Measures to Reduce Radiation in a Modern Cardiac Catheterization Laboratory

Differing radiation exposure in scrub technicians and rotating staff in Cardiac catheterization laboratory: occupation matters

BACKGROUND

Radiation exposure is a significant hazard associated with invasive Cardiology, with most studies based on primary operator exposure. This prospective, observational study aimed to find out over lead radiation exposure as effective dose acquired by non-physician staff comprising scrub technicians and rotating staff in the cath laboratory. Effective dose (ED) measured per procedure via Raysafe i2®dosimeter badges worn by both rotating staff and scrub technicians over lead aprons along with dose area product (DAP), fluoroscopy time (FT) and procedure time (PT) in minutes was collected prospectively over forty-six invasive Cardiology procedures.

RESULTS

This study shows that rotating staff acquire higher ED in comparison with their scrub technician colleagues in diagnostic, interventional and electrophysiology cases. However, a statistically significant difference in radiation exposure of both staff groups was demonstrated in diagnostic and interventional Cardiology procedures, with p values of 0.04 and 0.01, respectively.

CONCLUSIONS

These findings highlight occupational role and mobility around fluoroscopic sources as major factors in radiation exposure, which should be addressed within current radiation protection practices.

Statewide Initiative to Reduce Patient Radiation Doses During Percutaneous Coronary Intervention

BACKGROUND

Improved radiation safety practices are needed across hospitals performing percutaneous coronary intervention (PCI). This study was performed to assess the temporal trend in PCI radiation doses concurrent with the conduct of a statewide radiation safety initiative.

METHODS

A statewide initiative to reduce PCI radiation doses was conducted in Michigan between 2017 and 2021 and included focused radiation safety education, reporting of institutional radiation doses, and implementation of radiation performance metrics for hospitals. Using data from a large statewide registry, PCI discharges between July 1, 2016, and July 1, 2022, having a procedural air kerma (AK) recorded were analyzed for temporal trends. A multivariable regression analysis was performed to determine whether declines in procedural AK over time were attributable to changes in known predictors of radiation doses.

RESULTS

Among 131 619 PCI procedures performed during the study period, a reduction in procedural AK was observed over time, from a median dose of 1.46 (0.86-2.37) Gy in the first year of the study to 0.97 (0.56-1.64) Gy in the last year of the study (P<0.001). The proportion of cases with an AK ≥5 Gy declined from 4.24% to 0.86% over the same time period (P<0.0001). After adjusting for variables known to impact radiation doses, a 1-year increase in the date of PCI was associated with a 7.61% (95% CI, 7.38%-7.84%) reduction in procedural AK (P<0.0001).

CONCLUSIONS

Concurrent with the conduct of a statewide initiative to reduce procedural radiation doses, a progressive and significant decline in procedural radiation doses was observed among patients undergoing PCI in the state of Michigan.

Preoperative flow analysis of arteriovenous malformations and obliteration response after stereotactic radiosurgery

OBJECTIVE

Morphological and angioarchitectural features of cerebral arteriovenous malformations (AVMs) have been widely described and associated with outcomes; however, few studies have conducted a quantitative analysis of AVM flow. The authors examined brain AVM flow and transit time on angiograms using direct visual analysis and a computer-based method and correlated these factors with the obliteration response after Gamma Knife radiosurgery.

METHODS

A retrospective analysis was conducted at a single institution using a prospective registry of patients managed from January 2013 to December 2019: 71 patients were analyzed using a visual method of flow determination and 38 were analyzed using a computer-based method. After comparison and validation of the two methods, obliteration response was correlated to flow analysis, demographic, angioarchitectural, and dosimetric data.

RESULTS

The mean AVM volume was 3.84 cm3 (range 0.64-19.8 cm3), 32 AVMs (45%) were in critical functional locations, and the mean margin radiosurgical dose was 18.8 Gy (range 16-22 Gy). Twenty-seven AVMs (38%) were classified as high flow, 37 (52%) as moderate flow, and 7 (10%) as low flow. Complete obliteration was achieved in 44 patients (62%) at the time of the study; the mean time to obliteration was 28 months for low-flow, 34 months for moderate-flow, and 47 months for high-flow AVMs. Univariate and multivariate analyses of factors predicting obliteration included AVM nidus volume, age, and flow. Adverse radiation effects were identified in 5 patients (7%), and 67 patients (94%) remained free of any functional deterioration during follow-up.

CONCLUSIONS

AVM flow analysis and categorization in terms of transit time are useful predictors of the probability of and the time to obliteration. The authors believe that a more quantitative understanding of flow can help to guide stereotactic radiosurgery treatment and set accurate outcome expectations.

Effect of Different Anthropometric Body Indexes on Radiation Exposure in Patients Undergoing Cardiac Catheterisation and Percutaneous Coronary Intervention

BACKGROUND

Patient factors, such as sex and body mass index (BMI), are known to influence patient radiation exposure. Body surface area (BSA) and its association with patient radiation exposure has not been well studied.

