A Combination of Ex Vivo and In Vivo Strategies for Evaluating How Much New Oral Anticoagulants Exacerbate Experimental Intracerebral Bleeding

Background  Intracerebral hemorrhage is the most serious complication of anticoagulant therapy but the effects of different types of oral anticoagulants on the expansion of these hemorrhages are still unclear. Clinical studies have revealed controversial results; more robust and long-term clinical evaluations are necessary to define their outcomes. An alternative is to test the effect of these drugs in experimental models of intracerebral bleeding induced in animals. Aims  To test new oral anticoagulants (dabigatran etexilate, rivaroxaban, and apixaban) in an experimental model of intracerebral hemorrhage induced by collagenase injection into the brain striatum of rats. Warfarin was used for comparison. Methods  Ex vivo anticoagulant assays and an experimental model of venous thrombosis were employed to determine the doses and periods of time required for the anticoagulants to achieve their maximum effects. Subsequently, volumes of brain hematoma were evaluated after administration of the anticoagulants, using these same parameters. Volumes of brain hematoma were evaluated by magnetic resonance imaging, H&E (hematoxylin and eosin) staining, and Evans blue extravasation. Neuromotor function was assessed by the elevated body swing test. Results and Conclusions  The new oral anticoagulants did not increase intracranial bleeding compared with control animals, while warfarin markedly favored expansion of the hematomas, as revealed by magnetic resonance imaging and H&E staining. Dabigatran etexilate caused a modest but statistically significant increase in Evans blue extravasation. We did not observe significant differences in elevated body swing tests among the experimental groups. The new oral anticoagulants may provide a better control over a brain hemorrhage than warfarin.

Anticoagulant activity of apixaban can be estimated by multiple regression analysis

BACKGROUND

Information on apixaban anticoagulant activity is required to prevent major bleeding or thrombosis during its use.

METHODS

We enrolled 194 patients with nonvalvular atrial fibrillation (NVAF) in whom warfarin was replaced with apixaban: 105 (54.1%) received the standard dose of apixaban (5 mg twice daily [BID]; 5 mg group) and 89 (45.9%) received a reduced dose (2.5 mg BID; 2.5 mg group). Multiple regression analysis was performed to predict the prothrombin time of apixaban (PTa) based on factors including age, body weight (BW), serum creatinine, and CHA2DS2-VASc score.

RESULTS

PTa and PT of warfarin (PTw) were significantly correlated in both groups (correlation coefficient R = 0.239 [P = .014] in the 5 mg group; R = 0.248 [P = .019] in the 2.5 mg group). PTa in the 5 mg group was predicted as follows: 16.952-0.036 × BW +0.299 × CHA2DS2-VASc score (P < .0004; R = 0.378). However, in the 2.5 mg group, PTa could not be predicted. The mean of the predicted and measured PTa values in the 5 mg group was 15.6 s, which was similar to the mean measured PTa of 15.5 s in the 2.5 mg group.

CONCLUSIONS

PT can be predicted by a formula including simple clinical parameters in patients receiving the standard dose of apixaban. This simple predictive formula may help to stratify bleeding and thrombosis risks in patients treated with apixaban.

Intracranial hemorrhage in patients taking oral anticoagulants. Current possibilities for therapy

The paper reviews an update on the possibilities of providing care for patients with spontaneous non-traumatic intracranial hemorrhage (ICH) developing in patients with atrial fibrillation who use oral anticoagulants. The incidence of ICH is shown to be considerably lower when nonvitamin K-dependent anticoagulants (NOACs) are used, but the hematoma evolution scenarios do not differ between the groups of patients receiving vitamin K antagonists or NOACs. The results of studies assessing hypertension therapy in patients with ICH are compared. The possibilities of using various reversal agents for various oral anticoagulants are also discussed. Since one of the main problems associated with increased mortality and severe disabilities is the progression rate of ICH, the possibility of using a specific antagonist can determine the choice of an anticoagulant for the primary prevention of ischemic stroke in a patient with atrial fibrillation.

