Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation

doi:10.1016/j.hrthm.2017.05.035

Heart Rhythm

Volume 14, Issue 9, September 2017, Pages 1291-1296

https://doi.org/10.1016/j.hrthm.2017.05.035 Get rights and content

Background

Asymptomatic cerebral embolism (ACE) is sometimes detected after cryoballoon ablation of atrial fibrillation. The removal of air bubbles from the cryoballoon before utilization may reduce the rate of ACE.

Objective

This study aims to compare the incidence of ACE between a conventional and a novel balloon massaging method during cryoballoon ablation.

Methods

Of 175 consecutive patients undergoing initial cryoballoon ablation of paroxysmal atrial fibrillation, 60 (34.3%) patients underwent novel balloon massaging with extracorporeal balloon inflation in saline water (group N) before the cryoballoon was inserted into the body. The remaining 115 (65.7%) patients underwent conventional balloon massaging in saline water while the balloon remained folded (group C). Of those, 86 propensity score–matched patients were included.

Results

The baseline characteristics were similar between the 2 groups. In group N, even after balloon massaging in saline water was carefully performed, multiple air bubbles remained on the balloon surface when the cryoballoon was inflated in all cases. Postprocedural cerebral magnetic resonance imaging detected ACE in 14.0% of all patients. The incidence of ACE was significantly lower in group N than in group C (4.7% vs 23.3%; P = .01). According to multivariable analysis, the novel method was the sole factor associated with the presence of ACE (odds ratio 0.161; 95% confidence interval 0.033–0.736; P = .02).

Conclusion

Preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation reduced the incidence of ACE. Since conventional balloon massaging failed to remove air bubbles completely, this novel balloon massaging method should be recommended before cryoballoon utilization.

Introduction

Cryoballoons have proven to be effective for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). Several recent randomized trials have shown the noninferiority of cryoballoon ablation to radiofrequency ablation with respect to the treatment efficacy in patients with drug-refractory paroxysmal AF.1, 2

Symptomatic cerebral embolism occurred during cryoballoon ablation of AF in 0%–0.5% of patients.1, 2, 3, 4, 5, 6, 7, 8 However, procedural asymptomatic cerebral embolism (ACE) was detected by cerebral magnetic resonance imaging (MRI) in 4%–27% of patients after cryoballoon ablation of AF.4, 5, 6, 7, 8 A previous study reported that the incidence of ACE was not markedly different between radiofrequency and cryoballoon ablation of AF.⁵ Before the insertion of a cryoballoon catheter into the femoral vein, balloon massaging for removal of air bubbles on the cryoballoon may be crucial to reduce the risk of ACE. However, conventional balloon massaging may be insufficient to remove air bubbles on the cryoballoon completely.

The purpose of this study was to evaluate the benefits of our novel balloon massaging method during cryoballoon ablation of AF.

Section snippets

Study subjects

A total of 175 consecutive patients who underwent cryoballoon ablation of paroxysmal AF were included in the present study. Before the cryoballoon was inserted into the body, 115 (65.7%) patients underwent conventional balloon massaging while the balloon remained folded for air removal in heparinized (1000 U of heparin in 1000 mL of NaCl 0.9%) saline water (group C). In the remaining 60 (34.3%) patients, novel balloon massaging in heparinized saline water with extracorporeal cryoballoon

Study population

Conventional and novel air removal methods were performed in 115 (65.7%) and 60 (34.3%) patients, respectively. The resulting propensity score–matched data set included 86 patients—43 with the conventional method and 43 with the novel method. The area under the receiver operating characteristic curve (C-statistic) of the propensity score model was 0.71. After the propensity score–matched analysis, there were no significant differences between the 2 groups with regard to the baseline patient

Discussion

This is the first study to evaluate the benefits of a novel strategy for removing air bubbles with preliminary extracorporeal cryoballoon inflation in heparinized saline water. Surprisingly, after careful conventional massaging of cryoballoon in heparinized saline water, multiple air bubbles were still detected in all cases on the cryoballoon surface. Removing the air bubbles by using the novel method significantly reduced the incidence of preprocedural ACE during cryoballoon ablation of AF.

Conclusion

Preliminary cryoballoon massaging in heparinized saline water with extracorporeal balloon inflation to remove air bubbles reduced the risk of ACE during cryoballoon ablation of AF. Since the conventional balloon massaging method was found to be insufficient for removing all air bubbles on the cryoballoon, our novel method should be widely applied in cases of cryoballoon ablation of AF.

Acknowledgments

We are grateful to Brian Quinn, MA (Japan Medical Communication Inc.), for the comments on the language of the article.

