Reducing Patient Radiation Dose With Image Noise Reduction Technology in Transcatheter Aortic Valve Procedures

Impact of dose reducing software on patient and staff temple dose during fluoroscopically guided pacemaker insertion, closure devices implantation and coronary angiography procedures

The aim of this study is to investigate the effectiveness of dose reducing software (ClarityIQ) on patient and staff dose during fluoroscopically guided cardiac procedures. Dose measurements were collected in a room without dose reducing software (n = 157) and compared with similar procedures performed in two rooms with the software (n = 1141). Procedures included diagnostic coronary angiography, percutaneous coronary intervention, deployment of cardiac closure devices (for occlusion of atrial septal defect, patent foramen ovale, and atrial appendage) and insertion of permanent pacemakers. The dose reducing software was found to be effective in reducing patient and staff dose by approximately 50%. This study has added to the limited literature reporting on the capability of dose reducing software to decrease radiation exposure during the implantation of cardiac closure devices, as well as demonstrating a reduction in dose to the cardiologist and nursing staff. Administrators should ensure timely upgrades to angiographic equipment to safeguard patients and staff against the potentially adverse effects of radiation exposure. Regardless of the use of dose reducing software, the mean occupational dose during closure devices was in descending order scout > scrub > cardiologist. Scrub nurse dose was found to be higher than the cardiologist during closure devices (0.98/0.26 μSv) and diagnostic coronary angiograms (1.51/0.82 μSv). Nursing staff should be aware that their levels of radiation dose during some cardiac procedures may come close to or even exceed that of the cardiologist.

Evaluation of a Low-Dose Radiation Protocol During Transcatheter Aortic Valve Implantation

We aimed to evaluate the efficacy and safety of a low-dose imaging protocol to reduce intraprocedural radiation during transcatheter aortic valve implantation (TAVI). Observational analysis: 802 transfemoral TAVI patients receiving balloon-expandable devices ≥23 mm at a high-volume centre. After propensity score matching, a standard-dose group (SD, n = 333) treated between January 2014 and February 2016 was compared with a low-dose group (LD, n = 333) treated between August 2017 and March 2019 after departmental uptake of a low-dose imaging protocol (reduced field size, high table height, use of "fluoro save," 3.75 frames/second acquisition, increased filtering). Primary end point was dose-area product (DAP). Secondary safety end points were VARC-2 device success and a composite of in-hospital complications. The LD protocol was associated with lower DAP (4.64 [2.93, 8.42] vs 22.73 [12.31, 34.58] Gy⋅cm², p <0.001) and fluoroscopy time (10.4 [8.1, 13.9] vs 11.5 [9.1, 15.3] minutes, p = 0.001). Contrast use was higher in the LD group (LD 110 [94, 130] vs SD 100 [80, 135] milliliters, p = 0.042). Device success (LD 88.3% vs SD 91.3%, p = 0.25), and the composite end point (LD 8.1% vs SD 11.4%, p = 0.19) were similar. In multivariate analysis, the low-dose protocol was associated with a 19.8 Gy⋅cm² reduction in procedural DAP (p <0.001). In conclusion, compared with standard imaging, a low-dose protocol for TAVI significantly reduced radiation dose without compromising outcomes.

Radiation Exposure During Transcatheter Aortic Valve Replacement: Impact of Arterial Approach and Prosthesis Type

BACKGROUND

The impact of novel alternative access and valve type on radiation exposure during transcatheter aortic valve replacement (TAVR) has not yet been evaluated. This study sought to determine the impact of a transarterial approach and prosthesis type on physician and patient exposure to radiation during TAVR.

METHODS

This was a prospective study including 140 consecutive patients undergoing TAVR by transfemoral (n = 102) or transcarotid (TC) (n = 38) access at 2 centers. Implanted valves were the self-expanding Evolut R/PRO system (Medtronic, Minneapolis, MN; n = 38) and the balloon-expandable SAPIEN 3 valve (Edwards Lifesciences, Irvine, CA; n = 102). The primary endpoint was first operator radiation exposure. The secondary endpoint was patient radiation exposure.

