Systematic review of observational research studying the long-term use of antithrombotic medicines following intracerebral hemorrhage

Hemorrhagic Coagulation Disorders and Ischemic Stroke: How to Reconcile Both?

Coagulation and fibrinolytic system disorders are conditions in which the blood's ability to clot is impaired, resulting in an increased risk of thrombosis or bleeding. Although these disorders are the expression of two opposing tendencies, they can often be associated with or be a consequence of each other, contributing to making the prognosis of acute cerebrovascular events more difficult. It is important to recognize those conditions that are characterized by dual alterations in the coagulation and fibrinolytic systems to reduce the prognostic impact of clinical conditions with difficult treatment and often unfortunate outcomes. Management of these individuals can be challenging, as clinicians must balance the need to prevent bleeding episodes with the potential risk of clot formation. Treatment decisions should be made on an individual basis, considering the specific bleeding disorder, its severity, and the patient's general medical condition. This review aims to deal with all those forms in which coagulation and fibrinolysis represent two sides of the same media in the correct management of patients with acute neurological syndrome. Precision medicine, personalized treatment, advanced anticoagulant strategies, and innovations in bleeding control represent future directions in the management of these complex pathologies in which stroke can be the evolution of two different acute events or be the first manifestation of an occult or unknown underlying pathology.

Anticoagulation medication in nontraumatic intracranial hemorrhage survivors with atrial fibrillation

BACKGROUND

The relative effectiveness of anticoagulation agents in patients with atrial fibrillation (AF) who survive an intracranial hemorrhage (ICH) is unknown. This study was performed to examine the comparative effectiveness of different oral anticoagulation (OAC) on clinical outcomes in this group of patients.

METHODS

We performed a Bayesian network meta-analysis of randomized controlled trials (RCTs) and observational studies comparing different OAC (direct oral anticoagulant [DOAC] and warfarin) for the treatment of patients with AF who sustained ICH. Outcomes included repeat ICH, thromboembolic events, and all-cause mortality. The values derived from the surface under the cumulative ranking curve were obtained to rank the treatment hierarchy.

RESULTS

We identified 12 studies (two RCTs and ten observational studies) involving 23,265 patients; 346 patients were treated with any OAC agents; 5,006 received DOAC; 5,271 received warfarin; 12,007 received antiplatelet or no therapy, and 635 did not received relevant therapy. Both DOAC and warfarin (RR, 0.58; 95% CI, 0.45-0.74; RR, 0.83; 95% CI, 0.69-0.98) were superior to antiplatelet or no therapy in preventing thromboembolic events. Moreover, DOAC also showed superiority in preventing thromboembolic events (RR, 0.70; 95% CI, 0.58-0.83), repeat ICH (RR, 0.52; 95% CI, 0.40-0.67), and all-cause mortality (RR, 0.51; 95% CI, 0.46-0.56) than warfarin.

CONCLUSIONS

Our study suggests DOACs may be a reasonable alternative to anti-platelet therapy and warfarin for patients with AF who experienced ICH. However, given the available evidence is primarily observational, further validation by ongoing trials directly comparing these two classes of drugs are needed.

Risk of intracranial hemorrhage (RICH) in users of oral antithrombotic drugs: Nationwide pharmacoepidemiological study

Background

The risks of intracranial haemorrhage (ICH) associated with antithrombotic drugs outside clinical trials are gaining increased attention. The aim of this nationwide study was to investigate the risk of ICH requiring hospital admission in users of antithrombotic drugs.

