Thromboembolic Risks of the Procedural Process in Second-Generation Cryoballoon Ablation Procedures

Incidence of silent cerebral events detected by MRI in patients with atrial fibrillation undergoing pulsed field ablation vs thermal ablation: A systematic review and network meta-analysis

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and catheter ablation has been demonstrated to achieve superior success rates compared with antiarrhythmic drugs. However, this procedure entails certain risks, including silent cerebral events (SCEs), which may affect cognitive function. This network meta-analysis aimed to determine the global incidence of SCEs in patients with AF undergoing catheter ablation and to compare the incidence across energy sources and catheter types. Our analysis included 86 trials involving 10,456 patients with AF, with a pooled SCE incidence of 19.1%. For pulsed field ablation, the incidence of SCEs was 14.4%; thermal ablation techniques showed rates of 17.7% for radiofrequency ablation, 20.8% for cryoballoon ablation, and 32.7% for laser ablation. No significant differences were found between pulsed field ablation and thermal ablation in SCE incidence. The comparison of SCE incidence between different catheter types revealed variations. The HD Mesh Ablator demonstrated the lowest incidence rate (15.1%), whereas the PVAC catheter had the highest (36.2%). The Farawave catheter had an incidence rate of 18.5% and showed no significant differences compared with most thermal catheters, except for the HD Mesh Ablator (relative risk, 0.15; 95% credible interval, 0.03-0.89). Our findings indicate that a substantial proportion of patients experience SCEs after catheter ablation for AF, with an overall incidence of approximately 19.1% occurring within 1 week (mostly within 72 hours) after ablation. No significant differences were observed in SCE incidence between pulsed field ablation and thermal ablation or between the Farawave catheter and most thermal catheters.

Neuroprotection Devices in Cardiac Catheterization Laboratories: Does It Sufficiently Protect Our Patients?

Stroke is a devastating complication of cardiovascular interventions. Intraprocedural stroke is a well-documented and feared risk of cardiac percutaneous transcatheter procedures. If clinically significant strokes are absent, silent strokes remain the next in line to pose large concerns related to future cognitive decline, stroke risk, and overall increased morbidity and mortality. Cerebral protection devices (CPD) developed overtime aim to neutralize this risk through either a capture-based filter or a deflector mechanism. Many CPDs exist currently, each one unique, with varying degrees of evidence. The adoption of CPDs has allowed cardiac percutaneous transcatheter procedures to be carried out in patients with high thromboembolic risks who may have historically been discommended. Though skewed towards certain devices and transcatheter procedures, a large body of evidence is still present across other devices and procedures. This review will discuss clinical importance and respective stroke rates, updated evidence surrounding CPDs, differing opinions across types of CPDs, cost benefits, and what lies ahead for CPDs within the realm of procedures undertaken in cardiac catheterization laboratories.

Microembolizations in the arterial cerebral circulation during atrial fibrillation ablation: cryoballoon technique advantages and neurocognitive safety-results of a prospective observational study

AIMS

The significance of micro-embolic signals (MESs) during atrial fibrillation (AF) ablation is unclear. Previous studies had limitations, and cryoballoon (CB) ablation patients were under-represented. Minimizing MESs is recommended due to their uncertain neurocognitive impact.

METHODS AND RESULTS

This prospective observational study included AF patients from a German centre between February 2021 and August 2022. Patients were equally divided into paroxysmal (Group A) and persistent (Group B) AF. Group A received cryoballoon-pulmonary vein isolation only, while Group B also had left atrial roof ablation. MESs were detected using transcranial Doppler ultrasonography during ablation. Neurocognitive status was assessed pre- and post-procedure and at 3 months using the CERAD Plus battery. The study analyzed 100 patients with a median age of 65.5 years. A total of 19 698 MESs were observed, with 80% being gaseous and 20% solid in origin, primarily occurring during pulmonary vein angiography and the balloon freeze and thawing phase. The median MES per patient was 130 (IQR: 92-256) in total, 298 (IQR: 177-413) in bilateral (36%), and 110 (IQR: 71-130) in unilateral (64%) recordings. No significant difference in total MES counts was found between the groups. None of the 11 neuropsychological tests showed cognitive decline post-procedure or at 3 months.

CONCLUSION

Our observations confirm that neurocognitive abilities are not affected either 24 h or 3 months after AF ablation using the CB technique. However, despite the low MES burden associated with the CB, more work is needed to reduce small embolic events during AF ablation.

