A Randomized Controlled Trial of Dabigatran versus Warfarin for Periablation Anticoagulation in Patients Undergoing Ablation of Atrial Fibrillation

A Novel Hemostatic Belt Allowing Ambulation Soon After Atrial Fibrillation Ablation

We aimed to develop a hemostatic device with physiological evidence that allows ambulation soon after atrial fibrillation (AF) ablation. We measured right femoral vein pressure in 57 participants to clarify why groin post-venipuncture rebleeding often occurs during the transition from supine to sitting under compression bandage application and found that it increased more than threefold when raising the upper body (8.6 ± 4.1 to 27.6 ± 6.9 mmHg; P < 0.001). Based on that data, we created a novel hemostatic belt. Its capability test including 25 participants demonstrated that the belt gave much higher compression pressures on the right groin while sitting than the compression bandage (59.5 ± 14.9 vs. 8.1 ± 4 mmHg; P < 0.001), achieving pressures above the maximum femoral vein pressure in 92% of participants. A randomized trial comparing the belt with compression bandage in 74 AF patients demonstrated that the belt reduced time to ambulation without any rebleeding (340 [92.5-360] vs. 360 [360-360] min; P < 0.001) and satisfied more patients. The novel hemostatic belt provided a much higher compression pressure on the right groin during the sitting position than the conventional compression bandage, achieving a pressure above the maximum femoral vein pressure in 92% of the participants.

The Effect of Direct Oral Anticoagulant Therapy (DOACs) on oral surgical procedures: a systematic review

BACKGROUND

Direct oral anticoagulants (DOACs) were developed to overcome the drawbacks of oral anticoagulants. However, not much has been discussed about the perioperative management of patients on DOACs during oral surgical procedures. Thus, we aim to determine the risk of perioperative and postoperative bleeding during oral surgical procedures in patients on DOACs.

METHODS

A detailed literature search was performed to find potentially relevant studies using the Cochrane Library, Clinical Key, ClinicalTrials.gov, Google Scholar, Ovid, ScienceDirect, and Scopus. Every article available for free in English literature for the past 10 years, between 2012 and 2022, was searched.

RESULTS

A total of 2792 abstracts were selected through a search strategy across various search engines. Based on inclusion and exclusion criteria, eleven clinical studies using DOACs as anticoagulants or studies comparing patients with and without DOACs under oral surgery procedures were found. The results were inconsistent and varied, with a few studies recommending DOAC administration with the bare minimum reported complications and others finding no statistically significant difference between discontinuation or continuation of drugs, especially across basic dental procedures.

CONCLUSION

Within the limitations of the study, it can be concluded that minor oral surgical procedures are safe for patients on DOAC therapy. However, the continuation or discontinuation of DOACs in patients undergoing oral surgical procedures remains controversial and requires further studies to extrapolate the results.

Optimal Anticoagulant Strategy for Periprocedural Management of Atrial Fibrillation Ablation: A Systematic Review and Network Meta-Analysis

This network meta-analysis was performed to rank the safety and efficacy of periprocedural anticoagulant strategies in patients undergoing atrial fibrillation ablation. MEDLINE, EMBASE, CENTRAL, and Web of Science were searched to identify randomized controlled trials comparing anticoagulant regimens in patients undergoing atrial fibrillation ablation up to July 1, 2021. The primary efficacy and safety outcomes were thromboembolic and major bleeding events, respectively, and the net clinical benefit was investigated as the primary-outcome composite. Seventeen studies were included (n = 6950). The mean age ranged from 59 to 70 years; 74% of patients were men and 55% had paroxysmal atrial fibrillation. Compared with the uninterrupted vitamin-K antagonist strategy, the odds ratios for the composite of primary safety and efficacy outcomes were 0.61 (95%CI: 0.31–1.17) with uninterrupted direct oral anticoagulants, 0.63 (95%CI: 0.26–1.54) with interrupted direct oral anticoagulants, and 8.02 (95%CI: 2.35–27.45) with interrupted vitamin-K antagonists. Uninterrupted dabigatran significantly reduced the risk of the composite of primary safety and efficacy outcomes (odds ratio, 0.21; 95%CI, 0.08–0.55). Uninterrupted direct oral anticoagulants are preferred alternatives to uninterrupted vitamin-K antagonists. Interrupted direct oral anticoagulants may be feasible as alternatives. Our results support the use of uninterrupted direct oral anticoagulants as the optimal periprocedural anticoagulant strategy for patients undergoing atrial fibrillation ablation.

Direct-acting oral anti-coagulants in dental practice: A Retrospective Observational Study (Part 1)

OBJECTIVES

The objective of this retrospective observational study was to determine the incidence of direct-acting oral anti-coagulant (DOA) use in patients receiving invasive dental procedures. The secondary objective was to investigate the precautionary measures implemented and the post/intraoperative complications associated with DOA use.

METHODS

Electronic record database, Axium, was retrospectively reviewed, and patients using NGOA and treated between 2010 and 2017 were identified. Charts of patients who underwent invasive dental procedures were further reviewed to investigate the preoperative/intraoperative precautionary measures taken and identify any intraoperative/postoperative complications.

RESULTS

A total of 130 patients were identified, with their annual number steadily rising from 12 in 2011 to 52 in 2016. Among those, 64 patients (49.23%) underwent invasive dental procedures. Pretreatment medical consults were obtained in all patients undergoing invasive procedures; however, only 7 (10.94%) were instructed to discontinue their DOA. Preoperative laboratory testing was obtained for two patients. Intraoperatively, 34 (53.13%) cases of excessive bleeding were reported, all were locally controlled with hemostatic agents. Only 4 instances of postoperative complications were documented.

CONCLUSIONS

Despite the rise in the use of DOA, there is no consistent pattern for preoperative laboratory testing and DOA discontinuations. Expert consensus may be of great importance to develop practice guidelines.

