The Norwegian tenecteplase stroke trial (NOR-TEST): randomised controlled trial of tenecteplase vs. alteplase in acute ischaemic stroke

Revolutionizing Stroke Care: Nanotechnology-Based Brain Delivery as a Novel Paradigm for Treatment and Diagnosis

Stroke, a severe medical condition arising from abnormalities in the coagulation-fibrinolysis cycle and metabolic processes, results in brain cell impairment and injury due to blood flow obstruction within the brain. Prompt and efficient therapeutic approaches are imperative to control and preserve brain functions. Conventional stroke medications, including fibrinolytic agents, play a crucial role in facilitating reperfusion to the ischemic brain. However, their clinical efficacy is hampered by short plasma half-lives, limited brain tissue distribution attributed to the blood-brain barrier (BBB), and lack of targeted drug delivery to the ischemic region. To address these challenges, diverse nanomedicine strategies, such as vesicular systems, polymeric nanoparticles, dendrimers, exosomes, inorganic nanoparticles, and biomimetic nanoparticles, have emerged. These platforms enhance drug pharmacokinetics by facilitating targeted drug accumulation at the ischemic site. By leveraging nanocarriers, engineered drug delivery systems hold the potential to overcome challenges associated with conventional stroke medications. This comprehensive review explores the pathophysiological mechanism underlying stroke and BBB disruption in stroke. Additionally, this review investigates the utilization of nanocarriers for current therapeutic and diagnostic interventions in stroke management. By addressing these aspects, the review aims to provide insight into potential strategies for improving stroke treatment and diagnosis through a nanomedicine approach.

Characteristics and predictors of stroke mimics in young patients in the norwegian tenecteplase stroke trial (NOR-TEST)

BACKGROUND

Several studies have shown that stroke mimics occur more often among young patients. Our aims were to identify the common mimics in young patients under the age of 60 years who received thrombolysis, to analyze the risk of hemorrhage after treatment with thrombolysis, and to identify risk factors and clinical parameters that might identify mimics in this group.

METHODS

Norwegian Tenecteplase Stroke Trial was a phase-3 trial investigating safety and efficacy of tenecteplase vs. alteplase in patients with acute ischemic stroke. Patients diagnosed with either acute cerebral ischemia or transient ischemic attack were categorized as stroke group, and patients with any diagnosis other than ischemic stroke or transient ischemic attack as mimics group. Patients were grouped post-hoc into young (< 60 years) and old (≥ 60 years). Logistic regression analyses were performed with mimics vs. stroke as dependent variable to identify predictors of mimics.

RESULTS

Of the 1091 patients included in the trial, 211 patients (19.3%) were under the age of 60 years. Out of the 1091 patients, 434 (39.8%) were female, median age 77 years (18-99 years), and median NIHSS was 4. Sixty-nine patients (32.7%) out of the 211 patients under the age of 60 were diagnosed as mimic. Mimics were significantly more frequent among the young (OR = 3.3, 32.7% vs. 12.8%, p = < 0.001). The most frequent mimics diagnoses among patients under 60 years of age were migraine (11.8%), no definite diagnosis (11.4%) and peripheral vertigo (3.3%). Mimics were independently associated with age < 50 years (OR = 4.97, p = < 0.001), not currently working/studying (OR = 3.38, p = 0.002) and not having aphasia on admission (OR = 2.95, p = 0.025). None of the mimics under the age of 60 years had symptomatic or asymptomatic intracerebral hemorrhage as a complication to thrombolysis.

CONCLUSION

We found significantly more mimics in the young, of which migraine was the most predominant diagnosis. Thrombolysis with alteplase or tenecteplase did not cause ICH in any mimics under 60 years.

Tenecteplase, 0.4 mg/kg, in Moderate and Severe Acute Ischemic Stroke: A Pooled Analysis of NOR-TEST and NOR-TEST 2A

Background The optimal dose of tenecteplase in acute ischemic stroke remains to be defined. We present a pooled analysis of the 2 NOR-TESTs (Norwegian Tenecteplase Stroke Trials) exploring the efficacy and safety of tenecteplase, 0.4 mg/kg. Methods and Results We retrospectively reviewed 2 PROBE (Prospective Randomized Open, Blinded End-point) trials, NOR-TEST and NOR-TEST 2A. Patients were randomized to either tenecteplase, 0.4 mg/kg, or alteplase, 0.9 mg/kg. The primary end point was favorable functional outcome at 3 months (modified Rankin Scale score, 0-1) or return to baseline if prestroke modified Rankin Scale score was 2. Secondary end points included favorable functional and clinical outcome and safety data. The pooled analysis includes patients with National Institutes of Health Stroke Scale score ≥6 from both trials and an additional post hoc analysis of patients with National Institutes of Health Stroke Scale score ≤5 from NOR-TEST. The per-protocol analysis contains 483 patients, of whom 235 were assigned to tenecteplase and 248 were assigned to alteplase. In per-protocol analysis, functional outcome was better in the alteplase arm with cutoff modified Rankin Scale score of 2 (odds ratio [OR], 0.52 [95% CI, 0.33-0.80]; P=0.003) and expressed by ordinal shift analysis (OR, 1.64 [95% CI, 1.17-2.28]; P=0.004). Mortality at 3 months was higher in the tenecteplase arm (OR, 2.48 [95% CI, 1.20-5.10]; P=0.01). Mortality and intracranial hemorrhage rates were higher in the severe stroke group randomized to tenecteplase, whereas these rates were similar for alteplase and tenecteplase in moderate and mild stroke. Conclusions Tenecteplase, 0.4 mg/kg, is unsafe in moderate and severe stroke, and the risk of death and intracranial hemorrhage probably increases with stroke severity. A lower tenecteplase dose should be tested in future trials. Registration URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01949948, NCT03854500.

