Fluoroless left atrial access for radiofrequency and cryoballoon ablations using a novel radiofrequency transseptal wire

Purpose

Conventional catheter ablation for atrial fibrillation requires fluoroscopy, which has inherent risks of radiation exposure to patients and medical staff. Optimization of fluoroscopy parameters and use of three-dimensional electroanatomic mapping (EAM) and intracardiac echocardiography (ICE) have helped to reduce radiation exposure; however, despite growing evidence, there are still concerns about safety and added procedure time associated with fluoroless procedures, particularly in left-sided ablations, due to the potential risk of complications. Herein, we report our initial experience using a radiofrequency (RF) wire for completely fluoroless radiofrequency ablation (RFA) and cryoballoon ablation (CBA).

Methods

A retrospective analysis was conducted on ablation procedures for various cardiac arrhythmias performed non-fluoroscopically at two centers using the VersaCross RF wire transseptal system under EAM and ICE guidance.

Results

A total of 72 and 54 patients underwent RFA and CBA, respectively, successfully without any procedural complications. Transseptal access time for RFA was 14.5 ± 6.6 min from procedure start (including sheath and catheter placements ± right-sided ablation) or 2.8 ± 1.0 min from RF wire insertion into the femoral introducer. Transseptal access time for CBA was 19.2 ± 11.7 min from procedure start (including sheath and catheter placements ± right-sided ablation) or 3.5 ± 1.6 min from RF wire insertion into the femoral introducer. Average procedure time was 104.4 ± 38.0 min for RFA and 91.1 ± 22.1 min for CBA.

Conclusions

A RF wire can be used to achieve completely fluoroless transseptal puncture safely and effectively while improving procedural efficiency in both RFA and CBA.

Results from a real-time dosimetry study during left atrial ablations performed with ultra-low dose radiation settings

Background

Three-dimensional mapping systems and the use of ultra-low dose radiation protocols have supported minimization of radiation dose during left atrial ablation procedures. By using optimal shielding, scattered radiation reaching the operator can be further reduced. This prospective study was designed to determine the remaining operator radiation exposure during left atrial catheter ablations using real-time dosimetry.

Methods

Radiation dose was recorded using real-time digital dosimetry badges outside the lead apron during 201 consecutive left atrial fibrillation ablation procedures. All procedures were performed using the same X‑ray system (Siemens Healthineers Artis dBc; Siemens Healthcare AG, Erlangen, Germany) programmed with ultra-low dose radiation settings including a low frame rate (two frames per second), maximum copper filtration, and an optimized detector dose. To reduce scattered radiation to the operators, table-suspended lead curtains, ceiling-suspended leaded plastic shields, and radiation-absorbing shields on the patient were positioned in an overlapping configuration.

Results

The 201 procedures included 139 (69%) pulmonary vein isolations (PVI) (20 cryoballoon ablations, 119 radiofrequency ablations, with 35 cases receiving additional ablation of the cavotricuspid isthmus) and 62 (31%) PVI plus further left atrial substrate ablation.

Mean radiation dose measured as dose area product for all procedures was 128.09 ± 187.87 cGy ∙ cm² with a mean fluoroscopy duration of 9.4 ± 8.7 min. Real-time dosimetry showed very low average operator doses of 0.52 ± 0.10 µSv. A subanalysis of 51 (25%) procedures showed that the radiation burden for the operator was highest during pulmonary vein angiography.

Conclusion

The use of ultra-low dose radiation protocols in combination with optimized shielding results in extremely low scattered radiation reaching the operator.

Safe procedures despite ultra low radiation doses during catheter ablations of atrial and ventricular arrhythmias-A multicenter experience

INTRODUCTION

Despite the development of non-fluoroscopic catheter visualization options, fluoroscopy is still used in most ablation procedures. The aim of this multicenter study was to evaluate the safety and efficacy of a new ultra-low dose radiation protocol for EP procedures in a large number of patients.

METHODS AND RESULTS

A total of 3462 consecutive patients (male 1926 (55.6%), age 64.4 ± 14.0 years, BMI 26.65 ± 4.70) undergoing radiofrequency ablation (left atrial (n = 2316 [66.9%], right atrial (n = 675 [19.5%], or ventricular (n = 471 [13.6%]) in three German centers were included in the analysis. Procedures were performed using a new ultra-low dose protocol operating at 8nGy for fluoroscopy and 36nGy for cine-loops. Additionally a very low framerate (2-3FPS) was used. Using the new protocol very low Air kerma-area product (KAP) values were achieved for left atrial ablations (104.25 ± 84.22 μGym² ), right atrial ablations (70.98 ± 94.79 μGym² ) and ablations for ventricular tachycardias or PVCs (78.62 ± 66.59 μGym² ). Acute procedural success was achieved in 3289/3388 (97.1%) while the rate of major complications was very low compared to previously published studies not using low dose settings (n = 20, 0.6%).

