A modified fluoroscopy protocol to minimize radiation exposure during pulmonary vein isolation with second-generation cryoballoon

Cryoballoon Pulmonary Vein Isolation in Obese Patients with Atrial Fibrillation Compared to Non-Obese Counterparts: A Meta-Analysis

Introduction: Obesity is an important risk factor for atrial fibrillation (AF) development. Data on cryoballoon ablation (CBA) outcomes in obese patients have so far been scarce. We reviewed the existing literature to compare the efficacy and safety of CBA in obese versus non-obese AF patients. Methods: A systematic literature search was conducted for studies comparing clinical outcomes (arrhythmia recurrence and/or procedural data and/or safety outcomes) between obese and non-obese patients undergoing CBA for AF. Statistical pooling was performed according to a random-effects model with generic inverse-variance weighting of relative risks (RRs) and standardised mean differences (SMDs) computing risk estimates with 95% confidence intervals (CIs). Results: Obese and non-obese patients had comparable arrhythmia recurrence rates (normal versus overweight, RR = 0.95, 95% CI: 0.82-1.11, p = 0.55, I2% = 91%; normal versus class I obesity, RR = 0.97, 95% CI: 0.82-1.13, p = 0.68, I2% = 87%; normal versus class II obesity, RR = 0.98, 95% CI: 0.91-1.07, p = 0.29, I2% = 65%). Procedure time was marginally increased in obese patients compared to non-obese counterparts (normal versus overweight, SMD = 0.05, 95% CI: -0.15-0.26, p = 0.62, I2% = 74%; normal versus class I obesity, SMD = 0.10, 95% CI: -0.00-0.19, p = 0.06, I2% = 2%; overweight versus class I obesity, SMD = 0.11, 95% CI: 0.01-0.21, p = 0.048, I2% = 25%). Regarding radiation exposure, fluoroscopy time was increased in patients with class I obesity compared to normal-weight or overweight patients and dose area product was also increased in obese patients compared to non-obese patients. Lastly, the risk of complications did not differ between obese and non-obese patients. Statistical heterogeneity and the small number of patients included are the main limitations of this study. Conclusion: CBA seems to be effective for obese patients suffering from AF, featuring also similar safety outcomes with non-obese individuals. Radiation exposure was increased in obese patients.

Impact of Body Mass Index on the Outcomes of Cryoballoon Pulmonary Vein Isolation for Paroxysmal Atrial Fibrillation

BACKGROUND

Atrial fibrillation (AF) is prevalent among obese patients, and cryoballoon ablation (CBA) is an effective strategy for the rhythm control of AF. The impact of body mass index (BMI) on the clinical outcomes of CBA for AF is not fully explored.

METHODS

85 consecutive patients with paroxysmal AF were enrolled and were categorized into three groups as per their BMI: normal weight (BMI 18.5-25 kg/m2), overweight (BMI 25-30 kg/m2), and obese patients (BMI > 30 kg/m2). The primary study endpoint was a late (12 month) recurrence of AF. Early recurrence of AF, symptom improvement, and procedural outcomes were some key secondary outcomes.

RESULTS

20 patients had normal weight, 35 were overweight, and 30 were obese. Obese patients featured a higher prevalence of diabetes mellitus, heavier exposure to smoking, and worse baseline symptoms (as assessed through EHRA class at admission and 12 months before CBA) compared to overweight and normal weight patients. Both late and early (<3 months) AF recurrence rates were comparable across the three groups. Of note, obese patients showed greater improvement in their symptoms post-CBA, defined as improvement by at least one EHRA class, compared to normal weight patients; this might be explained by improved diastolic function. Total procedure time and dose area product were significantly increased in obese patients. The multivariate logistic regression analysis indicated that early AF recurrence and the duration of hypertension are independent predictors of late AF recurrence.

CONCLUSION

CBA is effective in overweight and obese patients with paroxysmal AF. Procedure time and radiation exposure are increased in obese patients undergoing CBA.

Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during cryoballoon ablation of atrial fibrillation: the SWEET-Cryo strategy

AIMS

Cryoballoon pulmonary vein isolation (CB-PVI) offers similar efficacy to point-by-point radiofrequency PVI for patients with atrial fibrillation (AF), but generally with higher X-ray exposure. Strategies aimed at reducing fluoroscopy mostly rely on other costly imaging techniques, limiting their applicability. We designed a Systematic Workflow and Electrogram guidance to reduce X-ray Exposure Time during CB-PVI (SWEET-Cryo) strategy and analysed its impact on fluoroscopy use and acute procedural and clinical outcomes.