Prognosis for intracerebral hemorrhage during ongoing oral anticoagulant treatment

BACKGROUND

Intracerebral hemorrhage (ICH) is the most serious adverse effect of treatment with oral anticoagulants. Prognostic data after ICH associated with non-vitamin K antagonist oral anticoagulants (NOAC) compared to vitamin K antagonists (VKA) are sparse. We compared 90-day survival and functional outcome following NOAC-ICH versus VKA-ICH using data from the Swedish Stroke Register (Riksstroke).

METHODS

Using data from Riksstroke and the Swedish Causes of Death Register between 2012 and 2016, we compared all-cause 90-day mortality for patients with NOAC-ICH versus VKA-ICH using Kaplan-Meier survival analysis and Log-rank test. Cox regression, with adjustment for age, sex, previous stroke, and level of consciousness (LOC) on admission, was used to estimate hazard ratios (HR) for 90-day mortality. Estimated functional outcome at 90 days, based on the modified Rankin Scale (mRS), was compared between VKA- and NOAC-associated ICH using chi-squared test.

RESULTS

We included 2483 patients; 300 with NOAC-ICH and 2183 with VKA-ICH. In both groups, mean age was 79 years, and 58% were male. No significant difference between NOAC-ICH and VKA-ICH was found for all-cause 90-day mortality (44.3% NOAC-ICH versus 42.6% VKA-ICH; P = 0.54, HR = 0.93; 95% confidence interval (CI): 0.78-1.12) or 90-day estimated functional outcome (mRS 0-2:13.7% and 15.3%; mRS 3-5:27.3% and 28.9%, respectively (P = 0.52)). Factors predicting death were increased age (HR = 1.03; 95%CI: 1.02-1.04) and reduced LOC (drowsy: HR = 3.48; 95%CI: 2.86-4.23; comatose: HR = 12.27; 95%CI: 10.13-14.87).

CONCLUSION

In this large study on anticoagulant-associated ICH, we found no significant difference in mortality and functional outcome at 90 days between NOAC-ICH versus VKA-ICH.

Intracerebral hemorrhage associated with warfarin versus non-vitamin K antagonist oral anticoagulants in Asian patients

Non-valvular atrial fibrillation patients receiving non-vitamin K antagonist oral anticoagulants (NOACs) have half the incidence of intracerebral hemorrhage (ICH) compared to those receiving warfarin. However, the differences in outcomes of NOAC-associated ICH (NICH) and warfarin-associated ICH (WICH) remain controversial. In this study, we investigated the clinical outcome and radiologic findings of ICH in Asian patients receiving NOACs or warfarin. We retrospectively reviewed the medical records of 544 ICH patients admitted to our hospital from January 2013 through December 2017, and compared the baseline demographics, clinical characteristics, ICH-related radiologic findings, and clinical outcome between the WICH and NICH groups. WICH and NICH were diagnosed in 46 and 13 patients, respectively. Lesions were located more frequently in the supratentorial deep area (45.7% and 46.2%) than the lobar area (30.4% and 30.8%) or brainstem and cerebellum (23.9% and 23.1%) in the WICH and NICH groups, respectively. The hematoma expansion and concomitant intraventricular hemorrhage (IVH) rate was significantly higher in the WICH group than in the NICH group (58.7% versus 7.7%, P = 0.001 and 50.0% versus 15.4%, P = 0.030, respectively). Hematoma expansion (odds ratio [OR]: 50.546; 95% confidence interval [CI]: 2.763-924.748; P = 0.008) and concomitant IVH (OR: 9.240; 95% CI: 1.450-58.892; P = 0.019) were independently associated with mortality at three months, after adjustment for confounding variables. Our results indicate that the radiological findings and clinical outcome at three months in patients with ICH are more favorable in those receiving NOAC therapy than in those receiving warfarin treatment.

