Safety and Outcome of Intravenous Thrombolysis in Stroke Patients on Prophylactic Doses of Low Molecular Weight Heparins at Stroke Onset

Improving treatment for acute ischemic stroke—Clot busting innovation in the pipeline

Acute ischemic stroke is a consequence of disrupted blood flow to the brain, caused by thrombosis—the pathological formation of occlusive clots within blood vessels, which can embolize distally to downstream tissues and microvasculature. The highest priority of stroke treatment is the rapid removal of occlusive clots and restoration of tissue perfusion. Intravenous thrombolysis is the pharmacological standard-of-care for the dissolution of blood clots, wherein thrombolytic drugs are administered to restore vessel patency. While the introduction of recombinant tissue-plasminogen activator (rtPA) in 1996 demonstrated the benefit of acute thrombolysis for clot removal, this was countered by severe limitations in terms of patient eligibility, lytic efficacy, rethrombosis and safety implications. Development of safer and efficacious treatment strategies to improve clot lysis has not significantly progressed over many decades, due to the challenge of maintaining the necessary efficacy-safety balance for these therapies. As such, rtPA has remained the sole approved acute therapeutic for ischemic stroke for over 25 years. Attempts to improve thrombolysis with coadministration of adjunct antithrombotics has demonstrated benefit in coronary vessels, but remain contraindicated for stroke, given all currently approved antithrombotics adversely impact hemostasis, causing bleeding. This Perspective provides a brief history of stroke drug development, as well as an overview of several groups of emerging drugs which have the potential to improve thrombolytic strategies in the future. These include inhibitors of the platelet receptor glycoprotein VI and the signaling enzyme PI3-Kinase, novel anticoagulants derived from hematophagous creatures, and proteolysis-targeting chimeras.

Bleeding risk in patients with cardiac disease from ischaemic stroke reperfusion therapy: an update

Background

Intravenous tissue plasminogen activator (rtPA) and arterial endovascular therapy (ET) rapidly restore cerebral perfusion in eligible patients who had an acute ischaemic stroke (AIS). It is unknown whether patients who had an AIS with premorbid cardiac disease respond differently to reperfusion therapies than those without. These patients may have risk factors that worsen outcomes or may represent those who would most benefit from reperfusion therapy.

Objective

To determine whether patients who had an AIS with the most frequently encountered pre-existing cardiac conditions, atrial fibrillation (AF), heart failure (HF), left ventricular assist devices (LVADs), or taking anticoagulation for cardiac indications, are at increased risk for poor outcome, such as symptomatic intracranial haemorrhage (sICH), after reperfusion therapy.

Results

Although AF is an independent risk factor for poor poststroke outcomes, intravenous rtPA is not associated with increased risk of sICH for those not on anticoagulants. Likewise, HF is independently associated with mortality post stroke, yet these patients benefit from reperfusion therapies without increased rates of sICH. Patients with LVADs or who are on anticoagulation should not be given IV rtPA; however, ET remains a viable option in those who meet criteria, even patients with LVAD.

Conclusion

There is no evidence of an increased risk for sICH after intravenous rtPA or ET for those with AF or HF. Intravenous rtPA should not be given to patients on anticoagulation or with LVADs, but ET should be offered to them when eligible. Whenever possible, future AIS reperfusion research should include patients with premorbid cardiac disease as they are frequently excluded, representing a gap in evidence.

[Efficacy of apixaban in prevention of haemorrhagic complications in treatment of deep vein thromboses with endovascular techniques]

PURPOSE

This study was undertaken to investigate efficacy of apixaban in prevention of haemorrhagic complications during treatment of proximal thromboses of deep veins of the lower extremities using endovascular techniques.

PATIENTS AND METHODS

We retrospectively studied the results of treating a total of 50 patients presenting with deep vein thromboses at late stages of the pathological process. The patients were subdivided into 2 statistically homogeneous groups. Group One was composed of 30 patients undergoing treatment consisting in a combination of catheter-guided thrombolysis with urokinase and percutaneous mechanical thrombectomy, with rivaroxaban used for prolonged anticoagulation therapy. Group Two comprised 20 patients subjected to similar endovascular treatment with additional venous stenting. Prolonged 6-month anticoagulation therapy was carried out with apixaban. The results of treatment were assessed after 12 months by means of control ultrasonographic and clinical examination in order to determine the degree of restoration of the lumen of deep veins and severity of venous outflow impairments.

