The Incidence of Asymptomatic Cerebral Microthromboembolism after Atrial Fibrillation Ablation: Comparison of Warfarin and Dabigatran

Omitting transesophageal echocardiography before catheter ablation of atrial fibrillation

BACKGROUND

Data about necessity of performing transesophageal echocardiography (TOE) prior to every catheter ablation (CA) of atrial fibrillation (AF) is scarce. We aimed to evaluate the safety of an individualized risk-based approach to TOE with respect to thromboembolic cerebrovascular events (CVE) in patients undergoing CA for AF or left atrial tachycardia (AT).

METHODS

We performed a retrospective clinical study based on our institutional registry database. Patients undergoing CA for AF or left-sided AT following initial AF ablation at two participating centers were enrolled. Prior to the procedure, patients were scheduled for TOE only if they had a history of thromboembolic stroke, left atrial appendage (LAA) thrombus, or inappropriate anticoagulation regimen in the previous 3 to 4 weeks. The incidence of periprocedural cerebrovascular thromboembolic events was assessed.

RESULTS

We analyzed 1155 patients (median age 70 years, 54.8% male, 48.1% had persistent AF/AT). In 261 patients, a TOE was performed; in 2 patients (0.7%), an LAA thrombus was detected, which led to cancellation of the catheter ablation; in 894 patients, the TOE was omitted. Of the 1153 (0.35%) patients who underwent ablation, 4 (0.35%) experienced a CVE (one TIA and three strokes). The rate of CVE in our study does not exceed that reported in most multicenter trials. The low event rates limited statistical analysis of possible risk factors for CVE. In all 4 patients with CVE, post-CVE imaging showed the absence of LAA thrombus.

CONCLUSIONS

An individualized selective approach to TOE before catheter ablation of AF or left AT showed a very low risk of overt intraprocedural thromboembolic events for the population in our study. A further randomized controlled study is needed to determine whether TOE prior to catheter ablation without ICE could be omitted in patients with uninterrupted OAC without previous thromboembolic events or a history of left atrial thrombus.

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.

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.

Symptomatic and asymptomatic intracerebral hemorrhages detected by magnetic resonance imaging after catheter ablation of atrial fibrillation

PURPOSE

Symptomatic intracerebral hemorrhages (ICHs) are a rare complication after atrial fibrillation (AF) catheter ablation, while the incidence of asymptomatic ICHs detected by magnetic resonance (MR) imaging remains unclear. This study aimed to investigate the incidence, characteristics, and predictors of new-onset ICHs on MR imaging after AF ablation.

METHODS

We retrospectively studied 1257 consecutive AF ablation procedures in 1201 patients who underwent MR imaging on the day after the procedure. Repeat MR imaging within 3 months post-ablation was available in 352 procedures.

RESULTS

Old ICHs on the initial MR imaging were observed in 28 procedures (2.2%). Post-ablation new ICHs were observed in 14 procedures (4.0%), including one symptomatic (0.3%) and 13 (3.7%) asymptomatic ICHs. One patient had a new ICH on the initial MR imaging, while the remaining 13 had such on the repeat MR imaging. A univariate analysis revealed that a previous ischemic stroke or transient ischemic attack (TIA) and the CHA₂DS₂-VASc score were positive predictors of new ICHs (odds ratios, 5.502 and 1.435; P = 0.004 and 0.044). The lesion diameter did not significantly differ between the old and new ICHs (median, 6.1 mm vs. 8.0 mm, P = 0.281), while the predominant location differed (lobar areas, 22.6% vs. 53.3%; cerebellum, 22.6% vs. 20.0%; others, 54.8% vs. 26.7%; P = 0.026).

CONCLUSIONS

A few asymptomatic ICHs may occur after AF ablation. Most of the post-ablation new ICHs occurred a few days or later after the procedure. A previous ischemic stroke/TIA and the CHA₂DS₂-VASc score may be risk factors for post-ablation ICHs.

Effect of preventing air intrusion on silent strokes during atrial fibrillation ablation using a mini-basket catheter

BACKGROUND

Air bubble intrusion through transseptal sheaths during left atrial (LA) catheter ablation can cause cerebral embolisms, especially when using complex-shape catheters. This study aimed to compare the incidence of silent cerebral events (SCEs) after atrial fibrillation (AF) catheter ablation using a mini-basket catheter (IntellaMap Orion; Boston Scientific) between the following groups: group SP, strict prevention of LA air intrusion and group CP, conventional air intrusion prevention.

METHODS

We enrolled 123 consecutive AF patients (group SP, n = 61 and group CP, n = 62) who underwent brain magnetic resonance imaging after a local-impedance-guided ablation using one mini-basket catheter and one circular mapping catheter. The preventive strategy in group SP included (a) the insertion of the mini-basket catheter into the transseptal sheaths in a container filled with heparinized saline and (b) no exchange of all catheters over the sheaths.

RESULTS

SCEs were detected in 67 patients (54.5%), and the incidence of SCEs did not significantly differ between groups SP and CP (55.7% vs 53.2%; P = .780). A multivariate analysis demonstrated that an older age, non-paroxysmal AF, and radiofrequency (RF) power output were independent positive predictors of SCEs (odds ratios: 1.079, 5.613, and 1.405; P = .005, <.001, and .012). On the follow-up MR imaging, 83.5% of the SCEs in group SP and 87.7% in group CP disappeared (P = .398).

CONCLUSIONS

Strict prevention of LA air intrusion may have no additional effect for reducing the incidence of SCEs after local impedance-guided AF ablation using a mini-basket catheter. An older age, non-paroxysmal AF, and high-power RF applications may increase the risk of SCEs.