Methods and findings

Data from the Norwegian Patient Registry and Norwegian Prescription Database were linked on an individual level. The primary outcome was incidence rates of ICH associated with use of antithrombotic drugs. Secondary endpoints were risk of ICH and fatal outcome following ICH assessed by Cox models. Among 3,131,270 individuals ≥18 years old observed from 2008 through 2014, there were 729,818 users of antithrombotic medications and 22,111 ICH hospitalizations. Annual crude ICH rates per 100 person-years were 0.076 (95% CI, 0.075–0.077) in non-users and 0.30 (95% CI, 0.30–0.31) in users of antithrombotic medication, with the highest age and sex adjusted rates observed for aspirin-dipyridamole plus clopidogrel (0.44; 95% CI, 0.19–0.69), rivaroxaban plus aspirin (0.36; 95% CI, 0.16–0.56), warfarin plus aspirin (0.34; 95% CI, 0.26–0.43), and warfarin plus aspirin and clopidogrel (0.33; 95% CI, 0.073–0.60). With no antithrombotic medication as reference, the highest adjusted hazard ratios (HR) for ICH were observed for aspirin-dypiridamole plus clopidogrel (6.29; 95% CI 3.71–10.7), warfarin plus aspirin and clopidogrel (4.38; 95% CI 2.71–7.09), rivaroxaban plus aspirin (3.82; 95% CI, 2.46–5.95), and warfarin plus aspirin (3.40; 95% CI, 2.99–3.86). All antithrombotic medication regimens were associated with an increased risk of ICH, except dabigatran monotherapy (HR 1.20; 95% CI, 0.88–1.65) and dabigatran plus aspirin (HR 1.79; 95% CI, 0.96–3.34). Fatal outcome within 90 days was more common in users (2,603 of 8,055) than non-users (3,228 of 14,056) of antithrombotic medication (32.3% vs 23.0%, p<0.001), and was associated with use of warfarin plus aspirin and clopidogrel (HR 2.89; 95% CI, 1.49–5.60), warfarin plus aspirin (HR 1.37; 95% CI, 1.11–1.68), aspirin plus clopidogrel (HR 1.30; 95% CI, 1.05–1.61), and warfarin (HR 1.19; 95% CI, 1.09–1.31). Increased one-year mortality was observed in users of antithrombotic medication following hemorrhagic stroke, subdural hemorrhage, subarachnoid hemorrhage, and traumatic ICH (all p<0.001). Limitations include those inherent to observational studies including the inability to make causal inferences, certain assumptions regarding drug exposure, and the possibility of residual confounding.

Conclusions

The real-world incidence rates and risks of ICH were generally higher than reported in randomized controlled trials. There is still major room for improvement in terms of antithrombotic medication safety (clinicaltrials.gov NCT02481011).

Resuming anticoagulants after anticoagulation-associated intracranial haemorrhage: systematic review and meta-analysis

OBJECTIVE

To determine the adverse outcomes following resumption of anticoagulation in patients with anticoagulation-associated intracranial haemorrhage (ICH).

DESIGN

We performed a systematic review and meta-analysis in this clinical population. The Preferred Reporting Items for Systemic Reviews and Meta-Analyses statement was followed, and two authors independently assessed eligibility of all retrieved studies and extracted data.

DATA SOURCES

Medline, Embase and the Cochrane Central Register of Controlled Trials, from inception to February 2017.

ELIGIBILITY CRITERIA AND OUTCOMES

Randomised controlled trials or cohort studies that recruited adults who received oral anticoagulants at the time of ICH occurrence and survived after the acute phase or hospitalisation were searched. Primary outcomes, including long-term mortality, recurrent ICH and thromboembolic events. Secondary outcomes were the frequency of resuming anticoagulant therapy and related factors.

RESULTS

We included 12 cohort studies (no clinical trials) involving 3431 ICH participants. The pooled frequency of resuming anticoagulant therapy was 38% (95% CI 32% to 44%), but this was higher in participants with prosthetic heart valves, subarachnoid haemorrhage or dyslipidaemia. There was no evidence that resuming anticoagulant therapy was associated with higher long-term mortality (pooled relative risk (RR) 0.60, 95% CI 0.30 to 1.19; p=0.14) or ICH recurrence (pooled RR 1.14, 95% CI 0.72 to 1.80; p=0.57). Resumption of anticoagulation was associated with significantly fewer thromboembolic events (pooled RR 0.31, 95% CI 0.23 to 0.42; p<0.001). In a subgroup of patients with atrial fibrillation, resuming anticoagulant therapy was associated with fewer long-term mortality (pooled RR 0.27, 95% CI 0.20 to 0.37, p<0.001).

