Efficacy of NOACs in Valvular and Non-Valvular Atrial Fibrillation: A Systematic Review View PDF

Globally, atrial fibrillation (AF) prevalence is about 37000 million, which has been a major cause of related mortalities. In Japan, the incidences of AF are less than 1% of the country’s population as one of the most prevalent arrhythmia [1]. For over the past five decades, warfarin has been the prioritized drug employed to treat strokes associated with AF. Today, the advancement in the field of medicine has led to the emergence of a new kind of anticoagulant drug with more efficacy and options. Although, the prevalence of AF increases with age to an extent where individuals nearing 80 years of age are at high risk of developing AF, reaching about 14% [1,2]. Stroke, systemic embolism, and mortality are all at risk because of AF [3,4]. For eligible individuals with non-valvular atrial fibrillation who have never used an oral anticoagulant, recent guidelines advise treating them with NOACs (apixaban, edoxaban, dabigatran, and rivaroxaban) [2,5]. Numerous randomized controlled studies have substantiated the advantages of NOACs over warfarin in people with NVAF, and a meta-analysis has confirmed that NOACs considerably reduce the stroke risk or SE with a risk of great bleeding that is comparable to that of warfarin [6-10]. Although RCTs are the best standard for proving the efficacy of therapies, their partial representation of a randomly chosen world population limits the applicability of their outcomes to clinical practice [11-14]. As a result, various observational, World evidence studies have been conducted to prove that NOACs are safe and efficacious for use in therapeutic settings [15-18].

However, there are still a number of unresolved knowledge breaches in the literature addressing the clinical results of treatment with NOAC inpatient roles with NVAF, especially inpatient subcategories with a high chance of unfavorable outcomes [19,20]. To treat affected roles with NVAF at risk for stroke and SE, Japan has approved all NOACs (apixaban, edoxaban, dabigatran, and rivaroxaban) [21]. Certain the greater bleeding problem rates recorded in East Asian individuals, it is significant that the dosage of NOACs like in Japan varies a little from that in other nations; for instance, the permitted dosage of rivaroxaban in Japan is 10 mg to 15 mg every day [21]. Given the special circumstances surrounding their administration and the fact that they are frequently started at lower doses, more research is needed to determine how NOACs affect the safety and efficacy outcomes of patients with NVAF in Japan.

Any kind of AF increases the risk of thromboembolism due to the development of atrial thrombi. Henceforth, long-term oral anticoagulation is advised for the majority of AF patients. Regardless of baseline risk, anticoagulation decreases the thromboembolic risks by roughly 2-3rd [22]. All antithrombotic medications did, however, increase the bleeding risk, with cerebral haemorrhage being the most severe bleeding consequence. Oral anticoagulants that are nonvitamin K antagonists have been added to the treatment arsenal for the subordinate and primary prevention of thromboembolic occurrence in patients with AF. In randomized controlled trials, anticoagulation with slightly of the accepted NOACs associated with comparable or reduced rates of severe bleeding and ischemic stroke in patients with AF and a risk of cerebral haemorrhage that was less than half that of warfarin at the adjusted dose [6,10].

Individuals with mechanical valves, rheumatic heart disease, and mitral stenosis has been excluded from the majority of medical trials of antithrombotic treatment in patients with AF. Independent of the fundamental cardiac rhythm, valvular heart disease is present in more than 50% of individuals with AF and is linked to an increased risk of thromboembolic events [23]. AF predicts a significant thromboembolic risk in individuals with mitral valve stenosis and prosthetic valves, and vitamin K antagonists are recommended for stroke and systemic embolism prevention [24]. The NOAC trials have included several patients with VHD. 26% of participants in the ARISTOTLE trial had a history of severe or moderate VHD, most having mitral vomiting or having undergone earlier valve surgery [25]. There was no evidence that patients with and without VHD experienced different effects of apixaban relative to warfarin on stroke, severe bleeding, or all-cause mortality, despite the fact that these individuals had greater rates of systemic embolism and stroke than those without. 14.1% of people with severe VHD and 5.3% of people with past valvular operations were found in a post hoc examination of the ROCKET-AF ((Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation)) [26]. Systemic thromboembolism and all-cause death rates among patients with VHD were comparable, although the risk of severe bleeding was considerably higher with rivaroxaban than with warfarin. The existence of VHD could not change the comparison among warfarin and dabigatran, according to a recent study of the RE-LY trial ((Randomized Evaluation of Long-Term Anticoagulation Therapy), which also showed that 21.8% of patients with AF had it [27].

Warfarin and other VKAs used to be the typical care for individuals with non-valvular AF who wanted to prevent strokes [28]. Warfarin anticoagulation has been replaced by the non-vitamin K antagonist OACs (oral anticoagulants) apixaban, rivaroxaban, dabigatran, and edoxaban because they are more practical, effective, and acceptable [10]. The NOACs are being utilized more frequently in standard clinical practice, which is not surprising. Due to these variations, it is crucial to assess whether an AF patient role with a history of bleeding can experience different results when treated with NOACs as opposed to warfarin [29,30]. As their use continues to rise, more information will also be required to fully comprehend the risk-benefit profiles linked to individually NOAC. The majority of studies on anticoagulant treatment in AF after a significant hemorrhagic occurrence have, to date, concentrated on warfarin treatment alone or warfarin compared to NOACs together rather than contrasting the various NOACs versus warfarin and to one another [31-33]. Pharmacokinetic variations among NOACs might alter their individual efficiency and safety, and this is a crucial omission. Data on this particular segment of the AF sample could be important for making therapeutic choices, assuming that the efficacy and tolerability of pharmaceutical treatment in people with NVAF can be prejudiced by pre-existing individual comorbidities, such as past bleeding. This research compared the risk of stroke, MB, and SE among NVAF individuals with past bleeding linked with NOACs in valvular and non-valvular AF compared to warfarin and one another.