Incidence and characteristics of silent cerebral embolisms after radiofrequency-based atrial fibrillation ablation: A propensity score-matched analysis between different mapping catheters and indices for guiding ablation

INTRODUCTION

The difference in the incidence and characteristics of silent cerebral events (SCEs) after radiofrequency-based atrial fibrillation (AF) ablation between the different mapping catheters and indices used for guiding radiofrequency ablation remains unclear. This study aimed to compare the incidence and characteristics of postablation SCEs between the following two groups: Group C, Ablation Index-guided ablation using two circular mapping catheters with CARTO (Biosense Webster); Group R, local impedance-guided ablation using one mini-basket catheter and one circular mapping with Rhythmia (Boston Scientific).

METHODS AND RESULTS

Of 211 consecutive patients who underwent an AF ablation and brain magnetic resonance (MR) imaging after the ablation, 120 patients (each group, n = 60) were selected by propensity score matching. SCEs were detected in 37 patients (30.8%). Group R had a higher incidence of SCEs (51.7% vs. 10.0%; p < .001) and more SCEs per patient (median, 3 vs. 1, p = .028) than Group C. A multivariate analysis demonstrated that nonparoxysmal AF and being Group R were independent positive predictors of SCEs (odds ratios, 6.930 and 15.464; both p < .001). On the follow-up MR imaging, all SCEs in Group C and 87.9% of the SCEs in Group R disappeared (p = .537).

CONCLUSIONS

Group R had a significantly higher incidence of SCEs than Group C. Most probably the use of a complexly designed basket mapping catheter is the reason for the difference in the incidence of SCEs but further validation is needed. A nonparoxysmal form of AF may also increase the risk of SCEs during these ablation procedures.

Peri-procedural novel oral anticoagulants dosing strategy during atrial fibrillation ablation: A meta-analysis

BACKGROUND

This study aimed at determining whether uninterrupted novel oral anticoagulant (UI-NOAC) would have similar rates of bleeding and thromboembolic events as minimally interrupted NOAC (MI-NOAC) at the time of ablation for atrial fibrillation (AF) as relevant studies are scarce.

METHODS

We searched through the PubMed, EMBASE, and Cochrane Library databases for prospective observational studies (POSs) or randomised controlled trials (RCTs) comparing UI-NOAC versus MI-NOAC from their establishment to January 2020. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to compare the pooled treatment effect.

RESULTS

Nine studies (three POSs and six RCTs) with 2578 patients were included in the final analysis (55% patients received MI-NOAC). No significant difference was found regarding the risk of major bleeding (OR 0.92, 95% CI 0.43-2.00, P = .84, I²   = 0%). Both groups were comparable in all subgroups ([Asians: OR 1.00, 95% CI 0.43-2.36, P = .99, I²   = 0%], [non-Asians: OR 0.64, 95% CI 0.11-3.88, P = .63, I²   = 0%], [RCTs: OR 0.85, 95% CI 0.37-1.97, P = .71, I²   = 0%], and [POSs: OR 0.52, 95% CI 0.19-12.01, P = .69, I²   = 0%]). The risk of minor bleeding (P = .88) or stroke (P = .69) was comparable between the groups. UI-NOAC resulted in a significant reduction in silent stroke (SS) (OR 0.44, 95% CI 0.23-0.83, P = .01, I²   = 72%). No significant difference was found in SS between once-daily and twice-daily NOACs (OR 0.91, 95% CI 0.63-1.33, P = .64, I²   = 0%) in the MI-NOAC group.

CONCLUSIONS

UI-NOAC, as a peri-procedural anticoagulation strategy for catheter ablation in AF, had similar safety compared with MI-NOAC, but was advantageous in terms of SS.

Meta-analysis of the safety and efficacy of using minimally interrupted novel oral anticoagulants in patients undergoing catheter ablation for atrial fibrillation

PURPOSE

The ideal periprocedural anticoagulation strategy for patients being treated with a novel oral anticoagulant (NOAC) during catheter ablation (CA) for atrial fibrillation (AF) is unclear. We evaluated the safety and efficacy of using a minimally interrupted NOAC strategy versus an uninterrupted NOAC or vitamin K antagonist (VKA) strategy during AF ablation.

METHODS

The Cochrane Library, PubMed, and EMBASE databases were searched for randomized controlled or prospective observational studies that compared a minimally interrupted NOAC strategy with an uninterrupted NOAC or VKA strategy from the time of database establishment up to December 2019. The primary endpoints were major bleeding, minor bleeding, and symptomatic thromboembolism. The secondary endpoint was silent cerebral infarction (SCI) as detected by post-ablation brain magnetic resonance imaging (MRI). A measurement of treatment effect for the endpoint was reported as pooled odds ratio (OR) with 95% confidence interval (CI).

RESULTS

A total of 18 studies (6 randomized, 11 observational, and 1 randomized registry) with 6203 patients were included in the final analysis (47% of the patients received minimally interrupted NOAC). There was no significant difference between treatment groups regarding the risk for major bleeding (OR 1.04, 95% CI 0.69-1.57, P = 0.86, I² = 27%). Different stratification methods did not yield significant difference regarding the risk for major bleeding. There was no difference between groups regarding the risk for minor bleeding (P = 1.00) or symptomatic thromboembolism (P = 0.26). Brain MRI results showed that both uninterrupted NOAC (OR 0.44, 95% CI 0.23-0.83, P = 0.01, I² = 72%) and uninterrupted VKA (OR 0.48, 95% CI 0.24-0.97, P = 0.04, I² = 36%) produced a significant reduction in the rate of SCI when compared with minimally interrupted NOAC.