CONCLUSIONS

Based on these observational studies, resuming anticoagulant therapy after anticoagulation-associated ICH has beneficial effects on long-term complications. Clinical trials are needed to substantiate these findings.

PROSPERO REGISTRATION NUMBER

CRD42017063827.

Long-term antithrombotic treatment in intracranial hemorrhage survivors with atrial fibrillation

OBJECTIVE

To perform a systematic review and meta-analysis of studies reporting recurrent intracranial hemorrhage (ICH) and ischemic stroke (IS) in ICH survivors with atrial fibrillation (AF) during long-term follow-up.

METHODS

A comprehensive literature search including MEDLINE, EMBASE, Cochrane library, clinical trials registry was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. We considered studies capturing outcome events (ICH recurrence and IS) for ≥3 months and treatment exposure to vitamin K antagonists (VKAs), antiplatelet agents (APAs), or no antithrombotic medication (no-ATM). Corresponding authors provided aggregate data for IS and ICH recurrence rate between 6 weeks after the event and 1 year of follow-up for each treatment exposure. Meta-analyses of pooled rate ratios (RRs) were conducted with the inverse variance method.

RESULTS

Seventeen articles met inclusion criteria. Seven observational studies enrolling 2,452 patients were included in the meta-analysis. Pooled RR estimates for IS were lower for VKAs compared to APAs (RR = 0.45, 95% confidence interval [CI] 0.27-0.74, p = 0.002) and no-ATM (RR = 0.47, 95% CI 0.29-0.77, p = 0.002). Pooled RR estimates for ICH recurrence were not significantly increased across treatment groups (VKA vs APA: RR = 1.34, 95% CI 0.79-2.30, p = 0.28; VKA vs no-ATM: RR = 0.93, 95% CI 0.45-1.90, p = 0.84).

CONCLUSIONS

In observational studies, anticoagulation with VKA is associated with a lower rate of IS than APA or no-ATM without increasing ICH recurrence significantly. A randomized controlled trial is needed to determine the net clinical benefit of anticoagulation in ICH survivors with AF.

Antithrombotic treatment after stroke due to intracerebral haemorrhage

BACKGROUND

Survivors of stroke due to intracerebral haemorrhage (ICH) are at risk of thromboembolism. Antithrombotic (antiplatelet or anticoagulant) treatments may lower the risk of thromboembolism after ICH, but they may increase the risks of bleeding.

OBJECTIVES

To determine the overall effectiveness and safety of antithrombotic drugs for people with ICH.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (24 March 2017). We also searched the Cochrane Central Register of Controlled Trials (CENTRAL: the Cochrane Library 2017, Issue 3), MEDLINE Ovid (from 1948 to March 2017), Embase Ovid (from 1980 to March 2017), and online registries of clinical trials (8 March 2017). We also screened the reference lists of included trials for additional, potentially relevant studies.

SELECTION CRITERIA

We selected all randomised controlled trials (RCTs) of any antithrombotic treatment after ICH.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data. We converted categorical estimates of effect to the risk ratio (RR) or odds ratio (OR), as appropriate. We divided our analyses into short- and long-term treatment, and used fixed-effect modelling for meta-analyses. Three review authors independently assessed the included RCTs for risks of bias and we created a 'Summary of findings' table using GRADE.