RESULTS

After 1 year, in Group One patients there was no evidence of impaired venous outflow in 40% of patients, with a mild degree revealed in 40%, moderate degree in 13.3%, and severe degree in 6.7% of patients. In Group Two patients, there were no symptoms of venous insufficiency in 83.4%, with a mild degree revealed in 16.6%. Neither moderate nor severe impairments of venous outflow were observed. In Group One, manifestations of haemorrhagic syndrome on the background of taking rivaroxaban were noted to occur in 10% of patients and in Group Two on the background of taking apixaban also in 10% of patients.

CONCLUSION

The use of apixaban in patients with proximal thromboses of deep veins of lower limbs on the background of treatment by endovascular techniques proved effective and safe.

Off-label use of intravenous thrombolysis for acute ischemic stroke: a critical appraisal of randomized and real-world evidence

Intravenous thrombolysis (IVT) represents the only systemic reperfusion therapy able to reverse neurological deficit in patients with acute ischemic stroke (AIS). Despite its effectiveness in patients with or without large vessel occlusion, it can be offered only to a minority of them, because of the short therapeutic window and additional contraindications derived from stringent but arbitrary inclusion and exclusion criteria used in landmark randomized controlled clinical trials. Many absolute or relative contraindications lead to disparities between the official drug label and guidelines or expert recommendations. Based on recent advances in neuroimaging and evidence from cohort studies, off-label use of IVT is increasingly incorporated into the daily practice of many stroke centers. They relate to extension of therapeutic time windows, and expansion of indications in co-existing conditions originally listed in exclusion criteria, such as use of alternative thrombolytic agents, pre-treatment with antiplatelets, anticoagulants or low molecular weight heparins. In this narrative review, we summarize recent randomized and real-world data on the safety and efficacy of off-label use of IVT for AIS. We also make some practical recommendations to stroke physicians regarding the off-label use of thrombolytic agents in complex and uncommon presentations of AIS or other conditions mimicking acute cerebral ischemia. Finally, we provide guidance on the risks and benefits of IVT in numerous AIS subgroups, where equipoise exists and guidelines and treatment practices vary.

Examining Outcomes following Thrombolysis in An Increasingly Older and Dependent Stroke Population

Background

Thrombolysis for acute ischaemic stroke (AIS) patients aged ≥80 years is evidence based, although its use in previously dependent patients is controversial.

Methods

Data from 831 thrombolysed AIS patients in our centre from 2009–2017 were used to compare demographic trends and outcomes (haemorrhage, mortality, three-month independence) in patients aged <80 and ≥80 years and with prior dependency. Comparison with UK and world registry data regarding age and pre-stroke dependency was made.

Results

The percentage of treated patients aged ≥80 years increased year-on-year, doubling from 25% to 50% (p<0.01), with increasing average age and pre-stroke dependency in world centres. Patients ≥80 years had higher (p<0.001) stroke severity, symptomatic intracerebral haemorrhage (5% vs. 1.5%), mortality (35% vs. 13%) and lower three month independent survival (24% vs. 60%). Patients with pre-stroke dependency had especially higher three month mortality (57–71%, OR 3.75 [95% CI 1.97–7.15]) in both age groups.

Conclusion

Patients aged ≥80 years and with dependency increasingly receive thrombolysis. Given poorer outcomes thrombolysis trials are needed in pre-stroke dependent patients.

Intravenous thrombolysis for the management of acute ischemic stroke in patients therapeutically anticoagulated with heparin: A review

BACKGROUND

Intravenous thrombolysis (IVT) with alteplase is effective in acute ischemic stroke (AIS). However, its use rate remains low due to the many exclusion criteria. Recent guidelines recommend excluding patients suffering AIS with an elevated aPTT secondary to heparin exposure from receiving IVT. The purpose of this review is to explore the safety and efficacy of IVT in patients therapeutically anticoagulated with heparin. We also propose a treatment algorithm for IVT in patients with AIS that are therapeutically anticoagulated with heparin.

METHODS

We performed a systematic review of PubMed and Embase through March 2020 to identify the literature regarding AIS in patients exposed to heparin, followed by IVT treatment, emphasizing safety, efficacy, and clinical outcome using PRISMA guidelines.

RESULTS

We included thirteen articles in the final analysis, including three retrospective studies, two observational studies, one randomized trial, five case reports, and two case series.

CONCLUSION

There is limited information about the off-label use of IVT in patients with elevated aPTT. Patients with AIS are excluded from IVT if they have recent exposure to heparin. Our review indicates that this population of patients may benefit from IVT as the cases of active bleeding after IVT are few, and functional outcomes are favorable in the long term suggesting that IVT in therapeutically anticoagulated patients may be safe and efficacious.