Pulsed field ablation for atrial fibrillation - Lessons from magnetic resonance imaging

Pulsed field ablation (PFA) is a promising technology for the treatment of atrial fibrillation (AF). Due to its unique tissue selectivity, PFA potentially bears superior characteristics as compared to established thermal energy sources in AF ablation procedures. Cardiovascular magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE) is an established tool in the analysis of myocardial fibrosis representing atrial cardiomyopathy as well as ablation-induced atrial scar formation following catheter ablation with thermal energy. Mechanisms of atrial lesion formation differ between thermal ablation and electroporation and its impact on results of CMR imaging are not fully understood until now. In this review article, the potential of CMR imaging for PFA lesion assessment and available data are discussed. Further, additional needs to adopt imaging approaches to the cellular mechanisms of electroporation are considered.

Atrial fibrillation catheter ablation associated silent cerebral emboli: A narrative review

The incidence of silent cerebral emboli (SCE) associated with atrial fibrillation catheter ablation (AFCA) is much higher than that of stroke/transient ischemic attack (TIA). Interventional electrophysiologists have been increasingly alerted to asymptomatic cerebral infarction over the years. Plentiful studies revealed that diagnostic definitions, detection modalities, energy sources, ablation strategies, perioperative anticoagulation regimens, and patient-related factors were associated with the risk of AFCA-associated SCE. Studies related to non-interventional procedures found that SCE may prompt stroke, cognitive decline, and dementia later in life, suggesting a possible role of AFCA-associated SCE in the cognitive function of patients with AF. However, there is no consistent evidence for this view to date. Given that the majority of patients with AF being elderly and the increased risk of cognitive impairment in AF itself, efforts should be made to minimize the occurrence of AFCA-associated SCE.

Fighting Cardiac Thromboembolism during Transcatheter Procedures: An Update on the Use of Cerebral Protection Devices in Cath Labs and EP Labs

Intraprocedural stroke is a well-documented and feared potential risk of cardiovascular transcatheter procedures (TPs). Moreover, subclinical neurological events or covert central nervous system infarctions are concerns related to the development of dementia, future stroke, cognitive decline, and increased risk of mortality. Cerebral protection devices (CPDs) were developed to mitigate the risk of cardioembolic embolism during TPs. They are mechanical barriers designed to cover the ostium of the supra-aortic branches in the aortic arch, but newer devices are able to protect the descending aorta. CPDs have been mainly designed and tested to provide cerebral protection during transcatheter aortic valve replacement (TAVR), but their use in both Catheterization and Electrophysiology laboratories is rapidly increasing. CPDs have allowed us to perform procedures that were previously contraindicated due to high thromboembolic risk, such as in cases of intracardiac thrombosis identified at preprocedural assessment. However, several concerns related to their employment have to be defined. The selection of patients at high risk of thromboembolism is still a subjective choice of each center. The aim of this review is to update the evidence on the use of CPDs in either Cath labs or EP labs, providing an overview of their structural characteristics. Future perspectives focusing on their possible future employment are also discussed.

Silent cerebral lesions following catheter ablation for atrial fibrillation: a state-of-the-art review

Atrial fibrillation is associated with neurocognitive comorbidities such as stroke and dementia. Evidence suggests that rhythm control-especially if implemented early-may reduce the risk of cognitive decline. Catheter ablation is highly efficacious for restoring sinus rhythm in the setting of atrial fibrillation; however, ablation within the left atrium has been shown to result in MRI-detected silent cerebral lesions. In this state-of-the-art review article, we discuss the balance of risk between left atrial ablation and rhythm control. We highlight suggestions to lower the risk, as well as the evidence behind newer forms of ablation such as very high power short duration radiofrequency ablation and pulsed field ablation.

Microembolizations in the Arterial Cerebral Circulation in Patients with Atrial Fibrillation Ablation Using the Cryoballoon Technique-Protocol and Methodology of a Prospective Observational Study

There is considerable uncertainty regarding the impact of microembolic signals (MESs) on neuropsychological abilities in patients receiving pulmonary vein isolation and beyond using the cryoballoon technique. We conducted the largest prospective observational study on this topic, providing insights into the gradual unmasking of procedure-related MESs and their impacts on neuropsychological outcomes. MESs were continuously detected periprocedurally using transcranial Doppler ultrasonography. Neuropsychological status was evaluated comprehensively using the CERAD Plus test battery, which consists of 11 neuropsychological subtests. Patients with atrial fibrillation were included in the study with an equal distribution (50:50) of paroxysmal or persistent presentations. Of 167 consecutive eligible patients, 100 were included within the study enrollment period from February 2021 to August 2022. The study, including the documentation of all follow-up visits, ended in November 2022. This paper focuses on describing the study protocol and methodology and presenting the baseline data.