The use of intravenous thrombolytics in acute ischemic stroke management: A scoping review from 2008 till 2021 in the Arab world in the Middle East and North Africa

OBJECTIVE

The aim of this review was to assess and analyze the research output on intravenous thrombolysis in acute ischemic stroke in the Arab world in the Middle East and North Africa.

METHODS

Published literature on intravenous thrombolysis for acute ischemic stroke from 2008 to 2021 were retrieved from several electronic databases. Extracted records were analyzed in terms of year of publication, country, journal, research area, authors, and organizational affiliations.

RESULTS

A total of 37 studies were published between 2008 and 2021 from different Arab countries. Eight studies assessed the safety and efficacy of thrombolytic agents in AIS. Three studies were KAP studies addressing the knowledge, attitude and practice towards IVT. The majority of the selected studies (n=16) discussed the utilization rate of IVT among patients in different hospital settings across these countries. Ten studies reported the outcomes associated with the use of IVT for AIS.

CONCLUSION

This is the first scoping review to study the research activity related to the use of IVT in stroke in the Arab nations. In the last 15 years, stroke research productivity was very low in the Arab world compared to other regions of the world due to several impeding factors. Given the high burden of in-adherence to acute stroke treatment in the Arab nations, there is a serious need for an increased high-quality research activity to highlight the roadblocks associated with the limited use of IVT.

Effectiveness and Safety of Tecneplase vs. Alteplase in the Acute Treatment of Ischemic Stroke

Not all hospitals have interventional radiology services. This fact implies that in centers where this resource is not available, the treatment of stroke in the acute phase must be adapted and individualized. The aim of the study is to determine and compare the combined effect of thrombolysis and thrombectomy effectiveness and safety of tenecteplase versus alteplase in the acute treatment of ischemic stroke in patients who are candidates for endovascular therapy according to clinical practice guidelines. This paper details a retrospective multicenter cohort study of patients with ischemic stroke admitted in three hospitals between 2018 and 2020. The main outcome variables were the degree of recanalization and the functional outcome at 3 months; safety variables were mortality and the occurrence of intracranial hemorrhage (ICH). In total, 100 patients were included, 20 of which were treated with tenecteplase (TNK) and 80 with alteplase (rtPA). Of those treated with TNK, 75% obtained a successful recanalization compared to 83.8% in those treated with rtPA (OR 0.58; 95% CI 0.18–1.88; p = 0.56). No differences were found in obtaining an excellent functional result at 3 months (35% TNK vs. 58.8% rtPA; p = 0.38). Tenecteplase showed worse neurological results after 24 h (unfavorable result of 70% with TNK vs. 45% with rtPA; OR = 5.4; 95% CI 1.57–18.6). No significant differences were identified in mortality; 17.5% with rtPA and 20% with TNK (p = 0.79), nor in the appearance of intracranial hemorrhage ICH (15.2% with rtPA vs. 30% with TNK (p = 0.12). In our series, there were not significant differences shown regarding effectiveness and safety between tenecteplase and alteplase.

Major Bleeding Postadministration of Tenecteplase Versus Alteplase in Acute Ischemic Stroke

BACKGROUND

Tenecteplase is a genetically engineered fibrinolytic with growing interest in the treatment of acute ischemic stroke. Compared to alteplase, tenecteplase is effective for neurologic improvement following ischemic stroke in patients with large vessel occlusions who are eligible for thrombectomy and for mild ischemic strokes with National Institutes of Health Stroke Scale of 0 to 5.

OBJECTIVE

The purpose of this study is to determine if safety outcomes are different in patients receiving tenecteplase and alteplase for acute ischemic stroke.

METHODS

This retrospective cohort reviewed all patients who received alteplase or tenecteplase from January 2019 to December 2020. Patients admitted before April 28, 2020, received alteplase intravenous bolus over 1 minute followed by an infusion over 1 hour, for a total of 0.9 mg/kg. Patients admitted after this date received tenecteplase 0.25 mg/kg as an intravenous bolus over 5 to 10 seconds. Any patient transferring from an outside facility was excluded. The primary outcome was major bleeding.