Outcomes of intraparenchymal hemorrhage after direct oral anticoagulant or vitamin K antagonist therapy: A systematic review and meta-analysis

Direct Oral Anticoagulants (DOAC) are increasingly used as an alternative to vitamin-K antagonists (VKA) for anticoagulation and have shown lower rates of intracranial hemorrhage; however, there is disagreement in the literature over the outcomes of the intraparenchymal hemorrhages (IPH) associated with DOACs, and clinical concern regarding the lack of standardized reversal strategies for DOACs. Thus, the aim of this meta-analysis was to compare mortality, hematoma volume, and risk of hematoma expansion in patients who developed an IPH on DOACs versus VKA. A systematic review of the literature was conducted in accordance with the PRISMA guidelines. Studies were selected that reported on mortality, hematoma expansion, and hematoma volume in DOAC-associated IPH. Pooled risk ratios (RR) were calculated for mortality and hematoma expansion and pooled mean difference (MD) was calculated for hematoma volume (ml) using random-effect models. 15 studies reporting on 1238 patients were included in the systematic review. Eleven of these compared DOAC-IPH to VKA-IPH and were pooled quantitatively. DOAC-IPH was not associated with increased mortality risk (RR: 0.95, 95%-CI: 0.72 -1.27) or increased hematoma expansion risk (RR: 0.92; 95%-CI: 0.75-1.12) compared to VKA-IPH. The hematoma volume of DOAC- IPH was statistically significantly smaller than VKA-IPH (MD: -12.14 ml; 95%-CI: -15.38; -8.89). In conclusion, DOAC-IPH was not associated with increased mortality or hematoma expansion compared to VKA-IPH and may be associated with a smaller hematoma volume.

Protective effects of oral anticoagulants on cerebrovascular diseases and cognitive impairment in patients with atrial fibrillation: protocol for a multicentre, prospective, observational, longitudinal cohort study (Strawberry study)

INTRODUCTION

Non-valvular atrial fibrillation (NVAF) is known as a robust risk factor for stroke. Recent reports have suggested a risk of dementia with NVAF, but much remains unknown regarding the relationship between this mechanism and the potential protective effects of novel anticoagulants (direct oral anticoagulants (DOACs), or non-vitamin K oral anticoagulants).

METHODS AND ANALYSIS

This study, the strategy to obtain warfarin or DOAC's benefit by evaluating registry, is an investigator-initiated, multicentre, prospective, observational, longitudinal cohort study comparing the effects of warfarin therapy and DOACs on cerebrovascular diseases and cognitive impairment over an estimated duration of 36 months. Once a year for 3 years, the activities of daily living and cognitive functioning of non-demented patients with NVAF will be assessed. Demographics, risk factors, laboratory investigations, lifestyle, social background and brain MRI will be assessed.

ETHICS AND DISSEMINATION

This protocol has been approved by the ethics committee of the National Center for Geriatrics and Gerontology (No. 1017) and complies with the Declaration of Helsinki. Informed consent will be obtained before study enrolment and only coded data will be stored in a secured database. The results will be published in peer-reviewed journals and presented at scientific meetings to ensure the applicability of the findings in clinical practice.

TRIAL REGISTRATION NUMBER

UMIN000025721.

Neuroimaging and clinical outcomes of oral anticoagulant-associated intracerebral hemorrhage

OBJECTIVE

Whether intracerebral hemorrhage (ICH) associated with non-vitamin K antagonist oral anticoagulants (NOAC-ICH) has a better outcome compared to ICH associated with vitamin K antagonists (VKA-ICH) is uncertain.

METHODS

We performed a systematic review and individual patient data meta-analysis of cohort studies comparing clinical and radiological outcomes between NOAC-ICH and VKA-ICH patients. The primary outcome measure was 30-day all-cause mortality. All outcomes were assessed in multivariate regression analyses adjusted for age, sex, ICH location, and intraventricular hemorrhage extension.