CONCLUSIONS

A periprocedural anticoagulation strategy of minimally interrupted NOAC is not superior to uninterrupted NOAC or VKA when used during AF ablation. There is evidence favoring the use of uninterrupted NOAC or VKA in terms of the risk for SCI.

A randomized comparison of two direct oral anticoagulants for patients undergoing cardiac ablation with a contemporary warfarin control arm

BACKGROUND

The safety and efficacy of periprocedural use of direct oral anticoagulants (DOACs) for atrial fibrillation (AF) remain unclear. We compared the incidence of asymptomatic cerebral micro-thromboembolism and hemopericardium following AF ablation among patients receiving edoxaban, rivaroxaban, and warfarin and between normal- and low-dose use of edoxaban and rivaroxaban.

METHODS

This prospective randomized study included 170 consecutive AF patients. Patients taking DOACs upon admission to our hospital were randomly assigned to an edoxaban group or to a rivaroxaban group. Warfarin was continued in patients receiving warfarin at admission. All patients underwent AF ablation, and cerebral MRI was performed to evaluate asymptomatic cerebral micro-thromboembolism the day after the procedure.

RESULTS

Sixty-one patients were assigned to edoxaban and 63 to rivaroxaban. Warfarin was continued in 46 patients. Although asymptomatic cerebral micro-thromboembolism was detected in 25 patients (16.3%), there were no significant differences among the groups. Hemopericardium occurred in 2 patients (one each in the rivaroxaban and warfarin groups). The incidence of asymptomatic cerebral micro-thromboembolism was higher in the low-dose group (9 patients, 25.7%) than in the normal-dose group (8 patients, 10.0%) for patients prescribed either edoxaban or rivaroxaban (p < 0.05). The proportion of males (88.0%, 69.5%, p < 0.05), history of prior AF ablation (64.0%, 42.2%, p < 0.05), and hypertension (68.0%, 46.1%, p < 0.05) were significantly higher in patients with cerebral thromboembolism.

CONCLUSIONS

The incidence of asymptomatic cerebral micro-thromboembolism and hemopericardium in AF ablation was similar among patients using edoxaban, rivaroxaban, and warfarin. However, low doses of DOACs may increase the risk of asymptomatic stroke.

Blood Coagulation Status during Cryofreezing Ablation and Effects of the Direct Anticoagulants Dabigatran and Edoxaban

Cryoballoon ablation is an established catheter-based approach to treat atrial fibrillation (AF). However, thromboembolic events cannot be avoided during cryoablation. There is little data regarding the blood coagulation status during freezing.The thrombin antithrombin complex (TAT) and prothrombin fragment 1+2 (F 1+2) of patient blood were measured during cryoballoon application when the cryoballoon temperature reached the nadir in 63 AF patients. TAT was also measured from porcine blood during cryoballoon freezing in 5 pigs.The TAT and F 1+2 increased from 6.60 ± 5.65 to 9.16 ± 7.28 ng/mL (P = 0.004) and from 279.6 ± 146.4 to 323.6 ± 169.1 pmol/L (P = 0.003) between the control and during freezing, respectively. The TAT increased from 0.46 to 0.87 ng/mL during freezing compared to that of pre-freezing (P < 0.05), and it returned to 0.39 ng/mL in 30 minutes after an intravenous edoxaban administration (N.S.).Dabigatran failed to exert sufficient anticoagulant effects during cryofreezing. In contrast, intravenous edoxaban seemed to provoke anticoagulation effects under extreme low temperature circumstances.

Higher Incidence of Asymptomatic Cerebral Emboli After Atrial Fibrillation Ablation Found With High-Resolution Diffusion-Weighted Magnetic Resonance Imaging

Background:

Asymptomatic cerebral emboli (ACE) are commonly seen on cerebral magnetic resonance imaging (MRI) after atrial fibrillation ablation, but the incidence in previous studies varies widely. No data exists to compare the effects of different diffusion-weighted imaging (DWI) settings on detecting ablation-related ACE. This self-control study sought to compare the incidence and characteristics of ablation-related ACE between high-resolution DWI and conventional DWI.

Methods:

A total of 55 consecutive patients referred for atrial fibrillation ablation between December 2017 and September 2018 were enrolled. Patients underwent high-resolution DWI 1 day before ablation and repeated high-resolution DWI and conventional DWI within 48 hours post-ablation. The incidence, number, size, and location of ACE were compared between 2 DWI settings in the same patients.

Results:

The high-resolution DWI revealed a higher incidence of acute ACE compared with conventional DWI (67.3% versus 41.8% of patients, P <0.001) and significantly more ACE (106 versus 45 lesions, P =0.001). For ACE seen on both scans, the size measured by high-resolution DWI was larger (5.42 versus 4.21 mm, P <0.001). No patients had any impaired neurocognitive performance during follow-up. Impaired left ventricular ejection fraction ( P =0.012) and low intraoperative activated clotting time ( P =0.009) level were associated with the occurrence of ACE in a multivariate analysis.

Conclusions:

High-resolution DWI revealed a higher incidence and greater details of post-ablation ACE in patients with atrial fibrillation. MRI settings significantly impact the detection of ACE and should be considered when comparing incidence rates of ACE among different studies.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov . Unique identifier: NCT01761188.

Perioperative Safety and Efficacy of Different Anticoagulation Strategies With Direct Oral Anticoagulants in Pulmonary Vein Isolation: A Meta-Analysis

OBJECTIVES

The purpose of this study was to evaluate the safety and efficacy of uninterrupted and interrupted direct oral anticoagulant (DOAC) administration in patients undergoing pulmonary vein isolation (PVI).

BACKGROUND

The optimal periprocedural management of DOACs in patients undergoing PVI is not well defined, and different strategies are used.