Interrupted or Uninterrupted Oral Anticoagulants in Patients Undergoing Atrial Fibrillation Ablation

BACKGROUND AND PURPOSE

The safety and efficacy of uninterrupted, minimally interrupted (one dose skipped) or completely interrupted (24 h skipped) oral anticoagulant therapy in patients with atrial fibrillation (AF) ablation are poorly defined. We conducted a network meta-analysis to explore the effect of interrupted or uninterrupted oral anticoagulants in patients with AF undergoing ablation.

METHODS

The Cochrane Library, PubMed and Embase databases were systematically searched for studies comparing uninterrupted, minimally interrupted or completely interrupted non-vitamin K antagonist oral anticoagulants (NOACs) with continuous or interrupted warfarin in patients undergoing AF ablation.

RESULTS

Twelve randomized clinical trials (RCTs) with a total of 5597 patients with AF undergoing catheter ablation were included. For thromboembolism, minimally interrupted NOACs (OR 0.03, 95% CI 0.01-0.35), uninterrupted NOACs (OR 0.04, 95% CI 0.01-0.23) and continuous VKAs (OR 0.05, 95% CI 0.01-0.21) were better than interrupted warfarin. The risk of total bleeding appeared higher in the completely interrupted NOAC group compared with the minimally interrupted NOACs (OR 2.74, 95% CI 1.18-6.37), uninterrupted NOACs (OR 2.15, 95% CI 1.05-4.38) and uninterrupted warfarin (OR 2.04, 95% CI 1.02-4.08). To reduce the risk of total bleeding, minimally interrupted NOACs (OR 0.15, 95% CI 0.08-0.27), uninterrupted NOACs (OR 0.19, 95% CI 0.14-0.42) and uninterrupted warfarin (OR 0.24, 95% CI 0.15-0.39) were better than interrupted warfarin. In the event of major bleeding, there was no significant difference in the interrupted NOAC, uninterrupted NOAC, interrupted VKA and uninterrupted VKA groups.

CONCLUSIONS

These three NOAC strategies may have similar safety and efficacy in terms of thromboembolism and major bleeding complications. The total bleeding risk of completely interrupted oral anticoagulants is higher than that of uninterrupted and minimally interrupted NOACs. For thromboembolism, minimally interrupted NOACs, uninterrupted NOACs and continuous VKAs were better than interrupted warfarin.

Meta-analysis of efficacy and safety of new oral anticoagulants compared with warfarin in Japanese patients undergoing catheter ablation for atrial fibrillation

OBJECTIVES

This meta-analysis was designed to evaluate the efficacy and safety of new oral anticoagulants (NOACs) for perioperative anticoagulation of atrial fibrillation (AF) catheter ablation (CA) in Japanese patients with non-valvular atrial fibrillation (NVAF).

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched for articles published up to June 30, 2019. Two reviewers independently screened literature, extracted data, and assessed the methodological quality of the included studies according to the inclusion and exclusion criteria. Then, meta-analysis was performed using RevMan 5.3 software.

RESULTS

Nineteen studies with a total of 6827 patients were included in this meta-analysis. The experimental group received dabigatran, rivaroxaban, apixaban, or edoxaban; the control group received warfarin. The safety endpoints were bleeding complications; the efficacy endpoints were thromboembolic complications. Results were as follows: Patients with NOACs had a lower risk of overall bleeding complications (OR = 0.69, 95% CI (0.54, 0.87), P = 0.002), including major bleeding complications (OR = 0.52, 95% CI (0.32, 0.84), P = 0.007) and minor bleeding complications (OR = 0.73, 95% CI (0.56, 0.94), P = 0.02). There was no significant difference in thromboembolic complications between NOACs and warfarin after CA (OR = 0.39, 95% CI (0.14, 1.10), P = 0.08).

CONCLUSIONS

In Japanese NVAF patients undergoing CA, NOACs have similar effects to warfarin in the prevention of stroke and systemic embolism. Moreover, NOACs were associated with a lower incidence of bleeding complications.

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.

Non-vitamin K oral anticoagulants in nonvalvular atrial fibrillation: a network meta-analysis

OBJECTIVES

We conducted a systematic review and network meta-analysis of randomized controlled trials (RCTs) including the comparison of non-vitamin K antagonist oral anticoagulants (NOACs) with warfarin for patients with atrial fibrillation (AF).

DESIGN

Network meta-analysis. Two authors independently extracted data. All authors evaluated overall confidence in the evidence.

RESULTS

Eighteen RCTs included in our review, a total of 78,796 patients with AF, with sample sizes from 90 to 21,105 patients. Apixaban 5 mg (OR: 0.79, 95% CI: 0.66 to 0.95), dabigatran 110 mg (0.91, 0.74-1.12), dabigatran 150 mg (0.66, 0.53-0.82), edoxaban 60 mg (0.87, 0.74-1.02), and rivaroxaban 20 mg (0.88, 0.74-1.03) reduced the risk of stroke or systemic embolism compared with warfarin. Dabigatran 150 mg had the highest P-score for reducing stroke or systemic embolic events. The risk of haemorhagic stroke and all-cause mortality was lower with all NOACs than with warfarin. Apixaban 5 mg (0.69, 0.60-0.80), dabigatran 110 mg (0.80, 0.69-0.93), dabigatran 150 mg (0.93, 0.80-1.08), edoxaban 30 mg (0.46, 0.40-0.54), and edoxaban 60 mg (0.78, 0.69-0.90) reduced the risk of major bleeding compared with warfarin. Edoxaban 30 mg had the highest P-score for reducing major bleeding. The plots of P-scores rank showed that apixaban offered the most favorable balance of efficacy and safety.

CONCLUSIONS

This study adds an attempt for treatment ranking of both efficacy and safety outcomes. Future trials comparing directly NOACs are needed in order to provide conclusive proofs for these results and not only circumstantial evidence offered by a network meta-analysis.

