Atrial fibrillation: a review of recent studies with a focus on those from the duke clinical research institute

Sirt1 Deficiency Promotes Age-Related AF Through Enhancing Atrial Necroptosis by Activation of RIPK1 Acetylation

BACKGROUND

Aging is one of the most potent risk determinants for the onset of atrial fibrillation (AF). Sirts (sirtuins) have been implicated in the pathogenesis of cardiovascular disease, and their expression declines with aging. However, whether Sirts involved in age-related AF and its underlying mechanisms remain unknown. The present study aims to explore the role of Sirts in age-related AF and delineate the underlying molecular mechanisms.

METHODS

Sirt1 levels in the atria of both elderly individuals and aging rats were evaluated using quantitative real-time polymerase chain reaction and Western blot analysis. Mice were engineered to specifically knockout Sirt1 in the atria and right ventricle (Sirt1mef2c/mef2c). Various techniques, such as echocardiography, atrial electrophysiology, and protein acetylation modification omics were employed. Additionally, coimmunoprecipitation was utilized to substantiate the interaction between Sirt1 and RIPK1 (receptor-interacting protein kinase 1).

RESULTS

We discerned that among the diverse subtypes of sirtuin proteins, only Sirt1 expression was significantly diminished in the atria of elderly people and aged rats. The Sirt1mef2c/mef2c mice exhibited an enlarged atrial diameter and heightened vulnerability to AF. Acetylated proteomics and cell experiments identified that Sirt1 deficiency activated atrial necroptosis through increasing RIPK1 acetylation and subsequent pseudokinase MLKL (mixed lineage kinase domain-like protein) phosphorylation. Consistently, necroptotic inhibitor necrosulfonamide mitigated atrial necroptosis and diminished both the atrial diameter and AF susceptibility of Sirt1mef2c/mef2c mice. Resveratrol prevented age-related AF in rats by activating atrial Sirt1 and inhibiting necroptosis.

CONCLUSIONS

Our findings first demonstrated that Sirt1 exerts significant efficacy in countering age-related AF by impeding atrial necroptosis through regulation of RIPK1 acetylation, highlighting that the activation of Sirt1 or the inhibition of necroptosis could potentially serve as a therapeutic strategy for age-related AF.

APPROACHES TO THE CHOICE OF ANTICOAGULANT THERAPY IN THE TREATMENT OF PATIENTS WITH COMBINATION OF ATRIAL FIBRILLATION WITH CORONARY HEART DISEASE OR PERIPHERAL ATHEROSCLEROSIS: POTENTIAL OF APIXABAN

The choice of anticoagulant therapy in patients with atrial fibrillation (AF) and concomitant diseases – coronary heart disease (CHD), including acute coronary syndrome (ACS) in history, peripheral arterial disease (PAD), is discussed in the article. The overall mortality and incidence of myocardial infarction in patients with CHD and AF is higher than in patients with AF without CHD. Patients with AF and PAD compared to patients with AF without PAD have higher risks both stroke and systemic embolism. The prescription of triple antithrombotic therapy is necessary for patients with a combination of AF and CHD who underwent percutaneous coronary interventions (in ACS or elective surgery). The possibility of prescription and duration, the choice of specific drugs and their doses should be determined individually, based on the risks of ischemic events associated with stenting, the risk of ischemic stroke and bleeding. Use of new oral anticoagulants (NOAC) instead of vitamin K antagonists (eg, warfarin), low doses of NOAC, studied in trials and proven efficacy in the prevention of stroke/systemic embolism, the use of clopidogrel as a drug of choice from the P2Y12 inhibitor group, the use of low doses of acetylsalicylic acid (ASA), the routine administration of drugs from the proton pump inhibitor group is recommended to minimize the risk of bleeding. The data of subanalysis of the ARISTOTEL randomized clinical trial, indicating a high profile of efficacy and safety of apixaban in patients with AF, depending on the presence of CHD, PAD, concomitant use of ASA, are also presented in the article. The benefits of apixaban over warfarin for reducing the risk of stroke/systemic embolism, total mortality and the risk of bleeding in a subgroup of CHD patients are just as obvious as in the general population of the ARISTOTLE study, and in the subgroup of patients without CHD. Treatment with apixaban, both in the subgroup of patients taking ASA, and a subgroup of patients without ASA, is accompanied by a lower risk of strokes and systemic embolism and a lower incidence of major bleeding. The risk of stroke or systemic embolism was similar in patients with AF and PAD randomized to the apixaban group or to the warfarin group, as well as in patients with AF without PAD. Patients with AF and PAD who received apixaban or warfarin had a similar incidence of major bleeding or clinically significant minor bleeding.

Apixaban to prevent stroke in patients with atrial fibrillation: a review

Atrial fibrillation is a common, costly and morbid cardiovascular arrhythmia. Stroke prevention remains the mainstay of treatment for atrial fibrillation, and the recent advent of novel oral anticoagulants with direct factor IIa or factor Xa inhibition has significantly revolutionized this aspect of treatment for atrial fibrillation patients. This review focuses on the tolerability and efficacy of apixaban and tackles the generalizability of the findings with apixaban to broader patient populations than those primarily enrolled in the clinical trials, drawing from the AVERROES and ARISTOTLE trials and their subsequent secondary analyses. Taken together, findings from these trials show that apixaban is superior to warfarin in preventing stroke with a lower risk of major bleeding in the general population of patients with atrial fibrillation as well as in several key high-risk patient subgroups.

Results from the Registry of Atrial Fibrillation (AFABE): Gap between Undiagnosed and Registered Atrial Fibrillation in Adults--Ineffectiveness of Oral Anticoagulation Treatment with VKA

Objective. This study aimed to examine the effectiveness of the use of oral anticoagulation (OAC) medication, recommended by national guidelines for stroke prevention but reportedly underused in AF patients with moderate to high stroke risk. Method. A multicentre and cross-sectional study of undiagnosed AF among out-of-hospital patients over 60 years old was carried out, visiting 3,638 patients at primary health centres or at home for AF diagnosis using the IDC-10 classification. The main outcome measures were CHA₂DS₂VAS_C, HAS-BLED scores, cardiovascular comorbidity, pharmacological information, TTR, and SAMe-TT2R2 scores. Results. The main findings were undiagnosed AF in 26.44% of cases; 31.04% registered with AF but not using OAC despite 95.6% having a CHA₂DS₂VAS_C ≥ 2 score; a risk of bleeding in important subgroups using OAC without indication (37.50% CHA₂DS₂VAS_C < 2 score); the use of OAC with TTR < 60% (33.1%), of whom 47.6% had a HAS-BLED score ≥3. Thus, 35.4% of the expected AF prevalence achieved an optimal time in the therapeutic range. Conclusions. The expected AF prevalence was 10.9% (n 5267), but the registered prevalence was 7.5% (n 3638). Only 35.04% (CI = 95%, 33.7–36.3) of AF patients treated with vitamin K antagonists (VKAs) achieve the goal of TTR > 60%.