METHODS

A systematic search of PubMed/MEDLINE, Ovid/MEDLINE, and EMBASE was performed. Three strategies for periprocedural DOAC administration were considered: uninterrupted, mildly interrupted (<12 h), and interrupted (≥12 h). Primary endpoints were major bleeding (MB) and thromboembolic (TE) complications; pooled weighted mean incidence (WMI) was calculated using a random-effects model. A secondary endpoint was the WMI of overall bleeding (OB).

RESULTS

The analysis included 43 studies for a total of 8,362 patients. DOACs showed similar safety and efficacy in the 3 subgroups. The WMI of MB was 1.02%, 1.49%, and 1.17% for the uninterrupted, mildly interrupted, and interrupted strategy, respectively; the WMI of TE complications was 0.16%, 0.46%, and 0.49% for the uninterrupted, mildly interrupted, and interrupted strategy, respectively, with no heterogeneity. OB appeared to be higher in uninterrupted (6.33%) and mildly interrupted (8.62%) groups compared with the interrupted (3.53%), with substantial heterogeneity among studies. No interaction was found between the incidence of MB and TE complications and different DOACs.

CONCLUSIONS

In patients undergoing PVI, these 3 anticoagulation strategies may have similar safety and efficacy in terms of MB and TE complications. OB appears to be higher in uninterrupted and mildly interrupted strategies compared with the interrupted strategy. No substantial differences were observed among DOACs regarding the incidence of MB and TE complications.

Impact of the type of electroanatomic mapping system on the incidence of cerebral embolism after radiofrequency catheter ablation of left atrial tachycardias

BACKGROUND

Left atrial tachycardias (ATs) often occur after left atrial ablation. The incidence of symptomatic and silent cerebral embolism after radiofrequency catheter ablation of left ATs and the impact of the type of 3-dimensional electroanatomic mapping (3D-EAM) system on the incidence of cerebral embolism remain unclear.

OBJECTIVES

This study aimed to investigate the incidence of cerebral embolism after a 3D-EAM system-guided left AT ablation procedure and compare that between the different 3D-EAM systems.

METHODS

We prospectively enrolled 59 patients who underwent left AT ablation and brain magnetic resonance imaging after the procedure: 30 were guided by the Rhythmia system (Boston Scientific, Marlborough, MA) and 29 by the CARTO system (Biosense Webster, Diamond Bar, CA) (groups R and C, respectively).

RESULTS

One transient ischemic attack occurred in group R, and no symptomatic embolism occurred in group C. Silent cerebral ischemic lesions (SCILs) were observed in 35 patients (59.3%), and group R had a significantly higher incidence of SCILs than did group C (86.2% vs 33.3%; P < .001). In multivariate analysis, group R and left atrial linear ablation were independent positive predictors of SCILs (odds ratio 12.822 and 8.668; P = .001 and P = .005). The incidence of bleeding complications was comparable between groups R and C (0% vs 3.3%; P = .508).

CONCLUSION

Group R exhibited a higher incidence of postablation cerebral embolism than did group C. The use of the high-resolution 3D-EAM system with a mini-basket catheter to guide radiofrequency ablation of left atrial macroreentrant tachycardias may markedly increase the risk of silent cerebral embolism. The present results require further validation in a randomized study.

Asymptomatic Cerebral Infarction During Catheter Ablation for Atrial Fibrillation: Comparing Uninterrupted Rivaroxaban and Warfarin (ASCERTAIN)

OBJECTIVES

This randomized study compared uninterrupted rivaroxaban therapy with warfarin therapy as prophylaxis against catheter ablation (CA)-induced asymptomatic cerebral infarction (ACI) and identified the risk factors of rivaroxaban.

BACKGROUND

The reported incidence of ACI during CA for atrial fibrillation (AF) remains at 10% to 30%, and periprocedural oral anticoagulation could affect this incidence.

METHODS

Patients with nonvalvular AF undergoing radiofrequency CA were randomly assigned to receive either uninterrupted rivaroxaban or warfarin as periprocedural anticoagulation therapy. CA was performed after at least 1 month of adequate anticoagulation. Cerebral magnetic resonance imaging (MRI) was performed within 2 weeks before and 1 day after CA to detect ACI.

RESULTS

A total 132 patients were enrolled; 127 (median: 60.0 years of age; 83.5% males; 64.6% incidence of paroxysmal AF) complied with the study protocol and were analyzed; 64 patients received rivaroxaban, and 63 patients received warfarin. The rates of CA-induced ACI in the rivaroxaban group (15.6% [10 of 64 patients]) were similar to those in the warfarin group (15.9% [10 of 63 patients]; p = 1.000). No thromboembolic events developed; no differences in major or nonmajor bleeding rates were observed between the 2 drug groups (3.1% vs. 1.6%, respectively, or 18.8% vs. 19.0%, respectively). Multiple regression analysis indicated that the presence of deep and subcortical white matter hyperintensity (p = 0.002; odds ratio [OR]: 5.323) and the frequency of cardioversions (p = 0.016; OR: 1.250) were associated with the incidence of ACI.

CONCLUSIONS

No notable differences were found between the incidence of CA-induced ACI in the rivaroxaban group and that in the warfarin group in this randomized study.

