Brain microbleeds, anticoagulation, and hemorrhage risk: Meta-analysis in stroke patients with AF

Resumption of oral anticoagulation after spontaneous intracerebral hemorrhage

Background

Given an ageing population the incidence of both patients suffering from intracerebral hemorrhage (ICH) and those requiring oral anticoagulation will increase. Up to now there are no results from randomized trials available whether or not, and when, ICH survivors should resume OAC. This review summarizes the most important observational studies, and initiated ongoing trials, to help guiding physicians in daily routine decision making.

Findings

Several large observational studies and meta-analyses verified that OAC resumption was associated with a significant reduction of thromboembolic complications and mortality without leading to increased rates of recurrent ICH. OAC resumption seemed further associated with improved functional recovery and favorable long-term outcome. Given the general bleeding risk reduction in patients using Non–vitamin K antagonist oral anticoagulants (NOAC) compared to Vitamin-K-antagonist (VKA), NOAC use should also be preferred after ICH, although specific comparative studies are pending. Patients with lobar ICH need special attention as these patients showed increased ICH recurrence rates, why decision making should include extended diagnostic work-up evaluating cerebral microbleed burden, cortical subarachnoid hemorrhage and superficial siderosis. Further, patients with mechanical heart valves need specific consideration as restarting VKA may be unsafe until two weeks, whereas optimal balancing of hemorrhagic with thromboembolic complications may allow earlier re-initiation one week after ICH. In patients with atrial fibrillation, resumption generally should take place between 4 and 8 weeks after ICH depending on a patient’s individual risk profile. Left atrial appendage occlusion (LAAO) might represent an alternative strategy in high-risk patients. Ongoing clinical trials will clarify whether OAC resumption versus LAAO versus no antithrombotic therapy may represent the best possible secondary stroke prevention in ICH survivors with atrial fibrillation.

Conclusions

According to observational data OAC resumption after ICH seems beneficial and safe. Ongoing clinical trials will create evidence regarding treatment effects of pharmaceutical resumption and interventional alternatives. Yet, individual decision making weighing the patient’s individual thromboembolic versus hemorrhagic risks remains essential.

Prevention and Treatment of Acute Stroke in the Nonagenarians and Beyond: Medical and Ethical Issues

PURPOSE OF REVIEW

As one of the fastest growing portions of the population, nonagenarians will constitute a significant percentage of the stroke patient population in the near future. Nonagenarians are nevertheless not specifically targeted by most clinical guidelines. In this review, we aimed to summarise the available evidence guiding stroke prevention and treatment in this age group.

RECENT FINDINGS

Several recent observational studies have shown that the benefits of anticoagulation for the oldest old patients with atrial fibrillation may outweigh the bleeding risk. A sub-analysis of the IST-3 trial has shown for the first time that thrombolysis treatment in acute ischaemic stroke may be beneficial and safe even in octogenarian patients and older. Several recent observational studies have assessed thrombolysis in nonagenarians. The latest of these has shown better disability outcomes without increased rates of symptomatic intracerebral haemorrhage with thrombolysis. Nonagenarian stroke patients may benefit from similar preventative and therapeutic strategies as their younger counterparts. A few important exceptions include primary prevention using aspirin or statins. Patient selection is nevertheless essential given the increased adverse event rates. Patient preference should play a key role in the decision-making process. Clinical trials including more nonagenarian patients are required to yield more robust evidence.

MRI predicts intracranial hemorrhage in patients who receive long-term oral anticoagulation

OBJECTIVE

We tested the hypothesis that the risk of intracranial hemorrhage (ICH) in patients with cardioembolic ischemic stroke who are treated with oral anticoagulants (OAs) can be predicted by evaluating surrogate markers of hemorrhagic-prone cerebral angiopathies using a baseline MRI.