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Cited by (18)

Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation: A prospective randomized study
2022, IJC Heart and Vasculature
Citation Excerpt :
The pre-inflation method did not reduce the incidence of ACE during cryoballoon ablation of AF. In a previous study reported from our institute, extracorporeal air removal reduced the incidence of ACE during cryoballoon ablation [11]. This method has been widely practiced in some areas and is recommended to be performed with a novel cryoballoon system (POLARx, Boston Scientific, St. Paul, MN, USA).
It was previously reported, based on a retrospective study, that preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation reduced the incidence of asymptomatic cerebral embolism (ACE). The present study aims to compare the incidence of ACE between a conventional and pre-inflation method during cryoballoon ablation in a prospective randomized controlled study.
A total of 98 atrial fibrillation patients were enrolled and randomized into conventional and pre-inflation groups. Patients in the pre-inflation group received balloon massaging with preliminary extracorporeal balloon inflation in saline water before the cryoballoon was inserted into the body.
The baseline characteristics were similar between the two groups. Post-procedural 3-Tesla MRI revealed CE in 27.6% of patients. Symptomatic CE only occurred in two patients in the pre-inflation group. One patient had transient dysarthria and mild muscle weakness in one hand; the other patient complained of transient left upper limb weakness, left lower limb paresthesia and dysarthria. The incidence of ACE detected by cerebral MRI did not differ between the two groups to a statistically significant extent (conventional vs. pre-inflation; 22.9% vs. 29.2%; P = 0.49). In the multivariable analysis, eGFR was independently associated with the presence of ACE (odds ratio 0.95; 95% confidence interval 0.907–0.995; P = 0.03).
In this prospective randomized study, the preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation had no impact on the incidence of ACE.
Achieving contrast-free ultra-low radiation exposure without compromising safety and acute efficacy through evolving AF cryoballoon ablation procedure techniques: Ultra-low radiation during cryoballoon procedures
2020, International Journal of Cardiology
In general, early experience with the first-generation cryoballoon introduced an increase in radiation exposure as compared to traditional radiofrequency ablations for atrial fibrillation (AF). However, through operator vigilance and the incorporation of various techniques and technologies, procedural radiation exposure can be managed to an exceptionally low level while maintaining the safety and efficacy of the cryoballoon procedure.
A retrospective chart review of all consecutive AF ablation procedures performed by a single operator at a single high-volume center with the second-generation cryoballoon (Arctic Front Advance) was performed between 2014 and 2017. Procedural and radiation exposure data were collected and analyzed year-over-year. 307 cases were reviewed with the majority as index procedures (95%) and patients presenting in paroxysmal AF (87%). The observed median absorbed dose was 2.4 mGy (interquartile range (IQR) = 1.0,6.2) and decreased significantly from 6.7 mGy (IQR = 1.6,6.2) in 2014 to 2.0 mGy (IQR = 1.5,4.5) in 2017 (P < 0.001). Median fluoroscopy time was 0.4 min (IQR = 0.25,0.75) and demonstrated reductions from 0.75 min (IQR = 0.40,1.4) in 2014 to 0.20 min (IQR = 0.10,0.40) in 2017 (P < 0.001). No radiopaque contrast agent was used in any procedure. A complication rate of 2% (6 total events) was observed, and no cases resulted in stroke, death, permanent phrenic nerve injury, or pulmonary vein stenosis. In total, 304 of 307 (99%) procedures resulted in complete isolation of all pulmonary veins.
Ultra-low radiation doses and contrast-free procedures can be achieved as part of an overall “safety-first” approach during cryoballoon AF ablation without compromising safety or acute efficacy.
Clinical comparative study regarding interrupted and uninterrupted dabigatran therapy during perioperative periods of cryoballoon ablation for paroxysmal atrial fibrillation
2019, Journal of Cardiology
Catheter manipulation in the left-sided heart is known as a risk for cerebral embolisms (CEs). However, anticoagulation therapy is terminated before catheter ablation (CA) of atrial fibrillation (AF) concerning adverse bleeding events. Little is known whether uninterrupted direct oral anticoagulants (DOACs) during perioperative period of CA could render the ablation procedure safer and reduce the incidence of CEs compared to interrupted DOACs. The aim of this study was to investigate the safety and usefulness of uninterrupted dabigatran during the periprocedural period for CA of AF.
We included 333 patients with paroxysmal AF undergoing cryoballoon CA (CBA). They were prospectively divided into 2 groups based on whether DOACs were interrupted on the day of the CA (Group A, n = 228) or dabigatran was not interrupted throughout perioperative period (Group B, n = 105) in a non-randomized fashion. When the Group B patients had taken other DOACs rather than dabigatran before assignment, we changed those DOACs to dabigatran. Brain magnetic resonance imaging (MRI) was undertaken on the following day of the CA. Serious bleeding event cases were excluded from the study.
The baseline characteristics including the CHADs2 score did not exhibit any significant differences between the groups. The brain MRI revealed an acute CEs in 82 patients, and was significantly higher in Group A than B (29% vs. 13%, respectively, p < 0.01). There were no significant differences regarding the bleeding events (7% vs. 4%, respectively, p = 0.62).