Incidence and predictors of silent cerebral thromboembolic lesions after catheter ablation for atrial fibrillation in patients treated with direct oral anticoagulants

There are few reports about the incidence and predictors of silent cerebral thromboembolic lesions (SCLs) after atrial fibrillation (AF) ablation in patients treated with direct oral anticoagulants (DOACs). The purpose of this study is to evaluate the incidence and predictors of SCLs after AF ablation with cerebral magnetic resonance imaging (C-MRI) in patients treated with DOACs. We enrolled 117 consecutive patients who underwent first AF ablation and received DOACs, including apixaban, dabigatran, edoxaban, and rivaroxaban. DOACs were discontinued after administration 24 h before the procedure, and restarted 6 h after the procedure. During the procedure, activated clotting time (ACT) was measured every 15 min, and intravenous heparin infusion was performed to maintain ACT at 300-350 s. All patients underwent C-MRI the day after the procedure. SCLs were detected in 28 patients (24%) after AF ablation. Age, female sex, the presence of persistent AF, left atrial volume, procedure time, radiofrequency energy, electrical cardioversion, and mean ACT showed no correlations with the incidence of SCLs. Multivariate analysis revealed independent predictors of SCLs were CHA₂DS₂VASc scores ≥3, left atrial appendage (LAA) emptying velocity ≤39 cm/s, and minimum ACT ≤260 s. Patients with both CHA₂DS₂VASc scores ≥3 and LAA flow velocity ≤39 cm/s had the highest incidence of SCLs 15 of 26 patients (58%). In patients treated with DOACs, CHA₂DS₂VASc score ≥3, minimum ACT ≤260 s, and LAA emptying velocity ≤39 cm/s were independent risk factors for the SCLs after AF ablation.

Atrial Fibrillation Ablation and Stroke

Catheter ablation has become a widely available and accepted treatment to restore sinus rhythm in atrial fibrillation patients who fail antiarrhythmic drug therapy. Although generally safe, the procedure carries a non-negligible risk of complications, including periprocedural cerebral insults. Uninterrupted anticoagulation, maintenance of an adequate ACT during the procedure, and measures to avoid and detect thrombus build-up on sheaths and atheters during the procedure, appears useful to reduce the risk of embolic events. This is a review of the incidence, mechanisms, impact, and methods to reduce catheter ablation related cerebral insults.

Efficacy and Safety of Novel Oral Anticoagulants for Atrial Fibrillation Ablation: An Updated Meta-Analysis

INTRODUCTION

Novel oral anticoagulants (NOACs) have been approved for prevention of stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). A large number of patients are on NOACs when they present for AF ablation. We intended to evaluate the safety and efficacy of NOACs for AF ablation during the periprocedural period by performing a meta-analysis of trials comparing NOACs with warfarin.

METHODS

Studies comparing NOACs (dabigatran and rivaroxaban) with warfarin as periprocedural anticoagulants for AF ablation were identified using an electronic search. Primary outcomes were: (1) a composite endpoint of stroke, transient ischemic attack (TIA), peripheral arterial embolism, or silent cerebral lesions on magnetic resonance imaging (MRI) and (2) major bleeding complications. A random effects model was used to pool the safety and efficacy data across all included trials.

RESULTS

When compared to warfarin, there was an increased risk of the composite endpoint of stroke, TIA, peripheral arterial embolism, or silent cerebral lesions on MRI with NOACs as periprocedural anticoagulants for AF ablation [odds ratio (OR): 1.69, 95% confidence interval (CI): 1.06-2.68]. Sub-group analysis revealed a higher risk of composite endpoint with dabigatran as a periprocedural anticoagulant for AF ablation (OR: 2.01, 95% CI: 1.19-3.39) whereas the risk was similar with rivaroxaban (OR: 0.90, 95% CI: 0.34-2.41). Sensitivity analysis after excluding silent cerebral lesions on MRI showed there was no increased risk of thromboembolic events with either dabigatran (OR: 1.69, 95% CI: 0.81-3.51) or rivaroxaban (OR: 0.70, 95% CI: 0.12-4.04). Risk of bleeding with NOACs was similar to warfarin (OR: 0.91, 95% CI: 0.62-1.34).

CONCLUSION

NOACs are comparable to warfarin in terms of bleeding complications. However, dabigatran therapy is potentially associated with a higher risk of silent cerebral lesions on MRI. The results of this study should be considered as hypothesis-generating and assessed further in prospective randomized clinical studies.

Are Some Anticoagulants More Equal Than Others? - Evaluating the Role of Novel Oral Anticoagulants in AF Ablation

Left atrial ablation strategies are being increasingly performed as a Class 1 therapeutic indication for drug refractory paroxysmal atrial fibrillation (AF). Traditionally AF ablation has been performed with patients on uninterrupted warfarin therapy, however over the last few years, novel oral anticoagulants (NOACs) have emerged as attractive alternatives to warfarin in order to reduce stroke risk due to AF. NOACs are therefore increasingly being used instead of warfarin in the management of AF. There is also mounting evidence mainly in the form of small randomised studies and meta-analysis that have demonstrated that the use of NOACs for AF ablation is efficacious, safe and convenient. However the peri-procedural dosing protocols used in various studies especially in terms of whether NOAC use is interrupted or uninterrupted during AF ablation, have significant inter-operator and inter-institution variability. Currently there is also a lack of randomised controlled trials to validate the data obtained from meta-analyses. There is also evidence that use of NOACs may increase the requirement of unfractionated heparin during the procedure. This review article shall examine the currently available evidence-base, appraise the gaps in the current evidence and also underscore the need for larger randomised clinical trials in this rapidly developing field.

Network meta-analysis of efficacy and safety of competitive oral anticoagulants in patients undergoing radiofrequency catheter ablation of atrial fibrillation

PURPOSE

The aim of this network meta-analysis was to evaluate the comparative efficacy and safety of dabigatran, rivaroxaban, apixaban, interrupted vitamin K antagonist (I-VKA), and continuous VKA (C-VKA) in patients undergoing radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF).