RESULTS

There was no significant difference in major bleeding between alteplase and tenecteplase (40 [18%] vs 21 [18.1%], P = 0.985). There was no significant difference in all-cause inpatient mortality for alteplase versus tenecteplase (10 [5%] vs 5 [4%], P = 0.934) or in adverse events between the groups (22 [9%] vs 14 [12%], P = 0.541) for alteplase and tenecteplase, respectively.

CONCLUSIONS AND RELEVANCE

Tenecteplase had similar rates of major bleeding versus alteplase and may be a reasonable alternative in the treatment of acute ischemic stroke.

Short-Term Efficacy Outcomes of Tenecteplase versus Alteplase for Acute Ischemic Stroke: A Meta-Analysis of 5 Randomized Trials

Tenecteplase (TNK) has been shown to be noninferior to Alteplase (ALT) for long term efficacy and safety outcomes. Whether this also applies to short term efficacy outcomes such as early clinical improvement and recanalization is unknown. To compare TNK and ALT regarding the short term efficacy outcomes: early neurological improvement and recanalization. The PRISMA was used to conduct a meta analysis, adapted to noninferiority analysis. The primary outcome was early (24-72 h) neurological improvement, defined as either NIHSS score 0 or reduction of at least 8 points compared to baseline. Recanalization was a secondary outcome. The noninferiority margin was set at 6.5%. Search strategy yielded 5 randomized clinical trials (1585 patients: 828 TNK, 757 ALT). Mean age was 70.8, 58.8% were men, mean baseline NIHSS was 7, and mean onset to treatment time was 148 min. Patients in intervention group received TNK at doses of 0.1 mg/kg (6.8%), 0.25 mg/kg (24.6%), and 0.4 mg/kg (68.6%), while all ALT patients received 0.9 mg/kg. In random effects meta analysis, TNK was noninferior to ALT for the primary outcome, early major neurological improvement (risk difference 8% in favor of TNK, 95% CI 1%-15%). Recanalization was also noninferior for the TNK compared to the ALT group (risk difference 9% in favor of TNK, 95% CI 6% to 23%). Fixed effects models yielded similarly noninferior results and signaled for a possible TNK superiority for both early neurological improvement and recanalization. TNK is noninferior to ALT at the short term efficacy outcomes: early neurological improvement and recanalization.

Tenecteplase in Ischemic Stroke: Challenge and Opportunity

PURPOSE OF REVIEW

Intravenous thrombolysis is the first-line therapy for ischemic stroke, and alteplase has been used as an intravenous thrombolysis drug for over 20 years. However, considering its low rate of recanalization and risk of intracerebral hemorrhage, alteplase may not be the optimal thrombolytic drug of choice for ischemic stroke. Tenecteplase (TNK) is a genetically engineered, mutant, tissue plasminogen activator that is a potential substitute to alteplase in ischemic stroke. The pharmacokinetic advantages of TNK include greater fibrin selectivity than alteplase and prolonged half-life time. In this review, we have summarized the clinical trials of TNK in ischemic stroke.

RECENT FINDINGS

Clinical trials showed a higher recanalization rate of TNK over alteplase without increasing the rate of intracerebral hemorrhage. However, not all clinical trials showed superiority of TNK over alteplase in functional outcomes and early neurological improvement. TNK was superior to alteplase in terms of recanalization in patients who fulfilled the imaging mismatch criteria and in those planning to undergo mechanical thrombectomy.

SUMMARY

TNK has the potential to substitute alteplase for ischemic stroke therapy. Future TNK clinical trials that target functional outcomes are warranted.

Adapting Clinical Practice of Thrombolysis for Acute Ischemic Stroke Beyond 4.5 Hours: A Review of the Literature

Several clinical trials have demonstrated that advanced neuroimaging can select patients for recanalization therapy in an extended time window. The favorable functional outcomes and safety profile of these studies have led to the incorporation of neuroimaging in endovascular treatment guidelines, and most recently, also extended to decision making on thrombolysis. Two randomized clinical trials have demonstrated that patients who are not amenable to endovascular thrombectomy within 4.5 hours from symptoms discovery or beyond 4.5 hours from the last-known-well time may also be safely treated with intravenous thrombolysis and have a clinical benefit above the risk of safety concerns. With the growing aging population, increased stroke incidence in the young, and the impact of evolving medical practice, healthcare and stroke systems of care need to adapt continuously to provide evidence-based care efficiently. Therefore, understanding and incorporating appropriate screening strategies is critical for the prompt recognition of potentially eligible patients for extended-window intravenous thrombolysis. Here we review the clinical trial evidence for thrombolysis for acute ischemic stroke in the extended time window and provide a review of new enrolling clinical trials that include thrombolysis intervention beyond the 4.5 hour window.

Intra-arterial thrombolysis for early hepatic artery thrombosis after liver transplantation

BACKGROUND

Early hepatic artery thrombosis (E-HAT) is a serious complication after liver transplantation (LT), which often results in graft failure and can lead to patient deaths. Treatments such as re-transplantation and re-anastomosis are conventional therapeutic methods which are restricted by the shortage of donors and the patient’s postoperative intolerance to re-laparotomy. Due to the advances in interventional techniques and thrombolytics, endovascular treatments are increasingly being selected by more and more centers. This study reviews and reports our single-center experience with intra-arterial thrombolysis as the first choice therapy for E-HAT after deceased donor LT.

