A randomised controlled trial of antiplatelet therapy in combination with Rt-PA thrombolysis in ischemic stroke: rationale and design of the ARTIS-Trial

Efficacy and safety of short-term high dosage dual antiplatelet therapy after 0.6 mg/kg rt-PA intravenous thrombolysis for acute ischemic stroke

OBJECTIVE

To evaluate the efficacy and safety of short-term high-dose of dual antiplatelet therapy after 0.6 mg/kg rt-PA intravenous thrombolysis for acute ischemic stroke (AIS).

METHODS

All 208 patients with AIS were randomized into group 1 (103 cases, after 0.6 mg/kg rt-PA, 300 mg of oral aspirin(ASP) q.d. and 225 mg of oral clopidogrel (CLO) q.d. for for 5 days, then 100 mg of oral ASP q.d. for the next 85 days and 75 mg of oral CLO q.d. for the next 16 days) and group 2 (105 cases, after 0.9 mg/kg rt-PA, 100 mg of oral ASP q.d. for 90 days and 75 mg of oral CLO q.d. for 21 days).The efficacy index was the mRS score, NIHSS score and recurrence risk of stroke, while the safety index was the incidence of bleeding events and mortality. All parameters were evaluated at 30 and 90 days after thrombolysis. Patients whose characteristics may provide the best treatment benefit were further analyzed using the logistic regression model in group 1.

RESULTS

The proportion of mRS scores between 0 and 1 in group 1 was higher than that in group 2 at both 30 days (44.7% vs 32.4%, P < .05) and 90 days (50.5% vs 35.2%, P < .05). Compared to group 2, the proportion of NIHSS scores less than 4 was significantly higher in group 1 at both 30 days (37.9% vs 25.7%, P < .05) and 90 days (46.6% vs 30.5%, P < .05). At 90 days, Group 1 had a lower stroke recurrence risk than Group 2 (3.9% vs 10.5%, P < .05). The incidence of SICH was significantly different between the 2 groups at both 30 days (2.9% vs 9.5%, P < .05) and 90 days (2.9% vs 10.5%, P < .05). However, other bleeding events and mortality rates were not significantly different between the 2 groups. The lower the baseline NIHSS score and the shorter the OTT, the more favorable the outcomes obtained at 90 days.

CONCLUSIONS

Compared to standard doses, short term high-dose dual antiplatelet therapy after 0.6 mg/kg rt-PA intravenous thrombolysis may be a good choice for AIS patients.

Exploring the Essential Stroke Care Structures in Tertiary Healthcare Facilities in Rivers State, Nigeria

This study evaluated the essential stroke care structure available in the two Tertiary Health Facilities in Rives State, Nigeria. This was a descriptive survey involving the Stroke Care Survey and Assessment Tool (checklist/questionnaire) developed by the World Stroke Organisation to obtain information about the available essential stroke care structure (facilities, equipment, personnel and management protocol) at the two tertiary health facilities (RSUTH & UPTH). The study gathered relevant information, which was summarised into tables and graphs using Microsoft Excel 2016. From the results, although facilities had A and E departments, dedicated stroke units (fixed or mobile) were unavailable, and there was no locally developed protocol to support rapid triage of stroke patients. The facilities and equipment were either unavailable or insufficient. Only one health facility (RSUTH) provided 24 hrs/7 days laboratory services. The workforces were a mix between regular clinical staff and some specialists. Tissue plasminogen activator (tPA) use was non-existent, though specialists were trained on its administration. There was no locally developed or adopted stroke-specific clinical guidelines. In conclusion, the structural services available for stroke care within the studied tertiary health facilities were poor, unavailable or grossly insufficient. The state facility (RSUTH) suffered the most in terms of unavailable national support and staff development.

Reperfusion therapy in acute ischemic stroke: dawn of a new era?

Following the success of recent endovascular trials, endovascular therapy has emerged as an exciting addition to the arsenal of clinical management of patients with acute ischemic stroke (AIS). In this paper, we present an extensive overview of intravenous and endovascular reperfusion strategies, recent advances in AIS neurointervention, limitations of various treatment paradigms, and provide insights on imaging-guided reperfusion therapies. A roadmap for imaging guided reperfusion treatment workflow in AIS is also proposed. Both systemic thrombolysis and endovascular treatment have been incorporated into the standard of care in stroke therapy. Further research on advanced imaging-based approaches to select appropriate patients, may widen the time-window for patient selection and would contribute immensely to early thrombolytic strategies, better recanalization rates, and improved clinical outcomes.