RESULTS

We included 7 eligible studies comprising 219 NOAC-ICH and 831 VKA-ICH patients (mean age = 77 years, 52.5% females). The 30-day mortality was similar between NOAC-ICH and VKA-ICH (24.3% vs 26.5%; hazard ratio = 0.94, 95% confidence interval [CI] = 0.67-1.31). However, in multivariate analyses adjusting for potential confounders, NOAC-ICH was associated with lower admission National Institutes of Health Stroke Scale (NIHSS) score (linear regression coefficient = -2.83, 95% CI = -5.28 to -0.38), lower likelihood of severe stroke (NIHSS > 10 points) on admission (odds ratio [OR] = 0.50, 95% CI = 0.30-0.84), and smaller baseline hematoma volume (linear regression coefficient = -0.24, 95% CI = -0.47 to -0.16). The two groups did not differ in the likelihood of baseline hematoma volume < 30cm³ (OR = 1.14, 95% CI = 0.81-1.62), hematoma expansion (OR = 0.97, 95% CI = 0.63-1.48), in-hospital mortality (OR = 0.73, 95% CI = 0.49-1.11), functional status at discharge (common OR = 0.78, 95% CI = 0.57-1.07), or functional status at 3 months (common OR = 1.03, 95% CI = 0.75-1.43).

INTERPRETATION

Although functional outcome at discharge, 1 month, or 3 months was comparable after NOAC-ICH and VKA-ICH, patients with NOAC-ICH had smaller baseline hematoma volumes and less severe acute stroke syndromes. Ann Neurol 2018;84:702-712.

Length of hospitalization and mortality for bleeding during treatment with warfarin, dabigatran, or rivaroxaban

Background

Different outcomes among patients hospitalized for bleeding after starting anticoagulation could influence choice of anticoagulant. We compared length of hospitalization, proportion of Intensive Care Unit (ICU) admissions, ICU length of stay, and 30- and 90-day mortality for adults with atrial fibrillation hospitalized for bleeding after starting warfarin, dabigatran, or rivaroxaban.

Methods

An US commercial database of 38 million members from 1 November 2010 to 31 March 2014 was used to examine adults with atrial fibrillation hospitalized for bleeding after starting warfarin (2,446), dabigatran (442), or rivaroxaban (256). Outcomes included difference in mean total length of hospitalization, proportion of ICU admissions, mean length of ICU stay, and all-cause 30- and 90-day mortality.

Results

Warfarin users were older and had more comorbidities. Multivariable regression modeling with propensity score weighting showed warfarin users were hospitalized 2.0 days longer (95% CI 1.8–2.3; p < 0.001) than dabigatran users and 2.6 days longer (95% CI 2.4–2.9; p < 0.001) than rivaroxaban users. Dabigatran users were hospitalized 0.6 days longer (95% CI 0.2–1.0; p = 0.001) than rivaroxaban users. There were no differences in the proportion of ICU admissions. Among ICU admissions, warfarin users stayed 3.0 days (95% CI 1.9–3.9; p < 0.001) longer than dabigatran users and 2.4 days longer (95% CI 0.9–3.7; p = 0.003) than rivaroxaban users. There was no difference in ICU stay between dabigatran and rivaroxaban users. There were no differences in 30- and 90-day all-cause mortality.

Conclusions

Rivaroxaban and dabigatran were associated with shorter hospitalizations; however, there were no differences in 30- and 90-day mortality. These findings suggest bleeding associated with the newer agents is not more dangerous than bleeding associated with warfarin.

Impact of Antiplatelets and Anticoagulants on the Prognosis of Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) associated with antithrombotic therapy (AT) is becoming more common as the use of those medications increases in the aging population.

METHODS

This study included 490 consecutive patients hospitalized for nontraumatic ICH in a single center during an 8-year period, which was subdivided into former (2008-2011) and latter (2012-2015). Patients were classified into those with no antithrombotic drugs (NATs) and those with AT. The AT group was divided into 4 subgroups according to medications: antiplatelet (AP1), multiple antiplatelets (AP2), anticoagulant (AC), and antiplatelet and anticoagulant (APC). We evaluated the clinical characteristics and prognosis and compared the number of patients on AT between the former and latter groups.