RESULTS

First operator radiation exposure was 4-fold greater during TC TAVR (P < .001). The use of a self-expanding valve was associated with a longer x-ray time (P = .015) and a 2-fold greater first operator radiation dose (P = .018). Patient radiation dose was not significantly affected by arterial approach (P = .055) or valve type (P = .095). After adjustment for potential confounders, the TC approach remained associated with a 174.8% (95% confidence interval, 80.6-318.3, P < .001) increase in first operator radiation dose, whereas the use of a self-expanding valve no longer influenced the first operator dose (P = .630).

CONCLUSIONS

TC access and the use of a self-expanding valve were associated with a 4- and 2-fold greater first operator radiation exposure during TAVR procedures, respectively. Unlike the arterial approach, the effect of bioprosthesis type on radiation exposure was mainly related to x-ray time and was no longer significant after adjustment.

Comprehensive strategies to minimize radiation exposure during Interventional electrophysiology procedures: state-of-the-art review

INTRODUCTION

Cardiac electrophysiology (EP) procedures are frequently performed in patients with cardiac arrhythmias, chronic heart failure, and sudden cardiac death. Most EP procedures involve fluoroscopy, which results in radiation exposure to physicians, patients, and EP lab staff. Accumulated radiation exposure is a known health detriment to patients and physicians.

AREA COVERED

This review will summarize radiation exposure, dose metrics, complications of radiation exposure, factors affecting radiation exposure, minimizing radiation exposure, zero or near-zero fluoroscopy strategies, and up-to-date research in the area of reducing radiation exposure and best practices.

EXPERT COMMENTARY

Comprehensive strategies should be implemented in EP laboratories to minimize radiation exposure with standard fluoroscopy. There are routine techniques that can mitigate significant amounts of radiation exposure using standard equipment within the EP lab. The operators need to emphasize that EP practices routinely incorporate non-ionizing radiation sources for cardiac imaging (e.g. magnetic resonance imaging, advanced electroanatomical mapping systems, intracardiac ultrasonography) in addition to other novel technologies to mitigate radiation exposure to patients and physicians.

The role of a commercial radiation dose index monitoring system in establishing local dose reference levels for fluoroscopically guided invasive cardiac procedures

PURPOSE

The primary goal was to evaluate local dose level for fluoroscopically guided invasive cardiac procedures in a high-volume activity catheterization laboratory, using automatic data registration with minimal impact on operator workload. The secondary goal was to highlight the relationship between dose indices and acquisition parameters, in order to establish an effective strategy for protocols optimization.

METHODS

From September 2016 to December 2018, a dosimetric survey was conducted in the 2 rooms of the catheterization laboratory of our institution. Data collection burden was minimized using a commercial Radiation Dose Index Monitoring System (RDIMs) that analyzes dicom files automatically sent by the x-ray equipment. Data were combined with clinical information extracted from the HIS records reported by the interventional cardiologist. Local dose levels were established for different invasive cardiac procedures.

RESULTS

A total of 3029 procedures performed for 2615 patients were analyzed. Median KAP were 21 Gycm² for invasive coronary angiography (ICA) procedures, 61 Gycm² for percutaneous coronary intervention (PCI) procedures, 59 Gycm² for combined (ICA+PCI) procedures, 87 Gycm² for structural heart intervention (TAVI) procedures. A significant dose reduction (51% for ICA procedures and 58% for PCI procedures) was observed when noise reduction acquisition techniques were applied.

CONCLUSIONS

RDIMs are effective tools in the establishment of local dose level in interventional cardiology, as they mitigate the burden to collect and register extensive dosimetric data and exposure parameters. Systematic review of data support the multi-disciplinary team in the definition of an effective strategy for protocol management and dose optimization.

