Novel stroke prevention strategies following catheter ablation for atrial fibrillation

Stroke prevention following successful catheter ablation of atrial fibrillation remains a controversial topic. Oral anticoagulation is associated with a significant reduction in stroke risk in the general atrial fibrillation population but may be associated with an increased risk of major bleeding, and the benefit: risk ratio must be considered. Improvement in successful catheter ablation and widespread use of cardiac monitoring devices may allow for novel anticoagulation strategies in a subset of patients with atrial fibrillation, which may optimize stroke prevention while minimizing bleeding risk. In this review, we discuss stroke risk in atrial fibrillation and the effects of successful catheter ablation on thromboembolic risk. We also explore novel strategies for stroke prevention following successful catheter ablation.

Oral anticoagulation after atrial fibrillation catheter ablation: benefits and risks

BACKGROUND AND AIMS

Few recent large-scale studies have evaluated the risks and benefits of continuing oral anticoagulant (OAC) therapy after catheter ablation (CA) for atrial fibrillation (AF). This study evaluated the status of continuation of OAC therapy and the association between continuation of OAC therapy and thromboembolic and bleeding events according to the CHADS2 score.

METHODS

This retrospective study included data from the Japanese nationwide administrative claims database of patients who underwent CA for AF between April 2014 and March 2021. Patients without AF recurrence assessed by administrative data of the treatment modalities were divided into two groups according to continuation of OAC therapy 6 months after the index CA. The primary outcomes were thromboembolism and major bleeding after a landmark period of 6 months. After inverse probability of treatment weighting analysis, the association between OAC continuation and outcomes was determined according to the CHADS2 score.

RESULTS

Among 231 374 patients included, 69.7%, 21.6%, and 8.7% had CHADS2 scores of ≤1, 2, and ≥3, respectively. Of these, 71% continued OAC therapy at 6 months. The OAC continuation rate was higher in the high CHADS2 score group than that in the low CHADS2 score group. Among all patients, 2451 patients (0.55 per 100 person-years) had thromboembolism and 2367 (0.53 per 100 person-years) had major bleeding. In the CHADS2 score ≤1 group, the hazard ratio of the continued OAC group was 0.86 [95% confidence interval (CI): 0.74-1.01, P = .06] for thromboembolism and was 1.51 (95% CI: 1.27-1.80, P < .001) for major bleeding. In the CHADS2 score ≥3 group, the hazard ratio of the continued OAC group was 0.61 (95% CI: 0.46-0.82, P = .001) for thromboembolism and was 1.05 (95% CI: 0.71-1.56, P = 0.81) for major bleeding.

CONCLUSIONS

This observational study suggests that the benefits and risks of continuing OAC therapy after CA for AF differ based on the patient's CHADS2 score. The risk of major bleeding due to OAC continuation seems to outweigh the risk reduction of thromboembolism in patients with lower thromboembolic risk.

It can be safe to discontinue oral anticoagulants after successful atrial fibrillation ablation: A systematic review and meta-analysis of cohort studies

BACKGROUND

Current guidelines recommended that oral anticoagulants (OACs) should last for a minimum first 2 months after atrial fibrillation (AF) ablation and the long-term decision of anticoagulation after AF ablation should be based on the individual patient's risk of stroke rather than the rhythm status. There is controversy about the safety of discontinuing OACs in patients with atrial fibrillation after the blanking period due to the divergences between consensus recommendations and clinical practice.

METHODS

Electronic bibliographic sources (PubMed, Embase, and Web of Science) were searched until August 2023 to identify cohort studies about the safety of discontinuing OACs in patients with AF after the blanking period. The primary outcome was thromboembolism (TE). The secondary outcome was major bleeding events (MBEs). Two authors extracted articles independently using predefined data fields. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated based on a random-effects model.

RESULTS

A total of 16 studies (11 prospective cohorts and 5 retrospective cohorts) enrolling 23,942 patients (14,382 OFF-OAC and 9560 ON-OAC) were included in our analysis. No significant difference emerged in the risk of TE between OFF-OAC and ON-OAC patients following AF ablation after the banking period (OR = 0.66; 95%CI, 0.43-1.01). Similar results emerged in the patients with a high risk of TE after stratification by the risk level of TE (OR = 0.72; 95%CI, 0.25-2.08). A significant reduction in incidences of major bleeding was found in the OFF-OAC patients compared with the ON-OAC patients (OR = 0.23; 95%CI, 0.12-0.42). Subgroup analyses for TE found a reduction of incidences in the subgroups who switched to antiplatelet drugs and with a follow-up duration <3 years. Subgroup analyses for MBEs found a significant reduction of incidences in all subgroups.