RESULTS

There were 125 patients treated with AT (25.5%), including 50 (10.2%) on AP1, 14 (2.9%) on AP2, 32 (6.5%) on ACs, and 29 (5.9%) on APCs. Compared with the former group, the latter group had a higher number of patients on AT (19.3% versus 31.7%), AP1 (9.8% versus 10.6%), AP2 (1.6% versus 4.1%), ACs (4.9% versus 8.1%), and APCs (2.90% versus 8.9%). Compared with the NAT group, the patients in the AT group had a larger ICH volume, more frequent hematoma expansion, and higher rate of poor outcome, particularly for those on APCs.

CONCLUSION

The number of ICH patients on AT has increased; these patients were more likely to have a poor prognosis than those who were not on AT. Care should be taken when giving a combination of antiplatelets and anticoagulants in ICH.

Analysis of Recurrent Stroke Volume and Prognosis between Warfarin and Four Non-Vitamin K Antagonist Oral Anticoagulants' Administration for Secondary Prevention of Stroke

OBJECTIVE

We investigated recurrent stroke volume with nonvalvular atrial fibrillation (NVAF) patients treated with non-vitamin K antagonist oral anticoagulants (NOACs) about clinical backgrounds and number of recurrent stroke.

METHODS

We administered 4 NOACs, dabigatran, rivaroxaban, apixaban, and edoxaban in 101 postcardioembolic strokes with NVAF. In a retrospective study, we measured recurrent stroke volume with magnetic resonance imaging volumetric software and compared them between 10 vitamin K anticoagulant (VKA: warfarin) cases and 13 NOAC cases under anticoagulant therapy.

RESULTS

Of 101 cases, 31 were started with a VKA and switched to NOACs after 10 recurrent strokes. Other 70 cases were directly started with NOACs and 13 cases with NOACs as first anticoagulants had recurrent stroke. The frequency of recurrent stroke during anticoagulant therapy is not different between the VKA group and the 3 NOACs group. Recurrent stroke volume is significantly larger in the VKA group (26.4 cm³) than in the NOACs group (1.2 cm³).

CONCLUSIONS

Secondary prevention with NOACs after stroke might be more beneficial than a VKA by reducing recurrent infarct volume.

Low risk of ICH after reperfusion therapy in acute stroke patients treated with direct oral anti-coagulant

BACKGROUND

The safety of intravenous thrombolysis (IVT) and endovascular therapy (EVT) in patients treated with DOAC is unclear. We investigated whether recanalization therapy in patients treated with DOAC is safe.

METHODS

A nationwide, multicenter, retrospective cohort questionnaire survey was conducted to investigate the: (1) frequency of intracerebral hemorrhage (ICH) after recanalization therapy in patients treated with DOAC; (2) independent factors related to ICH; (3) relationship between last intake time of DOAC and ICH; and (4) comparison of ICH frequency between patients treated with DOAC, vitamin K antagonist (VKA), and no-anticoagulation (no-ACT) (control).

RESULTS

One hundred eighteen stroke centers returned the questionnaire and 100 patients (56 IVT alone, 29 EVT alone, and 15 both IVT and EVT) on DOAC were registered. The frequency of asymptomatic and symptomatic (≥4-point NIHSS score increase) ICH within 24h in DOAC patients were 18% and 2%, and were not different compared with the VKA and no-ACT groups (p=0.728; and p=0.626). On multivariate analysis, systolic blood pressure (OR, 1.04; p<0.001) and blood glucose (OR, 1.02; p=0.019) were independent factors for ICH. Among the 52 patients with a known last intake time of DOAC, the rate of ICH was higher in patients ≤4h from last intake than those >4h (38% vs. 10%, p=0.033).

CONCLUSIONS

Risk of ICH after reperfusion therapy in patients treated with DOAC should be low. Systolic blood pressure, glucose level, and DOAC intake time appear to be factors for ICH.