Contemporary Management of Direct Oral Anticoagulants During Cardioversion and Ablation for Nonvalvular Atrial Fibrillation

As overall prevalence of atrial fibrillation (AF) continues to rise, the number of patients who undergo ablation, or electrical/chemical cardioversion, to restore normal sinus rhythm continues to increase as well. As direct oral anticoagulants (DOACs) have continued to be incorporated into clinical practice for long-term anticoagulation for AF, experience with how best to manage use of DOACs during electrophysiologic procedures is evolving. This review is intended to provide health care providers with a summary of current evidence regarding the use of DOACs during cardioversion and catheter ablation and provide key considerations for their use during such electrophysiologic procedures. PubMed and MEDLINE were searched from inception through June 2018 for studies in humans comparing DOACs alone or against vitamin K antagonists (VKAs) in adult patients (> 18 yrs) who underwent cardioversion or AF catheter ablation using the following key words: "rivaroxaban," "dabigatran," "apixaban," "edoxaban," "non-vitamin K antagonists," "direct or new oral anticoagulants," "warfarin," "vitamin K antagonists," "cardioversion," "ablation of atrial fibrillation," "uninterrupted," and "catheter ablation." Four retrospective studies and three prospective trials comparing DOACs with VKA in patients undergoing cardioversion and three prospective studies in patients undergoing catheter ablation for AF were identified. Observational data and meta-analyses were also critically reviewed. Prospective trials to date suggest similar efficacy and safety with using DOACs in the setting of cardioversion and AF ablation compared to traditional therapy with VKA, with or without bridging. Injectable anticoagulant overlap can be avoided in patients receiving DOACs in the setting of cardioversion for AF. Minimal interruption in anticoagulation may be only necessary for AF ablation in those with highest bleeding risk, such as in renal dysfunction and where drug-drug interactions may increase risk for anticoagulant accumulation. Periprocedural advantages of DOACs include convenience, rapid and predictable onset of effect, improved patient satisfaction, and potential for reduced costs.

Safety and efficacy of nonvitamin K antagonist oral anticoagulants during catheter ablation of atrial fibrillation: A systematic review and meta-analysis

AIMS

Catheter ablation for atrial fibrillation (AF) is associated with a transitory increase in the risk of both thromboembolic and bleeding events. Evidence on the use of nonvitamin K antagonist oral anticoagulants (NOACs) in patients undergoing AF ablation mostly comes from small observational studies, underpowered to detect differences in clinical outcomes between NOACs and vitamin K antagonists (VKAs) treated patients. This updated meta-analysis aimed to determine the safety and efficacy of periprocedural anticoagulation with NOACs compared with VKAs in AF patients undergoing catheter ablation.

METHODS

We searched MEDLINE, Cochrane library, and web sources for randomized and observational studies comparing periprocedural treatment with NOACs and VKAs in patients undergoing AF ablation. The primary safety endpoint was major bleeding events, and the primary efficacy endpoint was thromboembolic events (a composite of systemic thromboembolism, transient ischemic attack, and stroke).

RESULTS

A total of 29 studies with 12 644 patients were included in the meta-analysis. Overall, patients on NOACs had a significantly lower risk of major bleeding compared to VKAs either in observational studies (Peto OR 0.68; 95% CI: 0.48-0.95; P = 0.022; I²  = 20%) or in RCTs (Peto OR 0.30; 95% CI: 0.14-0.62; P = 0.001; I²  = 28%). Uninterrupted NOACs reduced the risk of major bleeding when compared to uninterrupted VKAs (Peto OR 0.66; 95% CI: 0.45-0.96; P = 0.028; I²  = 1%), similarly, interrupted NOACs lowered the risk of major bleeding compared to interrupted VKAs (Peto OR 0.29; 95% CI: 0.13-0.66; P = 0.003; I²  = 0%; P_interaction  = 0.076). The rate of thromboembolic complications was very low and did not significantly differ between the study groups either in observational studies (Peto OR 0.91; 95% CI: 0.49-1.67; P = 0.755; I²  = 0%) or in RCTs (Peto OR 0.14; 95% CI: 0.01-1.30; P = 0.083; I²  = 0%).

CONCLUSIONS

Use of NOACs compared to VKAs significantly reduced the risk of bleeding in patients with AF ablation. Similarly, the risk of bleeding was lower with uninterrupted NOACs than with uninterrupted VKAs, and with interrupted NOACs than with interrupted VKAs. The rate of thromboembolic complications was extremely low in both study groups without any differences.

Periprocedural Complications in Patients Undergoing Catheter Ablation of Atrial Fibrillation Without Discontinuation of a Vitamin K Antagonist and Direct Oral Anticoagulants

BACKGROUND

Periprocedural anticoagulation is important in catheter ablation (CA) of atrial fibrillation (AF) and there is increasing evidence that uninterrupted vitamin K antagonist (VKA) therapy is superior to interrupted anticoagulation strategies. Since the emergence of direct oral anticoagulants (DOACs), numerous studies have shown promising results for their use in uninterrupted strategies. However, further studies are needed to further define the efficacy and safety of performing AF ablation with uninterrupted factor XA inhibitors or direct thrombin inhibitors.

METHODS AND RESULTS

We have performed CA of AF without discontinuation of either VKA or DOAC therapy since April 2014. A total of 376 patients with AF underwent CA including pulmonary vein isolation. All of the patients were divided into 2 groups (uninterrupted VKA or uninterrupted DOACs). Anticoagulation with DOACs was associated with fewer complications than uninterrupted VKA therapy (P=0.04). There were significant differences between groups in the rates of congestive heart failure, left ventricular ejection fraction, body weight, and estimated glomerular filtration rate and of the CHADS2, CHA2DS2-VASc and HAS-BLED scores. Therefore, we also analyzed the results using the propensity score-matching method. We found no significant difference in periprocedural complications between uninterrupted VKA or DOACs therapy (P=0.65).