AIM

To evaluate the feasibility and reasonability of intra-arterial thrombolysis for E-HAT after deceased donor LT.

METHODS

A total of 147 patients who underwent deceased donor LT were retrospectively reviewed in our hospital between September 2011 and December 2016. Four patients were diagnosed with E-HAT. All of these patients underwent intra-arterial thrombolysis with alteplase as the first choice therapy after LT. The method of arterial anastomosis and details of the diagnosis and treatment of E-HAT were collated. The long-term prognosis of E-HAT patients was also recorded. The median follow-up period was 26 mo (range: 23 to 30 mo).

RESULTS

The incidence of E-HAT was 2.7% (4/147). E-HAT was considered when Doppler ultrasonography showed no blood flow signals and a definite diagnosis was confirmed by immediate hepatic arterial angiography when complete occlusion of the hepatic artery was observed. The patients were given temporary thrombolytics (mainly alteplase) via a 5-Fr catheter which was placed in the proximal part of the thrombosed hepatic artery followed by continuous alteplase using an infusion pump. Alteplase dose was adjusted according to activated clotting time. The recanalization rate of intra-arterial thrombolysis in our study was 100% (4/4) and no thrombolysis-related mortality was observed. During the follow-up period, patient survival rate was 75% (3/4), and biliary complications were present in 50% of patients (2/4).

CONCLUSION

Intra-arterial thrombolysis can be considered first-line treatment for E-HAT after deceased donor LT. Early diagnosis of E-HAT is important and follow-up is necessary even if recanalization is successful.

Tenecteplase-induced Nonaneurysmal Subarachnoid Hemorrhage in a Patient with Acute Ischemic Stroke: A Case Report and Literature Review

Recently, tenecteplase (TNK) has been used for intravenous thrombolysis in acute ischemic stroke (AIS). Although spontaneous subarachnoid hemorrhage (SAH) following thrombolysis with tissue plasminogen activator has been reported, there is a lack of literature regarding TNK-induced nonaneurysmal spontaneous SAH. Our index case received intravenous TNK within an hour of symptom onset of AIS. Following deterioration of sensorium, repeat noncontrast computed tomography was performed, which showed diffuse SAH. Cerebral angiography did not reveal any aneurysm. Nonaneurysmal SAH can be a complication of TNK thrombolysis, which is not reported in literature. Knowledge of this possible adverse reaction is critical for appropriate counseling and management.

Tenecteplase versus alteplase after acute ischemic stroke at high age

BACKGROUND

Stroke prevalence is increasing with age. Alteplase is the only agent approved for thrombolytic treatment for patients with ischemic stroke, including patients ≥80 years. In the present study, the aim was to compare efficacy and safety of tenecteplase and alteplase in patients ≥80 years.

METHODS

Data from the Norwegian Tenecteplase Stroke Trial, a randomized controlled trial comparing alteplase and tenecteplase, were assessed.

RESULTS

Of the 273 patients ≥80 years included, mean age was 85.5 years.In the intention-to-treat analyses, 43.1% receiving tenecteplase and 39.9% receiving alteplase reached excellent functional outcome (modified Rankin Scale score 0-1) after 3 months (odds ratio (OR) 1.14, 95% confidence interval (CI) 0.70-1.85, p=0.59). No significant differences among patients in the two treatment groups regarding frequency of symptomatic intracranial hemorrhage during the first 48 h were identified (11 (8.5%) in the tenecteplase group, 10 (7.0%) in the alteplase group, OR 1.23, 95% CI 0.50-3.00, p 0.65). Death within 3 months occurred in 18 patients (14.3%) in the tenecteplase group and in 21 (15.3%) in the alteplase group (p 0.84). After excluding stroke mimics, the proportion of patients with excellent functional outcome was 44.1% in the tenecteplase group and 34.4% in the alteplase group (OR 1.50 CI 0.90-2.52, p 0.12).

CONCLUSION

No differences in the efficacy and safety of tenecteplase versus alteplase in patients ≥80 years were identified.

TRIAL REGISTRATION

Clinicaltrials.gov (NCT01949948).

Border Zones of Evidence: How Non-evidence Based Factors Influence Evidence Generation and Clinical Practice in Stroke Medicine

The interpretation of the results of clinical trials should be done by examining the finer prints of extraneous factors such as stopping rules, interim analysis, intricacies of patient selection, and the rationale of decisions that lead to non-prespecified termination. This can be done only by critical education in the art and science of interpretation of evidence emerging from clinical trials. The pioneering pivotal studies, namely, NINDS rtPA and ECASS III trials, hold disproportionate influence in determining the contours of the subsequent fate of clinical trials and treatment guidelines. It needs to be recognized that the pooling of studies using dissimilar trial designs, notwithstanding similar patient profiles, would undermine the positive signal emerging from the studies that have used better selection methodologies to homogenize the study population.