METHODS AND RESULTS

We analysed height, weight, BMI and BSA in consecutive patients undergoing cardiac catheterisation and percutaneous coronary intervention (PCI) at a high-volume Australian centre between September 2016 and April 2020 to assess their association with dose-area product (DAP, Gycm2). The mean age of the cohort was 64.5 ± 12.3 years with males comprising 68.8% (n = 8100, 5124 diagnostic cardiac catheterisation cases and 2976 PCI cases). Median male BMI was 28.4 kg/m2 [IQR 25.2-32.1] versus 28.8 kg/m2 [24.7-33.7] for females, p = 0.01. Males had higher BSA (2.0 ± 0.2 m2) than females (1.78 ± 0.2 m2), p = 0.001. Each 0.4 m2 increase in BSA conferred a 1.32x fold change in DAP (95% CI 1.29-1.36, p ≤ 0.001). Each 5 kg/m2 increase in BMI was linked to a 1.13x DAP fold change (1.12-1.14, p ≤ 0.001). Male sex conferred a 1.23x DAP fold change (1.20-1.26, p ≤ 0.001). Multivariable modelling with BMI or BSA explained 14% of DAP variance (R2 0.67 vs. 0.53 for both, p ≤ 0.001).

CONCLUSIONS

BSA is an important anthropometric measure between the sexes and a key predictor of radiation dose and radiation exposure beyond sex, BMI, and weight.

Radiation reduction in a modern catheterization laboratory: A single-center experience

BACKGROUND

Measures were undertaken at the Cleveland Clinic to reduce radiation exposure to patients and personnel working in the catheterization laboratories. We report our experience with these improved systems over a 7-year period in patients undergoing diagnostic catheterization (DC) and percutaneous coronary interventions (PCIs).

METHODS

Patients were categorized into preinitiative (2009-2012) and postinitiative (2013-2019) groups in the DC and PCI cohorts. Propensity score matching was done between the pre- and postinitiative groups for both cohorts based on age, sex, body surface area, total fluoroscopy time, and total acquisition time. The effectiveness of radiation reduction measures was assessed by comparing the total air kerma (K_a,r ), and fluoroscopy- and acquisition-mode air kerma in patients in the two groups.

RESULTS

In the DC cohort, there was a significant reduction in K_a,r in the postinitiative group in comparison to the preinitiative group (median, 396 vs. 857 mGy; p < 0.001). In the PCI cohort, K_a,r in the postinitiative group was 1265 mGy, which was significantly lower than the corresponding values in the preinitiative group (1994 mGy; p < 0.001). We also observed a significant reduction in fluoroscopy- and acquisition-based air kerma rates, and air kerma area product in the postinitiative group in comparison to the preinitiative group in both matched and unmatched DC and PCI cohorts after the institution of radiation reduction measures.

CONCLUSION

There was a significant and sustained reduction in radiation exposure to patients in the catheterization laboratory with the implementation of advanced protocols. Similar algorithms can be applied in other laboratories to achieve a similar reduction in radiation exposure.

The use of digital magnification to reduce radiation dose in the cardiac catheter laboratory

OBJECTIVES

To audit whether using magnification of images by use of a large viewing screen using digital matrix magnification which enlarges the image by 33% without using the X-ray machine zoom magnification protocols on a Siemens Artis Zee X-ray machine in a cardiac catheter laboratory results in a reduction of kerma-area product (KAP) for both diagnostic and interventional procedures. This reduction was predicted in an in vitro study in our laboratory, which has previously shown a 20.4% reduction in KAP.

METHODS

A retrospective analysis was conducted of the radiation exposure to compare the measured KAP recorded during the period when conventional magnification with automatic brightness and dose control was used on a Siemens Artis Zee X-ray machine with a flat panel detector and when magnification settings were avoided by using a large screen to enlarge and project a non-magnified image by digital magnification. The analysis was carried out for patients having a diagnostic coronary angiogram and those having an interventional coronary procedure.

RESULTS

For diagnostic coronary angiograms the median KAP per procedure in the period using conventional magnification was 2124.5 µGy.m² compared to 1401 µGy.m² when image matrix magnification was used, a 34% reduction (p < 0.0001). For interventional coronary procedures, the median KAP per procedure in the period using conventional magnification was 3791 µGy.m² compared to 2568.5 µGy.m² when image matrix magnification was used, a 32% reduction (p < 0.0001).

CONCLUSION

Avoiding using conventional magnification in the cardiac catheter laboratory and using a large screen to magnify images was associated with a statistically significant greater than 30% reduction in KAP.

ADVANCES IN KNOWLEDGE

This paper is the proof in clinical practice of a theoretical conclusion that radiation dose (KAP) is reduced by use of Image matrix magnification using a large viewing screen without the need to use X-ray tube magnification without significant loss of image resolution in interventional cardiology. The same approach will be useful in interventional radiology.