METHODS

Patients were participants in a multicenter and prospective observational study. They were older than 64 years, had a recent cardioembolic ischemic stroke, and were new users of OAs. They underwent a baseline MRI analysis to evaluate microbleeds, white matter hyperintensities, and cortical superficial siderosis. We collected demographic variables, clinical characteristics, risk scores, and therapeutic data. The primary endpoint was ICH that occurred during follow-up. We performed bivariate and multivariate Cox regression analyses.

RESULTS

We recruited 937 patients (aged 77.6 ± 6.5 years; 47.9% were men). Microbleeds were detected in 207 patients (22.5%), moderate/severe white matter hyperintensities in 419 (45.1%), and superficial siderosis in 28 patients (3%). After a mean follow-up of 23.1 ± 6.8 months, 18 patients (1.9%) experienced an ICH. In multivariable analysis, microbleeds (hazard ratio 2.7, 95% confidence interval [CI] 1.1-7, p = 0.034) and moderate/severe white matter hyperintensities (hazard ratio 5.7, 95% CI 1.6-20, p = 0.006) were associated with ICH (C index 0.76, 95% CI 0.66-0.85). Rate of ICH was highest in patients with both microbleed and moderate/severe WMH (3.76 per 100 patient-years, 95% CI 1.62-7.4).

CONCLUSION

Patients taking OAs who have advanced cerebral small vessel disease, evidenced by microbleeds and moderate to severe white matter hyperintensities, had an increased risk of ICH. Our results should help to determine the risk of prescribing OA for a patient with cardioembolic stroke.

CLINICALTRIALSGOV IDENTIFIER

NCT02238470.

Antithrombotic treatment for secondary prevention of stroke and other thromboembolic events in patients with stroke or transient ischemic attack and non-valvular atrial fibrillation: A European Stroke Organisation guideline

Patients with ischemic stroke or transient ischemic attack and non-valvular atrial fibrillation have a high risk of recurrent stroke and other vascular events. The aim of this guideline is to provide recommendations on antithrombotic medication for secondary prevention of stroke and other vascular outcomes in these patients. The working group identified questions and outcomes, graded evidence, and developed recommendations according to the Grading of Recommendations Assessment, Development, and Evaluation approach and the European Stroke Organisation (ESO) standard operating procedure for guidelines. The guideline was reviewed and approved by the ESO guideline board and the ESO executive committee. In patients with atrial fibrillation and previous stroke or transient ischemic attack, oral anticoagulants reduce the risk of recurrence over antiplatelets or no antithrombotic treatment. Non-vitamin K antagonist oral anticoagulants are preferred over vitamin K antagonists because they have a lower risk of major bleeding and death. Recommendations are weak regarding timing of treatment, (re-)starting oral anticoagulants in patients with previous intracerebral haemorrhage, and treatment in specific patient subgroups of those of older age, with cognitive impairment, renal failure or small vessel disease, because of a lack of strong evidence. In conclusion, for patients with atrial fibrillation and ischemic stroke or transient ischemic attack, non-vitamin K antagonist oral anticoagulants are the preferred treatment for secondary prevention of recurrent stroke or thromboembolism. Further research is required to determine the best timing for initiating oral anticoagulants after an acute ischemic stroke, whether or not oral anticoagulants should be (re)started in patients with a history of intracerebral haemorrhage, and the best secondary preventive treatment in specific subgroups.

Risk of intracerebral haemorrhage in Chinese patients with atrial fibrillation on warfarin with cerebral microbleeds: the IPAAC-Warfarin study

BACKGROUND AND PURPOSE

Cerebral microbleeds (CMBs), which predict future intracerebral haemorrhage (ICH), may guide anticoagulant decisions for atrial fibrillation (AF). We aimed to evaluate the risk of warfarin-associated ICH in Chinese patients with AF with CMBs.