Mathematical Modelling of Intravenous Thrombolysis in Acute Ischaemic stroke: Effects of Dose Regimens on Levels of Fibrinolytic Proteins and Clot Lysis Time

Thrombolytic therapy is one of the medical procedures in the treatment of acute ischaemic stroke (AIS), whereby the tissue plasminogen activator (tPA) is intravenously administered to dissolve the obstructive blood clot. The treatment of AIS by thrombolysis can sometimes be ineffective and it can cause serious complications, such as intracranial haemorrhage (ICH). In this study, we propose an efficient mathematical modelling approach that can be used to evaluate the therapeutic efficacy and safety of thrombolysis in various clinically relevant scenarios. Our model combines the pharmacokinetics and pharmacodynamics of tPA with local clot lysis dynamics. By varying the drug dose, bolus-infusion delay time, and bolus-infusion ratio, with the FDA approved dosing protocol serving as a reference, we have used the model to simulate 13 dose regimens. Simulation results are compared for temporal concentrations of fibrinolytic proteins in plasma and the time that is taken to achieve recanalisation. Our results show that high infusion rates can cause the rapid degradation of plasma fibrinogen, indicative of increased risk for ICH, but they do not necessarily lead to fast recanalisation. In addition, a bolus-infusion delay results in an immediate drop in plasma tPA concentration, which prolongs the time to achieve recanalisation. Therefore, an optimal administration regimen should be sought by keeping the tPA level sufficiently high throughout the treatment and maximising the lysis rate while also limiting the degradation of fibrinogen in systemic plasma. This can be achieved through model-based optimisation in the future.

Organizing stroke systems in the field for patients with suspected large vessel occlusion acute stroke

Introduction: The dawn of endovascular stroke therapy has reshaped stroke care. Eligible patients need to be rushed to capable centers for intervention. This may entail bypassing closer hospitals that could confirm the diagnosis, administer thrombolytic therapy, then transfer patients for intervention. This has created a set of challenges: identifying endovascular candidates in the field, determining the best transport destination, and getting patients there quickly. Areas covered: This review provides a context for these emerging challenges. Current and emerging clinical prediction instruments for large vessel occlusion (LVO) are reviewed. The workflow in the thrombolysis-only primary stroke centers is reviewed, and interventions aimed at minimizing delays are highlighted. Innovations using mathematical modeling and devices for detection of LVO are reviewed. Expert commentary: More patients are expected to receive endovascular therapy as we push the boundaries for time and imaging criteria. Advances in detection and decision-making aids will improve the speed of treatment. Some patients will arrive at thrombolysis-only centers. This need to be triaged, diagnosed, treated, and transported promptly. Therefore, education of practitioners in these centers is paramount. Creating and facilitating infrastructure for imaging acquisition and sharing in such centers will reflect better care for stroke patients overall.

Safety and predictors of stroke mimics in The Norwegian Tenecteplase Stroke Trial (NOR-TEST)

Background

Stroke mimics are frequently treated with thrombolysis in clinical practice and thrombolytic trials. Although alteplase in stroke mimics has proven to be safe, safety of tenecteplase in stroke mimics has not been assessed in an ischemic stroke study setting. We aimed to assess clinical characteristics and safety of stroke mimics treated with thrombolysis in the Norwegian Tenecteplase Stroke Trial. We also aimed to identify possible predictors of stroke mimics as compared to patients with acute cerebral ischemia.

Methods

Norwegian Tenecteplase Stroke Trial was a phase-3 trial investigating safety and efficacy of tenecteplase vs. alteplase in patients with suspected acute cerebral ischemia. Two groups were defined based on diagnose at discharge: patients with a different diagnose than ischemic stroke or transient ischemic attack (stroke mimics group) and patients diagnosed with ischemic stroke or transient ischemic attack (acute cerebral ischemia group). Logistic regression analyses were performed with stroke mimics vs. acute cerebral ischemia as dependent variable to identify predictors of stroke mimics.

Results

Of 1091 randomized patients, 181 (16.6%) were stroke mimics. Migraine (22.2%) and peripheral vertigo (11.4%) were the two most frequent stroke mimic-diagnoses. There was no symptomatic intracerebral hemorrhage in the stroke mimics group. Stroke mimics were independently associated with age ≤60 years (OR 2.75, p < 0.001), female sex (OR 1.48, p = 0.026), no history of myocardial infarction (OR 2.03, p = 0.045), systolic BP ≤ 150 mmHg (OR 2.33, p < 0.001), NIHSS ≤ 6 points (OR 1.83, p = 0.011), sensory loss (OR 1.55, p = 0.015), and no facial paresis (OR 2.41, p < 0.001) on admission.

Conclusion

Thrombolysis with tenecteplase seems to be as safe as with alteplase in stroke mimics. Predictors were identified for stroke mimics which may contribute to differentiate stroke mimics from acute cerebral ischemia in future stroke trials.