Uninterrupted dabigatran therapy during the CBA of paroxysmal AF could significantly reduce the incidence of CEs.
Techniques for reducing air bubble intrusion into the left atrium during radiofrequency catheter and cryoballoon ablation procedures: An ex vivo study with a high-resolution camera
2019, Heart Rhythm
Citation Excerpt :
The highest reduction of air bubble intrusion was obtained after temporary inflation and air bubble removal on the balloon surface before balloon insertion. Tokuda et al14 retrospectively analyzed the incidence of asymptomatic cerebral emboli in patients who underwent CB ablation. The incidence of asymptomatic cerebral emboli was significantly lower for the temporary inflation group.
Air embolisms are serious complications during catheter ablation procedures.
The aims of the present study were to determine when air bubbles enter the left atrium (LA) during catheter ablation procedures and to identify techniques that reduce air bubble intrusion.
An ex vivo study was performed to monitor air bubbles using a silicone heart model and a high-resolution camera. In total, 280 radiofrequency catheter and cryoballoon ablation processes were tested.
Small and large air bubbles were often observed during catheter ablation processes. Many small air bubbles arose during sheath flushing at fast speeds (15 mL/2 s) (median bubble number [quartiles]: 35 [20–53] for SL0, 35 [23–44] for Agilis, and 98 [91–100] for FlexCath) and during initial cryoballoon inflation/freezing/deflation (34 [22–47]). Large (≥1.5 mm) air bubbles were observed during Lasso catheter insertion (1 [0–1]), cryoballoon insertion (2 [1–2]), and initial inflation/freezing/deflation (1 [1–3]). Massive air bubbles were observed during Optima catheter insertion into the sheath using an inserter (10 [2–15]). Sheath flushing at slow speeds (15 mL/5 s) significantly reduced the number of air bubbles. Before cryoballoon insertion, temporary balloon inflation and air bubble removal from the inflated surface were most effective in reducing air bubble intrusions. Optima catheter insertion without an inserter significantly reduced large air bubble intrusion.
Air bubbles entered the LA at specific times. Techniques such as sheath flushing at slow speeds, temporary cryoballoon inflation before insertion, inserting the Optima catheter without an inserter, and avoidance of negative pressure in the LA could reduce air bubble intrusion.
Silent cerebral events/lesions after second-generation cryoballoon ablation: How can we reduce the risk of silent strokes?
2019, Heart Rhythm
Citation Excerpt :
These results suggest that SCEs/SCLs in the CB procedure likely were the result of gaseous emboli and not of a clotting formation. Recently, the novel balloon massage technique to remove air bubbles with preliminary extracorporeal CB inflation in heparinized saline water significantly reduced SCEs compared to the conventional balloon massage in a retrospective case-control study.7 However, our study did not reproduce any results.
Atrial fibrillation (AF) ablation is associated with a substantial risk of silent cerebral events/lesions (SCEs/SCLs) detected on magnetic resonance imaging (MRI).
The purpose of this study was to investigate the factors associated with the incidence of SCEs/SCLs during second-generation cryoballoon ablation.
Two hundred fifty-six AF patients underwent brain MRI 1 day after pulmonary vein (PV) isolation using second-generation cryoballoons with a single 28-mm balloon and short freeze strategy.
Overall, 991 of 1016 PVs (97.5%) were successfully isolated by 4.9 ± 1.3 cryoballoon applications per patient, and 25 PVs required touch-up radiofrequency ablation. The total procedure time was 72.7 ± 26.1 minutes. SCEs and SCLs were detected in 68 (26.5%) and 27 (10.5%) patients, respectively. None of the patients reported any neurologic symptoms. Reinsertion of once withdrawn cryoballoons and subsequent applications significantly increased the incidence of SCEs (odds ratio [OR] 2.057; 95% confidential interval [CI] 1.051–4.028; P = .035), and additional left atrial mapping with a multielectrode catheter significantly increased the incidence of SCLs (OR 3.317; 95% CI 1.365–8.056; P = .008). Transient coronary air embolisms were significantly associated with the incidence of SCLs (OR 3.447; 95% CI 1.015–11.702; P = 0.047). On the contrary, an uninterrupted anticoagulation regimen, use of radiofrequency deliveries for transseptal access, cryoballoon air removal with extracorporeal balloon inflations, strength of the MRI magnet, internal electrical cardioversion, and touch-up ablation were not associated with the incidence of SCEs/SCLs.
A significant number of SCE/SCL occurrences was observed after second-generation cryoballoon ablation procedures. These results suggest that air embolisms are the main mechanism of SCEs/SCLs, and the injected air volume might determine the lesion type.
Atrial fibrillation catheter ablation associated silent cerebral emboli: A narrative review
2023, PACE - Pacing and Clinical Electrophysiology

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Focus Issue: Atrial FibrillationEffect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation

Background

Objective

Methods

Results

Conclusion

Introduction

Section snippets

Study subjects

Study population

Discussion

Conclusion

Acknowledgments

Heart Rhythm

J Am Coll Cardiol

Heart Rhythm

J Am Coll Cardiol

Heart Rhythm

Cryoballoon or radiofrequency ablation for paroxysmal atrial fibrillation

N Engl J Med

Cryoballoon versus open irrigated radiofrequency ablation in patients with paroxysmal atrial fibrillation: the prospective, randomized, controlled, noninferiority freeze AF study

Circulation

First-line catheter ablation of paroxysmal atrial fibrillation: outcome of radiofrequency vs. cryoballoon pulmonary vein isolation

Europace

Focus Issue: Atrial Fibrillation
Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation