Effectiveness of Nonvitamin K Antagonist Oral Anticoagulants and Warfarin for Preventing Further Cerebral Microbleeds in Acute Ischemic Stroke Patients with Nonvalvular Atrial Fibrillation and At Least One Microbleed: CMB-NOW Multisite Pilot Trial

Efficacy and Safety of Direct Oral Anticoagulants (DOACs) Versus Warfarin in Atrial Fibrillation Patients with Prior Stroke: a Systematic Review and Meta-analysis

BACKGROUND

The purpose of this meta-analysis was to compare efficacy and safety of direct oral anticoagulants (DOACs) to warfarin for secondary stroke prevention among adult patients with atrial fibrillation and prior stroke.

METHODS

Major repositories were screened for randomized controlled trials (RCTs), RCT subgroups, and observational studies (OBSs, divided in claims and non-claims). Occurrences of ischemic stroke or transient ischemic attack, systemic embolism, all-cause mortality, intracranial hemorrhage (ICH), and major bleeding were outcomes of interest. Hazard ratios (HRs) and their confidence intervals (95%CIs) were pooled using random-effects models for each study design. Claims studies were analyzed separately from non-claims, while RCT subgroups were grouped with OBSs (non-claims) as the randomization was broken.

RESULTS

Of 8647 articles, 20 were included (one RCT, six RCT subgroups, nine claims, and four non-claims). Comparing DOACs to warfarin, pooled HRs (95%CI) were consistently in favor of DOACs although some did not reach statistical significance: for ischemic stroke, 0.84 (0.66-1.07) in claims; 0.90 (0.77-1.06) in non-claims and RCT subgroups; for systemic embolism, 0.77 (0.62-0.96) in claims; 0.86 (0.77-0.96) in non-claims and RCT subgroups; for all-cause mortality, 0.57 (0.33-0.99) in claims; 0.87 (0.79-0.96) in non-claims and RCT subgroups; for ICH, 0.72 (0.39-1.33) in claims; 0.51 (0.38-0.67) in non-claims and RCT subgroups; and for major bleeding, 0.86 (0.71-1.03) in claims; 0.90 (0.76-1.08) for non-claims and RCT subgroups.

CONCLUSION

DOACs were associated with better efficacy and safety profiles than warfarin in atrial fibrillation patients with prior stroke, more specifically a lower risk of systemic embolism, all-cause mortality, and ICH.

Role of cerebral microbleeds in acute ischemic stroke and atrial fibrillation

Cerebral microbleeds (CMBs) are commonly detected in the brains of patients with acute ischemic stroke (AIS). With the development of neuroimaging, clinicians are paying more attention to the presence of CMBs. CMBs were found to significantly increase the risk of intracranial hemorrhagic transformation and hemorrhage in patients with AIS, especially in patients with concurrent atrial fibrillation (AF). Additionally, the presence of CMBs is thought to be a symbol of a high risk of recurrent ischemic stroke (IS). A few researchers have found that the presence of CMBs has no significant effect on the prognosis of patients with AIS. Therefore, the current views on the role of CMBs in the prognoses of patients with IS are controversial. The use of anticoagulants and other drugs has also become a dilemma due to the special influence of CMBs on the prognosis of these patients. Due to the large number of patients with AF and CMBs, many studies have been conducted on the effects of CMBs on these patients and subsequent pharmacological treatments. However, at present, there are no relevant guidelines to guide the secondary preventive treatment of patients with stroke, CMBs, and AF. In this paper, we summarized the role of CMBs in AIS combined with AF and relevant preventive measures against the recurrence of stroke and the occurrence of intracerebral hemorrhage to help clarify the specifics of drug therapies for this group of patients.

Impact of type of oral anticoagulants in patients with cerebral microbleeds after atrial fibrillation-related ischemic stroke or TIA: Results of the NOACISP-LONGTERM registry

Background

Cerebral microbleeds (CMBs) may have a differential impact on clinical outcome in stroke patients with atrial fibrillation (AF) treated with different types of oral anticoagulation (OAC).

Methods

Observational single-center study on AF-stroke-patients treated with OAC. Magnetic-resonance-imaging was performed to assess CMBs. Outcome measures consisted of recurrent ischemic stroke (IS), intracranial hemorrhage (ICH), death, and their combined analysis. Functional disability was assessed by mRS. Using adjusted logistic regression and Cox proportional-hazards models, we assessed the association of the presence of CMBs and OAC type (vitamin K antagonists [VKAs] vs. direct oral anticoagulants [DOACs]) with clinical outcome.