Volume and Characteristics of Intracerebral Hemorrhage with Direct Oral Anticoagulants in Comparison with Warfarin

Background

Patients undergoing anticoagulation therapy often experience intracerebral hemorrhages (ICHs), and warfarin in particular is known to increase hematoma expansion in ICHs, which results in a poor outcome. Recent studies reported that, in comparison with warfarin, direct oral anticoagulants (DOACs) cause fewer ICHs with better functional outcome. However, since it is still unknown whether DOACs are associated with a smaller hematoma volume of ICHs, we aimed to compare the volume, hematoma expansion, and outcomes associated with ICHs treated with DOACs and warfarin.

Methods

We performed a prospective multicenter cross-sectional study. The subjects included patients with acute ICHs who received either DOACs or warfarin. We evaluated the clinical characteristics, and measured initial and follow-up ICH volumes. The volume of ICHs and hematoma expansion were compared between the DOAC and warfarin groups. Mortality and modified Rankin score at discharge were evaluated as outcomes.

Results

There were 18 patients in the DOAC group and 71 in the warfarin group. The baseline characteristics were similar between the 2 groups. Initial median hematoma volume of ICHs in the DOAC group was significantly lower than that in the warfarin group (6.2 vs. 24.2 mL, respectively; p = 0.04). In cases involving follow-up computed tomography scanning, the median hematoma volume of ICHs at follow-up was lower in the DOAC group than in the warfarin group (initial: DOACs 4.4 vs. warfarin 13.5 mL; follow-up: 5.0 vs. 18.4 mL, respectively; p = 0.05). Further, the hematoma in ICHs associated with DOACs did not expand. Although the mortality of ICHs associated with DOACs (11%) was lower than that associated with warfarin (24%), this difference was not statistically significant. The univariate analysis showed that the anticoagulant type (DOACs vs. warfarin) and sex (male vs. female) were associated with ICH volume. The multivariable linear regression showed that the use of DOACs (compared to warfarin; β: −0.23, p = 0.03) and female sex (compared to male; β: −0.25, p = 0.02) were associated with a small hematoma volume.

Conclusions

Based on the results of the present study, in terms of the risks associated with ICHs, the use of DOACs appears to be safer than warfarin for anticoagulation therapy. Further studies are required to validate these findings.

Reversing the anticoagulation effects of dabigatran

The standard of care for oral anticoagulation therapy has primarily been warfarin, which is limited by its indirect mechanism-of-action, variable kinetics, tolerability, and routine monitoring concerns. The direct-acting oral anticoagulants (DOACs) have predictable pharmacokinetics and pharmacodynamics, and improved safety and efficacy compared to warfarin for the prevention of stroke in patients with nonvalvular atrial fibrillation and prevention or management of venous thromboembolism. Consequential bleeding is a concern with all anticoagulants. Vitamin K is not a rapid reversal agent for warfarin; rather it facilitates synthesis of new vitamin K-dependent clotting factors, which can take longer than 24 h. Other nonspecific agents, including recombinant activated factor VII, three- and four-factor prothrombin complex concentrates (PCC), and activated PCC or Factor Eight Inhibitor Bypassing Activity (FEIBA®), are options based on clinical need. Specific agents to quickly reverse the effects of DOACs have been under development, and idarucizumab, a monoclonal antibody fragment that rapidly binds dabigatran, has been approved for clinical use in cases of dabigatran-related life-threatening bleeding, or if a dabigatran-treated patient needs emergency surgery or an invasive procedure. Idarucizumab specifically and rapidly reverses dabigatran-induced anticoagulation as measured by established coagulation assays. However, this does not guarantee complete hemostasis, especially if a patient has underlying comorbidities such as renal or liver disease, or has experienced recent trauma that requires urgent surgery. In these cases, concomitant supportive therapy and/or administration of concentrated clotting factors may be considered. Emerging data from ongoing trials and clinical experience will further inform providers regarding optimal approaches for anticoagulation reversal.