A multicenter prospective randomized study comparing the incidence of periprocedural cerebral embolisms caused by catheter ablation of atrial fibrillation between cryoballoon and radiofrequency ablation (Embo-Abl study): Study design

BACKGROUND

Although catheter ablation (CA) has become a standard therapeutic approach to atrial fibrillation (AF), it imposes a low but relevant risk of thromboembolic complications of around 0.5%-1%, including ischemic strokes, and has an additional risk of clinically silent cerebral embolisms (SCEs) of 10%-40%. Both cryoballoon (CB) and radiofrequency (RF) ablation are routinely used clinically worldwide, yet there are few prospective data comparing the incidence of cerebral embolism after CA of AF between CB and RF ablation.

METHODS

The aim of the Embo-Abl study will be to compare the incidence of cerebral embolisms on 3 T diffusion-weighted image magnetic resonance imaging (MRI) after CA of AF between CB and RF ablation in patients with AF in a prospective, multicenter, open-label, controlled, randomized fashion. The primary endpoint of the Embo-Abl study will be the occurrence of MRI-detected SCE 1-3 days after CA. The patients will be registered and randomly assigned to either the CB or RF ablation group in a 1:1 ratio. The study cohort will include 230 patients with AF from a multicenter in Japan.

RESULTS

The results of this study are currently under investigation.

CONCLUSION

The Embo-Abl study will be the first to compare the incidence of periprocedural cerebral embolisms caused by CA of AF between CB and RF ablation in a prospective, multicenter, randomized, controlled fashion.

Simple periprocedural precautions to reduce Doppler microembolic signals during AF ablation

BACKGROUND

Doppler microembolic signals (MES) occur during atrial fibrillation ablation despite of permanent flushed transseptal sheaths, frequent controls of periprocedural coagulation status and the use of irrigated ablation catheters PURPOSE: To investigate the number and type of MES depending on the procedure time, prespecified procedure steps, the activated clotting time (ACT) during the ablation procedure and the catheter contact force.

METHODS

In a prospective trial, 53 consecutive atrial fibrillation patients underwent pulmonary vein isolation by super-irrigated "point-by-point" ablation. All patients underwent a periinterventional, continuous transcranial Doppler examination (TCD) of the bilateral middle cerebral arteries during the complete ablation procedure.

RESULTS

An average of 686±226 microembolic signals were detected by permanent transcranial Doppler. Thereby, 569±208 signals were differentiated as gaseous and 117±31 as solid MES. The number of MES with regard to defined procedure steps were as follows: gaseous: [transseptal puncture, 26 ± 28; sheath flushing, 24±12; catheter change, 21±11; angiography, 101±28; mapping, 9±9; ablation, 439±192; protamine administration, 0±0]; solid: [transseptal puncture, 8±8; sheath flushing, 9±5; catheter replacement, 6±6; angiography, not measurable; mapping, 2±5; ablation, 41±22; protamine administration, 0±0]. Significantly less MES occurred with shorter procedure time, higher ACT and the use of tissue contact force monitoring.

CONCLUSION

The current study demonstrates that during atrial fibrillation ablation using irrigated, "point-by-point" RF ablation, masses of microembolic signals are detected in transcranial ultrasound especially in the period of RF current application. The number of MES depends on the total procedure time and the reached ACT during ablation. The use of contact force monitoring might reduce MES during RF ablation.

Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation: A prospective randomized study

Background

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.

Methods

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.

Results

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).

Conclusion

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.

Cryoballoon atrial fibrillation ablation experience in Japan

PURPOSE OF REVIEW

In Japan, cryoballoon ablation has been widely accepted and more than 70 000 patients have undergone pulmonary vein isolation using this novel technology since the introduction. This review focused on the current status of cryoballoon ablation in Japan and clarified the characteristics as compared to Europe and the United States.

