Thrombolysis beyond 4.5 h in Acute Ischemic Stroke

Intravenous Thrombolytics in the Treatment of Acute Ischemic Stroke

Purpose of Review

To review the current evidence and ongoing clinical trials evaluating the efficacy and safety of tenecteplase (TNK), an alternative tissue plasminogen activator (tPA), in the acute management of arterial ischemic stroke (AIS). To date, alteplase is the only tPA approved by the United States FDA for use in AIS.

Recent Findings

There have been multiple phase two and three trials investigating the safety and efficacy of TNK in AIS. In patients with AIS due to large vessel occlusion, one randomized controlled trial demonstrated superiority of TNK for vessel recanalization rates and long-term functional outcomes when compared to alteplase. A meta-analysis of all phase two and three trials evaluating TNK in AIS concluded that TNK has a comparable safety and efficacy profile to alteplase. The results of these trials prompted new recommendations in the Acute Stroke Guideline published by the AHA suggesting it may be reasonable to use as an alternative to alteplase. Furthermore, recent real-world data has also reported decreased door-to-needle time with TNK utilization.

Summary

In patients with AIS, use of a thrombolytic agent is standard of care and has been shown to reduce neurological disability and improve functional outcome. Randomized controlled trials have demonstrated that TNK is non-inferior to alteplase from a clinical outcome and safety standpoint. The existing data evaluating the efficacy of TNK compared to alteplase in acute AIS within 4.5 h from symptom onset showed no significant difference between these two agents with regard to functional outcome at 90 days but improved median time to treatment and large vessel recanalization in TNK-treated patients. The results from ongoing TNK trials in larger patient cohorts and in wake-up stroke populations will be instrumental to the wide-scale utilization of TNK in acute AIS management.

Mothership vs. drip-and-ship: evaluation of initial treatment strategies for acute ischemic stroke in a well-developed network of specialized hospitals

PURPOSE

Two strategies of initial patient care exist in endovascular thrombectomy (ET) depending on the site of initial admission: the mothership (MS) and drip-and-ship (DnS) principles. This study compares both strategies in regard to patient outcome in a local network of specialized hospitals.

METHODS

Two-hundred-and-two patients undergoing ET in anterior circulation ischemic stroke between June 2016 and May 2018 were enrolled. Ninety two patients were directly admitted to our local facility (MS), One-hundred-and-ten were secondarily referred to our facility. Group comparisons between admission strategies in three-months modified Rankin Scale (mRS), Maas Score and Alberta-Stroke-Program-Early-computed-tomography-score (ASPECTS), National-Institutes-of-Health-Stroke-Scale (NIHSS), age and onset-to-recanalization-time were performed. Correlation between admission strategy and mRS was calculated. A binary logistic regression model was computed including mRS as dependent variable.

RESULTS

There were neither significant group differences in three-months mRS between MS and DnS nor significant correlations. Patients tended to achieve a better outcome with DnS. Collateralization status differed between MS and DnS (p = 0.003) with better collateralization in DnS. There were no significant group differences in NIHSS or ASPECTS but in onset-to-recanalization-time (p < 0.001) between MS and DnS. Binary logistic regression showed a high explanation of variance of mRS but no significant results for admission strategy.

CONCLUSIONS

Functional outcome in patients treated with ET is comparable between the MS and DnS principles. Tendentially better outcome in the DnS subgroup may be explained by selection bias due to a higher willingness to apply ET in patients with worse baseline conditions (e.g. worse collateralization), if patients undergoing MS are already on site.

Predictive Value of Apelin and Vaspin on Hemorrhagic Transformation in Patients with Acute Ischemic Stroke after Intravenous Thrombolysis and Analysis of Related Factors

BACKGROUND

Acute ischemic stroke (CIS) is a high-risk condition among the elderly, and intravenous thrombolytic therapy (ITT) is the most effective means for it. However, ITT is prone to induce hemorrhagic transformation (HT) that further threatens the life and health of patients. As paramount substances in cardiovascular and cerebrovascular diseases, adipocyte factor (Apelin) and serine protease inhibitor (Vaspin) are strongly bound up with CIS.

OBJECTIVE

To analyze the predictive significance of Apelin and Vaspin on HT in CIS patients after ITT and offer effective reference to HT prevention in the future.

METHODS

A total of 109 CIS patients treated with intravenous thrombolysis (IT) in two hospitals between June 2017 and February 2018 were enrolled. Among them, 48 patients who suffered HT after therapy were assigned to the research group (Res group) and the other 61 patients who did not suffer it after therapy were assigned to the control group (Con group). Serum Apelin, Vaspin, inflammatory factors, and oxidative stress levels were quantified, and receiver operating characteristic (ROC) curves were drawn for analyzing the predictive value of Apelin and Vaspin on HT after ITT and their associations with inflammatory factors and oxidative stress. CIS patients who suffered HT were followed up for 3 years for prognostic significance analysis of Apelin and Vaspin.

RESULTS

After ITT, the Res group showed lower Apelin and Vaspin levels than the Con group (all P < 0.05), and patients with a higher HT grade had lower Apelin and Vaspin levels (all P < 0.05). The joint detection of Apelin and Vaspin showed a sensitivity of 77.08% and a specificity of 73.77% for forecasting HT in CIS patients after thrombolytic therapy (all P < 0.001). In addition, after thrombolytic therapy, the Res group presented higher levels of interleukin-1β (IL-1β) and IL-6 as well as malondialdehyde (MDA) than the Con group, and the levels had negative associations with Apelin and Vaspin (all P < 0.05). The Res group showed a lower superoxide dismutase (SOD) level than the Con group, and the level presented a positive association with Apelin and Vaspin (all P < 0.05). According to Logistic analysis, IL-1β, IL-6, and MDA were independent risk factors for HT in CIS patients after IT, while Apelin, Vaspin, and SOD were independent protective factors (all P < 0.05). According to the follow-up results, Apelin and Vaspin demonstrated excellent value in forecasting the death of patients with both CIS and HT (P < 0.05), and their lower levels indicate a higher risk of death (all P < 0.05).

CONCLUSION

Apelin and Vaspin can help effectively forecast the occurrence of HT in CIS patients after ITT as independent protective factors of HT, so they are of a high clinical application value.

Understanding neural stem cell regulation in vivo and applying the insights to cell therapy for strokes

The use of neural stem cell (NSC) therapy for the treatment of stroke patients is successfully paving its way into advanced phases of large-scale clinical trials. To understand how to optimize NSC therapeutic approaches, it is fundamental to decipher the crosstalk between NSC and other cells that comprise the NSC microenvironment (niche) and regulate their function, in vivo; namely, the endothelial cells of the microvasculature. In this mini review, we first provide a concise summary of preclinical findings describing the signaling mechanisms between NSC and vascular endothelial cells and vice versa. Second, we describe the progress made in the development of NSC therapy for the treatment of strokes.

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.

Neuroprotective Effects of Guanosine in Ischemic Stroke-Small Steps towards Effective Therapy

Guanosine (Guo) is a nucleotide metabolite that acts as a potent neuromodulator with neurotrophic and regenerative properties in neurological disorders. Under brain ischemia or trauma, Guo is released to the extracellular milieu and its concentration substantially raises. In vitro studies on brain tissue slices or cell lines subjected to ischemic conditions demonstrated that Guo counteracts destructive events that occur during ischemic conditions, e.g., glutaminergic excitotoxicity, reactive oxygen and nitrogen species production. Moreover, Guo mitigates neuroinflammation and regulates post-translational processing. Guo asserts its neuroprotective effects via interplay with adenosine receptors, potassium channels, and excitatory amino acid transporters. Subsequently, guanosine activates several prosurvival molecular pathways including PI3K/Akt (PI3K) and MEK/ERK. Due to systemic degradation, the half-life of exogenous Guo is relatively low, thus creating difficulty regarding adequate exogenous Guo distribution. Nevertheless, in vivo studies performed on ischemic stroke rodent models provide promising results presenting a sustained decrease in infarct volume, improved neurological outcome, decrease in proinflammatory events, and stimulation of neuroregeneration through the release of neurotrophic factors. In this comprehensive review, we discuss molecular signaling related to Guo protection against brain ischemia. We present recent advances, limitations, and prospects in exogenous guanosine therapy in the context of ischemic stroke.

XQ-1H promotes cerebral angiogenesis via activating PI3K/Akt/GSK3β/β-catenin/VEGF signal in mice exposed to cerebral ischemic injury

Stroke still ranks as a most lethal disease worldwide. Angiogenesis during the chronic phase of ischemic stroke can alleviate ischemic injury and attenuate neurological deficit. XQ-1H is a new compound derived from the structure modification of ginkgolide B, which exerts anti-inflammation and neuroprotection against cerebral ischemic injury during the acute or subacute phase. However, whether XQ-1H facilitates angiogenesis and neural functional recovery during the chronic phase remains unclear. This research was designed to explore whether XQ-1H promotes angiogenesis after ischemic stroke and to preliminarily elucidate the mechanism. In vitro, XQ-1H was found to facilitate proliferation, migration and tube formation in bEnd.3 cells. In vivo, XQ-1H raised the CD31 positive microvessel number and increased focal cerebral blood flow in mice exposed to cerebral ischemic injury, and improved the neurological function. Mechanism studies revealed that XQ-1H exerted angiogenesis promoting effect via the PI3K/Akt/GSK3β/β-catenin/VEGF signal pathway, which was reversed by LY294002 (the specific inhibitor of PI3K/Akt). In conclusion, XQ-1H exerts angiogenetic effect both in vivo and in vitro, which is a potential agent against ischemic stroke during chronic phase.