CONCLUSIONS

CA of AF without discontinuation of DOACs is not inferior to CA without discontinuation of a VKA, with regard to ischemic or hemorrhagic complications.

Periprocedural Management of Direct Oral Anticoagulants Surrounding Cardioversion and Invasive Electrophysiological Procedures

Supplemental Digital Content is available in the text.

As direct oral anticoagulants (DOACs) have demonstrated favorable efficacy and safety outcomes compared with vitamin K antagonists for the treatment and prevention of venous thromboembolism and the prevention of stroke and systemic embolism in patients with nonvalvular atrial fibrillation, their role in the management of anticoagulation during electrophysiological procedures continues to evolve. At present, guidelines are limited regarding specific recommendations for the use of DOACs in these clinical settings. Here, we review available data regarding the risks and benefits associated with various periprocedural anticoagulation management approaches when patients receiving DOACs undergo electrophysiologic procedures including cardioversion, ablation, and device implantation. This discussion is intended to provide clinicians with an overview of available evidence and best practices to minimize the risk of both thromboembolic and bleeding events in the periprocedural setting.

[S1 guideline - Austrian consensus for anticoagulation in the context of atrial fibrillation ablation]

In summary, uninterrupted oral antikoagulation can be recommended, with different recommendation classes and levels of evidence, for both, VKA and NOAC therapy, in the framework of PVI. Even with low CHA₂DS₂ VASc scores, OAK is indicated 3-4 weeks before and 8 weeks after the procedure. Periinterventional bridging with heparins should be avoided due to increased bleeding events.The present Consensus provides recommendations on the current state of knowledge and has been prepared exclusively by members of the Rhythmology Working Group of the Austrian Cardiological Society who have great practical experience in catheter ablation and peri-interventional OAK in patients with atrial fibrillation. Publication of new randomized and controlled studies on the subject are expected in the coming months, so that there will certainly be changes in the recommendations. The Rhythmology Working Group of the Austrian Cardiological Society will strive to keep this S1 guideline regularly up to date. We hope that this consensus is used to increase the safety for patients undergoing PVI and to provide physicians with a homogeneous approach in Austria.

Comparison of uninterrupted anticoagulation with dabigatran etexilate or warfarin in the periprocedural period for atrial fibrillation catheter ablation: Results of the Japanese subgroup of the RE-CIRCUIT trial

Background

There are limited data on uninterrupted anticoagulation with direct oral anticoagulants during catheter ablation for atrial fibrillation (AF), particularly in Japan. We planned a subgroup analysis of the RE-CIRCUIT study, comparing the use of uninterrupted dabigatran therapy with warfarin therapy during catheter ablation among the Japanese subgroup and with that in the total population.

Methods

The RE-CIRCUIT study utilized a prospective, randomized, open-label, blinded endpoint design, and the primary endpoint was the incidence of major bleeding events (MBEs). Patients were randomized to uninterrupted dabigatran 150 mg twice daily or warfarin. In this study, we analyzed the results in Japanese patients.

Results

Of 704 enrolled patients in the study, 112 Japanese patients were randomized to dabigatran (n = 65) or warfarin (n = 47). MBEs were experienced by two patients: one in the dabigatran group (1.6%, cardiac tamponade) and one in the warfarin group (2.2%, groin hematoma) (risk difference vs warfarin -0.6%; 95% CI -5.8, 4.7). Within the Japanese subgroup, there were no thromboembolic events in both groups.

Conclusion

While not designed to show statistical difference between two treatment groups, our results from the Japanese subgroup supported those from the overall population. Furthermore, this study provided clinical information regarding MBE, especially cardiac tamponade, in Japanese patients.

A Prospective Randomized Trial of Apixaban Dosing During Atrial Fibrillation Ablation: The AEIOU Trial

OBJECTIVES

This study sought to determine whether uninterrupted apixaban would have similar rates of bleeding and thromboembolic events as does minimally interrupted apixaban at the time of atrial fibrillation (AF) ablation and to compare those results with rates in historical patients treated with uninterrupted warfarin.

BACKGROUND

The safety, efficacy, and optimal dosing regimen for apixaban at the time of AF ablation are uncertain.

METHODS

This prospective, multicenter clinical trial enrolled 306 patients undergoing catheter ablation for nonvalvular AF and randomized 300 to uninterrupted versus minimally interrupted (holding 1 dose) periprocedural apixaban. A retrospective cohort of patients treated with uninterrupted warfarin at the same centers was matched to the apixaban-treated subjects for comparison. Endpoints included clinically significant bleeding, major bleeding, and nonhemorrhagic stroke or systemic embolism (SE) from the time of ablation through 30 days.

RESULTS

There were no stroke or SE events. Clinically significant bleeding occurred in 11.3% of 150 evaluable patients on uninterrupted apixaban and 9.7% of 145 evaluable patients on interrupted apixaban (risk difference: 1.7% [95% confidence interval: -5.5% to 8.8%]; p = NS). Rates of major bleeding were 1.3% with uninterrupted apixaban, and 2.1% with interrupted (risk difference: -0.7%; p = NS). The rates of clinically significant and major bleeding were similar for all apixaban patients combined (10.5% and 1.7%), compared with the matched warfarin group (9.8% and 1.4%).

CONCLUSIONS

Both uninterrupted and minimally interrupted apixaban at the time of AF ablation were associated with a very low rate of thromboembolic events, and rates of both major (<2%) and clinically significant bleeding were similar to uninterrupted warfarin. (Apixaban Evaluation of Interrupted Or Uninterrupted Anticoagulation for Ablation of Atrial Fibrillation [AEIOU]; NCT02608099).

Safety and Efficacy of Underdosing Non-vitamin K Antagonist Oral Anticoagulants in Patients Undergoing Catheter Ablation for Atrial Fibrillation

Background:

Some patients with atrial fibrillation (AF) received underdoses of non-vitamin K antagonist oral anticoagulants (NOACs) in the real world. Underdosing is defined as administration of a dose lower than the manufacturer recommended dose.

