IN KNOWLEDGE

This study demonstrates that operator dose can be easily and routinely measured on a case by case basis to investigate dose trends for different procedures. Normalising the operator dose to DAP demonstrates radiation protection effectiveness for the individual operator which can then be optimised as part of an ongoing audit program.

Strategies to Reduce Radiation Exposure in Electrophysiology and Interventional Cardiology

Clinical diagnosis sometimes involves the use of medical instruments that employ ionizing radiation. However, ionizing radiation exposure is a workplace hazard that goes undetected and is detrimental to patients and staff in the catheterization laboratory. Every possible effort should be made to reduce the amount of radiation, including scattered radiation. Implementing radiation dose feedback may have a role in reducing exposure. In medicine, it is important to estimate the potential biologic effects on, and the risk to, an individual. In general, implantation of cardiac resynchronization devices is associated with one of the highest operator exposure doses due to the proximity of the operator to the radiation source. All physicians should work on the principle of as low as reasonably achievable. Methods for reducing radiation exposure must be implemented in the catheterization laboratory. In this article, we review the available tools to lower the radiation exposure dose to the operator during diagnostic, interventional, and electrophysiological cardiac procedures.

Imaging in Structural Heart Disease: The Evolution of a New Subspecialty

Structural heart disease is a new field in cardiovascular medicine, which has resulted in the creation of a new imaging subspecialty. Structural heart disease imagers have been instrumental in stimulating innovations in both the imaging and interventional spheres. Perhaps most importantly, they play a key role on the clinical heart team, interacting with team members and patients before, during, and long after a structural procedure is performed.

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.

Factors contributing to radiation dose for patients and operators during diagnostic cardiac angiography

INTRODUCTION

Diagnostic coronary angiography (CA) uses ionising radiation with relatively high doses, which impact on both patients and staff. This study sought to identify which patient and procedural factors impact patient and operator dose the most during CA.

METHODS

Patient and procedure related variables impacting on Kerma area product (PKA ) and operator dose (OD) were collected for 16 months. Procedures were separated into 10 different procedure categories. PKA was used for patient dose and OD was measured with an instantly downloadable dosimeter (IDD) - downloaded at the end of each procedure. High and low radiation dose was defined by binary variables based on the 75th percentile of the continuous measures. Univariate and multivariate regression were used to identify predictors.

RESULTS

Of 3860 patients included, the IDD was worn for 2591 (61.7%). Obesity (BMI > 30 compared to BMI < 25) was the strongest predictor for both a PKA (odds ratio (OR) = 19.1 (95% CI 13.5-26.9) P < 0.001) and OD (OR = 3.3 (2.4-4.4) P < 0.001) above the 75th percentile. Male gender, biplane imaging, the X-ray unit used, operator experience and procedure type also predicted a high PKA . Radial access, male gender, biplane imaging and procedure type also predicted a high OD.

CONCLUSION

Radiation dose during CA is multifactorial and is dependent on patient and procedure related variables. Many factors impact on both PKA and OD but obesity is the strongest predictor for both patients and operators to receive a high radiation dose.

Radiation protection for the echocardiographers: "To each their own"

This article illustrates the effectiveness of targeted radioprotective strategies for the interventional echocardiographer. The reader should recognize the importance of engagement of all team members in the multifaceted process of radiation exposure mitigation. Future efforts/studies should focus on the impact of team oriented training, lab design, and development of novel supplies and equipment to mitigate radiation exposure of all personnel in the cardiac catheterization lab, particularly during more complex interventional procedures.

Radioprotective strategies for interventional echocardiographers during structural heart interventions

OBJECTIVE

We investigated radioprotective strategies for the interventional echocardiographer (IE) during structural heart interventions in comparison with the interventional cardiologist (IC).

BACKGROUND

Structural heart interventions are expanding in complexity with increased reliance on IE. Recent reports have demonstrated concerning exposure and higher radiation to the IE.

METHODS

We monitored 32 structural interventions - 19 transcatheter aortic valve replacements (TAVR), 6 transcatheter mitral valve repairs, 5 paravalvular leak closures, and 2 atrial septal defect closures. Seventeen utilized transesophageal echocardiography (TEE) while 15 used transthoracic echocardiography (TTE). Members of the IC and IE teams wore multiple dosimeters on different sites of the body to measure radiation dose to the total body, lens of the eye, and hand. During each case, IE utilized dedicated radiation shielding.

RESULTS

Mean doses were higher for the primary IC than the primary IE: IC#1-99, 222, 378; IE#1-48, 52, 416 (body, lens, and hand doses in μSv). IE radioprotective strategies were able to reduce body and lens doses compared to IC during both TTE and TEE-guided procedures. Hand equivalent dose remained higher for the IE driven by exposure during TEE-guided procedures (IC#1 294 vs. IE#1 676 μSv). In a subgroup using radioprotective drapes during TTE-guided TAVR, IC dose was reduced without effect on the IE.

CONCLUSIONS

Radiation exposure during structural heart interventions is concerning. With dedicated shielding, IE received lower doses to the body and lens than IC. Further optimization of structural suite design and shielding is needed.