Results

Of 310 AF-stroke patients treated with OAC [DOACs: n = 234 (75%); VKAs: n = 76 (25%)], CMBs were present in 86 (28%) patients; of these, 66 (77%) received DOACs. In both groups, CMBs were associated with an increased risk for the composite outcome: VKAs: HR 3.654 [1.614; 8.277]; p = 0.002; DOACs: HR 2.230 [1.233; 4.034]; p = 0.008. Patients with CMBs had ~50% higher absolute rates of the composite outcome compared to the overall cohort, with a comparable ratio between treatment groups [VKAs 13/20(65%) vs. DOACs 19/66(29%); p < 0.01]. The VKA-group had a 2-fold higher IS [VKAs:4 (20%) vs. DOACs:6 (9%); p = 0.35] and a 10-fold higher ICH rate [VKAs: 3 (15%) vs. DOACs: 1 (1.5%); p = 0.038]. No significant interaction was observed between type of OAC and presence of CMBs. DOAC-patients showed a significantly better functional outcome (OR 0.40 [0.17; 0.94]; p = 0.04).

Conclusions

In AF-stroke patients treated with OAC, the presence of CMBs was associated with an unfavorable composite outcome for both VKAs and DOACs, with a higher risk for recurrent IS than for ICH. Strokes were numerically higher under VKAs and increased in the presence of CMBs.

Clinical trial registration

http://www.clinicaltrials.gov, Unique identifier: NCT03826927.

New cerebral microbleeds in AF patients on non-vitamin K oral anticoagulants or warfarin: One-year follow-up

Anticoagulant treatment increases the risk of intracerebral hemorrhage (ICH), but whether the treatment, more specifically non-vitamin K oral anticoagulants (NOACs), increases the risk of cerebral microbleeds (CMBs) remains uncertain. We performed this study to investigate the development of new CMBs due to NOACs or warfarin treatment in patients with atrial fibrillation (AF).We prospectively recruited AF patients before anticoagulation from June 2016 to June 2018. We performed susceptibility-weighted imaging (SWI) examinations on all enrolled AF patients and re-examined SWI 1 year later. We compared demographic features and new CMBs between the NOACs group and the warfarin group. Univariate analysis of clinical factors was performed according to the development of new CMBs; and age, a HAS-B(L)ED score, warfarin use, and the presence of baseline CMBs were then selected for inclusion in the multivariate logistic regression model.A total of 72 AF patients were recruited, 29 of whom were assigned to the NOACs group and 43 to the warfarin group. Finally, 1 patient in the NOACs group (3.4%) and 9 patients (20.9%) in the warfarin group developed new CMBs after 1 year follow-up (P = .08). Univariate analysis showed that age, a HAS-B(L)ED score ≥4, the presence of baseline CMBs were associated with the development of new CMBs (P < .05). And multivariate regression analysis showed baseline CMBs (P = .03, odds ratio = 6.37, 95% confidence interval 1.15-35.36) was independently related to the increase in new CMBs.AF patients treated with NOACs may have a decreased trend in the development of new CMBs compared with those treated with warfarin. Baseline CMBs increased the frequency of new CMBs during anticoagulant treatment. The development of new CMBs in AF patients with anticoagulation requires further longitudinal studies with longer follow-up in larger samples.

Cerebral microbleeds: from depiction to interpretation

Cerebral microbleeds (CMBs) are defined as hypointense foci visible on T2*-weighted and susceptible-weighted MRI sequences. CMBs are increasingly recognised with the widespread use of MRI in healthy individuals as well as in the context of cerebrovascular disease or dementia. They can also be encountered in major critical medical conditions such as in patients requiring extracorporeal mechanical oxygenation. The advent of MRI-guided postmortem neuropathological examinations confirmed that, in the context of cerebrovascular disease, the vast majority of CMBs correspond to recent or old microhaemorrhages. Detection of CMBs is highly influenced by MRI parameters, in particular field strength, postprocessing methods used to enhance T2* contrast and three dimensional sequences. Despite recent progress, harmonising imaging parameters across research studies remains necessary to improve cross-study comparisons. CMBs are helpful markers to identify the nature and the severity of the underlying chronic small vessel disease. In daily clinical practice, presence and numbers of CMBs often trigger uncertainty for clinicians especially when antithrombotic treatments and acute reperfusion therapies are discussed. In the present review, we discuss those clinical dilemmas and address the value of CMBs as diagnostic and prognostic markers for future vascular events.

Oral anticoagulant use and the development of new cerebral microbleeds in cardioembolic stroke patients with atrial fibrillation

OBJECTIVE

Cerebral microbleeds (CMBs) are a magnetic resonance imaging (MRI) marker for cerebral small vessel disease. Existing CMBs and those that newly develop are associated with the risks of stroke incidence and recurrence. The purpose of the present study was to investigate the association of oral anticoagulant (OAC) use and the development of new CMBs in cardioembolic stroke patients with atrial fibrillation.