CONCLUSION

The ultra-low dose, low framerate protocol leads to very low radiation doses for all EP procedures while neither procedural time, fluoroscopy time nor success or complication rates were compromised. When compared to current real-world Air KAP data the new ultra-low dose fluoroscopy protocol reduces radiation exposure by more than 90%.

Safety and feasibility of a 1 frame-per-second X-ray framerate in cardiac electrophysiology

BACKGROUND

We investigated the feasibility and safety of a framerate of 1 frame per second ("fps") for fluoroscopy and cine-angiography, to lower radiation exposure for patients and personnel in cardiac electrophysiology ("EP").

METHOD

Analysis of 2521 EP procedures, 899 (36%) with the lowest available conventional framerate (3.75 fps) and 1622 (64%) procedures performed with a framerate lowered further to 1.0 fps (by looping a 1 Hz square pulse to the ECG trigger) performed between 01/2016 and 01/2020.

RESULTS

Procedures performed with 1.0 fps had the same acute procedural success rates (p = 0.20) and adverse event rates (p = 0.34) as the 3.75 fps group. There was no difference in total X-ray operation time (p = 0.40). The dose-area-product (DAP) was significantly reduced from 638 to 316 cGy*cm² (p < < 0.0001) for all procedure types together, and for each subgroup. In a multivariable linear regression model, total X-ray operation time (estimate 38 cGy*cm² /min) and body mass index (estimate 32 cGy*cm² / index point) and a framerate of 1.0 fps (-314 cGy*cm² against 3.75 fps) were independent predictors of a lower DAP (p-value of t-statistic for all << 0.0001).

CONCLUSIONS

A framerate of 1.0 fps is safe and feasible in cardiac electrophysiology procedures. It was associated with a significant reduction of radiation exposure for patient and personnel.

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.

Safety and Effectiveness of a Novel Fluoroless Transseptal Puncture Technique for Lead-free Catheter Ablation: A Case Series

Increasing awareness of the health risks associated with the exposure of patients and staff in the catheterization laboratory to radiation has encouraged the pursuit of efforts to reduce the use of fluoroscopy during catheter ablation procedures. Although nonfluoroscopic guidance of ablation catheters has been previously described, transseptal access is still perceived as the last remaining barrier to completely fluoroless ablations. This study examined the safety and effectiveness of transseptal puncture and radiofrequency (RF) catheter ablation using a completely fluoroless approach. Three hundred eighty-two consecutive cases that had undergone completely nonfluoroscopic RF catheter ablation were evaluated. Ablation procedures were performed for atrial fibrillation, atrial flutter, atrioventricular reentry tachycardia, and pulmonary vein complex/ventricular tachycardia. Transseptal puncture and RF ablation were conducted under three-dimensional electroanatomic mapping and intracardiac echocardiography image guidance. Fluoroless transseptal puncture and catheter ablation were completed successfully in all cases, with no intraoperative complications. One patient required minimal use of fluoroscopy to visualize sheath advancement through an existing inferior vena cava filter. Procedural time was approximately 2.2 hours from transvenous access until case conclusion; transseptal access was obtained within 28 minutes of procedure initiation. Arrhythmia was found to recur in 27% of cases on average three months after the procedure. We demonstrate the safety and effectiveness of a completely fluoroless transseptal puncture and RF ablation technique that eliminates radiation exposure and enables complex electrophysiology procedures to be performed in a lead-free environment.

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

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

[Radiation reduction in interventional electrophysiology : Results from operators with different levels of experience]

BACKGROUND

Radiation exposure in the catherization laboratory is associated with significant health risks. It is unclear whether a reduction of radiation exposure with the use of "near-zero fluoroscopy" protocols is possible when applied by less experienced operators.

METHODS

Consecutive ablation procedures with the use of a 3D mapping system were analyzed. Three time periods were analyzed. During the first period (standard), no specific radiation-reduction protocol was used. During the second period (initial phase of radiation reduction) a near "near-zero fluoroscopy" protocol was implemented; however, the majority of procedures were performed by an expert. During the third period (routine use of radiation reduction), less experienced operators (fellow and beginner) performed a growing number of procedures with the "near-zero fluoroscopy" protocol.

RESULTS

In all, 290 procedures were analyzed. After implementation of a radiation-reduced protocol, a significant reduction of radiation exposure was observed (standard 850 ± 831.7 vs. initial phase 197.2 ± 481.8 μGy/m², p < 0.001, and vs. routine use 283 ± 493.8 μGy/m², p < 0.001). No significant difference was observed between the initial phase and routine phase (p = 1). Over the three periods, the proportion of procedures performed by less experienced operators grew significantly for complex (fellow: 0% vs. 10% vs. 30%; p < 0.001) and noncomplex procedures (fellow: 30% vs. 39% vs. 49%; beginner: 15% vs. 38% vs. 34%; p = 0.002). Complication rates were not significantly different.

