Short-Term Cessation of Dabigatran Causes a Paradoxical Prothrombotic State

Acute Ischaemic Stroke in Patients Treated with Direct Oral Anticoagulants: Potential Causes, Clinical Characteristics, and Short-Term Outcomes

Introduction

Direct oral anticoagulants (DOAC) are the first-line treatment for primary and secondary acute ischaemic stroke (AIS) prevention in patients with nonvalvular atrial fibrillation (NVAF), but a significant percentage of patients develop AIS despite being treated with DOAC. As the number of DOAC-treated patients is growing, so is the number of patients with AIS on DOAC. The aim of the study was to assess the incidence of AIS with prestroke DOAC treatment among patients hospitalised in the University Hospital in Kraków, to analyse the clinical characteristics of AIS occurring in patients on DOAC, and to identify potential causes of treatment ineffectiveness in this group.

Materials and Methods

In the study, we included all patients hospitalised in the Department of Neurology of the University Hospital in Kraków within one year (July 2022 to June 2023) with the diagnosis of AIS. The group was divided into two subgroups of patients with and without prestroke DOAC treatment. Based on medical files, we retrospectively analysed the profile of cardiovascular risk factors, stroke severity (assessed with National Institutes of Health Stroke Scale, NIHSS), use of causative stroke treatment and short-term outcomes (defined as NIHSS score, modified Rankin scale (mRS) score at discharge, in-hospital mortality, and secondary intracerebral haemorrhage among patients treated with mechanical thrombectomy, MT). Within the DOAC-treated subgroup, we looked for potential causes of AIS occurring despite DOAC treatment (valvular AF, poor adherence to treatment, underdosing, other prothrombotic conditions, aetiology of stroke other than thromboembolic, and drug-drug interactions).

Results

In the study, we included 768 AIS patients. 109 (14.2%) had a history of prestroke DOAC treatment. A potential cause of DOAC treatment failure was identified in the majority of them (n = 63, 57.8%). Patients with prestroke DOAC treatment had worse functional condition before stroke and higher stroke severity on admission but similar short-term outcomes and similar short-term effects of treatment with MT. DOAC (+) and DOAC (-) patients had different profiles of cardiovascular risk factors and different factors associated with short-term outcome. Conclusions and Clinical Implications. A potential cause of AIS occurring in DOAC-treated patients can be identified in most cases and in many of them prevented.

Towards a biomarker for acute arterial thrombosis using complete blood count and white blood cell differential parameters in mice

There is no blood biomarker diagnostic of arterial thrombosis. We investigated if arterial thrombosis per se was associated with alterations in complete blood count (CBC) and white blood cell (WBC) differential count in mice. Twelve-week-old C57Bl/6 mice were used for FeCl₃-mediated carotid thrombosis (n = 72), sham-operation (n = 79), or non-operation (n = 26). Monocyte count (/µL) at 30-min after thrombosis (median 160 [interquartile range 140-280]) was ~ 1.3-fold higher than at 30-min after sham-operation (120 [77.5-170]), and twofold higher than in non-operated mice (80 [47.5-92.5]). At day-1 and -4 post-thrombosis, compared with 30-min, monocyte count decreased by about 6% and 28% to 150 [100-200] and 115 [100-127.5], which however were about 2.1-fold and 1.9-fold higher than in sham-operated mice (70 [50-100] and 60 [30-75], respectively). Lymphocyte counts (/µL) at 1- and 4-days after thrombosis (mean ± SD; 3513 ± 912 and 2590 ± 860) were ~ 38% and ~ 54% lower than those in the sham-operated mice (5630 ± 1602 and 5596 ± 1437, respectively), and ~ 39% and ~ 55% lower than those in non-operated mice (5791 ± 1344). Post-thrombosis monocyte-lymphocyte-ratio (MLR) was substantially higher at all three time-points (0.050 ± 0.02, 0.046 ± 0.025, and 0.050 ± 0.02) vs. sham (0.003 ± 0.021, 0.013 ± 0.004, and 0.010 ± 0.004). MLR was 0.013 ± 0.005 in non-operated mice. This is the first report on acute arterial thrombosis-related alterations in CBC and WBC differential parameters.