Mechanical thrombectomy - is time still brain? The DAWN of a new era

PURPOSE

The purpose of this study is to review the history of treatments for acute ischemic stroke, examine developments in endovascular therapy, and discuss the future of the management of acute ischemic stroke.

METHODS

A selective review of recent clinical trials for the treatment of acute ischemic stroke was conducted.

RESULTS

We reviewed completed trials of the management of acute ischemic stroke including intravenous thrombolytics, intraarterial thrombolytics, and thrombectomy. We also assessed the future direction of research by reviewing ongoing clinical trials.

CONCLUSIONS

The advancement of endovascular treatment for stroke has led to improved morbidity and mortality for patients. Future challenges include delivering these treatments to stroke centers worldwide.

Contrast-enhanced sonothrombolysis in acute ischemic stroke patients without intracranial large-vessel occlusion

BACKGROUND

Contrast-enhanced sonothrombolysis (CEST) leads to a more rapid recanalization in acute ischemic stroke caused by intracranial large-vessel occlusion (LVO). Animal studies have shown that CEST also may be safe and efficient in treating the ischemic microcirculation in the absence of LVO. The exact mechanism behind this treatment effect is not known. We aimed to assess safety and efficacy of CEST in acute ischemic stroke patients included in the Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS) without LVO on admission CT angiography (CTA).

METHODS

NOR-SASS was a randomized controlled trial of CEST in ischemic stroke patients treated with intravenous thrombolysis within 4.5 hours after stroke onset. Patients were randomized to either CEST or sham CEST. In this study, patients were excluded if they had partial or total occlusion on admission CTA, ultrasound-resistant bone window, had received CEST with incorrect insonation as compared to stroke location on Magnetic resonance imaging (MRI), or were stroke mimics.

RESULTS

Of the 183 patients included in NOR-SASS, a total of 83 (45.4%) patients matched the inclusion criteria, of which 40 received CEST and 43 sham CEST. There were no patients with symptomatic intracranial hemorrhage (sICH) in the CEST group. Rates of asymptomatic ICH, microbleeds, and mortality were not increased in the CEST group. Neurological improvement at 24 hours and functional outcome at 90 days were similar in both groups.

CONCLUSION

CEST is safe in ischemic stroke patients without intracranial LVO. There were no differences in clinical outcomes between the treatment groups.

Clinical Importance of Temporal Bone Features for the Efficacy of Contrast-Enhanced Sonothrombolysis: a Retrospective Analysis of the NOR-SASS Trial

Contrast-enhanced sonothrombolysis (CEST) seems to be a safe and promising treatment in acute ischemic stroke. It remains unknown if temporal bone features may influence the efficacy of CEST. We investigated the association between different temporal bone features on admission computed tomography (CT) scan and the outcome in acute ischemic stroke patients included in the randomized Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS). Patients diagnosed as stroke mimics and those with infratentorial stroke or with incorrect insonation were excluded. We retrospectively assessed temporal bone heterogeneity (presence of diploë), diploë ratio, thickness, and density on admission CT scans. National institute of Health Stroke Scale (NIHSS) at 24 h and modified Rankin Scale (mRS) at 3 months were correlated with CT findings both in CEST and sham CEST patients. A total of 99 patients were included of which 52 were assigned to CEST and 47 to sham CEST. Approximately 20% patients had a heterogeneous temporal bone in both the CEST and sham CEST group. All temporal bone CT features studied were associated with female sex. In the CEST group, temporal bone heterogeneity (p = 0.006) and higher temporal bone diploë ratio (p = 0.002) were associated with higher NIHSS at 24 h. There was no association between temporal bone features and mRS at 3 months. Approximately 20% of acute ischemic stroke patients have heterogeneous temporal bone and may be resistant to standard 2-MHz transcranial Doppler ultrasound treatment. Sonothrombolysis resistance may easily be predicted by admission CT for better selection.

Therapeutic Strategies to Attenuate Hemorrhagic Transformation After Tissue Plasminogen Activator Treatment for Acute Ischemic Stroke

This review focuses on the mechanisms and emerging concepts of stroke and therapeutic strategies for attenuating hemorrhagic transformation (HT) after tissue plasminogen activator (tPA) treatment for acute ischemic stroke (AIS). The therapeutic time window for tPA treatment has been extended. However, the patients who are eligible for tPA treatment are still ＜5% of all patients with AIS. The risk of serious or fatal symptomatic hemorrhage increases with delayed initiation of treatment. HT is thought to be caused by 1) ischemia/reperfusion injury; 2) the toxicity of tPA itself; 3) inflammation; and/or 4) remodeling factor-mediated effects. Modulation of these pathophysiologies is the basis of direct therapeutic strategies to attenuate HT after tPA treatment. Several studies have revealed that matrix metalloproteinases and free radicals are potential therapeutic targets. In addition, we have demonstrated that the inhibition of the vascular endothelial growth factor-signaling pathway and supplemental treatment with a recombinant angiopoietin-1 protein might be a promising therapeutic strategy for attenuating HT after tPA treatment through vascular protection. Moreover, single-target therapies could be insufficient for attenuating HT after tPA treatment and improving the therapeutic outcome of patients with AIS. We recently identified progranulin, which is a growth factor and a novel target molecule with multiple therapeutic effects. Progranulin might be a therapeutic target that protects the brain through suppression of vascular remodeling (vascular protection), neuroinflammation, and/or neuronal death (neuroprotection). Clinical trials which evaluate the effects of anti-VEGF drugs or PGRN-based treatment with tPA will be might worthwhile.