Intracranial hemorrhage during administration of a novel oral anticoagulant

Objective: Oral anticoagulants are widely administered to patients with atrial fibrillation in order to prevent the onset of cardiogenic embolisms. However, intracranial bleeding during anticoagulant therapy often leads to fatal outcomes. Accordingly, the use of novel oral anticoagulants (NOACs), which less frequently have intracranial bleeding as a complication, is expanding. A nationwide survey of intracranial bleeding and its prognosis in Japan reported that intracranial bleeding of advanced severity was not common after NOAC administration. In this report, two cases from our institute are presented. Patients: Case 1 was an 85-year-old man with a right frontal lobe hemorrhage while under dabigatran therapy. Case 2 was an 81-year-old man who had cerebellar hemorrhage while under rivaroxaban therapy. Result: In both patients, the clinical course progressed without aggravation of bleeding or neurological abnormalities once anticoagulant therapy was discontinued. Conclusion: These observations suggest that intracranial hemorrhage during NOAC therapy is easily controlled by discontinuation of the drug. NOAC administration may therefore be appropriate despite the risk of such severe complications. Further case studies that include a subgroup analysis with respect to each NOAC or patient background will be required to establish appropriate guidelines for the prevention of cardiogenic embolisms in patients with atrial fibrillation.

Management and Outcomes of Bleeding Events in Patients in the Emergency Department Taking Warfarin or a Non-Vitamin K Antagonist Oral Anticoagulant

BACKGROUND

Most comparisons of bleeding patients who are taking warfarin or a non-vitamin K oral anticoagulant (NOAC) have been limited to admitted patients and major bleeding events in well-controlled, clinical trial settings.

OBJECTIVES

We describe the clinical characteristics, interventions, and outcomes in patients who are taking warfarin or a NOAC who presented to the emergency department (ED) with any bleeding event.

METHODS

We conducted a structured, retrospective, observational study of nonvalvular atrial fibrillation, pulmonary embolism, or deep vein thrombosis warfarin- or NOAC-treated patients presenting with any bleeding event to a large, academic ED between January 2012 and March 2015. We used descriptive statistics to summarize baseline characteristics, treatments, and outcomes and performed subgroup analyses based on the type of anticoagulant and site of bleeding.

RESULTS

The electronic search yielded 95 cases of patients taking a NOAC (i.e., dabigatran [33], rivaroxaban [32], or abixaban [30]) and 342 patients taking warfarin. Reversal agents were rarely used in all anticoagulant groups. Case fatality rates were similar among warfarin- and NOAC-treated patients for gastrointestinal bleeding (7% vs. 7%) and intracranial hemorrhage (18% vs. 4%), respectively. After adjustment for other factors, only intracranial hemorrhage (odds ratio 4.4; 95% confidence interval 1.4-13.3) was associated with mortality.

CONCLUSIONS

Despite the rare use of reversal strategies, mortality was low and outcomes were comparable among patients with bleeding events presenting to the ED while taking a NOAC compared with warfarin.

DOACs - advances and limitations in real world

The group of new oral anticoagulants or NOACs, now termed direct oral anticoagulants or DOACs, with their favourable results from large scale phase III clinical trials, represent a major advancement and expanded armamentarium in antithrombotic therapy. Dabigatran, rivaroxaban, apixaban and edoxaban are now in clinical routine use for prevention and treatment of arterial and venous thrombotic diseases as addressed in their clinical trials. Usage of the DOACs is expected to increase as clinicians gain more experience and reassurance with data from the real world studies which are generally consistent with that from clinical trials. Development of specific antidotes in management of bleeding complications and development of coagulation assays for their plasma levels will further boost the confidence in the DOACs. Nonetheless, there are still limitations associated with the DOACs. Many patients in need of anticoagulant therapy for indications not studied in the clinical trials will not be eligible for treatment with a DOAC. Conditions where more data is required include DOACs use in the paediatric age group, patients with atrial fibrillation and valvular heart disease, thrombosis associated with the anti-phospholipid syndrome and cancer associated thrombosis. The affordability and access to these drugs may pose an issue for many patients under healthcare systems not providing for these medications. With four new anticoagulants coming onboard very quickly, the focus has shifted to the practical approach and management in real life as many clinicians are not yet familiar with the DOACs. Clinicians need to be educated on how to manage this new class for drugs, from choosing the appropriate drug to prevention and managing bleeding complications as a lack of knowledge and understanding in these drugs will lead to inappropriate use and compromise on patient safety.