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.

How significant is the radiation exposure during electrophysiology study and ablation procedures for supraventricular tachycardia?

Radiation exposure during electrophysiology procedures has been a point of discussion. We measured the ionising radiation dosage during ablation procedures for supraventricular tachycardia. This was compared with coronary angiographies performed via the radial route to put it in perspective. We found that the radiation dosage during the ablation procedure was far lower, less than forty percent of that during coronary angiography (Air Kerma 249.1 mGy ± 266.95 mGy v/s 671.9 mGy ± 328.6 mGy; p < 0.001).

AN INTERVENTIONAL CARDIOLOGY INVESTIGATION: PATIENT EXPOSURE TO RADIATION AND INTER-OPERATOR VARIABILITY IN AN IRISH SETTING

AIM

To evaluate patient radiation exposure for Diagnostic Coronary Angiography (DCA) and Percutaneous Cardiac Intervention (PCI) performed by different operators.

METHODS AND RESULTS

Retrospective (n = 160) and prospective (n = 62) data for DCA (n = 179) and PCI (n = 43) examinations performed by interventional cardiologists (n = 3) using the same imaging equipment were reviewed. The operator with consistently low diagnostic reference levels (DRLs) was interviewed for their personal perceptions upon operator training. Retrospective Median [IQR] DAP was 18.8 [11.8-31.6] and 50.7 [35.3-85.6] Gy.cm2 for DCA and PCI, respectively. Prospective Median [IQR] DAP for DCA and PCI was 7.9 [5.2-10.6] and 15.9 [10.0-17.7] Gy.cm2, respectively. DRLs were within Irish and European DRLs; however, significant inter-operator variability (p < .001) was identified.

CONCLUSION

Radiation exposure in Interventional cardiology is highly operator dependent; further research is warranted in standardization of operator training with evolving technologies.

Impact of electroanatomical mapping-guided lead implantation on procedural outcome of His bundle pacing

Aims

Conventional His bundle pacing (HBP) can be technically challenging and fluoroscopy-intense, particularly in patients with His-Purkinje conduction disease (HPCD). Three-dimensional electroanatomical mapping (EAM) facilitates non-fluoroscopic lead navigation and HB electrogram mapping. We sought to assess the procedural outcome of routine EAM-guided HBP compared with conventional HBP in a real-world population and evaluate the feasibility and safety of EAM-guided HBP in patients with HPCD.

Methods and results 

We included 58 consecutive patients (72 ± 13 years; 71% male) who underwent an attempt to conventional (EAM− group; n = 29) or EAM-guided (EAM+ group; n = 29) HBP between June 2019 and April 2020. The centre’s learning curve was initially determined (n = 40 cases) to define the conventional control group and minimize outcome bias favouring EAM-guided HBP. His bundle pacing was successful in 26 patients (90%) in the EAM+ and 27 patients (93%) in the EAM− group (P = 0.64). The procedure time was 90 (73–135) and 110 (70–130) min, respectively (P = 0.89). The total fluoroscopy time [0.7 (0.5–1.4) vs. 3.3 (1.4–6.5) min; P &lt; 0.001] and fluoroscopy dose [21.9 (9.1–47.7) vs. 78.6 (27.2–144.9) cGycm2; P = 0.001] were significantly lower in the EAM+ than EAM− group. There were no significant differences between groups in His capture threshold (1.2 ± 0.6 vs. 1.4 ± 1.0 V/1.0 ms; P = 0.33) and paced QRS duration (113 ± 15 vs. 113 ± 17 ms; P = 0.89). In patients with HPCD, paced QRS duration was similar in both groups (121 ± 15 vs. 123 ± 12 ms; P = 0.77). The bundle branch-block recruitment threshold tended to be lower in the EAM+ than EAM− group (1.3 ± 0.7 vs. 1.8 ± 1.2 V/1.0 ms; P = 0.31). No immediate procedure-related complications occurred. One patient (2%) experienced lead dislodgement during 4-week follow-up.

Conclusion 

Implementation of routine EAM-guided HBP lead implantation is feasible and safe in a real-world cohort of patients with and without HPCD and results in a tremendous reduction in radiation exposure without prolonging procedure time or increasing procedure-related complications.

Cardiovascular Considerations in Caring for Pregnant Patients: A Scientific Statement From the American Heart Association

Cardio-obstetrics has emerged as an important multidisciplinary field that requires a team approach to the management of cardiovascular disease during pregnancy. Cardiac conditions during pregnancy include hypertensive disorders, hypercholesterolemia, myocardial infarction, cardiomyopathies, arrhythmias, valvular disease, thromboembolic disease, aortic disease, and cerebrovascular diseases. Cardiovascular disease is the primary cause of pregnancy-related mortality in the United States. Advancing maternal age and preexisting comorbid conditions have contributed to the increased rates of maternal mortality. Preconception counseling by the multidisciplinary cardio-obstetrics team is essential for women with preexistent cardiac conditions or history of preeclampsia. Early involvement of the cardio-obstetrics team is critical to prevent maternal morbidity and mortality during the length of the pregnancy and 1 year postpartum. A general understanding of cardiovascular disease during pregnancy should be a core knowledge area for all cardiovascular and primary care clinicians. This scientific statement provides an overview of the diagnosis and management of cardiovascular disease during pregnancy.