Acute Ischemic Stroke Therapy Overview

The treatment of acute ischemic stroke has undergone dramatic changes recently subsequent to the demonstrated efficacy of intra-arterial (IA) device-based therapy in multiple trials. The selection of patients for both intravenous and IA therapy is based on timely imaging with either computed tomography or magnetic resonance imaging, and if IA therapy is considered noninvasive, angiography with one of these modalities is necessary to document a large-vessel occlusion amenable for intervention. More advanced computed tomography and magnetic resonance imaging studies are available that can be used to identify a small ischemic core and ischemic penumbra, and this information will contribute increasingly in treatment decisions as the therapeutic time window is lengthened. Intravenous thrombolysis with tissue-type plasminogen activator remains the mainstay of acute stroke therapy within the initial 4.5 hours after stroke onset, despite the lack of Food and Drug Administration approval in the 3- to 4.5-hour time window. In patients with proximal, large-vessel occlusions, IA device-based treatment should be initiated in patients with small/moderate-sized ischemic cores who can be treated within 6 hours of stroke onset. The organization and implementation of regional stroke care systems will be needed to treat as many eligible patients as expeditiously as possible. Novel treatment paradigms can be envisioned combining neuroprotection with IA device treatment to potentially increase the number of patients who can be treated despite long transport times and to ameliorate the consequences of reperfusion injury. Acute stroke treatment has entered a golden age, and many additional advances can be anticipated.

Treatment of Acute Ischemic Stroke

Although stroke declined from the third to fifth most common cause of death in the United States, the annual incidence and overall prevalence continue to increase. Since the available US Food and Drug Administration-approved treatment options are time dependent, improving early stroke care may have more of a public health impact than any other phase of care. Timely and efficient stroke treatment should be a priority for emergency department and prehospital providers. This article discusses currently available and emerging treatment options in acute ischemic stroke focusing on the preservation of salvageable brain tissue, minimizing complications, and secondary prevention.

NOR-SASS (Norwegian Sonothrombolysis in Acute Stroke Study): Randomized Controlled Contrast-Enhanced Sonothrombolysis in an Unselected Acute Ischemic Stroke Population

Background and Purpose—

The NOR-SASS (Norwegian Sonothrombolysis in Acute Stroke Study) aimed to assess effect and safety of contrast-enhanced ultrasound treatment in an unselected acute ischemic stroke population.

Methods—

Patients treated with intravenous thrombolysis within 4.5 hours after symptom onset were randomized 1:1 to either contrast-enhanced sonothrombolysis (CEST) or sham CEST. A visible arterial occlusion on baseline computed tomography angiography was not a prerequisite for inclusion. Pulse-wave 2 MHz ultrasound was given for 1 hour and contrast (SonoVue) as an infusion for ≈30 minutes. Magnetic resonance imaging and angiography were performed after 24 to 36 hours. Primary study end points were neurological improvement at 24 hours defined as National Institutes of Health Stroke Scale score 0 or reduction of ≥4 National Institutes of Health Stroke Scale points compared with baseline National Institutes of Health Stroke Scale and favorable functional outcome at 90 days defined as modified Rankin scale score 0 to 1.

Results—

A total of 183 patients were randomly assigned to either CEST (93 patient) or sham CEST (90 patients). The rates of symptomatic intracerebral hemorrhage, asymptomatic intracerebral hemorrhage, or mortality were not increased in the CEST group. Neurological improvement at 24 hours and functional outcome at 90 days was similar in the 2 groups both in the intention-to-treat analysis and in the per-protocol analysis.

Conclusions—

CEST is safe among unselected ischemic stroke patients with or without a visible occlusion on computed tomography angiography and with varying grades of clinical severity. There was, however, statistically no significant clinical effect of sonothrombolysis in this prematurely stopped trial.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01949961.

Therapeutic Potential of Tenecteplase in the Management of Acute Ischemic Stroke

Given that alteplase has been the only approved thrombolytic agent for acute ischemic stroke for almost two decades, there has been intense interest in more potent and safer agents over the last few years. Tenecteplase is a bioengineered mutation of alteplase with advantageous pharmacodynamics and pharmacokinetics. The superiority of tenecteplase over alteplase has been proven by in vitro and animal studies, and it was approved for use in myocardial infarction more than a decade ago. In patients with acute ischemic stroke, tenecteplase has shown promise in randomized phase II trials and the drug is currently being tested in four phase III clinical trials that will start delivering definite results in the near future: NOR-TEST (NCT01949948), TASTE (ACTRN12613000243718), TEMPO-2 (NCT02398656), and TALISMAN (NCT02180204).