White matter hyperintensities and geriatric syndrome: An important role of arterial stiffness

White matter hyperintensities (WMH) are defined as cerebral white matter changes presumed to be of vascular origin, bilateral and mostly symmetrical. They can appear as hyperintense on T2-weighted and fluid-attenuated inversion recovery sequences, and as isointense or hypointense on T1-weighted magnetic resonance imaging of the brain. WMH have been focused on because of their clinical importance as a risk factor for cerebrovascular diseases and cognitive impairment. WMH are associated with geriatric syndrome, which is defined by clinical symptoms characteristic of older adults, including cognitive and functional impairment and falls. Cerebral small vessel diseases, such as WMH, might play an important role as risk factors for cerebrovascular diseases, cognitive impairment and geriatric syndrome through the mechanism of arterial stiffness. However, the vascular, physiological and metabolic roles of arterial stiffness remain unclear. Basically, arterial stiffness indicates microvessel arteriosclerosis presenting with vascular endothelial dysfunction. These changes might arise from hemodynamic stress as a result of a "tsunami effect" on cerebral parenchyma. In the present article, we review the clinical characteristics of WMH, focusing particularly on two associations: (i) those between cerebral small vessel diseases including WMH and arterial stiffness; and (ii) those between WMH and geriatric syndrome.

Characteristics of Symptomatic Intracranial Hemorrhage in Patients Receiving Non-Vitamin K Antagonist Oral Anticoagulant Therapy

Objectives

The first non-vitamin K antagonist oral anticoagulant (NOAC) introduced to the market in Japan was dabigatran in March 2011, and three more NOACs, rivaroxaban, apixaban, and edoxaban, have since become available. Randomized controlled trials of NOACs have revealed that intracranial hemorrhage (ICH) occurs less frequently with NOACs compared with warfarin. However, the absolute incidence of ICH associated with NOACs has increased with greater use of these anticoagulants, and we wanted to explore the incidence, clinical characteristics, and treatment course of patients with NOACs-associated ICH.

Methods

We retrospectively analyzed the characteristics of symptomatic ICH patients receiving NOACs between March 2011 and September 2014.

Results

ICH occurred in 6 patients (5 men, 1 woman; mean ± SD age, 72.8 ± 3.2 years). Mean time to onset was 146.2 ± 111.5 days after starting NOACs. Five patients received rivaroxaban and 1 patient received apixaban. None received dabigatran or edoxaban. Notably, no hematoma expansion was observed within 24 h of onset in the absence of infusion of fresh frozen plasma, activated prothrombin complex concentrate, recombinant activated factor VIIa or hemodialysis. When NOAC therapy was initiated, mean HAS-BLED and PANWARDS scores were 1.5 ± 0.5 and 39.5 ± 7.7, respectively. Mean systolic blood pressure was 137.8 ± 15.9 mmHg within 1 month before spontaneous ICH onset.

Conclusion

Six symptomatic ICHs occurred early in NOAC therapy but hematoma volume was small and did not expand in the absence of infusion of reversal agents or hemodialysis. The occurrence of ICH during NOAC therapy is possible even when there is acceptable mean systolic blood pressure control (137.8 ± 15.9 mmHg) and HAS-BLED score ≤ 2. Even stricter blood pressure lowering and control within the acceptable range may be advisable to prevent ICH during NOAC therapy.