Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Enhancing the evaluation of acute ischemic stroke risk in individuals with non-valvular atrial fibrillation by including laboratory indicators

To investigate the clinical significance of the CHA2DS2-VASc-60 score, lipoprotein (a) [Lp(a)], red blood cell distribution width (RDW), and their combined effect in patients with non-valvular atrial fibrillation (NVAF) who experience acute ischemic stroke (AIS). This retrospective analysis was conducted on the clinical data of hospitalized patients with NVAF at the Third Affiliated Hospital of Anhui Medical University between April 1, 2020, and April 1, 2023. Based on the diagnosis of acute ischemic stroke (AIS), the patients were divided into two groups: the AIS group (150 cases of NVAF patients with comorbid AIS) and the non-AIS group (163 cases of NVAF patients without AIS). We performed CHA2DS2-VASc-60 scoring for all patients and collected their laboratory indicators and echocardiographic indicators during hospitalization. The study comprised 313 individuals with NVAF in total. There is a statistically significant difference (P < 0.05) in the comparison of CHA2DS2-VASc-60 score (5.68 ± 1.12 vs. 3.67 ± 1.47), Lp(a) [23.98 (13.28, 42.22) vs. 14.32 (7.96, 21.91)] and RDW (13.67 ± 1.25 vs. 12.94 ± 0.76) between NVAF patients with and without concomitant AIS. The results of the Spearman correlation analysis demonstrate a positive association between Lp(a) and RDW levels and both the CHA2DS2-VASc score and the CHA2DS2-VASc-60 score in patients with NVAF. Multivariate logistic regression analysis revealed that CHA2DS2-VASc-60 score [OR = 6.549, 95% CI: 4.110-10.433, P < 0.05], Lp(a) [OR = 1.023, 95% CI: 1.005-1.041, P < 0.05], and RDW [OR = 1.644, 95% CI: 1.071-2.525, P < 0.05] were independent risk factors for AIS in patients with non-valvular atrial fibrillation (NVAF). The receiver operator characteristic (ROC) curves showed that the area under the curve of CHA2DS2-VASc-60 score, Lp(a), RDW, and CHA2DS2-VASc-60 score combined with Lp(a) and RDW predicted that NVAF patients with AIS were 0.881 [95% CI: 0.804-0.906], 0.685 [95% CI: 0.626-0.744], 0.695 [95% CI: 0.637-0.754], and 0.906 [95% CI: 0.845-0.921], respectively. The CHA2DS2-VASc-60 score, Lp(a), and RDW were significantly increased in NVAF patients with AIS, which were independent risk factors for NVAF patients with AIS. The combination of the three has a high predictive capacity for NVAF patients with AIS.

Simvastatin, but Not Atorvastatin, Is Associated with Higher Peak Rivaroxaban Serum Levels and Bleeding: an Asian Cohort Study from Singapore

AIMS

This study attempts to identify predictors associated with bleeding and stroke and systemic embolism (SSE) in Singaporean Asians taking rivaroxaban and apixaban.

METHODS

A total of 134 Singaporean patients on either rivaroxaban or apixaban for non-valvular atrial fibrillation were included for this study. Baseline characteristics were recorded at recruitment while bleeding and SSE events were recorded during a 1-year follow-up. Peak and trough drug plasma concentrations were collected based on the dosing interval and pharmacokinetics of the drugs and quantified using high performance liquid chromatography. Characteristics of patients with or without bleeds were compared using relevant statistical tests. Multivariable regression that included covariates with p < 0.1 from an initial univariable regression was performed to analyse predictors that resulted in higher risk of bleeding in patients.

RESULTS

Median creatinine clearance (CrCl) was significantly lower in patients on rivaroxaban who experienced bleeds as compared to patients who did not experience bleeds (61.5 vs 70.8 mL/min, p = 0.047), while concomitant simvastatin use was found to be independently associated with a sixfold increased risk of bleeding (adjusted OR = 6.14 (95% CI: 1.18-31.97), p = 0.031) for rivaroxaban after controlling for body mass index, CrCl and having experienced a previous SSE.

CONCLUSION

Our findings suggest that concomitant use of simvastatin with rivaroxaban may be associated with bleeding events in an Asian cohort. Further studies using physiologically based pharmacokinetic modelling are required to investigate the drug-drug interactions between these drugs.

Propensity score methods for comparative-effectiveness analysis: A case study of direct oral anticoagulants in the atrial fibrillation population

Objective

To explore methodological challenges when using real-world evidence (RWE) to estimate comparative-effectiveness in the context of Health Technology Assessment of direct oral anticoagulants (DOACs) in Scotland.

Methods

We used linkage data from the Prescribing Information System (PIS), Scottish Morbidity Records (SMR) and mortality records for newly anticoagulated patients to explore methodological challenges in the use of Propensity score (PS) matching, Inverse Probability Weighting (IPW) and covariate adjustment with PS. Model performance was assessed by standardised difference. Clinical outcomes (stroke and major bleeding) and mortality were compared for all DOACs (including apixaban, dabigatran and rivaroxaban) versus warfarin. Patients were followed for 2 years from first oral anticoagulant prescription to first clinical event or death. Censoring was applied for treatment switching or discontinuation.