Fluoroless Atrial Fibrillation Catheter Ablation: Technique and Clinical Outcomes

Fluoroscopy continues to be considered an indispensable part of atrial fibrillation (AF) ablation worldwide. Deleterious effects of radiation exposure to patients, physicians, and catheter laboratory personnel are gaining increased consideration. Safety and efficacy of a fluoroless approach for AF ablation is comparable with outcomes achieved with fluoroscopy use. This article focuses on AF ablation with zero fluoroscopy use as well as current evidence on efficacy and safety of this technique. In contrast, minimal fluoroscopy is an alternative. Relying on intracardiac echocardiography for transseptal access and electroanatomic mapping for catheter manipulation can help implement this approach on a wider scale.

Radiation protection in the cardiac catheterization laboratory

The trend towards more minimally invasive procedures in the past few decades has resulted in an exponential growth in fluoroscopy-guided catheter-based cardiology procedures. As these techniques are becoming more commonly used and developed, the adverse effects of radiation exposure to the patient, operator, and ancillary staff have been a subject of concern. Although occupational radiation dose limits are being monitored and seldom reached, exposure to chronic, low dose radiation has been shown to have harmful biological effects that are not readily apparent until years after. Given this, it is imperative that reducing radiation dose exposure in the cardiac catheterization laboratory remains a priority. Staff education and training, radiation dose monitoring, ensuring use of proper personal protective equipment, employment of shields, and various procedural techniques in minimizing radiation must always be diligently employed. Special care and consideration should be extended to pregnant women working in the cardiac catheterization laboratory. This review article presents a practical approach to radiation dose management and discusses best practice recommendations in the cardiac catheterization laboratory.

IMPACT OF PELVIC AND RAD-BOARD LEAD SHIELDS ON OPERATOR AND PATIENT RADIATION DOSE IN TRANS-RADIAL CORONARY PROCEDURES

BACKGROUND

Trans-radial approach for cardiac catheterisation procedures has long been associated with high operator and patient radiation dose. The aim of the present study was to determine the effect of pelvic and radial shields on decreasing coronary procedure radiation doses.

METHODS

A total of 418 patients randomly underwent diagnostic and therapeutic cardiac procedures with and without the pelvic and rad-board lead shields during the procedures. The operator and patient doses were then determined by means of a personal dosimeter and dose area product (DAP), respectively.

RESULTS

The shields decreased the operator radiation dose by 40% in coronary angiography (CA) and by 45% during angioplasty (PCI). These results were achieved at the cost of increased patient radiation dose.

CONCLUSION

Pelvic lead shields combined with rad-board shields are highly effective in reducing operator radiation dose in trans-radial approach, but it is only achieved at the cost of increased patient DAP.

Utilization of an Optimized Radiation Strategy in Primary Percutaneous Coronary Intervention for Patients with ST-Segment-Elevation Myocardial Infarction

Background

Recent reports about radiation risk gradually raised the safety concerns for interventional therapy. However, limited data exist on the optimized radiation strategy in primary percutaneous coronary intervention (P-PCI) for patients with ST-segment-elevation myocardial infarction (STEMI).

Methods

A total of 214 STEMI patients undergoing P-PCI were retrospectively analyzed. Patients were divided into the optimized radiation strategy (ORS) group (N = 151) and normal radiation strategy (NRS) group (N = 63) according to the radiation protocol utilized. The primary endpoint was the relative dose reduction of total air kerma. The secondary endpoint was 30-day major adverse cardiac and cerebrovascular events (MACCE), as a composite of all-cause death, reinfarction, ischemia-driven target vessel revascularization, and stroke.

Results

Patient groups were well matched for baseline characteristics. There were no differences in terms of age, body mass index, radial artery access, nonculprit vessel PCI, and fluoroscopy time between 2 groups. With optimized radiation strategy, a 40.9% radiation dose reduction (901.2 ± 628.7 mGy versus 1524.0 ± 866.6 mGy, p < 0.001) was obtained for total air kerma. No significant differences were found for 30-day MACCE between 2 groups (2.0% versus 1.6%, adjusted hazard ratio: 0.7, 95% confidence interval: 0.1 to 8.6, p=0.772).

Conclusion

With optimized radiation strategy, significant radiation dose reduction could be achieved in P-PCI for STEMI patients. It appears to be feasible and safe to carry out the optimized radiation strategy in P-PCI for STEMI patients.

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?

The Simulation Training in Coronary Angiography and Its Impact on Real Life Conduct in the Catheterization Laboratory

Our study aimed to evaluate the effectiveness of mentored simulation training (ST) in coronary angiography and to assess the transferability of acquired skills from virtual reality to the real world. Twenty cardiology residents were randomized to ST or control before performing real-life cases in the catheterization laboratory. The control group underwent secondary ST and reperformed real-life cases in the catheterization laboratory. Skill metrics were compared between the ST and the control group, and within the control group between before and after ST. In real-life cases, the procedure time was shorter (p = 0.002), the radiation dose lower (p = 0.001), and the global procedure skill score was higher (p = 0.0001) in the ST group as compared with the control (before ST) group. During virtual ST procedural time (p <0.001), fluoroscopic time (p <0.001), training contrast amount (p <0.001), and global training score (p <0.001) significantly decreased. In the control group, all monitoring procedure parameters were significantly improved after ST, as well as, the global procedure flow score (p <0.0001). In conclusion, simulator-based training in coronary angiography improved operator skills compared with traditional in catheterization laboratory mentor-based training. ST should be incorporated in the curriculum of the interventionalist to improve learning in coronary angiography.

Ischaemic heart disease and pregnancy

Although ischaemic heart disease is currently rarely encountered in pregnancy, occurring between 2.8 and 6.2 per 100 000 deliveries, it is becoming more common as women delay becoming pregnant until later life, when medical comorbidities are more common, and because of the higher prevalence of obesity in the pregnant population. In addition, chronic inflammatory diseases, which are more common in women, may contribute to greater rates of acute myocardial infarction (AMI). Pregnancy itself seems to be a risk factor for AMI, although the exact mechanisms are not clear. AMI in pregnancy should be investigated in the same manner as in the non-pregnant population, not allowing for delays, with investigations being conducted as they would outside of pregnancy. Maternal morbidity following AMI is high as a result of increased rates of heart failure, arrhythmia and cardiogenic shock. Delivery in women with history of AMI should be typically guided by obstetric indications not cardiac ones.

Safety and feasibility of a low frame rate protocol for percutaneous coronary intervention to chronic total occlusions: preliminary experience

AIMS

The present study aimed to evaluate the safety and feasibility of a low frame rate protocol for chronic total occlusion (CTO)-percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A total of 192 consecutive patients who underwent CTO-PCI following the low frame rate protocol were analysed. The low frame rate protocol adopted reduced frame rates and the addition of copper and aluminium filters. Procedural outcomes, radiation dose and in-hospital outcomes were ascertained. Meanwhile, a phantom experiment was designed to measure the radiation dose reduction. Overall technical and procedural success rates were 91.1% (175) and 90.6% (174), respectively. The retrograde approach was attempted in 56 (29.2%) lesions. The mean air kerma (AK) radiation exposure, fluoroscopy time and contrast volume were 2.6±2.0 Gy, 50.3±34.3 min and 294.1±131.8 ml, respectively. In-hospital major adverse events occurred in one patient (0.5%) and procedural complications occurred in six patients (3.1%). In the phantom experiment, a remarkable radiation dose reduction could be achieved for AK, dose area product (DAP), simulated first and second operator radiation exposure (reduction of 72.5%, 69.8%, 60.9% and 59.6%, respectively) in cineangiography from this protocol.

CONCLUSIONS

Our results provide the primary evidence that it appears to be safe and feasible to carry out the low frame rate protocol for CTO-PCI.

Image noise reduction technology allows significant reduction of radiation dosage in cardiac device implantation procedures

BACKGROUND

Novel x-ray systems with real-time image noise reduction technology (INRT) to reduce radiation dose during fluoroscopy and cine acquisition have become available. This study evaluated the reduction of radiation dose in device implantation with INRT.

METHODS

Radiation dose data from 132 consecutive new device implantation procedures (102 pacemaker [PM] or implantable cardioverter defibrillator [ICD] and 30 cardiac resynchronization therapy [CRT] devices) performed between January 2015 and December 2015 on an angiography system with INRT (Allura ClarityIQ) were collected. For comparison, radiation dose data from 147 consecutive device implantation procedures (121 PM/ICDs and 26 CRT devices) performed between June 2013 and September 2014 on a C-arm system with continuous and pulsed fluoroscopy option (4 frames/second) were evaluated. Total dose area product (DAP), fluoroscopy DAP, and cine DAP were evaluated.

RESULTS

Patient age, gender and body weight, procedure, and fluoroscopy times were similar between systems. In PM/ICD cases, DAP of INRT and C-arm system was similar (423 ± 381 cGycm²  vs 417 ± 517 cGycm) due to pulsed fluoroscopy with the C-arm system (78% of time) and sparse use of cine. In CRT procedures requiring higher image quality (82% use of continuous fluoroscopy with C-arm system), DAP of INRT was significantly lower (1,544 ± 834 cGycm vs 7,252 ± 6,431 cGycm, P < 0.001) due to less fluoroscopy DAP (1,414 ± 757 cGycm vs 5,854 ± 6,767 cGycm) and less cine DAP (130 ± 106 cGycm vs 1,399 ± 1,342 cGycm). Considering all procedures, total DAP was reduced by 60% using INRT.