Objectives:

To identify the efficacy and safety of underdosing NOACs as perioperative anticoagulation for atrial fibrillation ablation.

Methods:

We retrospectively analyzed patients who received rivaroxaban or dabigatran etexilate according to dosage: adjusted low dosage (reduced by disturbed renal function; n = 30), underdosage (n = 307), or standard dosage (n = 683). Non-vitamin K antagonist oral anticoagulants and dosing decisions were at the discretion of treating cardiologists.

Results:

Patients who received underdosed NOACs were older, more often female, and had lower body weight and lower renal function than those who received standard dosages. Activated clotting time at baseline in patients who received adjusted low dosage or underdosages was slightly longer than that in patients receiving standard dosages (156 ± 23, 151 ± 224, and 147 ± 24 seconds, respectively). Meaningful differences were not observed in other coagulation parameters. Adjusted low-, under-, and standard-dosing regimens did not differ in perioperative thromboembolic complications (0/30, 0.0%; 1/307, 0.3%; and 0/683, 0%, respectively) or major (0/30, 0.0%; 2/307, 0.6%; 3/683, 0.4%) and minor (1/30, 3.3%; 13/307, 4.2%; 25/683, 3.6%) bleeding episodes. When comparisons were performed for each NOAC, similar results were observed.

Conclusions:

With consideration of patient condition, age, sex, body weight, body mass index, and renal function, underdosing NOACs was effective and safe as a perioperative anticoagulation therapy for atrial fibrillation ablation. The therapeutic range of NOACs is potentially wider than manufacturer recommendations.

Comparison of the Incidences of Complications After Second-Generation Cryoballoon Ablation of Atrial Fibrillation Using Vitamin K Antagonists Versus Novel Oral Anticoagulants

Data evaluating the impact of the periprocedural administration of novel oral anticoagulants (NOACs) on complications in the setting of pulmonary vein (PV) isolation using cryoballoon (CB) is limited. In the present study, our aim was to analyze procedural characteristics and incidence of complications in those patients who underwent CB ablation for atrial fibrillation and the impact of NOACs on adverse events compared with vitamin K antagonists (VKAs). Consecutive patients with drug resistant atrial fibrillation who underwent PV isolation by CB as index procedure were retrospectively included in our analysis. In group I, 290 of 454 patients (63.9%) received VKAs (warfarin: n = 222 and acenocoumarol: n = 68), and in group II, 164 of 454 patients (36.1%) were treated with NOACs (rivaroxaban: n = 71; dabigatran: n = 60; and apixaban: n = 33). Age was significantly higher in the group II (62.8 ± 9.7 vs 58.6 ± 11.3; p <0.001). During the study period, 454 consecutive patients (male 71%, age 60.1 ± 10.9 years) were enrolled. Major complications occurred in 9 patients (2.0%): peripheral vascular complications were observed in 6 patients (1.3% per procedure), persistent phrenic nerve palsy occurred in 2 (0.4%), and transient ischemic attacks in 1 (0.2%). In both groups, the incidence of major complications was similar (group I [VKAs]: 7 patients [2.4%] vs group II [NOACs]: 2 patients [1.2%]; p = 0.5). In conclusion, CB ablation is a safe procedure for PV isolation and is associated with low complication rates. The incidence of adverse events in PV isolation using the second-generation CB with the periprocedural administration of NOACs is not significantly different than VKA treatment.

Uninterrupted Dabigatran versus Warfarin for Ablation in Atrial Fibrillation

BACKGROUND

Catheter ablation of atrial fibrillation is typically performed with uninterrupted anticoagulation with warfarin or interrupted non-vitamin K antagonist oral anticoagulant therapy. Uninterrupted anticoagulation with a non-vitamin K antagonist oral anticoagulant, such as dabigatran, may be safer; however, controlled data are lacking. We investigated the safety of uninterrupted dabigatran versus warfarin in patients undergoing ablation of atrial fibrillation.

METHODS

In this randomized, open-label, multicenter, controlled trial with blinded adjudicated end-point assessments, we randomly assigned patients scheduled for catheter ablation of paroxysmal or persistent atrial fibrillation to receive either dabigatran (150 mg twice daily) or warfarin (target international normalized ratio, 2.0 to 3.0). Ablation was performed after 4 to 8 weeks of uninterrupted anticoagulation, which was continued during and for 8 weeks after ablation. The primary end point was the incidence of major bleeding events during and up to 8 weeks after ablation; secondary end points included thromboembolic and other bleeding events.

RESULTS

The trial enrolled 704 patients across 104 sites; 635 patients underwent ablation. Baseline characteristics were balanced between treatment groups. The incidence of major bleeding events during and up to 8 weeks after ablation was lower with dabigatran than with warfarin (5 patients [1.6%] vs. 22 patients [6.9%]; absolute risk difference, -5.3 percentage points; 95% confidence interval, -8.4 to -2.2; P<0.001). Dabigatran was associated with fewer periprocedural pericardial tamponades and groin hematomas than warfarin. The two treatment groups had a similar incidence of minor bleeding events. One thromboembolic event occurred in the warfarin group.

CONCLUSIONS

In patients undergoing ablation for atrial fibrillation, anticoagulation with uninterrupted dabigatran was associated with fewer bleeding complications than uninterrupted warfarin. (Funded by Boehringer Ingelheim; RE-CIRCUIT ClinicalTrials.gov number, NCT02348723 .).