RECENT FINDINGS

The number of atrial fibrillation patients undergoing cryoballon ablation has rapidly increased over the last 6 years. Most of the Japanese physicians consider the indication of cryoballoon ablation based on the anatomy of the pulmonary veins and left atrium evaluated on preprocedural computed tomography, and often perform adjunctive radiofrequency ablation after the pulmonary vein isolation. The reported overall efficacy and safety were similar to that in Europe and the United States; however, there are some distinctive complications of the cryoballoon procedure in Japan, such as air embolisms, gastric hypomotility and coronary artery spasms.

SUMMARY

Currently, the cryoballoon pulmonary vein isolation is widely accepted in Japan owing to the low incidence of lethal complications, shorter procedure time and acceptable single procedure atrial fibrillation freedom.

Clinically Manifesting Air Embolisms in Cryoballoon Ablation: Can Novel Water Buckets Reduce the Risk?

Air embolisms can lead to lethal results; however, few reports have systemically investigated this issue. Of 348 consecutive patients with atrial fibrillation who underwent cryoballoon ablation, procedures were performed conventionally in 251 patients. In the remaining 97 patients, a water bucket was used while inserting the cryoballoon into the sheath. A total of 10 coronary air embolisms with ST-segment elevation in the inferior leads were observed among 9 (2.6%) patients. Multiple air bubbles were identified in 2 patients on emergent coronary angiography. All recovered under conservative treatment without any sequela. The incidence decreased when using the water bucket (1 of 97 [1.03%] vs. 8 of 251 [3.2%], p = 0.454).

In vivo analysis of the origin and characteristics of gaseous microemboli during catheter-mediated irreversible electroporation

Aims 

Irreversible electroporation (IRE) ablation is a non-thermal ablation method based on the application of direct current between a multi-electrode catheter and skin electrode. The delivery of current through blood leads to electrolysis. Some studies suggest that gaseous (micro)emboli might be associated with myocardial damage and/or (a)symptomatic cerebral ischaemic events. The aim of this study was to compare the amount of gas generated during IRE ablation and during radiofrequency (RF) ablation.

Methods and results

In six 60–75 kg pigs, an extracorporeal femoral shunt was outfitted with a bubble-counter to detect the size and total volume of gas bubbles. Anodal and cathodal 200 J IRE applications were delivered in the left atrium (LA) using a 14-electrode circular catheter. The 30 and 60 s 40 W RF point-by-point ablations were performed. Using transoesophageal echocardiography (TOE), gas formation was visualized. Average gas volumes were 0.6 ± 0.6 and 56.9 ± 19.1 μL (P < 0.01) for each anodal and cathodal IRE application, respectively. Also, qualitative TOE imaging showed significantly less LA bubble contrast with anodal than with cathodal applications. Radiofrequency ablations produced 1.7 ± 2.9 and 6.7 ± 7.4 μL of gas, for 30 and 60 s ablation time, respectively.

Conclusion 

Anodal IRE applications result in significantly less gas formation than both cathodal IRE applications and RF applications. This finding is supported by TOE observations.

Clinical Effect of Adaptive Servo-Ventilation on Left Atrial Pressure During Catheter Ablation in Sedated Patients With Atrial Fibrillation

BACKGROUND

Sedation during pulmonary vein isolation (PVI) for atrial fibrillation often provokes a decline in left atrial (LA) pressure (LAP) under atmospheric pressure and increases the risk of systemic air embolisms. This study aimed to investigate the efficacy of adaptive servo-ventilation (ASV) on the LAP in sedated patients.

METHODS AND RESULTS

Fifty-one consecutive patients undergoing cryoballoon PVI were enrolled. All patients underwent sedation using propofol throughout the procedure. After the transseptal puncture and the insertion of a long sheath into the LA, the LAP was measured. Then, the ASV treatment was started, and the LAP was re-measured. The LAP before and after the ASV support was investigated. Before ASV, the LAP during the inspiratory phase was significantly smaller than that during the expiratory phase (4.9±5.4 mmHg vs. 14.0±5.2 mmHg, P<0.01). The lowest LAP was -2.2±5.1 mmHg and was under 0 mmHg in 37 (73%) patients. After the ASV, the LAP during the inspiratory phase significantly increased to 8.9±4.1 mmHg (P<0.01), and lowest LAP increased to 4.7±5.9 mmHg (P<0.01). The negative lowest LAP value became positive in 30/37 (81%) patients. There were no statistical differences regarding obstructive sleep apnea (OSA), obesity, gender, or other comorbidities between patients with and without a negative lowest LAP after ASV support.