CONCLUSION

Novel INRT results in a substantial lowering of radiation dose in device implantation, in particular, in complex CRT implantation procedures requiring high image quality.

Reducing radiation exposure during procedures performed in the electrophysiology laboratory

INTRODUCTION

Expert societies recently published strong recommendations to reduce the exposure of patients and staff to ionizing radiation (IR) during interventional and electrophysiology (EP) procedures. However, adherence to these guidelines remains difficult and the impact of implementing such recommendations is poorly characterized.

METHODS AND RESULTS

We conducted a single-center cohort study to quantify radiation exposure over time in three EP laboratories at the Montreal Heart Institute during 5,546 consecutive procedures from 2012 to 2015 by 11 primary operators. Overall, 2,618 (47.2%) procedures were catheter-based and 2,928 (52.8%) were device interventions. Interventions to reduce radiation exposure included educational initiatives to raise awareness (i.e., limiting cine acquisition, patient position, table height), slower frame rate, lower radiation dose per pulse, collimation, and integration with 3-D mapping systems and/or MediGuide technology. An 85% reduction in IR exposure was observed from 2012 to 2015, with the mean dose-area-product (DAP) decreasing from 7.65 ± 0.05 Gy·cm² to 1.15 ± 0.04 Gy·cm² (P < 0.001). This was true for catheter-based procedures (mean DAP 16.99 ± 0.08 to 2.00 ± 0.06 Gy·cm² , P < 0.001) and device interventions (mean DAP 4.18 ± 0.06 to 0.64 ± 0.05 Gy·cm² , P < 0.001). The median effective dose of IR recorded per quarter by 282 cervical dosimeters on EP staff decreased from 0.57 (IQR 0.18, 1.03) mSv in 2012 to 0.00 (IQR 0.00, 0.19) mSv in 2015, P < 0.001.

CONCLUSION

Enforcing good clinical practices with simple measures and low-dose fluoroscopy settings are highly effective in reducing IR exposure in the EP lab. These promising results should encourage other EP labs to adopt similar protective measures.

Radiation exposure levels according to vascular access sites during PCI : A prospective controlled study

BACKGROUND

We previously showed that using the radial artery access site as opposed to the femoral artery site decreases the radiation exposure of patients during coronary artery interventions. The objective of this study was to compare radiation exposure levels of the operating physician during coronary interventions when incorporating both radial and femoral artery approaches.

METHODS

The study assessed all coronary angioplasties performed in a major metropolitan general hospital. The study design was prospective and observational, in which we measured the radiation exposure of the patient and the operator. Measurements of radiation levels were made using an electronic personal dosimeter (Diamentor® E2-DAP) at the radial and at the femoral artery access sites. An interventional cardiologist operator performed all the percutaneous coronary interventions (PCI) using a single-plane angiography unit via both femoral and radial artery approaches.

RESULTS

Data from 252 PCIs were recorded. The mean physician radiation exposure levels from the femoral access site and the right radial access site were 40.5 ± 20.2 µSv and 47.5 ± 26.5 µSv, respectively (p < 0.02). There was a strong correlation between physician and patient radiation exposure levels. However, there was no correlation between patient body mass index and radiation exposure levels.

CONCLUSION

We found significantly higher physician radiation exposure levels with the radial artery than with the femoral artery access site.

Towards Robot-Assisted Echocardiographic Monitoring in Catheterization Laboratories : Usability-Centered Manipulator for Transesophageal Echocardiography

This paper proposes a robotic Transesophageal Echocardiography (TOE) system concept for Catheterization Laboratories. Cardiovascular disease causes one third of all global mortality. TOE is utilized to assess cardiovascular structures and monitor cardiac function during diagnostic procedures and catheter-based structural interventions. However, the operation of TOE underlies various conditions that may cause a negative impact on performance, the health of the cardiac sonographer and patient safety. These factors have been conflated and evince the potential of robot-assisted TOE. Hence, a careful integration of clinical experience and Systems Engineering methods was used to develop a concept and physical model for TOE manipulation. The motion of different actuators of the fabricated motorized system has been tested. It is concluded that the developed medical system, counteracting conflated disadvantages, represents a progressive approach for cardiac healthcare.