MAIN RESULTS

We included two RCTs with a total of 121 participants. Both RCTs were of short-term parenteral anticoagulation early after ICH: one tested heparin and the other enoxaparin. The risk of bias in the included RCTs was generally unclear or low, with the exception of blinding of participants and personnel, which was not done. The included RCTs did not report our chosen primary outcome (a composite outcome of all serious vascular events including ischaemic stroke, myocardial infarction, other major ischaemic event, ICH, major extracerebral haemorrhage, and vascular death). Parenteral anticoagulation did not cause a statistically significant difference in case fatality (RR 1.25, 95% confidence interval (CI) 0.38 to 4.07 in one RCT involving 46 participants, low-quality evidence), ICH, or major extracerebral haemorrhage (no detected events in one RCT involving 75 participants, low-quality evidence), growth of ICH (RR 1.64, 95% CI 0.51 to 5.29 in two RCTs involving 121 participants, low-quality evidence), deep vein thrombosis (RR 0.99, 95% CI 0.49 to 1.96 in two RCTs involving 121 participants, low quality evidence), or major ischaemic events (RR 0.54, 95% CI 0.23 to 1.28 in two RCTs involving 121 participants, low quality evidence).

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support or discourage the use of antithrombotic treatment after ICH. RCTs comparing starting versus avoiding antiplatelet or anticoagulant drugs after ICH appear justified and are needed in clinical practice.

Reasons for non-recruitment of eligible patients to a randomised controlled trial of secondary prevention after intracerebral haemorrhage: observational study

Background

Recruitment to randomised prevention trials is challenging, not least for intracerebral haemorrhage (ICH) associated with antithrombotic drug use. We investigated reasons for not recruiting apparently eligible patients at hospital sites that keep screening logs in the ongoing REstart or STop Antithrombotics Randomised Trial (RESTART), which seeks to determine whether to start antiplatelet drugs after ICH.

Method

By the end of May 2015, 158 participants had been recruited at 108 active sites in RESTART. The trial coordinating centre invited all sites that kept screening logs to submit screening log data, followed by one reminder. We checked the integrity of data, focused on the completeness of data about potentially eligible patients and categorised the reasons they were not randomised.

Results

Of 108 active sites, 39 (36%) provided usable screening log data over a median of ten (interquartile range = 5–13) months of recruitment per site. During this time, sites screened 633 potentially eligible patients and randomised 53 (8%) of them. The main reasons why 580 patients were not randomised were: 43 (7%) patients started anticoagulation, 51 (9%) patients declined, 148 (26%) patients’ stroke physicians were not uncertain about using antiplatelet drugs, 162 (28%) patients were too unwell and 176 (30%) patients were not randomised due to other reasons.

Conclusion

RESTART recruited ~8% of eligible patients. If more physicians were uncertain about the therapeutic dilemma that RESTART is addressing, RESTART could have recruited up to four times as many participants. The trial coordinating centre continues to engage with physicians about their uncertainty.

Trial registration

EU Clinical Trials, EudraCT 2012-003190-26. Registered on 3 July 2012.

Recurrent Intracerebral Hemorrhage: Associations with Comorbidities and Medicine with Antithrombotic Effects

Background

Intracerebral hemorrhage (ICH) is a disease with high mortality and a substantial risk of recurrence. However, the recurrence risk is poorly documented and the knowledge of potential predictors for recurrence among co-morbidities and medicine with antithrombotic effect is limited.

Objectives

1) To estimate the short- and long-term cumulative risks of recurrent intracerebral hemorrhage (ICH). 2) To investigate associations between typical comorbid diseases, surgical treatment, use of medicine with antithrombotic effects, including antithrombotic treatment (ATT), selective serotonin reuptake inhibitors (SSRI’s), and nonsteroidal anti-inflammatory drugs (NSAID’s) with recurrent ICH.

Methods

The cohort consisted of all individuals diagnosed with a primary ICH in Denmark 1996–2011. Information on comorbidities, surgical treatment for the primary ICH, and the use of ATT, SSRI’s and NSAID’s was retrieved from the Danish national health registers. The cumulative recurrence risk of ICH was estimated using the Aalen-Johansen estimator, thus taking into account the competing risk of death. Associations with potential predictors of recurrent ICH were estimated as rate ratios (RR’s) using Poisson regression. Propensity score matching was used for the analyses of medicine with antithrombotic effects.