Tenecteplase versus alteplase in stroke thrombolysis: An individual patient data meta-analysis of randomized controlled trials

Background

Tenecteplase, a modified plasminogen activator with higher fibrin specificity and longer half-life, may have advantages over alteplase in acute ischemic stroke thrombolysis.

Aims

We undertook an individual patient data meta-analysis of randomized controlled trials that compared alteplase with tenecteplase in acute stroke.

Methods

Eligible studies were identified by a MEDLINE search, and individual patient data were acquired. We compared clinical outcomes including modified Rankin Scale at three months, early neurological improvement at 24 h, intracerebral hemorrhage, symptomatic intracerebral hemorrhage, and mortality at three months between all dose tiers of tenecteplase and alteplase.

Results

Three relevant studies (Haley et al., Parsons et al., and ATTEST) included 291 patients and investigated three doses of tenecteplase (0.1, 0.25, 0.4 mg/kg). There were no differences between any dose of tenecteplase and alteplase for either efficacy or safety end points. Tenecteplase 0.25 mg/kg had the greatest odds to achieve early neurological improvement (OR [95%CI] 3.3 [1.5, 7.2], p = 0.093), excellent functional outcome (modified Rankin Scale 0–1) at three months (OR [95%CI] 1.9 [0.8, 4.4], p = 0.28), with reduced odds of intracerebral hemorrhage (OR [95%CI] 0.6 [0.2, 1.8], P = 0.43) compared with alteplase. Only 19 patients were treated with tenecteplase 0.4 mg/kg, which showed increased odds of symptomatic intracerebral hemorrhage compared with alteplase (OR [95% CI] 6.2 [0.7, 56.3]).

Conclusions

While no significant differences between tenecteplase and alteplase were found, point estimates suggest potentially greater efficacy of 0.25 and 0.1 mg/kg doses with no difference in symptomatic intracerebral hemorrhage, and potentially higher symptomatic intracerebral hemorrhage risk with the 0.4 mg/kg dose. Further investigation of 0.25 mg/kg tenecteplase is warranted.

Wake-up stroke: Dawn of a new era

Wake-up stroke or stroke with unclear onset of symptoms is known to occur in one-fourth of ischemic stroke patients. These patients are not considered for thrombolytic therapy based on time designation of their symptom onset as per the current guidelines. Observational studies have investigated the pathophysiology and suggested actual onset of symptoms to be approximate to the awakening time for these patients. Use of advanced imaging modalities in these patients tends to identify favorable patient profiles for thrombolysis. Results of the ongoing trials will likely beckon a seminal juncture in stroke therapy and deliver critical modifications in the current treatment guidelines for thrombolysis in this substantial, yet neglected, group of stroke patients. In this article, we have reviewed the predisposing factors, preferred imaging modalities and various ongoing thrombolytic and endovascular trials to date for patients with unclear time of symptom onset or who wake up with stroke symptoms.

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.

Novel Thrombolytics for Acute Ischemic Stroke: Challenges and Opportunities

Progress in finding a better alternative to alteplase has been slow. Tenecteplase and desmoteplase have better pharmacological profiles compared with alteplase, but definite clinical evidence of their superiority is lacking. The two major phase III studies that have tested the efficacy and safety of desmoteplase in ischemic stroke patients have shown neutral results and a promising safety profile, but the trials compared desmoteplase with placebo only in late admitted patients. Future trials should focus on testing novel thrombolytics in the early time window either as the sole acute recanalizing treatment or combined with thrombectomy.

Thrombolysis for acute ischemic stroke by tenecteplase in the emergency department of a Moroccan hospital

INTRODUCTION

Thrombolysis has radically changed the prognosis of acute ischemic stroke. Tenecteplase is a modified form of rt-PA with greater specificity for fibrin and a longer half-life. We report the experience of a Moroccan tertiary hospital in thrombolysis using Tenecteplase.

METHODS

We conducted an open prospective study of all patients who were treated with Tenecteplase for an acute ischemic stroke admitted to our emergency department. Tenecteplase was administered intravenously at a dose of 0.4 mg/kg single bolus. The primary outcome measure was the proportion of patients achieving significant early neurological recovery defined as an improvement of 4 or more points on the NIHSS score at 24h.

RESULTS

13 patients had been treated by intravenous thrombolysis. 31% were women. Mean age was 63 years old. The mean NIHSS score at admission was 14.3 and 24h after was at 9.1. The right middle cerebral artery was involved in 69% of cases. The carotid atherosclerosis was predominant 63.3% and the cardio embolic etiology 27%. The mean time to the first medical contact after the onset of symptoms was 3h 30 min. One patient presented a capsulo-lenticular hematoma of 5 mm(3) in the same side of the ischemic stroke.

CONCLUSION

Tenecteplase is a more interesting thrombolytic than alteplase, it seems to be more suitable for thrombolysis in our center.

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.