Update on the effects of treatment with recombinant tissue-type plasminogen activator (rt-PA) in acute ischemic stroke

INTRODUCTION

Acute ischemic stroke (AIS) represents a major cause of death and disability all over the world. The recommended therapy aims at dissolving the clot to re-establish quickly the blood flow to the brain and reduce neuronal injury. Intravenous administration of recombinant tissue-type plasminogen activator (rt-PA) is clinically used with this goal.

AREAS COVERED

A description of beneficial and detrimental effects of rt-PA treatment is addressed. An overview of new therapies against AIS, such as new thrombolytics, sonolysis and sonothrombolysis, endovascular procedures, and association therapies is provided. Updates on the pathophysiological process leading to intracranial hemorrhage (ICH) is also discussed.

EXPERT OPINION

rt-PA treatment in AIS patients is beneficial to recovery outcomes. To weaken risks and improve benefits, it might be relevant to consider: i) a definitive identification of risk factors for symptomatic ICH; ii). a better organization of the health care system to reduce time-to-treatment and enhance discharge management. The pharmacological improvement of new thrombolytic drugs (such as tenecteplase and desmoteplase) targeting harmful and maximally exploiting beneficial effects might further reduce mortality and disability in AIS.

Changing Management of Acute Ischaemic Stroke: the New Treatments and Emerging Role of Endovascular Therapy

OPINION STATEMENT

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment, and the last two decades have seen a rapid advancement in the medical and endovascular treatment of acute ischaemic stroke. Intravenous tissue plasminogen activator (tPA) was first introduced as a safe and effective thrombolytic agent followed by the introduction of newer thrombolytic agents as well as anticoagulant and antiplatelet agents, proposed as potentially safer drugs with more favourable interaction profiles. In addition to chemo-thrombolysis, other techniques including transcranial sonothrombolysis and microbubble cavitation have been introduced which are showing promising results, but await large-scale clinical trials. These developments in medical therapies which are undoubtedly of great importance due to their potential widespread and immediate availability are paralleled with gradual but steady improvements in endovascular recanalisation techniques which were initiated by the introduction of the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) and Penumbra systems. The introduction of the Solitaire device was a significant achievement in reliable and safe endovascular recanalisation and was followed by further innovative stent retrievers. Initial trials failed to show a solid benefit in endovascular intervention compared with IV-tPA alone. These counterintuitive results did not last long, however, when a series of very well-designed randomised controlled trials, pioneered by MR-CLEAN, EXTEND-IA and ESCAPE, emerged, confirming the well-believed daily anecdotal evidence. There have now been seven positive trials of endovascular treatment for acute ischaemic stroke. Now that level I evidence regarding the superiority of endovascular recanalisation is abundantly available, the clinical challenge is how to select patients suitable for intervention and to familiarise and educate stroke care providers with this recent development in stroke care. It is important for the interventional services to be provided only in comprehensive stroke centres and endovascular interventions attempted by experienced well-trained operators, at this stage as an adjunct to the established medical treatment of IV-tPA, if there are no contraindications.

Effect of Heparin on Recanalization in Acute Stroke Patients with Intra-Arterial Thrombi