Results

Among 15,270 individuals diagnosed with a primary ICH, 2,053 recurrences were recorded, resulting in cumulative recurrence risk of 8.9% after one year and 13.7% after five years. Surgical treatment and renal insufficiency were associated with increased recurrence risks (RR 1.64, 95% CI 1.39–1.93 and RR 1.72, 95% CI 1.34–2.17, respectively), whereas anti-hypertensive treatment was associated with a reduced risk (RR 0.82, 95% CI 0.74–0.91). We observed non-significant associations between the use of any of the investigated medicines with antithrombotic effect (ATT, SSRI’s, NSAID’s) and recurrent ICH.

Conclusions

The substantial short-and long-term recurrence risks warrant aggressive management of hypertension following a primary ICH, particularly in patients treated surgically for the primary ICH, and patients with renal insufficiency.

Risk of intracranial hemorrhage in users of oral antithrombotic drugs: Study protocol for a nationwide study

Background A wide range of antithrombotic medications can be used in the prevention and treatment of thrombosis. Among hemorrhagic complications of antithrombotic drugs, intracranial hemorrhage may have particularly devastating consequences with high morbidity, disability and mortality rates. The incidence and risks of intracranial hemorrhage in patients on antithrombotic treatments from regular clinical practice outside clinical trials remain largely unknown. It is not known if results from clinical trials can be extrapolated to everyday clinical practice. We will conduct a nationwide study to investigate the risks and incidence rates of intracranial hemorrhage in users oral antithrombotic drugs in Norway from 2008 through 2014.  

Methods and design The aim of this nationwide study is to investigate the incidence rates of intracranial hemorrhage requiring hospitalization in users of oral antithrombotic drugs. The study will be conducted within the approximately 4.7 million inhabitants of Norway from January 1 ^st, 2008, to December 31 ^st, 2014. Treatment and outcome data are obtained from the Norwegian patient registry and the Norwegian prescription database.  

Trial registration number Clinicaltrials.gov (NCT02481011)

Apixaban versus Antiplatelet drugs or no antithrombotic drugs after anticoagulation-associated intraCerebral HaEmorrhage in patients with Atrial Fibrillation (APACHE-AF): study protocol for a randomised controlled trial

BACKGROUND

There is a marked lack of evidence on the optimal prevention of ischaemic stroke and other thromboembolic events in patients with non-valvular atrial fibrillation and a recent intracerebral haemorrhage during treatment with oral anticoagulation. These patients are currently treated with oral anticoagulants, antiplatelet drugs, or no antithrombotic treatment, depending on personal and institutional preferences. Compared with warfarin, the direct oral anticoagulant apixaban reduces the risk of stroke or systemic embolism, intracranial haemorrhage, and case fatality in patients with atrial fibrillation. Compared with aspirin, apixaban reduces the risk of stroke or systemic embolism in patients with atrial fibrillation, and has a similar risk of intracerebral haemorrhage. Novel oral anticoagulants have not been evaluated in patients with atrial fibrillation and a recent intracerebral haemorrhage. To inform a phase III trial, the phase II Apixaban versus Antiplatelet drugs or no antithrombotic drugs after anticoagulation-associated intraCerebral HaEmorrhage in patients with Atrial Fibrillation (APACHE-AF) trial aims to obtain estimates of the rates of vascular death or non-fatal stroke in patients with atrial fibrillation and a recent anticoagulation-associated intracerebral haemorrhage treated with apixaban and in those in whom oral anticoagulation is avoided.

METHODS/DESIGN

APACHE-AF is a phase II, multicentre, open-label, parallel-group, randomised clinical trial with masked outcome assessment. One hundred adults with a history of atrial fibrillation and a recent intracerebral haemorrhage during treatment with anticoagulation in whom clinical equipoise exists on the optimal stroke prevention strategy will be enrolled in 14 hospitals in The Netherlands. These patients will be randomly assigned in a 1:1 ratio to either apixaban or to avoiding oral anticoagulation. Patients in the control group may be treated with antiplatelet drugs at the discretion of the treating physician. The primary outcome is the composite of vascular death or non-fatal stroke during follow-up. We aim to include 100 patients in 2.5 years. All patients will be followed-up for the duration of the study, but at least for 1 year. Recruitment commenced in September 2014 and is ongoing. This trial is funded by the Dutch Heart Foundation (2012 T077) and ZonMW (015008048).