CONCLUSIONS

ASV is effective for increasing the LAP above 0 mmHg and might prevent air embolisms during PVI.

Cerebral Emboli Monitoring Using Transcranial Doppler Ultrasonography in Adults and Children: A Review of the Current Technology and Clinical Applications in the Perioperative and Intensive Care Setting

Transcranial Doppler (TCD) ultrasonography is the only noninvasive bedside technology for the detection and monitoring of cerebral embolism. TCD may identify patients at risk of acute and chronic neurologic injury from gaseous or solid emboli. Importantly, a window of opportunity for intervention-to eliminate the source of the emboli and thereby prevent subsequent development of a clinical or subclinical stroke-may be identified using TCD. In this review, we discuss the application of TCD sonography in the perioperative and intensive care setting in adults and children known to be at increased risk of cerebral embolism. The major challenge for evaluation of emboli, especially in children, is the need to establish the ground truth and define true emboli identified by TCD. This requires the development and validation of a predictive TCD emboli monitoring technique so that appropriately designed clinical studies intended to identify specific modifiable factors and develop potential strategies to reduce pathologic cerebral embolic burden can be performed.

Real-World Safety Profile of Atrial Fibrillation Ablation Using a Second-Generation Cryoballoon in Japan: Insight From a Large Multicenter Observational Study

OBJECTIVES

This study sought to investigate the incidence and characteristics of the real-world safety profile of second-generation cryoballoon ablation (2nd-CBA) in Japan.

BACKGROUND

Pulmonary vein isolation using second-generation cryoballoons is an accepted atrial fibrillation ablation strategy.

METHODS

This multicenter observational study included 4,173 patients with atrial fibrillation (3,807 paroxysmal) who underwent a 2nd-CBA in 18 participating centers. The baseline data and details of all procedure-related complications within 3 months post-procedure in consecutive patients from the first case at each center were retrospectively collected.

RESULTS

Adjunctive ablation after the pulmonary vein isolation was performed in 2,745 (65.8%) patients. Complications associated with the entire procedure were observed in 206 (4.9%) total patients, and in the multivariate analysis, the age (odds ratio: 1.015; 95% confidence interval: 1.001 to 1.030; p = 0.035) and study period were predictors. Air embolisms manifesting as ST-segment elevation and cardiac tamponade requiring drainage occurred in 63 (1.5%) and 15 (0.36%) patients, respectively. Six (0.14%) patients had strokes/transient ischemic attacks, among whom 5 underwent ablation under an interrupted anticoagulation regimen. No atrioesophageal fistulae occurred; however, 10 (0.24%) patients had symptomatic gastric hypomotility. Esophageal temperature monitoring did not reduce the incidence, and the incidence was significantly higher in patients with adjunctive posterior wall isolations or mitral isthmus ablation than those without (p = 0.004). Phrenic nerve injury occurred during the 2nd-CBA in 58 (1.4%) patients; however, all were asymptomatic and recovered within 13 months. One patient died of aspiration pneumonia.

CONCLUSIONS

This study had a high safety profile of 2nd-CBA despite including the early experience and high rate of adjunctive ablation. Care should be taken for air embolisms during 2nd-CBA.

Keeping it Simple: Balloon Devices for Atrial Fibrillation Ablation Therapy

Atrial fibrillation is a common disease of increasing prevalence. Catheter ablation has evolved into an established therapeutic option that mainly aims to electrically isolate the pulmonary veins from atrial myocardium. The traditional method comprises point-by-point radiofrequency current ablation guided by electroanatomical mapping and has proven to be effective and safe in experienced hands. However, this approach is technically highly demanding and associated with a long learning curve, limiting its widespread utilization. To address these shortcomings, simplified ablation tools for pulmonary vein isolation are needed. In this context, balloon devices promise to ease the procedure by approaching the entire orifice of a targeted pulmonary vein in a single maneuver. This requires less catheter manipulation in the left atrium and often allows ablation of a large volume of tissue with a single application of ablative energy. Two balloon devices-one using cryoenergy, the other laser energy-have already been established in clinical routine and have demonstrated noninferiority when compared with radiofrequency ablation in large randomized trials. More balloon devices are on the verge of being introduced into clinical practice and bear the potential to expand the interventional electrophysiologist's armamentarium when treating atrial fibrillation. The authors review the use of the established balloon devices available for atrial fibrillation ablation and provide a detailed outlook on upcoming balloon technologies, including 3 different balloons utilizing radiofrequency energy as well as a novel cryoballoon.