METHODS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched to identify clinical trials comparing dabigatran, rivaroxaban, or apixaban with I-VKA or C-VKA, or against each other, in AF patients undergoing RFCA. A network meta-analysis was conducted to directly and indirectly compare the efficacy and safety of competitive anticoagulation regimens with a Bayesian random-effects model.

RESULTS

A total of 39 studies enrolling 27,766 patients were included. C-VKA demonstrated significant superiority over I-VKA in reducing thromboembolic events (risk difference [RD] -0.0068, 95 % confidence interval [CI] -0.0106 to -0.0032) and major bleeding complications (RD -0.0044, 95 % CI -0.0098 to -0.0006). Rivaroxaban compared with I-VKA was associated with a lower risk of thromboembolism (RD -0.0073, 95 % CI -0.0134 to -0.0012), being at the best ranking position among all of the compared anticoagulation regimens in terms of both the efficacy and safety. None of the remaining comparisons reached statistically significant difference in the rate of thromboembolism or major bleeding.

CONCLUSIONS

The present study suggests that C-VKA is superior to I-VKA for AF patients undergoing RFCA. Rivaroxaban is the highest probability to be the optimal alternative to C-VKA among the three non-VKA oral anticoagulants in AF ablation.

Meta-Analysis of Efficacy and Safety of New Oral Anticoagulants Compared With Uninterrupted Vitamin K Antagonists in Patients Undergoing Catheter Ablation for Atrial Fibrillation

Anticoagulation in catheter ablation (CA) of atrial fibrillation (AF) is of paramount importance for prevention of thromboembolic events, and recent studies favor uninterrupted vitamin K antagonists (VKAs). We aimed to compare the efficacy and safety of new oral anticoagulants (NOACs) to uninterrupted VKAs for anticoagulation in CA by performing a meta-analysis. PubMed, EMBASE, the Cochrane Library, and Clinicaltrials.gov databases were searched for studies comparing NOACs with uninterrupted VKAs in patients who underwent CA for AF from January 1, 2000, to August 31, 2015. Odds ratio (OR) and Peto's OR (POR) were used to report for event rates >1% and <1%, respectively. A total of 11,686 patients with AF who underwent CA in 25 studies were included in this analysis. There was no significant difference between NOACs and uninterrupted VKAs in occurrence of stroke or transient ischemic attacks (POR 1.35, 95% CI 0.62 to 2.94) and major bleeding (POR 0.87, 95% CI 0.58 to 1.31), which were consistent in subgroup analysis of interrupted and uninterrupted NOACs. A lower risk of minor bleeding was observed with NOACs (OR 0.80, 95% CI 0.65 to 1.00), and no major differences were observed for the risk of thromboembolic events, cardiac tamponade or pericardial effusion requiring drainage, and groin hematoma. NOACs, whether interrupted preprocedure or not, were associated with equal rates of stroke or TIA and major bleeding complications and less risk of minor bleeding compared with uninterrupted VKAs in CA for AF.

A Patient With Asymptomatic Cerebral Lesions During AF Ablation: How Much Should We Worry?

Silent brain lesions due to thrombogenicity of the procedure represent recognized side effects of atrial fibrillation (AF) catheter ablation. Embolic risk is higher if anticoagulation is inadequate and recent studies suggest that uninterrupted anticoagulation, ACT levels above 300 seconds and administration of a pre-transeptal bolus of heparin might significantly reduce the incidence of silent cerebral ischemia (SCI) to 2%. Asymptomatic new lesions during AF ablation should suggest worse neuropsychological outcome as a result of the association between silent cerebral infarcts and increased long-term risk of dementia in non-ablated AF patients. However, the available data are discordant. To date, no study has definitely linked post-operative asymptomatic cerebral events to a decline in neuropsychological performance. Larger volumes of cerebral lesions have been associated with cognitive decline but are uncommon findings acutely in post-ablation AF patients. Of note, the majority of acute lesions have a small or medium size and often regress at a medium-term follow-up. Successful AF ablation has the potential to reduce the risk of larger SCI that may be considered as part of the natural course of AF. Although the long-term implications of SCI remain unclear, it is conceivable that strategies to reduce the risk of SCI may be beneficial.

Bleeding risks with novel oral anticoagulants during catheter ablation of atrial fibrillation: a systematic review and network meta-analysis

BACKGROUND

Comprehensive comparisons of safety (measured by bleeding risk) between multiple novel oral anticoagulants (NOACs and warfarin) in the peri-procedural period of catheter ablation (CA) for atrial fibrillation (AF) are rare.

METHODS AND RESULTS

MEDLINE, EMBASE, and COCHRANE LIBRARY were searched up to February 2015 by two reviewers independently. Predefined inclusion criteria identified 24 studies which were included in the analysis. Data were extracted by two researchers, and a network meta-analysis was conducted in R with R2WinBugS package, within Bayesian framework. Pooled odds ratios (OR) and 95% confidence intervals (CI) were summarized to evaluate the bleeding risks of three novel anticoagulants (dabigatran, rivaroxaban, apixaban) in AF patients undergoing catheter ablation (CA). With respect to total bleeding risk, no significant difference was observed between dabigatran, rivaroxaban, apixaban, and vitamin K antagonists (VKAs) by mixed-treatment comparison. The similar results were seen in the direct comparison. While dabigatran was associated with a lower rate of minor bleeding in comparison to VKAs (OR = 0.67 with 95%CI 0.49-0.93).

CONCLUSIONS

Risks of bleeding with dabigatran, rivaroxaban, apixaban, and VKAs were similar in peri-procedural period of CA for AF.