METHODS

In this prospective, observational, multicentre study, we recruited Chinese patients with AF who were on or intended to start anticoagulation with warfarin from six hospitals in Hong Kong. CMBs were evaluated with 3T MRI brain at baseline. Primary outcome was clinical ICH at 2-year follow-up. Secondary outcomes were ischaemic stroke, systemic embolism, mortality of all causes and modified Rankin Scale ≥3. Outcome events were compared between patients with and without CMBs.

RESULTS

A total of 290 patients were recruited; 53 patients were excluded by predefined criteria. Among the 237 patients included in the final analysis, CMBs were observed in 84 (35.4%) patients, and 11 had ≥5 CMBs. The mean follow-up period was 22.4±10.3 months. Compared with patients without CMBs, patients with CMBs had numerically higher rate of ICH (3.6% vs 0.7%, p=0.129). The rate of ICH was lower than ischaemic stroke for patients with 0 to 4 CMBs, but higher for those with ≥5 CMBs. CMB count (C-index 0.82) was more sensitive than HAS-BLED (C-index 0.55) and CHA2DS2-VASc (C-index 0.63) scores in predicting ICH.

CONCLUSIONS

In Chinese patients with AF on warfarin, presence of multiple CMBs may be associated with higher rate of ICH than ischaemic stroke. Larger studies through international collaboration are needed to determine the risk:benefit ratio of oral anticoagulants in patients with AF of different ethnic origins.

Management of oral anticoagulation after intracerebral hemorrhage

BACKGROUND

The most recent years have significantly expanded knowledge regarding risks and benefits of resuming oral anticoagulation (OAC) after intracerebral hemorrhage (ICH). No randomized data is yet available, though several large observational studies and meta-analyses have investigated the impact of resuming OAC on thromboembolic versus hemorrhagic complications in these high-risk patients after ICH.

AIMS

The present review will summarize the most important studies conducted over the last years and will focus on relevant factors help guiding on decision-making on whether to start OAC after ICH.

SUMMARY OF REVIEW

Several important factors (demographic, co-morbidities, clinical characteristics) need to be considered before individual decision-making for or against OAC is employed. Existing observational data suggest that patients after ICH with indication for long-term oral anticoagulation benefit from OAC given significant reductions of thromboembolic events without significantly increasing bleeding complications. Studies even suggest that thereby also clinical outcomes may be improved. Prospective trials currently recruiting patients will clarify whether OAC after ICH - or left atrial appendage closure as a meaningful alternative - is of clinical net-benefit.

CONCLUSIONS

Large sized and well-executed investigations (moderate quality of evidence) are showing that OAC resumption after ICH decreases thromboembolic complications and long-term mortality without significantly increasing bleeding complications. Further, data suggest that resumption may be safer in non-lobar ICH compared to lobar ICH, but overall, thoughtful selection, strict blood pressure control, and precise communication are paramount before starting a patient on OAC after ICH.

Cerebral microbleeds: Beyond the macroscope

While being increasingly recognized in clinical routine, brain microbleeds remain a puzzling finding for physicians. These small dot-like lesions are thought to be old perivascular collections of hemosiderin deposits. They can be found in different neurological settings such as cerebrovascular or neurodegenerative diseases. While their microscopic size would suggest considering these lesions as anecdotal, they are now regarded as biomarkers of severity of an underlying cerebrovascular disease. Their natural history and the interactions with surrounding brain cells remain unknown. However, their presence may impact therapeutic decisions. Deciphering the biological mechanisms leading to, or following microbleeds would enable us to address a key question: do microbleeds arise and impact the surrounding parenchyma like a miniature version of intracerebral hemorrhages or do they represent a different kind of injury? We hereby discuss, based on both clinical and experimental literature, the gap between the definition of microbleeds coming from neuroimaging and the pathophysiological hypotheses raised from histopathological and experimental data. Our analysis supports the need for a convergent effort from clinicians and basic scientists to go beyond the current “macro” view and disclose the cellular and molecular insights of these cerebral hemorrhagic microlesions.