Periprocedural Management of Novel Oral Anticoagulants During Atrial Fibrillation Ablation: Controversies and Review of the Current Evidence

Oral anticoagulation (OAC) has been the cornerstone for the prevention of thromboembolic complications in patients with atrial fibrillation (AF) at significant risk of stroke. Catheter ablation is an established efficacious technique for the treatment of AF. Ameliorating the risk of stroke or transient ischaemic attack (TIA) in patients with AF undergoing ablation requires meticulous planning of pharmacotherapy. The advent of non-vitamin K oral anticoagulants (NOACs) has broadened the therapeutic scope, representing a viable alternative to traditional vitamin K antagonists (VKA) in non-valvular AF. Potential advantages of NOACs include greater pharmacokinetic predictability, at least comparable efficacy as compared to VKA and a superior haemorrhagic complication profile. However, robust evidence for the safety and efficacy of periprocedural NOAC use for AF ablation remains uncertain with a non-uniform clinical approach between and within institutions. The following review will summarise the current and emerging evidence on periprocedural management of NOACs in patients undergoing catheter ablation of AF. An overview of NOAC pharmacology will provide a foundation for the review of reversal agents in the context of catheter ablation of AF. The purpose of the review is to outline key studies and identify key areas for further critical research with the ultimate aim of developing evidence-based guidelines for optimal care.

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.

Early Experience of Novel Oral Anticoagulants in Catheter Ablation for Atrial Fibrillation: Efficacy and Safety Comparison to Warfarin

PURPOSE

Compared with warfarin, novel oral anticoagulants (NOACs) are convenient to use, although they require a blanking period immediately before radiofrequency catheter ablation for atrial fibrillation (AF). We compared NOACs and uninterrupted warfarin in the peri-procedural period of AF ablation.

MATERIALS AND METHODS

We compared 141 patients treated with peri-procedural NOACs (72% men; 58 ± 11 years old; 71% with paroxysmal AF) and 281 age-, sex-, AF type-, and history of stroke-matched patients treated with uninterrupted warfarin. NOACs were stopped 24 hours before the procedure and restarted on the same procedure day after hemostasis was achieved.

RESULTS

We found no difference in the CHA₂DS₂-VASc (p=0.376) and HAS-BLED scores (p=0.175) between the groups. The preprocedural anticoagulation duration was significantly shorter in the NOAC group (76.3 ± 110.7 days) than in the warfarin group (274.7 ± 582.7 days, p<0.001). The intra-procedural total heparin requirement was higher (p<0.001), although mean activated clotting time was shorter (350.0 ± 25.0 s vs. 367.4 ± 42.9 s, p<0.001), in the NOAC group than in the warfarin group. There was no significant difference in thromboembolic events (1.4% vs. 0%, p=0.111) or major bleeding (1.4% vs. 3.9%, p=0.235) between the NOAC and warfarin groups. Minor stroke occurred in two cases within 10 hours of the procedure (underlying CHA₂DS₂-VASc scores 0 and 1) in the NOAC group.

CONCLUSION

Pre-procedural anticoagulation duration was shorter and intra-procedural heparin requirement was higher with NOAC than with uninterrupted warfarin during AF ablation. Although the peri-procedural thromboembolism and bleeding incidences did not differ, minor stroke occurred in two cases in the NOAC group.

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.

New oral anticoagulants in patients undergoing atrial flutter radiofrequency catheter ablation: an observational study

AIM

Atrial flutter (AFL) ablation requires optimal periprocedural anticoagulation in order to minimize thromboembolic events/bleeding risk. This study describes the characteristics of patients receiving new oral anticoagulants before AFL ablation and assesses complications.

METHODS

This multicenter, retrospective study reports ischemic and hemorrhagic predischarge, postprocedural complications.

RESULTS

We evaluated 60 patients (62.3% male; mean age: 69.2 ± 9.7 years; CHA2DS2-VASc score: 2.44 ± 1.46, HAS-BLED score: 1.14 ± 0.7). Twenty-one (35.0%) and 23 patients (38.3%) received twice-daily dabigatran 110 or 150 mg; 16 patients (26.6%) received once-daily rivaroxaban (15 mg [n = 5] or 20 mg [n = 11]). Four cases of postprocedural minor bleeding were reported.

CONCLUSION

This is the first study assessing new oral anticoagulants for periprocedural anticoagulation, specifically in patients undergoing AFL ablation. No major bleeding was reported. Further prospective investigation is warranted.

Low dose dabigatran versus uninterrupted acenocoumarol for peri-procedural anticoagulation in atrial fibrillation catheter ablation

BACKGROUND

Left atrial ablation for atrial fibrillation (AF) is associated with a transiently increased risk of thromboembolic and hemorrhagic events. We tested the hypothesis that the low dose dabigatran [110mg twice a day (bid)] can be safely used as an alternative to uninterrupted acenocoumarol for periprocedural anticoagulation in left atrial ablation procedures.

METHODS AND RESULTS

A total of 149 consecutive patients undergoing pulmonary vein antral isolation for AF were included; 64 patients were on low dose dabigatran (110mg bid) and 85 patients were on acenocoumarol with therapeutic international normalized ratios. Two doses of dabigatran were withheld before the procedure and the drug was restarted 4hours after vascular hemostasis. Overall, the two groups were well-matched. Hemorrhagic and thromboembolic complications were similar in both groups within 90days from the procedure (4.7% for the dabigatran group versus 9.4% for the acenocoumarol group; P=0.275). Major hemorrhage occurred in 1.6% in the dabigatran group versus 3.5% in the acenocoumarol group (P=0.462). A single thromboembolic event occurred in the dabigatran group (1.6%) versus 2 (2.4%) in the acenocoumarol group (P=0.734). Despite higher doses of intraprocedural heparin (P<0.01), the mean activated clotting time was significantly lower in patients who were on dabigatran than those on acenocoumarol (P<0.01).

CONCLUSIONS

The low dose dabigatran regimen provides safe and effective peri-procedural anticoagulation in patients undergoing left atrial ablation for AF compared with uninterrupted acenocoumarol therapy.

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.

Periprocedural Management of New Oral Anticoagulants in Atrial Fibrillation Ablation

BACKGROUND

Patients who undergo catheter ablation for atrial fibrillation (AF) are at increased risk of developing thromboembolic and bleeding complications periprocedurally. Many patients are now on newer oral anticoagulants (NOACs), but data regarding their safety and efficacy during AF ablation are limited.