A review of the safety aspects of radio frequency ablation

In light of recent reports showing high incidence of silent cerebral infarcts and organized atrial arrhythmias following radiofrequency (RF) atrial fibrillation (AF) ablation, a review of its safety aspects is timely. Serious complications do occur during supraventricular tachycardia (SVT) ablations and knowledge of their incidence is important when deciding whether to proceed with ablation. Evidence is emerging for the probable role of prophylactic ischemic scar ablation to prevent VT. This might increase the number of procedures performed. Here we look at the various complications of RF ablation and also the methods to minimize them. Electronic database was searched for relevant articles from 1990 to 2015. With better awareness and technological advancements in RF ablation the incidence of complications has improved considerably. In AF ablation it has decreased from 6% to less than 4% comprising of vascular complications, cardiac tamponade, stroke, phrenic nerve injury, pulmonary vein stenosis, atrio-esophageal fistula (AEF) and death. Safety of SVT ablation has also improved with less than 1% incidence of AV node injury in AVNRT ablation. In VT ablation the incidence of major complications was 5-11%, up to 3.4%, up to 1.8% and 4.1-8.8% in patients with structural heart disease, without structural heart disease, prophylactic ablations and epicardial ablations respectively. Vascular and pericardial complications dominated endocardial and epicardial VT ablations respectively. Up to 3% mortality and similar rates of tamponade were reported in endocardial VT ablation. Recent reports about the high incidence of asymptomatic cerebral embolism during AF ablation are concerning, warranting more research into its etiology and prevention.

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants versus Vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Radiofrequency Catheter Ablation of Atrial Fibrillation: A Meta-Analysis

BACKGROUND

Use of the non-vitamin K antagonist oral anticoagulants (NOACs) is endorsed by current guidelines for stroke prevention in patients with atrial fibrillation (AF). However efficacy and safety of NOACs in patients undergoing catheter ablation (RFCA) of AF has not been well established yet.

OBJECTIVES

To perform a meta-analysis of all studies comparing NOACs and vitamin K antagonist oral anticoagulants (VKAs) in patients undergoing RFCA.

DATA SOURCES

Studies were searched for in PubMed and Google Scholar databases.

STUDY ELIGIBILITY CRITERIA

Studies were considered eligible if: they evaluated the clinical impact of NOACs versus VKAs; they specifically analyzed the use of anticoagulants during periprocedural phase of RFCA; they reported clinical outcome data.

STUDY APPRAISAL AND SYNTHESIS METHODS

25 studies were selected, including 9881 cases. The summary measure used was the risk ratio (RR) with 95% confidence interval (CI). The random-effects or the fixed effect model were used to synthesize results from the selected studies.

RESULTS

There was no significant difference in thromboembolic complications (RR 1.39; p=0.13). Bleeding complications were significantly lower in the NOACs-treated arm as compared to VKAs (RR=0.67, p<0.001). Interestingly, a larger number of thromboembolic events was found in the VKAs-treated arm in those studies where VKAs had been interrupted during the periprocedural phase (RR=0.68; p=ns). In this same subgroup a significantly higher incidence of both minor (RR=0.54; p=0.002) and major bleeding (RR=0.41; p=0.01) events was recorded. Conversely, the incidence of thromboembolic events in the VKAs-treated arm was significantly lower in those studies with uninterrupted periprocedural anticoagulation treatment (RR=1.89; p=0.02).

LIMITATIONS

As with every meta-analysis, no patients-level data were available.

CONCLUSIONS AND IMPLICATIONS

The use of NOACs in patients undergoing RFCA is safe, given the lower incidence of bleedings observed with NOACs. On the other side, periprocedural interruption of VKAs and bridging with heparin is associated with a higher bleeding rate with no significant benefit on onset of thromboembolic events.

Influence of cardioversion on asymptomatic cerebral lesions following atrial fibrillation ablation

PURPOSE

Asymptomatic cerebral lesions detected by diffusion-weighted magnetic resonance imaging (MRI) following atrial fibrillation (AF) ablation were reported in recent years. It was reported that cardioversion during the procedure of AF ablation was one independent risk factor of asymptomatic cerebral lesions. However, in some studies, the similar association between asymptomatic cerebral lesions and intraprocedural cardioversion was not observed. Given the inconsistent results, we did a meta-analysis to explore the influence of intraprocedural cardioversion on the asymptomatic cerebral lesions detected by MRI following AF ablation.

METHODS

Studies exploring the association between cardioversion during AF ablation and asymptomatic cerebral lesions following AF ablation were systematically searched in PubMed, Web of Science and the Cochrane Library Databases. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled. Subgroup and sensitivity analyses were performed to explore the source of heterogeneity.

RESULTS

Nine studies involving 813 participants were included in the present meta-analysis. When we pooled data from nine studies using fixed-effects model, we found cardioversion during the procedure significantly increased the risk of asymptomatic cerebral lesions detected by MRI following AF ablation (pooled OR = 1.793, 95% CI 1.201-2.678, I (2) = 38.8%, P heterogeneity = 0.109).

CONCLUSIONS

Cardioversion during AF ablation significantly increased the risk of asymptomatic cerebral lesions on MRI following the procedure. Additional studies are required to further verify the association.

The optimal setting of complex fractionated atrial electrogram software in substrate ablation for atrial fibrillation

BACKGROUND

Complex fractionated atrial electrogram (CFAE)-targeted catheter ablation (CFAE ablation) requires a high rate of atrial fibrillation (AF) termination to provide good outcomes. We determined the optimal settings of CFAE software.