Prior Antithrombotic Therapy Is Associated With Cerebral Microbleeds in Ischemic Stroke Patients With Atrial Fibrillation and/or Rheumatic Heart Disease

Background and purpose: Cerebral microbleeds (CMBs) could contribute to an increased risk of intracerebral hemorrhage in patients with antithrombotic therapy (antiplatelets or anticoagulants). Antithrombotic agents are commonly prescribed to the patients with atrial fibrillation (AF) and/or rheumatic heart disease (RHD) for preventing ischemic stroke. However, the impact of antithrombotic therapy on CMBs remained controversial. We aimed to explore the association between the prevalence of CMBs and prior antithrombotic therapy in ischemic stroke patients with AF and/or RHD.

Materials and Methods: Ischemic stroke patients with AF and/or RHD within 7 days of onset from two hospitals were enrolled. Clinical information, prior use of antiplatelets or anticoagulation, presence and location of CMBs on susceptibility weighted imaging were recorded. We investigated the association of antithrombotic use with the presence or location of CMBs using multivariable logistic regression.

Results: A total of 160 patients (68 males; median age, 71 years) were included. CMBs were observed in 90 (56.3%) patients, of whom 37 were with strictly lobar CMBs and 53 were with deep or infratentorial CMBs. There was a significant difference in antiplatelet use between patients with and without CMBs (33.3 vs. 11.4%, P = 0.001), but not found in anticoagulants. Prior use of antiplatelets was independently associated with the presence of CMBs (OR 3.075, 95% CI 1.175–8.045, P = 0.022) and especially strictly lobar CMBs (OR 2.635, 95% CI 1.050–6.612, P = 0.039) in multivariate analysis.

Conclusions: The present study suggests that CMBs are common in ischemic stroke patients with AF and/or RHD and prior antiplatelet use may relate to the presence of CMBs predominantly in the strictly lobar region. Whether anticoagulants could cause CMBs need to be determined in future longitudinal studies.

Cerebral Microbleeds and the Safety of Anticoagulation in Ischemic Stroke Patients: A Systematic Review and Meta-Analysis

OBJECTIVES

The objective of this study was to investigate the safety of anticoagulation in ischemic stroke (IS) patients with cerebral microbleeds (CMBs).

METHODS

PubMed, Web of Science, Elsevier Clinical Key, Google Scholar, and Cochrane Library from 1996 to July 2018 were searched to identify relevant studies that included IS patients, underwent T2*-weighted gradient recalled echo, or susceptibility-weighted imaging for detection CMBs and used anticoagulants during follow-up. Primary outcome of interest was intracerebral hemorrhage (ICH). Secondary outcomes were hemorrhage transformation, IS, total mortality, and new developed CMBs. We critically appraised studies and conducted a systematic review and meta-analysis following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance.

RESULTS

We included 7 observational studies. Cerebral microbleeds were associated with a significantly elevated risk of anticoagulation-related ICH (odds ratio, 4.01; 95% confidence interval, 1.82-8.81; P = 0.001). It was significant for warfarin (odds ratio, 8.02; 95% confidence interval, 1.51-42.62; P = 0.015). New developed CMBs in patients on warfarin treatment were associated with baseline CMBs, and the appearance of hemorrhagic transformation did not have a significant relationship with baseline CMBs.

CONCLUSIONS

The presence of CMBs increases the risk of ICH during anticoagulant treatment (especially warfarin) in IS patients. Further studies with larger numbers of patients are needed to confirm our conclusions.

Cerebral microbleeds and intracranial haemorrhage risk in patients anticoagulated for atrial fibrillation after acute ischaemic stroke or transient ischaemic attack (CROMIS-2): a multicentre observational cohort study

BACKGROUND

Cerebral microbleeds are a potential neuroimaging biomarker of cerebral small vessel diseases that are prone to intracranial bleeding. We aimed to determine whether presence of cerebral microbleeds can identify patients at high risk of symptomatic intracranial haemorrhage when anticoagulated for atrial fibrillation after recent ischaemic stroke or transient ischaemic attack.