CONCLUSIONS

Our study suggests it can be safe to discontinue OACs after successful AF ablation. Discontinuation of OACs may reduce the risk of MBEs while not increasing the risk of TE.

Effect of Catheter Ablation for Atrial Fibrillation in Heart Failure With Mid-Range or Preserved Ejection Fraction - Pooled Analysis of the AF Frontier Ablation Registry and Hokuriku-Plus AF Registry

BACKGROUND

A recent randomized trial demonstrated that catheter ablation for atrial fibrillation (AF) in patients with heart failure with reduced ejection fraction (EF) is associated with a reduction in death or heart failure. However, the effect of catheter ablation for AF in patients with heart failure with mid-range or preserved EF is unclear.

METHODS AND RESULTS

We screened 899 AF patients (72.4% male, mean age 68.4 years) with heart failure and left ventricular EF ≥40% from 2 Japanese multicenter AF registries: the Atrial Fibrillation registry to Follow the long-teRm Outcomes and use of aNTIcoagulants aftER Ablation (AF Frontier Ablation Registry) as the ablation group (525 patients who underwent ablation) and the Hokuriku-Plus AF Registry as the medical therapy group (374 patients who did not undergo ablation). Propensity score matching was performed in these 2 registries to yield 106 matched patient pairs. The primary endpoint was a composite of cardiovascular death and hospitalization for heart failure. At 24.6 months, the ablation group had a significantly lower incidence of the primary endpoint (hazard ratio 0.32; 95% confidence interval 0.13-0.70; P=0.004) than the medical therapy group.

CONCLUSIONS

Compared with medical therapy, catheter ablation for AF in patients with heart failure and mid-range or preserved EF was associated with a significantly lower incidence of cardiovascular death or hospitalization for heart failure.

Trends over the recent 6 years in ablation modalities and strategies, post-ablation medication, and clinical outcomes of atrial fibrillation ablation

Background

Ablation strategies and modalities for atrial fibrillation (AF) have transitioned over the past decade, but their impact on post-ablation medication and clinical outcomes remains to be fully investigated.

Methods

We divided 682 patients who had undergone AF ablation in 2014-2019 (420 paroxysmal AFs [PAF], 262 persistent AFs [PerAF]) into three groups according to the period, that is, the 2014-2015 (n = 139), 2016-2017 (n = 244), and 2018-2019 groups (n = 299), respectively.

Results

Persistent AF became more prevalent and the left atrial (LA) diameter larger over the 6 years. Extra-pulmonary vein (PV)-LA ablation was more frequently performed in the 2014-2015 group than in the 2016-2017 and 2018-2019 groups (41.1% vs. 9.1% and 8.1%; p < .001). The 2-year freedom rate from AF/atrial tachycardias for PAF was similar among the three groups (84.0% vs. 83.1% vs. 86.7%; p = .98) but lowest in the 2014-2015 group for PerAF (63.9% vs. 82.7% and 86.3%; p = .025) despite the highest post-ablation antiarrhythmic drug use. Cardiac tamponade was significantly decreased in the 2018-2019 group (3.6% vs. 2.0% vs. 0.33%; p = 0.021). There was no difference in the 2-year clinically relevant events among the three groups.

Conclusion

Although ablation was performed in a more diseased LA and extra-PV-LA ablation was less frequent in recent years, the complication rate decreased, and AF recurrences for PAF remained unchanged, but that for PerAF decreased. Clinically relevant events remained unchanged over the recent 6 years, suggesting that the impact of the recent ablation modalities and strategies on remote clinically relevant events may be small during this study period.

Real-World Investigation on Anticoagulation Management Before and After Catheter Ablation for Atrial Fibrillation in Japan - Periprocedural and Long-Term Outcomes

BACKGROUND

Optimal periprocedural oral anticoagulant (OAC) therapy before catheter ablation (CA) for atrial fibrillation (AF) and the safety profile of OAC discontinuation during the remote period (from 31 days and up to 1 year after CA) have not been well defined.