METHODS

In our 430 consecutive patients, AF was terminated in 97 (234/242) and 79% (149/188) of patients with paroxysmal and persistent AF, respectively, by CFAE ablation combined with (31%) or without (69%) pulmonary vein isolation, occasionally with nifekalant infusion. We analyzed 109 consecutive patients who underwent CFAE ablation to determine the optimal settings for comparing subjective versus objective decisions by the CFAE software on CARTO3. We compared three settings: the default setting (0.05-0.15 mV, 50-120 ms) and two modified settings (#1: 0.05-0.30 mV, 40-70 ms, #2: 0.05-0.13 mV, 10-20 ms). We retrospectively analyzed 11,425 points during left atrial mapping before ablation and 10,306 points that were subjectively detected and ablated as CFAE points. An interval confidence level ≥6 denoted a site with CFAE.

RESULTS

With the default setting, the accuracy, sensitivity, specificity, positive productive value, and negative productive values were 67, 42, 77, 48, and 73%, respectively. With modified setting #1, the values were 78, 55, 87, 74, and 77%, respectively, versus 64, 82, 60, 53, and 91%, respectively, for modified setting #2.

CONCLUSION

These data suggest that setting #1 was generally superior to the default setting, whereas setting #2 was optimal for excluding areas not requiring ablation. The optimal CFAE software setting was a voltage of 0.05-0.30 mV and an interval parameter of 40-70 ms.

Association between ablation technology and asymptomatic cerebral injury following atrial fibrillation ablation

BACKGROUND

Asymptomatic cerebral injury (ACI) detected by diffusion-weighted magnetic resonance imaging (MRI) following atrial fibrillation (AF) ablation has been reported recently. The purpose of this study was to provide an overview of the incidence of ACI detected by MRI following AF ablation and to explore the association between ablation technology and ACI by systematically reviewing published trials.

METHODS AND RESULTS

PubMed, Web of Science, and the Cochrane Library Databases were systematically searched for studies exploring ACI detected by MRI following AF ablation. Incidence of ACI, odds ratios, and 95% confidence intervals (CIs) were pooled. We identified 21 eligible studies. The combined ACI incidence across all studies was 15.9% (95% CI: 0.124-0.202). We also did a subgroup analysis stratified by different technologies. The incidence of ACI stratified by ablation technology was 13.0%, 27.6%, 12.5%, 17.3%, and 32.6% of the irrigated radiofrequency (RF), multielectrode-phased RF pulmonary vein ablation catheter (PVAC), cryoballoon, laser balloon, and nMARQTM groups, respectively.

CONCLUSIONS

The incidence of ACI following AF ablation with PVAC was higher than with other technologies. Uninterrupted oral anticoagulant (OAC) during the procedure could lower the incidence of ACI. It seems prudent not to interrupt OACs during the procedure. In addition, intraprocedural activated clotting time was associated with ACI. Different MRI diagnostic criteria for ACI also influenced the results. To facilitate the future research, a generally accepted definition for silent cerebrovascular ischemia suitable to different kinds of MRI is needed.

Meta-analysis of risk of stroke or transient ischemic attack with dabigatran for atrial fibrillation ablation

Dabigatran is a novel oral anticoagulant and may be useful during atrial fibrillation (AF) ablation for prevention of thromboembolic events. However, the benefits and adverse effects of periprocedural dabigatran therapy have not been thoroughly evaluated. A meta-analysis was performed to evaluate the efficacy and safety of dabigatran for anticoagulation in AF ablation. PubMed, The Cochrane Library, EMBASE, Web of Science, and CINAHL databases were searched from January 01, 2001 through July 30, 2013. Two reviewers reviewed the studies for inclusion and extracted data from studies comparing dabigatran with warfarin for AF ablation. A total of 5,513 patients undergoing catheter ablation were included in 17 observational studies and 1 randomized trial. Fourteen events of stroke or transient ischemic attacks were reported in the dabigatran group and 4 in the warfarin group (Peto's odds ratio 3.94, 95% confidence interval [CI] 1.54 to 10.08, number needed to harm=284 patients). The risk of all thromboembolic complications was also higher in the dabigatran group compared with the warfarin group (Peto's odds ratio 2.81, 95% CI 1.23 to 6.45). No major differences were observed for the risk of major bleeding (odds ratio 0.99, 95% CI 0.55 to 1.78), pericardial tamponade, and groin hematoma. A lower risk of minor bleeding was observed with dabigatran (odds ratio 0.60, 95% CI 0.41 to 0.87). In conclusion, periprocedural use of dabigatran for AF ablation was related to a higher risk of thromboembolic complications including stroke and transient ischemic attack.

The Safetyof Dabigatran Versus Warfarin in Patients Undergoing Atrial Fibrillation Ablation

The safety and optimal strategy of the use of dabigatran versus uninterrupted warfarin in atrial fibrillation ablation is currently unclear. We performed a retrospective analysis between July 2011-October 2012 of all patients undergoing an AF ablation who received uninterrupted warfarin therapy (199) and the routine cessation of Dabigatran therapy (126) 4 days pre-ablation. Major safety endpoints included: pericardial effusion (requiring pericardiocentesis), peripheral thromboembolism, CVA, and groin hematoma requiring blood transfusion. Minor endpoints included pericardial effusion and groin hematoma. Dabigatran was restarted the following day after ablation. The warfarin group was older, had a higher CHADS₂, CHA₂DS₂VASc and HASBLED scores and greater prevalence of aortic plaque. The major complication rate was 2.0% in the warfarin group and 2.4% in the dabigatran group (P= 0.83). The minor complication rate was 2.5% in the warfarin group and <1% in the dabigatran group (P= 0.27). In the dabigatran group, there was one renal thromboembolic event 4 days post-ablation. All patients in the warfarin group who suffered a major complication required a blood transfusion. Cessation of dabigatran therapy 4 days pre AF ablation has a comparable safety profile to uninterrupted warfarin therapy.