METHODS AND RESULTS

We enrolled 100 patients with paroxysmal or persistent AF undergoing CB-PVI by two operators with different levels of expertise. Patients treated with the SWEET-Cryo strategy (prospective cohort; n = 50) or conventional fluoroscopy (retrospective control cohort; n = 50) were compared. When applied by the senior operator, the SWEET-Cryo strategy significantly reduced the mean fluoroscopy time (FT) (2.6 ± 1.25 vs. 20.3 ± 10.8 min) and mean dose area product (DAP) (5.1 ± 3.8 vs. 35.3 ± 22.3 Gy cm2) compared with those of the control group, respectively (P < 0.001). Significant reductions in FT (6.4 ± 2.5 min vs. 32.5 ± 10.05) and DAP (13.9 ± 7.7 vs. 92.3 ± 63.8) were also achieved by the less experienced operator (P < 0.001). No difference was observed in acute and long-term complications or freedom from AF between fluoroscopy strategies during a 33-month median follow-up. Mean FT was maintained below 3 min in randomly selected cases performed during the follow-up period.

CONCLUSION

In contrast to conventional protocols and regardless of the operator's experience, the optimized SWEET-Cryo strategy dramatically reduced fluoroscopy exposure during CB-PVI. The efficacy, safety, or added costs of the ablation procedure were not compromised.

Radiation dose reduction in the setting of cryoballoon ablation for atrial fibrillation: the value of optimized fluoroscopy settings and intracardiac echocardiography

Cryoballoon (CB) has proven to be very effective in the percutaneous treatment of atrial fibrillation (AF). CB ablation is still hampered by X-ray exposure and the doses applied are consistently higher if compared to radiofrequency ablation. All patients who underwent CB ablation between 2015 and 2020 were analysed. Intracardiac echography was consistently used for transeptal puncture. To demonstrate the differences in radiation exposure 3 groups of 50 consecutive patients were selected. In the first group (G1) 3D rotational angiography (3DRA) was used as an intraprocedural imaging method. In the second group (G2), traditional X-ray imaging was used and frame rates both for fluoro and cine modes of diascopy were lowered. In the third group (G3) only 2-3 frames per second were used, cine mode was abandoned and the grid was removed from the X-ray detector. A total of 150 patients were included (76% males, mean age 57.3 ± 11.5 years). A dramatic reduction of radiation dose was obtained from 9585 ± 5610 µGy/m² in G1 to 2469 ± 2002 µGy/m² in G2 and finally 227.1 ± 360 µGy/m² in G3 (p < 0.0001). There was also a significant decrease of procedural and fluoroscopy times. No difference in major complications and midterm outcomes was found between the groups. By following a few relatively simple steps (omitting the pre-procedural imaging, removing grid from the X-ray detector and using very low frame rates) CB ablation could be performed with ultralow radiation exposure without compromising the safety of efficacy of the procedure.

X-ray exposure in cryoballoon versus radiofrequency ablation for atrial fibrillation over 7 years: A single center study

Background

Facing an increasing number of radiofrequency ablation (RF) and cryoballoon ablation (CB) procedures for treatment of AF radiation exposure and its reduction is a focus point for interventional electrophysiologists.

Objective

This study evaluated the procedural parameters of the different ablation methods focusing on radiation exposure and the BMI of the patients.

Methods

One thousand one hundred and thirty-three first procedural cases of pulmonary vein isolation in patients with paroxysmal and persistent AF treated with RF and CB-based techniques were analyzed retrospectively over a period of 7 years focusing on the endpoints dose area product (DAP, cGycm2), fluoroscopy time (FT, min) and procedural time (PT, min).

Results

Of the 1133 patients (mean age 63.4 ± 11.4 years, BMI 28.9 ± 4.7) 335 patients received an RF procedure, 211 patients were treated with the cryoballoon first generation (CB1), and 587 patients with cryoballoon second generation (CB2), respectively. The mean DAP for the PVI was 508 ± 654 cGycm2 in RF procedures, 1077 ± 683 cGycm2 in CB1-procedures, and 587 ± 489 cGycm2 in CB2-procedures with fluoroscopy times significantly shorter in RF procedures (9.6 ± 5.2 min) as compared to 17.7 ± 5.9 min in CB1- and 16.3 ± 6.3 min in CB2-procedures (p < .001). At the same time, the procedure duration using RF (115 ± 33.5 min) was significantly longer than both in CB1 (96 ± 16.8 min) and CB2 procedures (75 ± 15.9 min).

Conclusions

Despite longer fluoroscopy durations in the CB technique, the CB2 resulted in a comparable low radiation exposure in PVI as compared to RF, accompanied by shorter procedure durations.