METHODS AND RESULTS

The RYOUMA registry is a prospective multicenter observational study of Japanese patients who underwent CA for AF in 2017-2018. Of the 3,072 patients, 82.3% received minimally interrupted direct-acting OACs (DOACs) and 10.2% received uninterrupted DOACs. Both uninterrupted and minimally interrupted DOACs were associated with an extremely low thromboembolic event rate. Female, long-standing persistent AF, low creatinine clearance, hepatic disorder, and high intraprocedural heparin dose were independent factors associated with periprocedural major bleeding. At 1 year after CA, DOAC was continued in 55.9% of patients and warfarin in 56.4%. The incidence of thromboembolic and major bleeding events for 1 year was 0.3% and 1.2%, respectively. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding events. Univariate analyses revealed that warfarin continuation and off-label overdose of DOACs were risk factors for major bleeding after CA.

CONCLUSIONS

High intraprocedural dose of heparin was associated with periprocedural major bleeding events. At 1 year after CA, over half of the patients had continued OAC therapy. Thromboembolic events were extremely low; however, major bleeding occurred in 1.2%. Age ≥73 years, dementia, and AF recurrence were independently associated with major bleeding after CA.

Different Determinants of the Recurrence of Atrial Fibrillation and Adverse Clinical Events in the Mid-Term Period After Atrial Fibrillation Ablation

BACKGROUND

It is unclear whether there are differences in the clinical factors between atrial fibrillation (AF) recurrence and adverse clinical events (AEs), including stroke/transient ischemic attack (TIA), major bleeding, and death, after AF ablation.

METHODS AND RESULTS

We examined the data from a retrospective multicenter Japanese registry conducted at 24 cardiovascular centers between 2011 and 2017. Of the 3,451 patients (74.1% men; 63.3±10.3 years) who underwent AF ablation, 1,046 (30.3%) had AF recurrence and 224 (6.5%) suffered AEs (51 strokes/TIAs, 71 major bleeding events, and 36 deaths) over a median follow-up of 20.7 months. After multivariate adjustment, female sex, persistent and long-lasting persistent AF (vs. paroxysmal AF), and stepwise increased left atrial diameter (LAd) quartiles were significantly associated with post-ablation recurrences. A multivariate analysis revealed that an age ≥75 years (vs. <65 years), body weight <50 kg, diabetes, vascular disease, left ventricular (LV) ejection fraction <40% (vs. ≥50%), Lad ≥44 mm (vs. <36 mm), and creatinine clearance <50 mL/min were independently associated with AE incidences, but not with recurrences.

CONCLUSIONS

This study disclosed different determinants of post-ablation recurrence and AEs. Female sex, persistent AF, and enlarged LAd were determinants of post-ablation recurrence, whereas an old age, comorbidities, and LV and renal dysfunction rather than post-ablation recurrence were AEs determinants. These findings will help determine ablation indications and post-ablation management.

Associations of anemia with death and major bleeding in patients with atrial fibrillation: A report from the Chinese Atrial Fibrillation Registry Study

Background

Anemia is a common comorbidity in patients with atrial fibrillation (AF). Reports on the association of anemia and adverse events in patients with AF, especially from Asia, are limited.

Methods and Results

Based on data from the Chinese Atrial Fibrillation Registry Study (CAFR), a total of 18,106 AF patients enrolled between August 2011 and December 2018 had hemoglobin (Hb) values recorded at baseline. Patients were classified into three groups according to Hb levels: 15,606 patients (86.2%) into the no anemia group (male Hb≥130 g/L; female Hb≥120 g/L), 1800 (9.9%) with mild anemia (male 110≤Hb<129 g/L; female 110≤Hb<119 g/L), and 700 (3.9%) with moderate to severe anemia (Hb≤109 g/L). Multivariable Cox regression models were used to determine if anemia was independently associated with all‐cause death, cardiovascular death, or major bleeding, after adjusting for confounders.

Anemia was present in 13.8% of the population at baseline. During a median follow‐up of 4.01 years, the incidences of all‐cause death (1.8, 4.9, and 8.9 per 100 person‐years), cardiovascular death (1.0, 2.9, and 4.5 per 100 person‐years), and major bleeding (0.5, 0.6, and 0.7 per 100 person‐years) were gradually accentuated in patients with no anemia, mild anemia, and moderate to severe anemia, respectively. Compared with patients with no anemia, those with anemia had higher risks for all‐cause death (mild anemia; adjusted hazard ratio [HR]: 1.22, 95% confidence interval [CI]: 1.08–1.38; moderate to severe anemia; adjusted HR: 1.53, 95% CI: 1.31–1.77); and cardiovascular death (mild anemia; adjusted HR: 1.29, 95% CI: 1.10–1.52; moderate to severe anemia; adjusted HR: 1.27, 95% CI: 1.03–1.57), but not for major bleeding. The association between anemia and all‐cause death was similar among subgroups stratified by sex, kidney function, anticoagulant, or ablation therapy.