Acute Procedural Complications of Cryoballoon Ablation: A Comprehensive Review

Catheter ablation is increasingly performed for treatment of atrial fibrillation (AF). Balloon based procedures have been developed aiming at safer, easier and more effective treatment as compared to point to point ablation. In the present review article, we aimed to discuss acute procedural complications of cryoballoon ablation.

Development of a novel ablation hood to prevent systemic embolization of microbubbles and particulate emboli

BACKGROUND

Atrial fibrillation ablation results in microbubbles and particulate emboli formation. We aimed to develop and test the early feasibility of a novel ablation hood to contain microbubbles and particulate emboli with the ultimate goal of preventing systemic embolization.

METHODS

In seven canines, we developed, iterated, and tested a novel retractable hood that can cover the catheter-tissue ablation site. The number and volume (nL) of microbubbles formed during ablation with and without the hood was measured using an extracorporeal circulation loop. Wilcoxon's signed-rank test was used to compare the number of bubbles detected with and without the hood.

RESULTS

The hood reduced systemic embolization of microbubbles in 21/28 (75%) of ablations. Both atrial and ventricular ablations showed a statistically significant reduction in bubble number (476 ± 811 without hood vs 173 ± 226 with hood, p = 0.02; 2669 ± 1623 without hood vs 1417 ± 970 with hood, p = 0.04, respectively) and bubble volume (3.3 ± 7.6 nL without hood vs 0.2 ± 0.56 nL with hood, p = 0.006; 6.1 ± 5.2 nL without hood vs 1.9 ± 1.4 nL with hood, p = 0.05, respectively).

CONCLUSIONS

Use of a novel hood to cover the ablation catheter at the site of catheter-tissue contact has the potential to provide a means to reduce systematic embolization of microbubbles. Further work is required to examine particulate emboli, but these data show the early feasibility of this design concept.

Over-the-needle trans-septal access using the cryoballoon delivery sheath and dilator in atrial fibrillation ablation

BACKGROUND

In the setting of second-generation cryoballoon (CB2) ablation, left atrial (LA) access is generally achieved using a standard sheath (SS) that is exchanged for the 15Fr cryoballoon delivery sheath (CBS) and dilator over a long wire (CBS over-the-wire technique, CBS-W). Our objective was to evaluate the direct use of the CBS to gain LA access, by advancing the latter over the trans-septal needle (CBS over-the-needle technique, CBS-N), under transesophageal echocardiographic (TEE) guidance.

METHODS

Consecutive patients who underwent CB2 ablation with the CBS-N technique were evaluated for feasibility of gaining LA access using TEE guidance and fluoroscopy views. Complications related to the LA access were compared with a matched CBS-W control group. Subanalysis (30 CBS-W vs 30 CBS-N patients) evaluated time-to-LA of the CBS: time from superior vena cava (with SS vs CBS) to LA insertion of the CBS, after exchange or directly, respectively.

RESULTS

LA access could be achieved in all 505 patients of the CBS-N group, without technique modification or additional equipment. Challenging interatrial septa were noted in 13% of these patients: previous atrial septal defect repair (1%), hypermobile (10%), aneurysmal (1%), and abnormally thickened/fibrotic (1%). Incidence of complications was similar to the CBS-W group. Subanalysis showed a shorter time-to-LA in the CBS-N versus CBS-W group, 72 ± 46 seconds versus 293 ± 180 seconds, P < .001.

CONCLUSIONS

Our study showed that the CBS-N technique is feasible and safe under echocardiographic guidance. Without sheath exchange, it simplifies the CB2 procedure, is less costly, time sparing, and might reduce the risk of air embolism.

Complications of Cryoballoon Pulmonary Vein Isolation

Since the cryoballoon (CB) was introduced into clinical practice, more than 400,000 patients have undergone a pulmonary vein (PV) isolation with a CB throughout the world. Although the efficacy of the first-generation CB was limited, the recently introduced second-generation CB has achieved a greater uniformity in cooling, which has facilitated a shorter time to PV isolation, shorter procedural times, higher rates of freedom from atrial fibrillation and low rates of PV reconnections. Currently, a single short freeze strategy with a single 28 mm balloon has become the standard technique based on the balance of procedural efficacy and safety. However, enhanced cooling characteristics may also result in a greater potential for collateral damage to non-cardiac structures. Knowledge about the potential complications is essential when performing the procedure. In this article, we describe the important complications that should be noted during a CB procedure, and how to minimise the risk of complications based on our experience.