METHODS

Our observational, multicentre, prospective inception cohort study recruited adults aged 18 years or older from 79 hospitals in the UK and one in the Netherlands with atrial fibrillation and recent acute ischaemic stroke or transient ischaemic attack, treated with a vitamin K antagonist or direct oral anticoagulant, and followed up for 24 months using general practitioner and patient postal questionnaires, telephone interviews, hospital visits, and National Health Service digital data on hospital admissions or death. We excluded patients if they could not undergo MRI, had a definite contraindication to anticoagulation, or had previously received therapeutic anticoagulation. The primary outcome was symptomatic intracranial haemorrhage occurring at any time before the final follow-up at 24 months. The log-rank test was used to compare rates of intracranial haemorrhage between those with and without cerebral microbleeds. We developed two prediction models using Cox regression: first, including all predictors associated with intracranial haemorrhage at the 20% level in univariable analysis; and second, including cerebral microbleed presence and HAS-BLED score. We then compared these with the HAS-BLED score alone. This study is registered with ClinicalTrials.gov, number NCT02513316.

FINDINGS

Between Aug 4, 2011, and July 31, 2015, we recruited 1490 participants of whom follow-up data were available for 1447 (97%), over a mean period of 850 days (SD 373; 3366 patient-years). The symptomatic intracranial haemorrhage rate in patients with cerebral microbleeds was 9·8 per 1000 patient-years (95% CI 4·0-20·3) compared with 2·6 per 1000 patient-years (95% CI 1·1-5·4) in those without cerebral microbleeds (adjusted hazard ratio 3·67, 95% CI 1·27-10·60). Compared with the HAS-BLED score alone (C-index 0·41, 95% CI 0·29-0·53), models including cerebral microbleeds and HAS-BLED (0·66, 0·53-0·80) and cerebral microbleeds, diabetes, anticoagulant type, and HAS-BLED (0·74, 0·60-0·88) predicted symptomatic intracranial haemorrhage significantly better (difference in C-index 0·25, 95% CI 0·07-0·43, p=0·0065; and 0·33, 0·14-0·51, p=0·00059, respectively).

INTERPRETATION

In patients with atrial fibrillation anticoagulated after recent ischaemic stroke or transient ischaemic attack, cerebral microbleed presence is independently associated with symptomatic intracranial haemorrhage risk and could be used to inform anticoagulation decisions. Large-scale collaborative observational cohort analyses are needed to refine and validate intracranial haemorrhage risk scores incorporating cerebral microbleeds to identify patients at risk of net harm from oral anticoagulation.

FUNDING

The Stroke Association and the British Heart Foundation.

Anticoagulation Resumption After Intracerebral Hemorrhage

Purpose of review

Decision-making on resuming oral anticoagulant (OAC) after intracerebral hemorrhage (ICH) evokes significant debate among clinicians. Such patients have been excluded from randomized clinical trials. This review article provides a comprehensive summary of the evidence on anticoagulation resumption after ICH.

Recent findings

OAC resumption does not increase the risk of recurrent ICH and can also reduce the risk of all-cause mortality. OAC cessation exposes patients to a significantly higher risk of thromboembolism, which could be reduced by resumption. The optimal timing of anticoagulation resumption after ICH is still unknown. Both early (< 2 weeks) and late (> 4 weeks) resumption should be reached only after very careful assessment of risks for ICH recurrence and thromboembolism. The introduction of new oral anticoagulants and other interventions, such as left atrial appendage closure, has provided some patients with more alternatives.

Summary

Given the lack of high-quality evidence to guide clinical decision-making, clinicians must carefully balance the risks of thromboembolism and recurrent ICH in individual patients. We propose a management approach which would facilitate the decision-making process on whether anticoagulation is appropriate, as well as when and how to restart anticoagulation after ICH.