Anticoagulant use, such as heparin, is usually contraindicated in acute stroke patients. We present a study of patients, who were treated with intravenous heparin after a stroke that were also found to have an intraluminal thrombus. Prior studies imply that recanalization is achieved with heparin; however heparin should only prevent thrombus propagation. Therefore it is unclear whether and how IV heparin can achieve recanalization of intraluminal thrombi in acute stroke patients. A retrospective review of all acute stroke patients from a single stroke center who received a therapeutic IV heparin infusion from 5/2006 to 9/2011 were included in the study. We compared patients who had complete/partial recanalization and/or improved flow versus those that did not, with both these groups on a standard intravenous heparin infusion protocol. Demographic data was compared between the groups. Average partial thromboplastin time (PTT) during heparin infusion, time between computed tomography angiographies (CTAs), time from stroke onset to receiving IV heparin, and vessel occluded were also compared between groups. Forty-one patients (19 female, 22 male) were included in the study with a total of 55 vessels (either carotid, middle cerebral artery, anterior cerebral artery, posterior cerebral artery/posterior circulation) having intraluminal thrombi; 31 patients had 41 vessels with either partial or complete recanalization of effected vessels, while 10 patients had 14 vessels that did not have at least one vessel recanalize while on heparin. Using t-test we noted that the average PTT between the vessels that had partial/complete recanalization group (61.74) and nonrecanalization group (66.30) was not statistical significantly different (P=0.37).The average time in days on heparin between vascular imaging studies (CTA/conventional angiogram) in the group of vessels with partial/complete recanalization (7.12 days) and the ones with no change (6.11 days) was not significantly different between the two groups (P=0.59). Patient's vessels receiving heparin for <24 hours versus those >24 hours did not significantly differ either (P=0.17). This study compares patient characteristics associated with recanalization of intraluminal thrombi in acute stroke patients on heparin. Recanalization of intraluminal thrombi are not associated with average PTT or duration on heparin.

Advances in medical revascularisation treatments in acute ischemic stroke

Urgent reperfusion of the ischaemic brain is the aim of stroke treatment and there has been ongoing research to find a drug that can promote vessel recanalisation more completely and with less side effects. In this review article, the major studies which have validated the use and safety of tPA are discussed. The safety and efficacy of other thrombolytic and anticoagulative agents such as tenecteplase, desmoteplase, ancrod, tirofiban, abciximab, eptifibatide, and argatroban are also reviewed. Tenecteplase and desmoteplase are both plasminogen activators with higher fibrin affinity and longer half-life compared to alteplase. They have shown greater reperfusion rates and improved functional outcomes in preliminary studies. Argatroban is a direct thrombin inhibitor used as an adjunct to intravenous tPA and showed higher rates of complete recanalisation in the ARTTS study with further studies which are now ongoing. Adjuvant thrombolysis techniques using transcranial ultrasound are also being investigated and have shown higher rates of complete recanalisation, for example, in the CLOTBUST study. Overall, development in medical therapies for stroke is important due to the ease of administration compared to endovascular treatments, and the new treatments such as tenecteplase, desmoteplase, and adjuvant sonothrombolysis are showing promising results and await further large-scale clinical trials.

Early administration of aspirin in patients treated with alteplase for acute ischaemic stroke: a randomised controlled trial

BACKGROUND

Thrombolysis with intravenous alteplase is the only approved treatment for acute ischaemic stroke. After alteplase-induced recanalisation, reocclusion occurs in 14-34% of patients, probably because of platelet activation. Early administration of antiplatelet therapy after alteplase could reduce the risk of reocclusion and improve outcome. We compared the effects of early addition of intravenous aspirin to alteplase with standard alteplase without aspirin.

METHODS

In this multicentre, randomised, open-label trial with blind-endpoint assessment, patients with acute ischaemic stroke treated with alteplase were randomly assigned to 300 mg intravenous aspirin within 90 min after start of alteplase treatment or to no additional treatment. In both groups, oral antiplatelet therapy was started 24 h after alteplase treatment. The primary endpoint was favourable outcome, defined as a score of 0-2 on the modified Rankin scale at 3 months. This trial is registered with the Netherlands Trial Register (NTR822).

FINDINGS

Between July 29, 2008, and April 20, 2011, 642 patients (322 patients aspirin, 320 patients standard treatment) of the targeted 800 patients were enrolled. At that time, the trial was terminated prematurely because of an excess of symptomatic intracranial haemorrhage (SICH) and no evidence of benefit in the aspirin group. At 3 months, 174 (54·0%) patients in the aspirin group versus 183 (57·2%) patients in the standard treatment group had a favourable outcome (absolute difference -3·2%, 95% CI -10·8 to 4·2; crude relative risk 0·94, 0·82 to 1·09, p=0·42). Adjusted odds ratio was 0·91 (95% CI 0·66-1·26, p=0·58). SICH occurred more often in the aspirin group (14 [4·3%] patients) than in the standard treatment group (five [1·6%]; absolute difference 2·8%, 95% CI 0·2-5·4; p=0·04). SICH was more often the cause of poor outcome in the aspirin group compared with the standard treatment group (11 vs 1, p=0·006).