Factors Associated with Platelet Activation-Recent Pharmaceutical Approaches

Platelets are at the forefront of human health and disease following the advances in their research presented in past decades. Platelet activation, their most crucial function, although beneficial in the case of vascular injury, may represent the initial step for thrombotic complications characterizing various pathologic states, primarily atherosclerotic cardiovascular diseases. In this review, we initially summarize the structural and functional characteristics of platelets. Next, we focus on the process of platelet activation and its associated factors, indicating the potential molecular mechanisms involving inflammation, endothelial dysfunction, and miRs. Finally, an overview of the available antiplatelet agents is being portrayed, together with agents possessing off-set platelet-inhibitory actions, while an extensive presentation of drugs under investigation is being given.

Pleural Effusions in the Critically Ill and "At-Bleeding-Risk" Population

Thoracentesis is a common bedside procedure, which has a low risk of complications when performed with thoracic ultrasound and by experienced operators. In critically ill or mechanically ventilated patients, or in patients with bleeding risks due to medications or other coagulopathies, the complication rate remains low. Drainage of pleural effusion in the intensive care unit has diagnostic and therapeutic utility, and perceived bleeding risks should be one part of an individualized and comprehensive risk-benefit analysis.

Relation of Pre-Stroke Aspirin Use With Cerebral Infarct Volume and Functional Outcomes

Objective

We investigated (1) the associations of pre‐stroke aspirin use with thrombus burden, infarct volume, hemorrhagic transformation, early neurological deterioration (END), and functional outcome, and (2) whether stroke subtypes modify these associations in first‐ever ischemic stroke.

Methods

This multicenter magnetic resonance imaging (MRI)‐based study included 5,700 consecutive patients with acute first‐ever ischemic stroke, who did not undergo intravenous thrombolysis or endovascular thrombectomy, from May 2011 through February 2014. Propensity score‐based augmented inverse probability weighting was performed to estimate adjusted effects of pre‐stroke aspirin use.

Results

The mean age was 67 years (41% women), and 15.9% (n = 907) were taking aspirin before stroke. Pre‐stroke aspirin use (vs nonuse) was significantly related to a reduced infarct volume (by 30%), particularly in large artery atherosclerosis stroke (by 45%). In cardioembolic stroke, pre‐stroke aspirin use was associated with a ~50% lower incidence of END (adjusted difference = −5.4%, 95% confidence interval [CI] = −8.9 to −1.9). Thus, pre‐stroke aspirin use was associated with ~30% higher likelihood of favorable outcome (3‐month modified Rankin Scale score < 3), particularly in large artery atherosclerosis stroke and cardioembolic stroke (adjusted difference = 7.2%, 95% CI = 1.8 to 12.5 and adjusted difference = 6.4%, 95% CI = 1.7 to 11.1, respectively). Pre‐stroke aspirin use (vs nonuse) was associated with 85% less frequent cerebral thrombus‐related susceptibility vessel sign (SVS) in large artery atherosclerosis stroke (adjusted difference = −1.4%, 95% CI = −2.1 to −0.8, p < 0.001) and was associated with ~40% lower SVS volumes, particularly in cardioembolic stroke (adjusted difference = −0.16 cm³, 95% CI = −0.29 to −0.02, p = 0.03). Moreover, pre‐stroke aspirin use was not significantly associated with hemorrhagic transformation (adjusted difference = −1.1%, p = 0.09).

Interpretation

Pre‐stroke aspirin use associates with improved functional independence in patients with first‐ever ischemic large arterial stroke by reducing infarct volume and/or END, likely by decreasing thrombus burden, without increased risk of hemorrhagic transformation. ANN NEUROL 2021;90:763–776

Development and Testing of Thrombolytics in Stroke

Despite recent advances in recanalization therapy, mechanical thrombectomy will never be a treatment for every ischemic stroke because access to mechanical thrombectomy is still limited in many countries. Moreover, many ischemic strokes are caused by occlusion of cerebral arteries that cannot be reached by intra-arterial catheters. Reperfusion using thrombolytic agents will therefore remain an important therapy for hyperacute ischemic stroke. However, thrombolytic drugs have shown limited efficacy and notable hemorrhagic complication rates, leaving room for improvement. A comprehensive understanding of basic and clinical research pipelines as well as the current status of thrombolytic therapy will help facilitate the development of new thrombolytics. Compared with alteplase, an ideal thrombolytic agent is expected to provide faster reperfusion in more patients; prevent re-occlusions; have higher fibrin specificity for selective activation of clot-bound plasminogen to decrease bleeding complications; be retained in the blood for a longer time to minimize dosage and allow administration as a single bolus; be more resistant to inhibitors; and be less antigenic for repetitive usage. Here, we review the currently available thrombolytics, strategies for the development of new clot-dissolving substances, and the assessment of thrombolytic efficacies in vitro and in vivo.