Controlling Radiation Exposure in Interventional Cardiology

Occupational Risks of Radiation Exposure to Cardiologists

PURPOSE OF REVIEW

Invasive cardiologists are exposed to large amounts of ionizing radiation. This review aims to summarize the main occupational risks in a radiation-exposed cardiology practice.

RECENT FINDINGS

We carried out a literature review on the subject. The studies reviewed allowed us to list six main health risk categories possibly associated with radiation exposure among cardiologists: deoxyribonucleic acid (DNA) and biochemical damages; cancers; ocular manifestations; olfaction, vascular, and neuropsychological alterations; musculoskeletal problems; and reproductive risks. Our descriptive analysis demonstrates higher risks of DNA damage and lens opacities among radiation-exposed cardiology staff. Surveys and questionnaires have demonstrated a higher risk of musculoskeletal disease in exposed workers. Studies reported no difference in cancer frequency between radiation-exposed workers and controls. Changes in olfactory performance, neuropsychological aspects, and vascular changes have also been reported. Limited literature supports the security of continuing radiation-exposed work during pregnancy. Therefore, there is an urgent need to increase knowledge of the occupational risks of radiation exposure and to adopt technologies to reduce them.

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.

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.

Prospective study of zero-fluoroscopy laser balloon pulmonary vein isolation for the management of atrial fibrillation

BACKGROUND

In recent years, there has been increased focus on the development of safe and effective strategies to minimize and ultimately eliminate fluoroscopy use in the electrophysiology lab due to the inherent risks to patients and staff associated with this imaging source. However, studies examining these innovative fluoroless strategies for pulmonary vein isolation (PVI) using catheters without direct 3D mapping system integration are lacking. We sought to develop a method to perform zero-fluoroscopy laser balloon PVI for patients with atrial fibrillation (AF), and to test the safety and efficacy of this approach.

METHODS

We developed a standardized method for performing PVI using the X3 laser balloon (LB) system, 3-dimensional electroanatomic mapping (3D-EAM) and intracardiac echocardiography (ICE) in a cohort of patients with symptomatic AF. The primary endpoint of the study was the ability to perform PVI without the use of fluoroscopy. Secondary outcomes were rate of successful transseptal puncture on first attempt, first pass isolation of target PVs, mean procedural time, active laser time to achieve PVI, need for use of supplemental energy sources, and procedural complication rates.

RESULTS

Two hundred consecutive patients undergoing PVI were recruited in the study. In the zero-fluoroscopy group, LB PVI was successfully performed in 100% of participants (n = 100) without the need for fluoroscopy. Transseptal access was achieved in 100% of cases on the first attempt. Successful first pass PVI was achieved in 360 of the 387 pulmonary veins attempted (93%). Mean procedural time was 68.2 ± 16.2 min in the zero-fluoroscopy group versus 67.5 ± 17.0 min in the conventional fluoroscopy group. PVI was able to be achieved in 100% of cases in both groups without need for use of supplemental energy sources. In the zero-fluoroscopy group there were minimal complications, with 3% of all cases having groin complications and 1 patient with a pericardial effusion noted post-procedure which was managed conservatively.

CONCLUSIONS

We demonstrated that successful zero-fluoroscopy LB PVI could be performed at a single high-volume center by experienced operators in an effective manner, without significant complications.

The Inverse Correlation Between the Duration of Lifetime Occupational Radiation Exposure and the Prevalence of Atrial Arrhythmia

Objective

Advancements in fluoroscopy-assisted procedures have increased radiation exposure among cardiologists. Radiation has been linked to cardiovascular complications but its effect on cardiac rhythm, specifically, is underexplored.

Methods

Demographic, social, occupational, and medical history information was collected from board-certified cardiologists via an electronic survey. Bivariate and multivariable logistic regression analyses were performed to assess the risk of atrial arrhythmias (AA).

Results

We received 1,478 responses (8.8% response rate) from cardiologists, of whom 85.4% were male, and 66.1% were ≤65 years of age. Approximately 36% were interventional cardiologists and 16% were electrophysiologists. Cardiologists > 50 years of age, with > 10,000 hours (h) of radiation exposure, had a significantly lower prevalence of AA vs. those with ≤10,000 h (11.1% vs. 16.7%, p = 0.019). A multivariable logistic regression was performed and among cardiologists > 50 years of age, exposure to > 10,000 radiation hours was significantly associated with a lower likelihood of AA, after adjusting for age, sex, diabetes mellitus, hypertension, and obstructive sleep apnea (adjusted OR 0.57; 95% CI 0.38-0.85, p = 0.007). The traditional risk factors for AA (age, sex, hypertension, diabetes mellitus, and obstructive sleep apnea) correlated positively with AA in our data set. Cataracts, a well-established complication of radiation exposure, were more prevalent in those exposed to > 10,000 h of radiation vs. those exposed to ≤10,000 h of radiation, validating the dependent (AA) and independent variables (radiation exposure), respectively.

Conclusion

AA prevalence may be inversely associated with radiation exposure in Cardiologists based on self-reported data on diagnosis and radiation hours. Large-scale prospective studies are needed to validate these findings.

Fractional flow reserve, quantitative flow ratio, and instantaneous wave-free ratio: a comparison of the procedure-related dose of ionising radiation

INTRODUCTION

The development of interventional cardiology increases the number of invasive procedures which are inevitably associated with increased exposure to ionizing radiation and associated risks. A percutaneous coronary intervention (PCI) substantiated by evaluation of the coronary artery lesion's functional significance is recommended by both European and American cardiologists. Nevertheless, the prevalence of physiology-guided PCIs does not exceed 10% all over the globe.

AIM

To identify the physiology evaluation method which is associated with the lowest exposure to ionising radiation.

MATERIAL AND METHODS

Anonymised data of 421 patients with stable angina pectoris for whom elective coronary artery angiography followed by physiological assessment of intermediate coronary artery stenosis was performed were prospectively included in this study. Only diagnostic-procedure-related data of dose of ionizing radiation were analysed. Physiological assessment of coronary artery lesions was performed by fractional flow reserve (FFR), quantitative flow ratio (QFR), or instantaneous wave-free ratio (iFR).

RESULTS

Compared to FFR as a reference, fluoroscopy time (FT) was almost half in QFR and almost double in iFR, p < 0.001. QFR was associated with more than 3 times shorter FT compared to iFR. The dose area product was 663.87 ±260.51 cGy/cm2 (p = 0.03) lower in QFR compared to iFR.

CONCLUSIONS

QFR is associated with significantly reduced exposure to ionising radiation compared to both FFR and iFR. Therefore, wider QFR application in clinical practice could eliminate any additional exposure to ionising radiation and increase the prevalence of physiology-guided coronary artery revascularization.

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.