METHODS AND RESULTS

This article reviews the literature in PubMed from 1998 to 2014 and includes clinical trials and meta-analysis that analyzed the safety and efficacy of NOACs during AF catheter ablation. Dabigatran seems to be as effective and safe as warfarin, although most data are from single-center studies, with small samples and very low overall bleeding and thromboembolic complications. Periprocedural anticoagulation protocols also vary greatly between studies. Some recent meta-analysis has shown that warfarin could still be a safer and more effective alternative. There are fewer studies with rivaroxaban in AF ablation, and there have been no meta-analysis yet comparing rivaroxaban to warfarin or dabigatran. There seems to be no significant differences in safety or efficacy of rivaroxaban compared to warfarin. Interestingly, there are no available data for apixaban in AF ablation yet.

DISCUSSION

There are no consensus guidelines regarding the use of NOACs during AF ablation. Dabigatran and rivaroxaban seem as safe and effective as warfarin, although larger studies with standardized protocols are needed, as available studies may be underpowered to detect small differences in bleeding and thromboembolic rates.

Safety of Novel Oral Anticoagulants Compared With Uninterrupted Warfarin for Catheter Ablation of Atrial Fibrillation

Background: The novel oral anticoagulants (NOACs) are used for stroke prevention in atrial fibrillation (AF), but their safety and efficacy in the periablation period are not well established. Additionally, no standard procedure for managing periprocedural and intraprocedural anticoagulation has been established. Objective: To evaluate the frequency of hemorrhagic and thrombotic events as well as periprocedural management strategies of NOACs compared with warfarin as anticoagulation therapy for AF ablation. Methods: This was a retrospective cohort study from a prospective AF ablation registry maintained at a large, academic medical center. Results: A total of 374 cases (173 warfarin, 123 dabigatran, 61 rivaroxaban, and 17 apixaban) were included in the analysis. The overall hemorrhagic/thrombotic event rate was 14.2 % (major hemorrhage 2.7%, minor hemorrhage 11.2%, thrombotic stroke 0.5%). The frequency of minor hemorrhage was significantly higher with warfarin compared with dabigatran (15% vs 5.7%, P = 0.012). The average heparin dose required to reach the goal activated clotting time (ACT) was 5600 units for warfarin, 12 900 units for dabigatran ( P < 0.001), 15 100 units for rivaroxaban ( P < 0.001), and 14 700 units for apixaban ( P < 0.001). The average time in minutes to reach the goal ACT was significantly longer, compared with warfarin, for dabigatran (57 vs 28, P < 0.001), rivaroxaban (63 vs 28, P < 0.001), and apixaban (72 vs 28, P < 0.001). Conclusions: Compared with warfarin, periprocedural anticoagulation with dabigatran resulted in fewer minor hemorrhages and total adverse events after AF ablation. Patients anticoagulated with NOACs required larger doses of heparin and took longer to reach the goal ACT compared with patients anticoagulated with warfarin.

Bleeding complications of targeted oral anticoagulants: what is the risk?

The vitamin K antagonists (VKAs) are a widely used class of agent to prevent thromboembolism. In recent years, numerous alternatives to VKAs have been developed, the target-specific oral anticoagulants (TSOACs), which are available in clinical practice. Currently available agents target thrombin and factor Xa. The most significant side effect of these agents, as with VKAs, is the development of bleeding complications. In this review, the risks of major bleeding complications with the TSOACs will be discussed. Data from meta-analyses, randomized controlled trials, and observational studies will be used to highlight bleeding complications associated with TSOACs and warfarin. We highlight the most common causes of major bleeding, GI and intracranial hemorrhage.

My Patient Taking A Novel Oral Anticoagulant Needs Surgery, Device Implantation, Or Ablation

Atrial fibrillation (AF) is a highly prevalent chronic condition and a growing number of patients are on chronic anticoagulation therapy with novel oral anticoagulant (NOAC) agents: dabigatran, rivaroxaban, and apixaban. Many of these patients are expected to require invasive procedures. There is no clear consensus regarding the peri-procedural management of patients using NOACs, as to how to minimize both bleeding risk and thromboembolism risk. This review of the current available literature is designed to help formulate peri-procedural anticoagulation strategies for patients with AF taking NOACs who are being considered for catheter ablation, device implant, or other surgery. To help frame the discussion, we offer 3 case vignettes that we will revisit to at the end of the review of the existing literature. Case 1: A 62 year-old female with hypertension, diabetes, and symptomatic paroxysmal AF who is prescribed dabigatran for thromboembolism prevention. She has failed attempts at maintaining sinus rhythm with antiarrhythmic drugs. She is now being considered for catheter ablation of AF. Case 2: A 76 year-old male with hypertension, diabetes, prior stroke, and ischemic cardiomyopathy who has persistent drug-refractory AF. He is maintained on chronic anticoagulation with dabigatran for thromboembolism prevention. He has an implantable cardioverter-defibrillator (ICD) which requires a generator change. Case 3: A 58 year-old male with hypertension and paroxysmal AF who takes rivaroxaban for thromboembolic prophylaxis and is being considered for a knee replacement surgery.

Warfarin versus dabigatran etexilate: an assessment of efficacy and safety in patients with atrial fibrillation

INTRODUCTION

Oral anticoagulation is the mainstay for stroke and thromboembolic event prevention in patients with atrial fibrillation (AF). Given limitations of warfarin therapy, non-vitamin K oral anticoagulants have been developed including direct thrombin inhibitors (i.e., dabigatran etexilate). Dabigatran etexilate has been tested thoroughly in terms of efficacy and safety in clinical trials and studies, involving 'real-world' cohorts. In this review, currently available evidence in patients with non-valvular AF is discussed.

AREAS COVERED

The pharmacology, efficacy and safety, and current aspects of use of dabigatran etexilate in patients with non-valvular AF are reviewed in a comparative manner to warfarin both for chronic anticoagulation and in different clinical settings.