Silent cerebral lesions and cognitive function after pulmonary vein isolation with an irrigated gold-tip catheter: REDUCE-TE Pilot study

Introduction

Stroke is one of the most feared complications during catheter ablation of atrial fibrillation (AF). While symptomatic thromboembolic events are rare, magnetic resonance imaging (MRI) may identify asymptomatic (ie, silent) cerebral lesions (SCLs) following pulmonary vein isolation (PVI) procedures.

Methods and Results

The REDUCE‐TE Pilot was a prospective multicenter, single‐arm observational study investigating the incidence of SCL in patients with symptomatic paroxysmal AF undergoing PVI with a novel gold‐tip, externally irrigated ablation catheter. After ablation, cerebral diffusion‐weighted MRI and a postablation follow‐up were performed at 1 to 3 days after the ablation procedure. A neurocognitive test was done before and after ablation. The primary study endpoint was the occurrence of one or more new SCLs. Secondary study endpoints included neurocognitive status, procedural success rate, and periprocedural complications including symptomatic thromboembolic events. A total of 104 patients were enrolled (69% male, mean age: 61.5 ± 9.7 years, mean CHA₂DS ₂‐VASc score: 1.7 ± 1.2). Postprocedural MRI examination was performed in 97 patients, and in nine of them (9.3%; 95% CI: 4.3‐16.9%) a total of 11 SCLs were detected. Univariate analyses did not reveal any significant predictor for new SCLs. Nonsignificant trends were observed for low activated clotting time during ablation and for international normalized ratio value outside the range of 2 to 3 at ablation. There was no evidence of significant deterioration of neurocognitive function after PVI. In four patients, a pericardial tamponade was noted but all patients fully recovered during follow‐up.

Conclusions

Ablation of AF using a novel gold‐tip, externally irrigated ablation catheter, resulted in SCLs in approximately one out of 10 patients without a measurable effect on neurocognitive function.

Postablation cerebral embolisms in balloon-based atrial fibrillation ablation with periprocedural direct oral anticoagulants: A comparison between cryoballoon and HotBalloon ablation

INTRODUCTION

This prospective observational study aimed to investigate the incidence of symptomatic and silent cerebral embolisms after balloon-based ablation of atrial fibrillation (AF) in patients receiving periprocedural anticoagulation with direct oral anticoagulants (DOACs), and compare that between cryoballoon and HotBalloon ablation (CBA and HBA).

METHODS AND RESULTS

We enrolled 123 consecutive AF patients who underwent a balloon-based pulmonary vein isolation (PVI) and brain magnetic resonance (MR) imaging after the ablation procedure (CBA, n = 65; HBA, n = 58). The DOACs were continued in 62 patients throughout the periprocedural period and discontinued in 61 on the procedural day. Intravenous heparin was infused to maintain an activated clotting time of 300 to 400 seconds during the procedure. No symptomatic embolisms occurred in this series. Silent cerebral ischemic lesions (SCILs) were observed on MR imaging in 22 patients (17.9%), and the incidence of SCILs did not significantly differ between the CBA and HBA groups (21.5 vs 13.8%; P = 0.263). According to a multivariate logistic regression analysis, an older age was an independent positive predictor of SCILs (odds ratio, 1.062; 95% CI, 1.001-1.126; P = 0.046), but neither the balloon catheter type nor periprocedural continuation or discontinuation of the DOACs were significant predictors. The incidence of major and minor bleeding complications was comparable between the CBA and HBA groups (1.5 vs 0%, P = 0.528; 7.7 vs 5.2%, P = 0.424).

CONCLUSIONS

Both CBA and HBA of AF revealed a similar incidence of postablation cerebral embolisms. Elderly patients may be at a risk of SCILs after a balloon-based PVI with periprocedural DOAC treatment.

Silent cerebral events/lesions after second-generation cryoballoon ablation: How can we reduce the risk of silent strokes?

BACKGROUND

Atrial fibrillation (AF) ablation is associated with a substantial risk of silent cerebral events/lesions (SCEs/SCLs) detected on magnetic resonance imaging (MRI).

OBJECTIVE

The purpose of this study was to investigate the factors associated with the incidence of SCEs/SCLs during second-generation cryoballoon ablation.

METHODS

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.

RESULTS

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.

CONCLUSION

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.