Results

Overall, a good balance of patients’ covariates was obtained with every PS model tested. IPW was found to be the best performing method in assessing covariate balance when applied to subgroups with relatively large sample sizes (combined-DOACs versus warfarin).

With the IPTW-IPCW approach, the treatment effect tends to be larger, but still in line with the treatment effect estimated using other PS methods. Covariate adjustment with PS in the outcome model performed well when applied to subgroups with smaller sample sizes (dabigatran versus warfarin), as this method does not require further reduction of sample size, and trimming or truncation of extreme weights.

Conclusion

The choice of adequate PS methods may vary according to the characteristics of the data. If assumptions of unobserved confounding hold, multiple approaches should be identified and tested. PS based methods can be implemented using routinely collected linked data, thus supporting Health Technology decision-making.

Anticoagulation in special patient populations with atrial fibrillation

Anticoagulation in patients with atrial fibrillation (AF) should be guided by considerations of the risk of thromboembolism, stroke, and bleeding as well as the patient's preference. Well-recognized scores have been developed to help the clinician in daily risk assessment, but there are several special patient populations for whom scores are not developed or validated. Furthermore, these patients were not adequately represented in the pivotal randomized trials for non-vitamin K antagonist oral anticoagulants (NOACs). In patients with cancer, the intrinsic hypercoagulable state has to be balanced against an increased risk of bleeding, and a dynamic concept should be applied, taking into account the cancer type, current disease state, therapeutic strategy, and patient-related factors, with NOACs playing an increasingly larger role. In women with planned pregnancy or already pregnant, NOACs should be avoided. However, accidental exposure during pregnancy should not lead to recommendations for pregnancy termination in view of current observational data. Whether patients on dialysis with AF benefit from anticoagulation at all is questionable. But if the decision for anticoagulation is made, NOACs may contribute to a more favorable risk-benefit profile than vitamin- K antagonists. Finally, patients on the ward deserve special considerations regarding periprocedural management of anticoagulation. Although for the majority of procedures a short discontinuation of oral anticoagulation seems appropriate, there are some low-bleeding-risk procedures that do not require cessation. The aim of the present review is to discuss the major particularities of these four patient subgroups and thus to facilitate the clinical decision-making.

Association of Atrial Fibrillation With Incidence of Extracranial Systemic Embolic Events: The ARIC Study

Background

Atrial fibrillation (AF) increases the risk of stroke and extracranial systemic embolic events (SEEs), but little is known about the magnitude of the association of AF with SEE.

Methods and Results

This analysis included 14 941 participants of the ARIC (Atherosclerosis Risk in Communities) study (mean age, 54.2±5.8, 55% women, 74% White) without AF at baseline (1987–1989) followed through 2017. AF was identified from study ECGs, hospital discharges, and death certificates, while SEEs were ascertained from hospital discharges. CHA₂DS₂‐VASc was calculated at the time of AF diagnosis. Cox regression was used to estimate associations of incident AF with SEE risk in the entire cohort, and between CHA₂DS₂‐VASc score and SEE risk in those with AF. Among eligible participants, 3114 participants developed AF and 270 had an SEE (59 events in AF). Incident AF was associated with increased risk of SEE (hazard ratio [HR], 3.58; 95% CI, 2.57–5.00), after adjusting for covariates. The association of incident AF with SEE was stronger in women (HR, 5.26; 95% CI, 3.28–8.44) than in men (HR, 2.68; 95% CI, 1.66–4.32). In those with AF, higher CHA₂DS₂‐VASc score was associated with increased SEE risk (HR per 1‐point increase, 1.24; 95% CI, 1.05–1.47).

Conclusions

AF is associated with more than a tripling of the risk of SEE, with a stronger association in women than in men. CHA₂DS₂‐VASc is associated with SEE risk in AF patients, highlighting the value of the score to predict adverse outcomes and guide treatment decisions in people with AF.

Comparison Between Oral Anticoagulation and Left Atrial Appendage Occlusion in the Prevention of Stroke With Regard to Non-Valvular Atrial Fibrillation

In the past, the most common type of atrial fibrillation leading to stroke was valvular; this was predominantly due to the prevalence of rheumatic fever, but with the advent of better-hospitalized care, the cases of valvular atrial fibrillation declined. In recent years, there has been an increase in cases of stroke due to non-valvular atrial fibrillation. Stasis of blood in the left atrial pouch leads to coagulation and thrombi formation, which may lead to stroke. Oral medication or mechanical intervention can prevent thrombi formation. Both oral anticoagulation and left atrial appendage occlusion (LAAO) have been compared to see which has better outcomes. It was observed that LAAO has greater efficacy, but with time throughout a couple of years, no considerable difference was seen when compared to warfarin. Most of the long-term randomized controlled trials have been performed with the Watchman^® device. Although the Lariat and Amplatzer LAAO devices have also shown favorable outcomes, there is still a deficiency when it comes to trials of high-quality evidence using these devices as an intervention. Dual therapy with both of these approaches showed a decline in the count of major bleeding episodes on follow-up. Overall, albeit both methods have proven useful, LAAO has a slight advantage in efficacy and leads to less hemorrhagic events.