Conclusions

Anemia was associated with increased risks of all‐cause death, cardiovascular death, but no major bleeding in AF patients. The effect of anemia correction on the prognosis of patients with AF requires further study.

Current Status of Catheter Ablation for Atrial Fibrillation in Japan

Catheter ablation for atrial fibrillation (AF) has been an established and frequently utilized approach in a variety of clinical settings. Nevertheless, real-world data about the clinical course of AF patients after initial catheter ablation remain limited, and these are mainly derived from particular registries or selected high-volume centers.In this study, we used health check-ups and insurance claims database from a Japanese insurance organization. The study population was comprised of 1777 patients who underwent catheter ablation for AF before June 2016. During the 3-year follow-up period, 396 (22.3%) patients underwent at least one repeated AF ablation, while 74 (4.2%) underwent two or more repeated ablations. In multivariate Cox regression analysis, longer time after AF diagnosis (7-11 months and ≥12 months versus 1-6 months) (HR, 1.05; 95% CI, 1.01-1.08 and HR, 1.04; 95% CI 1.02-1.07) was independently associated with repeated ablation. The discontinuation rates of OACs and AADs after the first ablation were 26.7% and 63.0% at 3 months and 75.2% and 89.1% at 1 year after the initial ablation, respectively. The former was independently associated with shorter time after AF diagnosis and lower diastolic blood pressure, whereas the latter was independently associated with older age, smaller CHADS₂ score, and shorter time after AF diagnosis.We presented real-world data regarding the clinical course of young Japanese AF patients after initial catheter ablation based on a claims database in Japan.

Impact of sinus rhythm maintenance on major adverse cardiac and cerebrovascular events after catheter ablation of atrial fibrillation: insights from AF frontier ablation registry

The impact of catheter ablation for atrial fibrillation (AF) on cardiovascular events and mortality is controversial. We investigated the impact of sinus rhythm maintenance on major adverse cardiac and cerebrovascular events after AF ablation from a Japanese multicenter cohort of AF ablation. We investigated 3326 consecutive patients (25.8% female, mean age 63.3 ± 10.3 years) who underwent catheter ablation for AF from the atrial fibrillation registry to follow the long-term outcomes and use of anti coagulants after ablation (AF frontier ablation registry). The primary endpoint was a composite of stroke, transient ischemic attack, cardiovascular events, and all-cause death. During a mean follow-up of 24.0 months, 2339 (70.3%) patients were free from AF after catheter ablation, and the primary composite endpoint occurred in 144 (4.3%) patients. The AF nonrecurrence group had a significantly lower incidence of the primary endpoint (1.8 per 100 person-years) compared with the AF recurrence group (3.0 per 100 person-years, p = 0.003). The multivariate analysis revealed that freedom from AF (hazard ratio 0.61, 95% confidence interval 0.44-0.86, p = 0.005) was independently associated with the incidence of the composite event. In the multicenter cohort of AF ablation, sinus rhythm maintenance after catheter ablation was independently associated with lower rates of major adverse cardiac and cerebrovascular events.

Surveys and Registries on Catheter Ablation of Atrial Fibrillation: Fifteen Years of History

Surveys and registries are widely used in medicine as valuable tools to integrate the information from randomized and observational studies. Early after its introduction in daily practice and parallel to its escalating popularity, catheter ablation of atrial fibrillation has been the subject of several surveys and registries. Over the years, relevant aspects associated with atrial fibrillation ablation have been investigated using these tools, including procedural safety and efficacy, discontinuation of anticoagulation therapy and risk of stroke postablation, and outcomes in special populations. The aim of this article is to provide a comprehensive review of the contributions offered by surveys and registries in catheter ablation of atrial fibrillation over the past 15 years.