Exposure to Ionizing Radiation in Patients Undergoing Transfemoral Transcatheter Aortic Valve Implantation

Transcatheter aortic valve implantation (TAVI) is currently becoming an alternative to surgical valve replacement for patients at low risk, a population that is likely to experience an increase in the radiation-induced cancer risk following TAVI. We aimed to evaluate the overall exposure to ionizing radiation in patients who underwent transfemoral TAVI, including the procedure itself as well as the procedures performed in the preintervention work-up and the post-TAVI interventions. All patients who underwent transfemoral TAVI for symptomatic aortic stenosis in our center over a 26 months period were included. Dosimetric indicators from preprocedural coronary angiography and computed tomography (CT), the TAVI procedure, and any postprocedural interventions (electrophysiology study and/or pacemaker implantation) were collected and converted into an effective dose. A total of 119 transfemoral TAVI procedures were included. The mean cumulative effective dose (ED) was 37.3 mSv. Three irradiating procedures were necessary for 84 patients (71% of the population, i.e., coronary angiography, CT scan and the TAVI procedure itself), whereas 30 patients (25%) required a fourth procedure, and 5 required a fifth (4%). The majority of the dose was from the CT, while only 11% of the dose derived from the TAVI procedure itself. In conclusion, overall exposure to ionizing radiation for patients who underwent transfemoral TAVI seems acceptable, and the majority of the overall ED comes from the CT scan.

Assessing the level of radiation experienced by anesthesiologists during transfemoral Transcatheter Aortic Valve Implantation and protection by a lead cap

OBJECTIVE

Transfemoral Transcatheter Aortic Valve Implantation (TAVI) has become a standard therapy for patients with aortic valve stenosis. Fluoroscopic imaging is essential for TAVI with the anesthesiologist's workplace close to patient's head side. While the use of lead-caps has been shown to be useful for interventional cardiologists, data are lacking for anesthesiologists.

METHODS

A protective cap with a 0.35 lead-equivalent was worn on 15 working days by one anesthesiologist. Six detectors (three outside, three inside) were analyzed to determine the reduction of radiation. Literature search was conducted between April and October 2018.

RESULTS

In the observational period, 32 TAVI procedures were conducted. A maximum radiation dose of 0.55 mSv was detected by the dosimeters at the outside of the cap. The dosimeters inside the cap, in contrast, displayed a constant radiation dose of 0.08 mSv.

CONCLUSION

The anesthesiologist's head is exposed to significant radiation during TAVI and it can be protected by wearing a lead-cap.

Contribution of interventional cardiology to the collective dose in Spain

INTRODUCTION AND OBJECTIVES

To estimate the contribution of interventional cardiology (IC) to the collective dose in Spain.

METHODS

Using the information on frequencies of examinations sourced from the Spanish Society of Cardiology and the patient dose values obtained by the national DOCCACI programme.

RESULTS

The fraction of the collective dose per million inhabitants derived from IC was 34 man-Sv (a total of 1600 man-Sv in Spain with 46.5 million inhabitants). The contribution of the IC derived from the medical use of x-rays in Spain resulted in 0.66% of the procedures and 4% of the x-ray collective dose.

CONCLUSIONS

Even if this collective radiation dose may seem moderate, at an individual level this medical practice delivers the greatest doses and, therefore, optimisation remains of paramount importance.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Characteristics of a New X-Ray Imaging System for Interventional Procedures: Improved Image Quality and Reduced Radiation Dose

Purpose

To compare image quality and radiation exposure between a new angiographic imaging system and the preceding generation system during uterine artery embolization (UAE).

Materials and Methods

In this retrospective, IRB-approved two-arm study, 54 patients with symptomatic uterine fibroids were treated with UAE on two different angiographic imaging systems. The new system includes optimized acquisition parameters and real-time image processing algorithms. Air kerma (AK), dose area product (DAP) and acquisition time for digital fluoroscopy (DF) and digital subtraction angiography (DSA) were recorded. Body mass index was noted as well. DF image quality was assessed objectively by image noise measurements. DSA image quality was rated by two blinded, independent readers on a four-rank scale. Statistical differences were assessed with unpaired t tests and Wilcoxon rank-sum tests.