SUBJECTS AND METHODS

We prospectively followed cardioembolic stroke patients with atrial fibrillation who had been hospitalized in the stroke center of our hospital, had been prescribed anticoagulants at discharge, and underwent repeated brain MRI with an interval of at least one year from the baseline MRI. Assessing the presence, number and location of CMBs using T2*-weighted gradient-recalled echo MRI, we used logistic regression models to investigate the associations between OAC use and the incidence of new CMBs. We also examined associations of subsequent stroke with OACs and CMBs during the follow-up.

RESULTS

A total of 81 patients, consisting of 45 patients receiving direct oral anticoagulants (DOACs) and 36 patients receiving warfarin (WF), were analyzed in the present study. Baseline CMBs were observed in 19/81 patients (23.5%) and new CMBs in 18/81 patients (22.2%) on follow-up MRI (median interval, 34 months). Of the 31 new CMBs, 25 (80.6%) developed in the lobar location and 6 (19.4%) in the deep or infratentorial location. New CMBs occurred in 4 patients (10.0%) taking DOACs　alone, in 10 patients (35.7%) taking WF alone, in 3 patients (37.5%) taking WF plus antiplatelet agents and in 1 patient (20.0%) taking DOAC plus antiplatelet agent. Regarding location, the new CMBs were the lobar type in 7 of the 10 patients taking WF alone, as well as in 3 of the 4 patients taking DOACs alone. In multivariate analysis, the presence of CMBs at baseline and WF use (vs. DOAC use) were associated with new CMBs (CMB presence at baseline: OR 4.16, 95% CI 1.19-14.44; WF use: OR 3.38, 95% CI 1.02-11.42). The presence of ≥ 2 CMBs at baseline was related to a higher risk of subsequent stroke (OR 7.25, 95% CI 1.01-52.35, P = 0.048).

CONCLUSION

Our findings suggest that DOAC compared with WF use at discharge is associated with a lower incidence of new CMBs in cardioembolic stroke patients with atrial fibrillation. Further prospective studies in the clinical setting are needed to confirm our exploratory data.

Advance of antithrombotic treatment in patients with cerebral microbleed

With the elder proportion increasing and the antithrombotic agents widely using as well as the newly magnetic resonance imaging sequence emerging, the detection rate of cerebral microbleed (CMB) is gradually raising in recent years. As we all know that CMB mainly reflects the severity of deeply small vessel lesions, which predicts hemorrhagic transformation. Whereby, to some patients with both CMB and remarkable antithrombotic indication, treatment becomes a dilemma. We have to face the challenge of weighing the pros and cons of both drug indication and bleeding risk when making a proper decision for patients. This study summarized recent advance on CMB diagnosis and treatment, to provide a useful reference to physicians in their clinical practice.

Use of anticoagulant therapy and cerebral microbleeds: a systematic review and meta-analysis

BACKGROUND

Anticoagulant therapy increases the risk that cerebral microbleeds (CMBs) progress to intracerebral hemorrhage, but whether the therapy increases risk of CMB occurrence is unclear. We performed a systematic review and meta-analysis to investigate the potential association between anticoagulant use and CMB occurrence in stroke and stroke-free individuals.

METHODS

We searched observational studies in PubMed, Ovid EMBASE, and Cochrane Library from their inception until September 2019. We calculated the pooled odds ratio (OR) and 95% confidence interval (CI) for the prevalence and incidence of CMBs in anticoagulant users relative to non-anticoagulant users.

RESULTS

Forty-seven studies with 25,245 participants were included. The pooled analysis showed that anticoagulant use was associated with CMB prevalence (OR 1.54, 95% CI 1.26-1.88). The association was observed in subgroups stratified by type of participants: stroke-free, OR 1.86, 95% CI 1.25-2.77; ischemic stroke/transient ischemic attack, OR 1.33, 95% CI 1.06-1.67; and intracerebral hemorrhage, OR 2.26, 95% CI 1.06-4.83. Anticoagulant use was associated with increased prevalence of strictly lobar CMBs (OR 1.68, 95% CI 1.22-2.32) but not deep/infratentorial CMBs. Warfarin was associated with increased CMB prevalence (OR 1.64, 95% CI 1.23-2.18), but novel oral anticoagulants were not. Anticoagulant users showed higher incidence of CMBs during long-term follow-up (OR 1.72, 95% CI 1.22-2.44).

CONCLUSION

Anticoagulant use is associated with higher prevalence and incidence of CMBs. This association appears to depend on location of CMBs and type of anticoagulants. More longitudinal investigations with adjustment for confounders are required to establish the causality.