TRIAL REGISTRATION

NTR4526 (16 April 2014).

Restarting Anticoagulant Treatment After Intracranial Hemorrhage in Patients With Atrial Fibrillation and the Impact on Recurrent Stroke, Mortality, and Bleeding

Background—

Intracranial hemorrhage is the most feared complication of oral anticoagulant treatment. The optimal treatment option for patients with atrial fibrillation who survive an intracranial hemorrhage remains unknown. We hypothesized that restarting oral anticoagulant treatment was associated with a lower risk of stroke and mortality in comparison with not restarting.

Methods and Results—

Linkage of 3 Danish nationwide registries in the period between 1997 and 2013 identified patients with atrial fibrillation on oral anticoagulant treatment with incident intracranial hemorrhage. Patients were stratified by treatment regimens (no treatment, oral anticoagulant treatment, or antiplatelet therapy) after the intracranial hemorrhage. Event rates were assessed 6 weeks after hospital discharge and compared with Cox proportional hazard models. In 1752 patients (1 year of follow-up), the rate of ischemic stroke/systemic embolism and all-cause mortality (per 100 person-years) for patients treated with oral anticoagulants was 13.6, in comparison with 27.3 for nontreated patients and 25.7 for patients receiving antiplatelet therapy. The rate of ischemic stroke/systemic embolism and all-cause mortality (per 100 person-years) for recurrent intracranial hemorrhage, the rate of ischemic stroke/systemic embolism, and all-cause mortality (per 100 person-years) patients treated with oral anticoagulants was 8.0, in comparison with 8.6 for nontreated patients and 5.3 for patients receiving antiplatelet therapy. The adjusted hazard ratio of ischemic stroke/systemic embolism and all-cause mortality was 0.55 (95% confidence interval, 0.39–0.78) in patients on oral anticoagulant treatment in comparison with no treatment. For ischemic stroke/systemic embolism and for all-cause mortality, hazard ratios were 0.59 (95% confidence interval, 0.33–1.03) and 0.55 (95% confidence interval, 0.37–0.82), respectively.

Conclusions—

Oral anticoagulant treatment was associated with a significant reduction in ischemic stroke/all-cause mortality rates, supporting oral anticoagulant treatment reintroduction after intracranial hemorrhage as feasible. Future trials are encouraged to guide clinical practice in these patients.

Antithrombotic medicines following intracerebral haemorrhage: where's the evidence?

The use of antithrombotic medicines in patients who have a history of intracerebral haemorrhage is widely perceived as being contraindicated. However, many patients with intracerebral haemorrhage may suffer from conditions for which antithrombotic medicines are indicated. Such scenarios represent a therapeutic dilemma whereby treating infers an increased risk of recurrent intracerebral haemorrhage, but not treating infers an increase of thrombotic complications. Despite the importance of this dilemma, there is very little guidance for prescribers. This perspective review considered previous systematic reviews that addressed this issue, together with recently published research findings from the Tayside Stroke Cohort. Systematic reviews of experimental and observational studies have concluded that there is a marked lack of data on which to judge the safety of oral anticoagulant agents following intracerebral haemorrhage. In addition, the limited data available regarding the use of antiplatelet medicines following intracerebral haemorrhage provide no evidence that they are harmful, and again further data are required. In the absence of such data, a decision analysis approach has been proposed. This considers the findings of other studies to infer the likely impact of using antithrombotic agents in patients with intracerebral haemorrhage. The success of this approach is contingent on the availability of reliable data that describe the rate of recurrent intracerebral haemorrhage; however, published data on this varies widely. There are a number of factors that conspire against researchers addressing this issue. The current paucity of evidence to guide prescribers faced with this therapeutic dilemma seems likely to remain for some time.