CONCLUSIONS

Implementation of a radiation-reduced protocol leads to a significant reduction of radiation exposure even in less experienced operators during training.

Minimizing Radiation in the Modern Electrophysiology Laboratory

Historically, the electrophysiology laboratory has relied heavily on the use of ionizing radiation in the form of fluoroscopy for a broad range of interventions and diagnostics. As the harmful effects of radiation have become increasingly recognized and procedural technologies have advanced, electrophysiologists have adopted new workflows. The purpose of this article is to review the available literature and experience in minimizing radiation in the modern electrophysiology laboratory. This review first covers general approaches to reducing fluoroscopy radiation in the electrophysiology suite, with concepts that apply across all procedure types. These include the reduction of infrared emission through fastidious fluoroscopy settings, new and proven solutions for radiation shielding, and methods of creating distance between the radiation source and the operator to reduce exposure. Following this discussion, we review specific task-based techniques for reducing radiation during special electrophysiologic procedures and workflows such as vascular access, coronary sinus lead placement, catheter manipulation, and periprocedural planning studies.

Implementation of a near-zero fluoroscopy approach in interventional electrophysiology: impact of operator experience

PURPOSE

Catheter ablation is performed under fluoroscopic guidance. Reduction of radiation dose for patients and staff is emphasized by current recommendations. Previous studies have shown that lower operator experience leads to increased radiation dose. On the other hand, less experienced operators may depend even more on fluoroscopic guidance. Our study aimed to evaluate feasibility and efficacy of a non-fluoroscopic approach in different training levels.

METHODS

From January 2017, a near-zero fluoroscopy approach was established in two centers. Four operators (beginner, 1st year fellow, 2nd year fellow, expert) were instructed to perform the complete procedure with the use of a 3-D mapping system without fluoroscopy. A historical cohort that underwent procedures with fluoroscopy use served as control group. Dose area product (DPA), procedure duration, acute procedural success, and complications were compared between the groups and for each operator.

RESULTS

Procedures were performed in 157 patients. The first 100 patients underwent procedures with fluoroscopic guidance, the following 57 procedures were performed with the near-zero fluoroscopy approach. The results show a significant reduction in DPA for all operators immediately after implementation of the near-zero fluoroscopy protocol (control 637 ± 611 μGy/m²; beginner 44.1 ± 79.5 μGy/m², p = 0.002; 1st year fellow 24.3 ± 46.4.5 μGy/m², p = 0.001; 2nd year fellow 130.3 ± 233.3 μGy/m², p = 0.003; expert 9.3 ± 37.4 μGy/m², P < 0.001). Procedure duration, acute success, and complications were not significantly different between the groups.

CONCLUSION

Our results show a 90% reduction of DPA shortly after implementation of a near-zero fluoroscopy approach in interventional electrophysiology even in operators in training.

Ultra-low radiation dose during electrophysiology procedures using optimized new generation fluoroscopy technology

BACKGROUND

Electrophysiology procedures require fluoroscopic guidance, with the associated potentially adverse effects of ionizing radiation. Newer fluoroscopy systems have more features that enable dose-reduction strategies. This study aimed to investigate any reduction in radiation dose between an older fluoroscopy system (Philips Integris H5000, Philips Healthcare, Einhoven, Netherlands) and one of the latest systems (Siemens Artis Q, Siemens Healthcare, Erlangen, Germany), optimized with dose-reduction strategies.

METHODS

Radiation dose measures were collected over a 2-year period in a single electrophysiology laboratory. Procedures were separated into seven groups: devices, biventricular devices, electrophysiology studies, standard radiofrequency ablation, complex atrial ablation, ablation for ventricular arrhythmias, and pulmonary vein isolation. In the first year, an older fluoroscopy system was used, and in the second year, a new system, with dose reduction strategies. Comparisons were also made to the literature with regard to radiation dose levels.

RESULTS

Patient characteristics, fluoroscopy times, number of digital acquisitions, procedural times, and procedural success were largely similar between the old and new system across procedure groups. Overall dose area product (DAP) was reduced by 91% (5.0 [2.0-17.0] to 0.45 [0.16-2.61] Gycm² [P > 0.001]) with the new system and was lower across all groups. DAP readings with the new system are some of the lowest published in the literature in all groups.

CONCLUSION

An optimized contemporary digital fluoroscopy system, with low radiation dose configuration and continued good procedural practice, can result in ultra-low radiation levels for all electrophysiology procedures, without compromising procedural time or procedural success.