LncRNA MACC1-AS1 attenuates microvascular endothelial cell injury and promotes angiogenesis under hypoxic conditions via modulating miR-6867-5p/TWIST1 in human brain microvascular endothelial cells

Background

Hypoxia following ischemic stroke is a common cause of brain insults. Mounting evidence suggests that long non-coding RNAs (lncRNAs) play a vital role in regulating certain physiological and pathological processes including ischemic stroke. For the first time, the present study investigated the effects and mechanism of LncRNA MACC1-AS1 on hypoxia-induced human brain microvascular endothelial cells (HBMECs).

Methods

LncRNA MACC1-AS1 levels in HBMECs were detected via reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay. Reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT), were detected using their respective kits. Flow cytometry and clone formation assay were performed to evaluate the effects of lncRNA MACC1-AS1 on cell apoptosis and cell proliferation respectively. Angiogenesis capacity was evaluated via tube formation assay. Transwell migration assay was performed for assessment of cell migration, Western blot assay was performed for measurement of Twist1 and VE-cadherin level, and permeability assay was performed for evaluation of the cell barrier function. The target gene was predicted via bioinformatics online tool and validated through luciferase reporter assay and RNA pull-down assay.

Results

LncRNA MACC1-AS1 was downregulated in hypoxia-induced HBMECs. Overexpression of LncRNA MACC1-AS1 reduced cell apoptosis and oxidative stress, while promoting cell proliferation, migration, and angiogenesis. Moreover, LncRNA MACC1-AS1 overexpression reduced cell permeability and elevated VE-cadherin level, which contributed to maintaining cell barrier function. TWIST1 was validated as the target of miR-6867-5p which was further targeted by lncRNA MACC1-AS1. Thus, LncRNA MACC1-AS1 functions in hypoxia-induced HBMECs by regulating miR-6867-5p/TWIST1.

Conclusions

In this study, we found that LncRNA MACC1-AS1 exerted a protective role in hypoxia-induced HBMECs via regulating miR-6867-5p/TWIST1, indicating a new therapeutic strategy for future ischemic stroke therapy.

Safety and Outcomes of Intravenous Thrombolysis in Posterior Versus Anterior Circulation Stroke: Results From the Safe Implementation of Treatments in Stroke Registry and Meta-Analysis

Background and Purpose- Posterior circulation stroke (PCS) accounts for 5% to 19% of patients with acute stroke receiving intravenous thrombolysis. We aimed to compare safety and outcomes following intravenous thrombolysis between patients with PCS and anterior circulation stroke (ACS) and incorporate the results in a meta-analysis. Methods- We included patients in the Safe Implementation of Treatments in Stroke Thrombolysis Registry 2013 to 2017 with computed tomography/magnetic resonance angiographic occlusion data. Outcomes were parenchymal hematoma, symptomatic intracerebral hemorrhage (SICH) per SITS-MOST (Safe Implementation of Thrombolysis in Stroke Monitoring Study), ECASS II (Second European Co-operative Stroke Study) and NINDS (Neurological Disorders and Stroke definition), 3-month modified Rankin Scale score, and death. Adjustment for SICH risk factors (age, sex, National Institutes of Health Stroke Scale, blood pressure, glucose, and atrial fibrillation) and center was done using inverse probability treatment weighting, after which an average treatment effect (ATE) was calculated. Meta-analysis of 13 studies comparing outcomes in PCS versus ACS after intravenous thrombolysis was conducted. Results- Of 5146 patients, 753 had PCS (14.6%). Patients with PCS had lower median National Institutes of Health Stroke Scale: 7 (interquartile range, 4-13) versus 13 (7-18), P<0.001 and fewer cerebrovascular risk factors. In patients with PCS versus ACS, parenchymal hematoma occurred in 3.2% versus 7.9%, ATE (95% CI): -4.7% (-6.3% to 3.0%); SICH SITS-MOST in 0.6% versus 1.9%, ATE: -1.4% (-2.2% to -0.7%); SICH NINDS in 3.1% versus 7.8%, ATE: -3.0% (-6.3% to 0.3%); SICH ECASS II in 1.8% versus 5.4%, ATE: -2.3% (-5.3% to 0.7%). In PCS versus ACS, 3-month outcomes (70% data availability) were death 18.5% versus 20.5%, ATE: 6.0% (0.7%-11.4%); modified Rankin Scale score 0-1, 45.2% versus 37.5%, ATE: 1.7% (-6.6% to 3.2%); modified Rankin Scale score 0-2, 61.3% versus 49.4%, ATE: 2.4% (3.1%-7.9%). Meta-analysis showed relative risk for SICH in PCS versus ACS being 0.49 (95% CI, 0.32-0.75). Conclusions- The risk of bleeding complications after intravenous thrombolysis in PCS was half that of ACS, with similar functional outcomes and higher risk of death, acknowledging limitations of the National Institutes of Health Stroke Scale for stroke severity or infarct size adjustment.