Results

There was no significant difference between the patients treated on the new (n = 36) and the old system (n = 18) regarding age (p = 0.10), BMI (p = 0.18), DF time (p = 0.35) and DSA time (p = 0.17). The new system significantly reduced the cumulative AK and DAP by 64 and 72%, respectively (median 0.58 Gy and 145.9 Gy*cm² vs. 1.62 Gy and 526.8 Gy*cm², p < 0.01 for both). Specifically, DAP for DF and DSA decreased by 59% (75.3 vs. 181.9 Gy*cm², p < 0.01) and 78% (67.6 vs. 312.2 Gy*cm², p < 0.01), respectively. The new system achieved a significant decrease in DF image noise (p < 0.01) and a significantly better DSA image quality (p < 0.01).

Conclusions

The new angiographic imaging system significantly improved image quality and reduced radiation exposure during UAE procedures.

Electronic supplementary material

The online version of this article (doi:10.1007/s00270-017-1821-z) contains supplementary material, which is available to authorized users.

Impact of Allura Clarity Technology on Radiation Dose Exposure During Left Atrial Appendage Closure

BACKGROUND

To evaluate the impact of the Clarity IQ technology on reducing radiation risk in patients undergoing cardiac interventional radiology (IR) procedures.

MATERIAL/METHODS

Phantom studies were performed with two angiographic systems, FD10 Allura Xper and FD10 Allura Clarity. In the study, we performed left atrial appendage closure. Dosimetric measurements were performed with thermoluminescent dosimeters (TLD) placed inside a CIRS anthropomorphic phantom. Radiation risk was estimated based on the TLD readings and expressed as the dose absorbed by particular organs. The Mann-Whitney U test was carried out to test for significance of differences in the absorbed radiation doses between the techniques.

RESULTS

During left atrial appendage closure, the estimated dose absorbed by particular organs was lower in the case of the FD10 Allura Clarity system in comparison to the Allura Xper. In this procedure, dose reduction for particular organs ranged between 49-86%.

CONCLUSIONS

Application of the FD10 Allura Clarity system resulted in a significant dose reduction, thereby leading to a significant decrease in radiation risk for patients undergoing IR procedures.

Image noise reduction technology reduces radiation in a radial-first cardiac catheterization laboratory

BACKGROUND

Transradial coronary angiography (TRA) has been associated with increased radiation doses. We hypothesized that contemporary image noise reduction technology would reduce radiation doses in the cardiac catheterization laboratory in a typical clinical setting.

METHODS AND RESULTS

We performed a single-center, retrospective analysis of 400 consecutive patients who underwent diagnostic and interventional cardiac catheterizations in a predominantly TRA laboratory with traditional fluoroscopy (N=200) and a new image noise reduction fluoroscopy system (N=200). The primary endpoint was radiation dose (mGy cm²). Secondary endpoints were contrast dose, fluoroscopy times, number of cineangiograms, and radiation dose by operator between the two study periods. Radiation was reduced by 44.7% between the old and new cardiac catheterization laboratory (75.8mGycm²±74.0 vs. 41.9mGycm²±40.7, p<0.0001). Radiation was reduced for both diagnostic procedures (45.9%, p<0.0001) and interventional procedures (37.7%, p<0.0001). There was no statistically significant difference in radiation dose between individual operators (p=0.84). In multivariate analysis, radiation dose remained significantly decreased with the use of the new system (p<0.0001) and was associated with weight (p<0.0001), previous coronary artery bypass grafting (p<0.0007) and greater than 3 stents used (p<0.0004). TRA was used in 90% of all cases in both periods. Compared with a transfemoral approach (TFA), TRA was not associated with higher radiation doses (p=0.20).

CONCLUSIONS

Image noise reduction technology significantly reduces radiation dose in a contemporary radial-first cardiac catheterization clinical practice.