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

Stroke Prevention in Atrial Fibrillation: A Scientific Statement of JACC: Asia (Part 2)

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with substantial increases in the risk for stroke and systemic thromboembolism. With the successful introduction of the first non-vitamin K antagonistdirect oral anticoagulant agent (NOAC) in 2009, the role of vitamin K antagonists has been replaced in most clinical settings except in a few conditions for which NOACs are contraindicated. Data for the use of NOACs in different clinical scenarios have been accumulating in the past decade, and a more sophisticated strategy for patients with AF is now warranted. JACC: Asia recently appointed a working group to summarize the most updated information regarding stroke prevention in AF. The aim of this statement is to provide possible treatment options in daily practice. Local availability, cost, and patient comorbidities should also be considered. Final decisions may still need to be individualized and based on clinicians' discretion. This is part 2 of the statement.

Comparative effectiveness and safety of pharmaceuticals assessed in observational studies compared with randomized controlled trials

BACKGROUND

There have been ongoing efforts to understand when and how data from observational studies can be applied to clinical and regulatory decision making. The objective of this review was to assess the comparability of relative treatment effects of pharmaceuticals from observational studies and randomized controlled trials (RCTs).

METHODS

We searched PubMed and Embase for systematic literature reviews published between January 1, 1990, and January 31, 2020, that reported relative treatment effects of pharmaceuticals from both observational studies and RCTs. We extracted pooled relative effect estimates from observational studies and RCTs for each outcome, intervention-comparator, or indication assessed in the reviews. We calculated the ratio of the relative effect estimate from observational studies over that from RCTs, along with the corresponding 95% confidence interval (CI) for each pair of pooled RCT and observational study estimates, and we evaluated the consistency in relative treatment effects.

RESULTS

Thirty systematic reviews across 7 therapeutic areas were identified from the literature. We analyzed 74 pairs of pooled relative effect estimates from RCTs and observational studies from 29 reviews. There was no statistically significant difference (based on the 95% CI) in relative effect estimates between RCTs and observational studies in 79.7% of pairs. There was an extreme difference (ratio < 0.7 or > 1.43) in 43.2% of pairs, and, in 17.6% of pairs, there was a significant difference and the estimates pointed in opposite directions.

CONCLUSIONS

Overall, our review shows that while there is no significant difference in the relative risk ratios between the majority of RCTs and observational studies compared, there is significant variation in about 20% of comparisons. The source of this variation should be the subject of further inquiry to elucidate how much of the variation is due to differences in patient populations versus biased estimates arising from issues with study design or analytical/statistical methods.

Many Good Reasons to Switch from Vitamin K Antagonists to Non-Vitamin K Antagonists in Patients with Non-Valvular Atrial Fibrillation

Non-vitamin K oral anticoagulants (NOACs) are the first choice for prophylaxis of cardioembolism in patients with non-valvular atrial fibrillation (AF) who are anticoagulant-naïve, as well as the preferable anticoagulation strategy in those who are on vitamin K antagonists (VKAs), but with a low time in therapeutic range (TTR). Nonetheless, there are many good reasons to consider switching from VKAs to NOACs also when TTR is >70%. From the pharmacological standpoint, anticoagulation with VKAs may remain erratic even in those patients who have high TTR values, owing to the mode of action of this drug class. Furthermore, experimental data suggest that, unlike VKAs, NOACs favorably modulate the effects of factor Xa and thrombin in the cardiovascular system through the protease-activated receptor family. Clinically, the most striking advantage provided by NOACs over VKAs, irrespective of the TTR, is the substantially lower risk of intracranial hemorrhage. NOACs have also been associated with less deterioration of renal function as compared with VKAs and may confer protection against cardiovascular events not strictly related to AF, especially the acute complications of peripheral artery disease. In this narrative review, we discuss the evidence according to which it is warranted to systematically substitute NOACs for VKAs for the prevention of AF-related stroke and systemic embolism.