Minimizing Ionizing Radiation Exposure in Invasive Cardiology Safety Training for Medical Doctors

Advanced imaging systems, such as C-Arm machines, greatly improve physicians' diagnostic abilities and provide greater precision. Yet, these benefits come with a price of ionizing radiation exposure to medical teams and patients. Supplying proper training and skill improvement to operators on how to use this technology safely can help minimize risk of exposure. Previous studies on radiation knowledge among physicians and radiologists presented disturbing results of underestimated risk of exposure. The following research is based on an innovation in simulation-based training (SBT), a simulator using the Wizard of Oz (WOZ) concept that incorporates an online human trainer and was used for training emergency room (ER) physicians and ultrasound medical personnel. This research integrated WOZ technology with a radiation exposure formula for training to minimize unnecessary radiation exposure. The exposure formula presents real-time and overall exposure levels to operators based on their technique. The simulator also incorporates 3D animation graphics, enabling trainees to simulate the control of various factors. Image quality and the operator's radiation exposure levels are also animated, assisting trainees to focus on their exposure based on their device settings. Contrary to most previous studies, we measured radiation dose to the operator and quantified image quality accordingly. Validation was done on different C-Arm machines. Validation of learning outcomes was done using knowledge exams. Results from our knowledge exams presented significant improvement. The average result of knowledge exams given prior to training was 54%, whereas the average result after training was 94% (p < 0.001). Additionally, after a gap of 2–3 months, high retention was also found.

Physician and Patient Radiation Exposure During Endovascular Procedures

OPINION STATEMENT

Endovascular procedures expose both patients and physicians to fluoroscopic ionizing radiation that carries a dose-dependent risk of acute toxicity and a small, but demonstrable, long-term risk of malignancy due to resultant genetic mutations. Exposure doses vary widely based upon patient-related factors including body size and anatomic complexity, operator technique, procedure type (diagnostic vs. therapeutic), vascular bed imaged, and imaging equipment employed. Effective dosage may vary as much as 200-fold for physicians and 20-fold for patients depending upon the procedure: for example, complex aortic interventions with branched graft devices may convey mean effective doses of more than 0.4 mSv for physicians and 100 mSv for patients, whereas distal, small-vessel angiography may entail mean effective doses of less than 0.002 mSv for physicians and 5 mSv for patients. Particular attention is given to physicians' ocular exposure, which may cause cataract development, and to hand exposure, which is significantly higher than total body exposure when operators work near the x-ray beam. Given the risks of radiation exposure, numerous strategies have been developed to reduce both physician and patient doses. These measures include physician education about dose-reducing imaging techniques, development of low-dose imaging equipment, introduction of new radiation shielding drapes and caps, and real-time dose monitoring. Here, we review physician and patient effective doses of radiation by procedure type as reported in the literature and present recent data regarding dose-reduction strategies.

Radiation exposure, the forgotten enemy: Toward implementation of national safety program

Radiation safety is an important counterpart in all facilities utilizing ionizing radiations. The concept of radiation safety has always been a hot topic, especially with the late reports pointing to increased hazards with chronic radiation exposure. Adopting a nationwide radiation safety program is considered one of the most urging topics, and is a conjoint responsibility of multiple disciplines within the health facility.

Analysis of Radiation Doses and Dose Reduction Strategies During Cerebral Digital Subtraction Angiography

OBJECTIVE

Adverse effects of increased use of cerebral digital subtraction angiography (DSA) include radiation-induced skin reactions and increased risk of malignancy. This study aimed to identify a method for reducing radiation exposure during routine cerebral DSA.

METHODS

A retrospective review of 138 consecutive adult patients who underwent DSA with a biplane angiography system (Artis Zee, Siemens, Germany) from September 2015 to February 2016 was performed. In January 2016, the dose parameter was reset by the manufacturer from 2.4 μGy to 1.2 μGy. Predose (group 1) and postdose parameter reduction (group 2) groups were established. Angiograms and procedure examination protocols were reviewed according to patient age, gender, and diagnosis and angiography techniques were reviewed on the basis of the following radiation dose parameters: fluoroscopy time, reference point air kerma (Ka,r; in mGy), and kerma-area product (PKA; in μGym²).

RESULTS

The mean Ka,r values in groups 1 and 2 were 1841.5 mGy and 1274.8 mGy, respectively. The mean PKA values in groups 1 and 2 were 23212.5 μGym² and 14854.0 μGym², respectively. Ka,r and PKA values were significantly lower in group 2 compared with group 1 (P < 0.001). Among individual factors, young age was a determining factor for reduced fluoroscopy time (P < 0.001), Ka,r (P = 0.047), and PKA (P = 0.022).

CONCLUSIONS

Increased awareness of radiation risks, as well as the establishment of strategies to reduce radiation dose, led to lower radiation doses for DSA. The use of appropriate examinations and low-dose parameters in fluoroscopy contributed significantly to the radiation dose reductions.