Long-term oral anticoagulant after catheter ablation for atrial fibrillation

Catheter ablation is superior to antiarrhythmic therapy for the reduction of symptomatic atrial fibrillation (AF), recurrence, and burden. The possibility of a true 'rhythm' control strategy with catheter ablation has re-opened the debate on rate vs. rhythm control and the subsequent impact on stroke risk. Some observation studies suggest that successful AF catheter ablation and maintenance of sinus rhythm are associated with a decrease in stroke risk, while the CABANA trial had demonstrated no apparent reduction. Other observational studies have demonstrated increased stroke risk when oral anticoagulation (OAC) is discontinued after catheter ablation. When and in whom OAC can be discontinued after ablation will need to be determined in properly conducted randomized control trials. In this review article, we discuss our current understanding of the interactions between AF, stroke, and anticoagulation following catheter ablation. Specifically, we discuss the evidence for the long-term anticoagulation following successful catheter ablation, the potential for OAC discontinuation with restoration of sinus rhythm, and novel approaches to anticoagulation management post-ablation.

Clinical outcomes of ablation versus non-ablation therapy for atrial fibrillation in Japan: analysis of pooled data from the AF Frontier Ablation Registry and SAKURA AF Registry

Whether ablation for atrial fibrillation (AF) is, in terms of clinical outcomes, beneficial for Japanese patients has not been clarified. Drawing data from 2 Japanese AF registries (AF Frontier Ablation Registry and SAKURA AF Registry), we compared the incidence of clinically relevant events (CREs), including stroke/transient ischemic attack (TIA), major bleeding, cardiovascular events, and death, between patients who underwent ablation (n = 3451) and those who did not (n = 2930). We also compared propensity-score matched patients (n = 1414 in each group). In propensity-scored patients who underwent ablation and those who did not, mean follow-up times were 27.2 and 35.8 months, respectively. Annualized rates for stroke/TIA (1.04 vs. 1.06%), major bleeding (1.44 vs. 1.20%), cardiovascular events (2.15 vs. 2.49%) were similar (P = 0.96, 0.39, and 0.35, respectively), but annualized death rates were lower in the ablation group than in the non-ablation group (0.75 vs.1.28%, P = 0.028). After multivariate adjustment, the risk of CREs was statistically equivalent between the ablation and non-ablation groups (hazard ratio [HR] 0.89, 95% confidence interval [CI] 0.71-1.11), but it was significantly low among patients who underwent ablation for paroxysmal AF (HR 0.68 [vs. persistent AF], 95% CI 0.49-0.94) and had a CHA₂DS₂-VASc score  < 3 (HR 0.66 [vs. CHA₂DS₂-VASc score ≥ 3], 95% CI 0.43-0.98]). The 2-year risk reduction achieved by ablation may be small among Japanese patients, but AF ablation may benefit those with paroxysmal AF and a CHA₂DS₂-VASc score < 3.

Long-term efficacy and safety of anticoagulation after atrial fibrillation ablation: data from the JACRE registry

BACKGROUND

Catheter ablation (CA) is an important strategy for managing atrial fibrillation (AF). However, long-term anticoagulation strategies and clinical outcomes following CA, including thromboembolism and bleeding, have not yet been elucidated.

METHODS

We established a prospective registry, called the JACRE registry, for patients on rivaroxaban or warfarin administration who received CA for AF. The outcomes up to 30 days following the procedure were reported previously. The present study involved longer follow-up of patients enrolled in this registry to evaluate long-term anticoagulation strategies and clinical outcomes.

RESULTS

Data of 975 patients (rivaroxaban, n = 823; warfarin, n = 152) were collected from 27 institutes. Patient population had mean age 63.7 ± 10.3 years, 710 (72.8%) males, mean CHA₂DS₂-VASc score 1.9 ± 1.5, and mean follow-up period 28.7 ± 12.7 months after the index procedure. Anticoagulants were continued in 496 (50.9%) patients during the follow-up. Thromboembolism occurred in 3 patients, hemorrhagic stroke in 5, and major bleeding events in 9 (annualized event rate, 0.13%, 0.22%, and 0.40% per patient-year, respectively). There were no differences in the composite event rate of thromboembolism and International Society on Thrombosis and Haemostasis major bleeding between rivaroxaban and warfarin cohorts (0.53% and 0.55% per patient-year, respectively).

CONCLUSIONS

Long-term incidence of thromboembolism was extremely low in patients with AF treated with CA, while that of major bleeding was not especially low. Clinical Trials Registry: UMIN000032829 / UMIN000032830.