Prescribing trends of oral anticoagulants in England over the last decade: a focus on new and old drugs and adverse events reporting

Direct-acting oral anticoagulants (DOACs) are replacing conventional VKA (vitamin K antagonist, i.e., warfarin) for various indications where a therapeutic anticoagulant effect is desired. We evaluated the prescribing patterns of the DOACs and warfarin, cost implications of the increasing DOACs prescribing, and deduce the reporting of serious and fatal events, during 2009–2019 in primary care England. Prescriptions and fatal or serious adverse events reporting data, between 2009 and 2019 were analysed, using linear regression to examine the trends in prescriptions, costs, and serious and fatal events reporting. We also compared the prescribing trends of four direct-acting oral anticoagulants and warfarin, normalised to per 1000 clinical commissioning group (CCG) patient population for the year 2019 to better understand the regional differences in DOACs prescribing. The overall use of any DOACs (as a proportion of total anticoagulants) increased from 16% in 2015 to 62% in 2019 with an average increase of 87% (95% CI 83.1, 90.5) per year. The reporting of serious and fatal events associated with DOACs decreased by 6% (95% CI 12.5, − 0.1) per year. Apixaban is by far the most prescribed with an average drug cost increasing to 156% (95% CI 140, 172) per year. In England, the lowest anticoagulant prescribing region was Greater London whereas the highest prescribing regions were Yorkshire and Humber for DOACs and the East Midlands for warfarin. Interestingly, Lancashire, Merseyside, and Cheshire showed a higher usage for warfarin over DOACs. The differing prescription patterns could be a result of changes in national guidelines and increasing population. Nevertheless, DOACs appear to make an increasing contribution to total anticoagulant prescription items and costs.

Non-vitamin K antagonist oral anticoagulants therapy for atrial fibrillation patients undergoing electrophysiologic procedures

Over the last 10 years since the introduction of non-vitamin K antagonist oral anticoagulants (NOACs) into routine clinical practice our experience with these drugs has increased tremendously, also in the context of patients undergoing electrophysiology procedures. While some open questions remain, the available evidence indicates that for the majority of cases, these interventions can safely be performed on NOACs if study-based standard operating procedures are in place and followed. This review summarizes the most current trial evidence and guidelines on the use of NOACs for patients undergoing cardioversion, atrial fibrillation ablation, and device implantations, based on previous work of the author and others.

Warfarin therapy in Chinese patients with atrial fibrillation treated with percutaneous coronary intervention: a 5 year follow-up retrospective cohort study

Objective: To evaluate warfarin use in Chinese patients with atrial fibrillation (AF) undergoing percutaneous coronary intervention (PCI) by investigating the stroke and major adverse cardiac and cerebral events (MACCEs) and bleeding events. Methods: Retrospective cohort study of the 5 year follow-up of 1134 patients with AF who underwent PCI. The patients were grouped according to whether they received warfarin or not. Baseline characteristics and the occurrence of MACCEs and bleeding events were compared between the two groups using the CHA2DS2-VASc and HAS-BLED scoring. Cox regression analysis was used to identify factors related to the occurrence of MACCEs and bleeding. Results: Overall MACCE (p = .008) and mortality (p = .004) rates were significantly lower in the warfarin group compared with the non-warfarin group. Major bleeding, minor bleeding and overall bleeding were comparable in the two groups. Recurrent myocardial infarction (HR = 10.129, 95% CI = 4.737-21.655; p < .001) and a baseline CHA2DS2-VASc score >4 (HR = 2.035, 95% CI = 1.121-3.692; p = .019) were independent predictors of MACCEs in the warfarin group. A baseline HAS-BLED score ≥3 (HR = 5.498, 95% CI = 3.773-8.013; p < .001) and previous bleeding (HR = 3.058, 95% CI = 1.319-7.088; p = .009) were independent predictors of bleeding. Conclusions: Warfarin reduces the incidence of MACCEs but does not increase bleeding events in Chinese patients with AF who underwent PCI. For patients taking warfarin, recurrent myocardial infarction and a baseline CHA2DS2-VASc score >4 were related to MACCE occurrence.