Ionizing radiation exposure in interventional cardiology: current radiation protection practice of invasive cardiology operators in Lithuania

Ionizing radiation management is among the most important safety issues in interventional cardiology. Multiple radiation protection measures allow the minimization of x-ray exposure during interventional procedures. Our purpose was to assess the utilization and effectiveness of radiation protection and optimization techniques among interventional cardiologists in Lithuania. Interventional cardiologists of five cardiac centres were interviewed by anonymized questionnaire, addressing personal use of protective garments, shielding, table/detector positioning, frame rate (FR), resolution, field of view adjustment and collimation. Effective patient doses were compared between operators who work with and without x-ray optimization. Thirty one (68.9%) out of 45 Lithuanian interventional cardiologists participated in the survey. Protective aprons were universally used, but not the thyroid collars; 35.5% (n  =  11) operators use protective eyewear and 12.9% (n  =  4) wear radio-protective caps; 83.9% (n  =  26) use overhanging shields, 58.1% (n  =  18)-portable barriers; 12.9% (n  =  4)-abdominal patient's shielding; 35.5% (n  =  11) work at a high table position; 87.1% (n  =  27) keep an image intensifier/receiver close to the patient; 58.1% (n  =  18) reduce the fluoroscopy FR; 6.5% (n  =  2) reduce the fluoro image detail resolution; 83.9% (n  =  26) use a 'store fluoro' option; 41.9% (N  =  13) reduce magnification for catheter transit; 51.6% (n  =  16) limit image magnification; and 35.5% (n  =  11) use image collimation. Median effective patient doses were significantly lower with x-ray optimization techniques in both diagnostic and therapeutic interventions. Many of the ionizing radiation exposure reduction tools and techniques are underused by a considerable proportion of interventional cardiology operators. The application of basic radiation protection tools and techniques effectively reduces ionizing radiation exposure and should be routinely used in practice.

Reducing Radiation Dose in Coronary Angiography and Angioplasty Using Image Noise Reduction Technology

This study sought to quantitatively evaluate the reduction of radiation dose in coronary angiography and angioplasty with the use of image noise reduction technology in a routine clinical setting. Radiation dose data from consecutive 605 coronary procedures (397 consecutive coronary angiograms and 208 consecutive coronary interventions) performed from October 2014 to April 2015 on a coronary angiography system with noise reduction technology (Allura Clarity IQ) were collected. For comparison, radiation dose data from consecutive 695 coronary procedures (435 coronary angiograms and 260 coronary interventions) performed on a conventional coronary angiography system from October 2013 to April 2014 were evaluated. Patient radiation dosage was evaluated based on the cumulative dose area product. Operators and operator practice did not change between the 2 evaluated periods. Patient characteristics were collected to evaluate similarity of patient groups. Image quality was evaluated on a 5-grade scale in 30 patients of each group. There were no significant differences between the 2 evaluated groups in gender, age, weight, and fluoroscopy time (6.8 ± 6.1 vs 6.9 ± 6.3 minutes, not significant). The dose area product was reduced from 3195 ± 2359 to 983 ± 972 cGycm(2) (65%, p <0.001) in coronary angiograms and from 7123 ± 4551 to 2431 ± 1788 cGycm(2) (69%, p <0.001) in coronary interventions using the new noise reduction technology. Image quality was graded as similar between the evaluated systems (4.0 ± 0.7 vs 4.2 ± 0.6, not significant). In conclusion, a new x-ray technology with image noise reduction algorithm provides a substantial reduction in radiation exposure without the need to prolong the procedure or fluoroscopy time.

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.

Radiation dose reduction during neurointerventional procedures by modification of default settings on biplane angiography equipment

BACKGROUND

Neurointerventional procedures represent a significant source of ionizing radiation. We sought to assess the effect during neurointerventional procedures of varying default rates of radiation dose in fluoroscopy (F) and image acquisition (IA) modes, and frame rates during cine acquisition (CINE) on total X-ray dose, acquisition exposures, fluoroscopy time, and complications.

METHODS

We retrospectively reviewed procedures performed with two radiation dose and CINE settings: a factory setting dose cohort (30 patients, F 45 nGy/pulse, IA 3.6 μGy/pulse, factory CINE frame rate) and a reduced dose cohort (30 patients, F 32 nGy/pulse, IA 1.2 μGy/pulse, with a decreased CINE frame rate). Total radiation dose, dose area product, number of acquisition exposures, fluoroscopy time, and complications were compared between the groups. Means comparisons (t tests) were employed to evaluate differences in the outcome variables between the two groups. p Value <0.05 was considered significant.

RESULTS

The reduced dose cohort had a significant reduction in mean radiation dose (factory, 3650 mGy; reduced, 1650 mGy; p=0.005) and dose area product (factory, 34 700 μGy×m(2); reduced, 15 000 μGy×m(2); p=0.02). There were no significant differences between cohorts in acquisition exposure (p=0.73), fluoroscopy time (p=0.45), or complications.

CONCLUSIONS

Significant reductions in radiation dose delivered by neurointerventional procedures can be achieved through simple modifications of default radiation dose in F and IA and frame rate during CINE without an increase in procedural complexity (fluoroscopy time) or rate of complications.