EXPERT OPINION

Dabigatran etexilate appeared to have several pharmacokinetic and pharmacodynamic advantages over warfarin, as well as a favorable efficacy and safety profile being at least noninferior and often superior to warfarin in patients with non-valvular AF. The latter was shown in the clinical trials, meta-analyses and studies with 'real-world' data. Currently ongoing trials will expand the body of evidence on warfarin and will aid decision making in currently controversial areas. Important limitations of dabigatran etexilate include contraindications for its use in patients with prosthetic heart valves and end-stage chronic kidney disease.

Management of non-vitamin K antagonist oral anticoagulants in the perioperative setting

The field of oral anticoagulation has evolved with the arrival of non-vitamin K antagonist oral anticoagulants (NOACs) including an anti-IIa agent (dabigatran etexilate) and anti-Xa agents (rivaroxaban and apixaban). The main specificities of these drugs are predictable pharmacokinetics and pharmacodynamics but special attention should be paid in the elderly, in case of renal dysfunction and in case of emergency. In addition, their perioperative management is challenging, especially with the absence of specific antidotes. Effectively, periods of interruption before surgery or invasive procedures depend on half-life and keeping a permanent balance between bleeding and thromboembolic risks. In addition, few data regarding the link between plasma concentrations and their effects are provided. Routine laboratory tests are altered by NOACs and quantitative measurements are not widely performed. This paper provides a review on the management of NOACs in the perioperative setting, including the estimation of the bleeding and thrombotic risk, the periods of interruption, the indication of heparin bridging, the usefulness of laboratory tests before surgery or invasive procedure, and the time of resuming. Most data are based on expert's opinions.

Hypercoagulability, D-dimer and atrial fibrillation: an overview of biological and clinical evidence

Atrial fibrillation (AF) is the most common among the severe cardiac arrhythmias and carries a significant risk of mortality and morbidity in the general population. The most important complication is represented by development of one or more thrombi in the left atrium of the dyskinetic heart, and their successive cerebral and peripheral embolization. The pathophysiological basis of the thromboembolic complications in AF entails the presence of a hypercoagulable state, which is mirrored by increased concentrations of a variety of prothrombotic markers. D-dimer is universally considered the gold standard among the various biomarkers that reflect activation of coagulation, fibrinolysis, or both, and several studies have assessed its diagnostic and prognostic role in AF. With a few exceptions and despite a broad heterogeneity in the study designs, published data seem to demonstrate that D-dimer values may be associated with the presence of atrial thrombosis, may be predictive of primary adverse outcomes and death, may be correlated with cerebral infarction volume, and may also be a useful parameter for assessing the degree of hypercoagulability of AF patients after cardioversion. If larger prospective studies confirm these findings, D-dimer assessment may hence become an integral part of the clinical decision-making in patients with AF.

Loading dose vs. maintenance dose of warfarin for reinitiation after invasive procedures: a randomized trial

BACKGROUND

There is uncertainty regarding the optimal dosing regimen for the resumption of warfarin after interruption for invasive procedures.

AIM

To determine the efficacy and safety of warfarin resumption with loading doses or with the most recent maintenance dose.

METHODS

Patients receiving warfarin treatment and planned for invasive procedures with an expected hospital stay of ≤ 1 day were randomized to resume warfarin on the day of the procedure, defined as day 1, with most recent maintenance dose or with 2 initial days of double maintenance dose. Efficacy outcomes were proportion of international normalized ratio (INR) levels ≥ 2.0 on day 5 (primary outcome) and day 10. Safety outcomes were bleeding and thromboembolic events. In addition, D-dimer levels were analyzed on days 5 and 10 in a subset of the population.

RESULTS

There were 49 patients analyzed in each group. INR of ≥ 2.0 had been achieved by day 5 for 13% in the maintenance-dose group and for 50% in the loading-dose group (relative risk [RR] 0.27, 95% confidence interval [CI] 0.10-0.60) and by day 10 for 68% and 87%, respectively (RR 0.78, 95% CI 0.65-1.00). There were no thromboembolic events, and there was one major bleed before resumption of warfarin and one minor bleed, both in the maintenance-dose group. There was no difference between the groups in the proportion of patients with excessive INRs or elevated D-dimer levels or in the median D-dimer level.

CONCLUSION

Resumption of warfarin after minor-moderately invasive procedures with two loading doses achieves therapeutic INR faster than does only maintenance dose.

The Rate Of Complications Associated With Concomitant Use Of Dabigatran With Cryoballoon Ablation For Atrial Fibrillation

INTRODUCTION

Catheter ablation is an evolving therapeutic strategy for the management of atrial fibrillation (AF). It is associated with a risk of thromboembolic events. The peri-procedural anticoagulation management with warfarin has been successful in mitigating this risk. However, introduction of novel oral anticoagulants like dabigatran offers more flexibility in anticoagulation approaches. Previous studies had evaluated the safety and efficacy of dabigatran in the radiofrequency ablation, but data related to cryoballoon ablation is lacking.

METHODS AND RESULTS

We performed a retrospective observational study involving patients who underwent cryoballoon ablation for drug-refractory, symptomatic AF while on dabigatran in periprocedural period. Thromboembolic, hemorrhagic or other complications occurring within the first 30 days after the ablation procedure were analyzed. Our study population comprised of 50 patients with mean age of 58.96 ± 3.54 years with 76% (n=38) being male. We found 3 (6%) minor complications in peri-procedural period including 2 groin hematomas and 1 trace asymptomatic pericardial effusion. There were no major intraprocedural or post procedural hemorrhagic or thromboembolic events. None of patients with the minor complications required significant additional workup or extended hospital stay. All the patients were able to continue dabigatran for 30 days without any additional side effects or complications.

CONCLUSION

Dabigatran is a safe and efficacious agent in patients undergoing cryoballoon AF ablation.

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.