INTERPRETATION

Early administration of intravenous aspirin in patients with acute ischaemic stroke treated with alteplase does not improve outcome at 3 months and increases the risk of SICH. The results of this trial do not support a change of the current guidelines, which advise to start antiplatelet therapy 24 h after alteplase.

FUNDING

The Dutch Heart Foundation.

Cilostazol Reduces the Risk of Hemorrhagic Infarction After Administration of Tissue-Type Plasminogen Activator in a Murine Stroke Model

Background and Purpose—

Prior use of antiplatelet agents improves stroke outcome in patients undergoing thrombolytic therapy as shown by reduced arterial reocclusion, although the risk of cerebral hemorrhage can be increased.

Methods—

The effect of cilostazol, an antiplatelet drug that improves endothelial function through upregulation of intracellular cAMP, on cerebral hemorrhage after thrombolytic therapy was investigated using a highly reproducible transient ischemia model.

Results—

Treatment with cilostazol for 7 days before ischemia significantly suppressed the risk and severity of cerebral hemorrhage after injection of tissue-type plasminogen activator, although treatment with aspirin had no such protective effect compared with nontreated mice. Immunohistological analysis revealed that treatment with cilostazol suppressed disruption of the microvasculature in the ischemic area associated with reduced matrix metalloproteinase-9 activity.

Conclusions—

Our results suggest that patients treated with cilostazol before onset of stroke could have a lower risk of cerebral hemorrhage after thrombolytic therapy and might also have a longer therapeutic time window for thrombolysis. Furthermore, the risk of cerebral hemorrhage can be significantly altered by prestroke therapies, and analysis of the effects of multiple drugs on tissue-type plasminogen activator-induced cerebral hemorrhage in animal models is essential for the extending safe and effective thrombolytic therapy to a wider group of patients.

Adjunctive and alternative approaches to current reperfusion therapy

BACKGROUND AND PURPOSE

Current ischemic stroke reperfusion therapy consists of intravenous thrombolysis given in eligible patients after review of a noncontrast CT scan and a time-based window of opportunity. Rapid clot lysis has a strong association with clinical improvement but remains incomplete in many patients. This review appraises novel adjunctive or alternative approaches to current reperfusion strategies being tested in all trial phases. Summary of Review- Alternative approaches to current reperfusion therapy can be separated into 4 main categories: (1) combinatory approaches with other drugs or devices; (2) novel systemic thrombolytic agents; (3) endovascular medical or mechanical reperfusion treatments; and (4) noninvasive or minimally invasive methods to augment cerebral blood flow and alleviate intracranial blood flow steal.

CONCLUSIONS

Reperfusion treatments must be provided as fast as possible in patients most likely to benefit. Patients who fail to rapidly reperfuse may benefit from other strategies that maintain collateral flow or protect tissue at risk.

Five years of Trials

This editorial marks the launch of a special collection of articles highlighting 'Five years of Trials' (http://www.trialsjournal.com/series/5years). The journal's achievements on its objectives since 2006 are described and some of the challenges still ahead are outlined - in particular further innovating in the reporting of trials and the publication of negative results. The other articles in this series are examples of where Trials has demonstrated progress on its objectives. These include the publication of raw data, extended versions of previously published trial-related articles, descriptions of 'lessons learned', negative results, and educational articles regarding ethics and reporting bias.

Impact of tissue plasminogen activator on the neurovascular unit: from clinical data to experimental evidence

About 15 million strokes occur each year worldwide. As the number one cause of morbidity and acquired disability, stroke is a major drain on public health-care funding, due to long hospital stays followed by ongoing support in the community or nursing-home care. Although during the last 10 years we have witnessed a remarkable progress in the understanding of the pathophysiology of ischemic stroke, reperfusion induced by recombinant tissue-type plasminogen activator (tPA-Actilyse) remains the only approved acute treatment by the health authorities. The objective of the present review is to provide an overview of our present knowledge about the impact of tPA on the neurovascular unit during acute ischemic stroke.