Thrombolysis in Stroke With Unknown Onset Based on Non-Contrast Computerized Tomography (TRUST CT)

[What is confirmed in the treatment of ischemic stroke]

Ischemic stroke is one of the leading causes of death worldwide and the most frequent cause of permanent disability in adulthood. The acute treatment of stroke is time-critical and, according to the time is brain principle, it is important to determine as soon as possible whether recanalization treatment that can save the penumbra is possible. Intravenous thrombolysis (IVT) and, if a large vessel occlusion is identified, endovascular treatment (EVT) possibly in combination with IVT, are recommended. Further treatment in a stroke unit is another important component of acute stroke treatment. The best secondary preventive treatment must already be initiated in the acute phase. The cause of stroke guides making decisions on the ideal secondary preventive strategy. The most important etiologies of stroke are cardiac embolism, atherosclerotic macroangiopathy and cerebral microangiopathy (small vessel disease). Less frequent causes are dissections of arteries supplying the brain or vasculitis. In up to 20-30% of all cases, however, no clear etiology can be determined despite intensive investigation of the cause. This means corresponding uncertainty in the optimal secondary prevention that consists in particular of an anticoagulant medication adapted to the etiology, treatment of cardiovascular risk factors and if necessary surgical or interventional desobliterative procedures. This article describes the diagnostic procedure and the evidence-based treatment of ischemic stroke.

[Intravenous thrombolysis of ischemic stroke-Current status]

Intravenous thrombolysis (IVT) treatment with alteplase (rtPA) is an essential part of the routine treatment of patients with ischemic stroke since its introduction in the late 1990s. Rapid treatment is of essential importance. For patients with an unclear time window, various mismatch concepts have been established to identify salvageable brain tissue prior to IVT. Numerous official contraindications for rtPA are not evidence-based; for example, current data from observational studies show that systemic thrombolytic treatment is possible even in patients receiving direct oral anticoagulant (DOAC) treatment. Tenecteplase (TNK) is an alternative thrombolytic agent with some pharmacologic advantages. The most recent guidelines indicate that TNK is particularly advantageous over rtPA in patients treated in combination with endovascular stroke therapy (EST). The combination of IVT and EST should primarily be performed in the 4.5‑h time window in patients without contraindications; in the later time window EST alone is conceivable if it can be performed without delay.

Access to and application of recanalizing therapies for severe acute ischemic stroke caused by large vessel occlusion

BACKGROUND

Groundbreaking study results since 2014 have dramatically changed the therapeutic options in acute therapy for severe ischemic stroke caused by large vessel occlusion (LVO). The scientifically proven advances in stroke imaging and thrombectomy techniques have allowed to offer the optimal version or combination of best medical and interventional therapy to the selected patient, yielding favorable or even excellent clinical outcomes within time windows unheard of before. The provision of the best possible individual therapy has become a guideline-based gold standard, but remains a great challenge. With geographic, regional, cultural, economic and resource differences worldwide, optimal local solutions have to be strived for.

AIM

This standard operation procedure (SOP) is aimed to give a suggestion of how to give patients access to and apply modern recanalizing therapy for acute ischemic stroke caused by LVO.

METHOD

The SOP was developed based on current guidelines, the evidence from the most recent trials and the experience of authors who have been involved in the above-named development at different levels.

RESULTS

This SOP is meant to be a comprehensive, yet not too detailed template to allow for freedom in local adaption. It comprises all relevant stages in providing care to the patient with severe ischemic stroke such as suspicion and alarm, prehospital acute measures, recognition and grading, transport, emergency room workup, selective cerebral imaging, differential treatment by recanalizing therapies (intravenous thrombolysis, endovascular stroke treatmet, or combined), complications, stroke unit and neurocritical care.

CONCLUSIONS

The challenge of giving patients access to and applying recanalizing therapies in severe ischemic stroke may be facilitated by a systematic, SOP-based approach adapted to local settings.

Normal Appearing Ischaemic Brain Tissue on CT and Outcome After Intravenous Alteplase

Background and Aims

The visibility of ischaemic brain lesions on non-enhanced CT increases with time. Obviously hypoattenuating lesions likely represent infarction. Conversely, viable ischaemic brain lesions may be non-visible on CT. We tested whether patients with normal appearing ischaemic brain tissue (NAIBT) on their initial CT are identifiable, and if NAIBT yields better outcomes with alteplase.

Methods

With data from the Third International Stroke Trial (IST-3, a large randomized-controlled trial of intravenous alteplase for ischaemic stroke) we used receiver-operating characteristic analysis to find a baseline National Institutes of Health Stroke Scale (NIHSS) threshold for identifying patients who developed medium-large ischaemic lesions within 48 h. From patients with baseline CT (acquired <6 h from stroke onset), we used this NIHSS threshold for selection and tested whether favorable outcome after alteplase (6-month Oxford Handicap Score 0-2) differed between patients with NAIBT vs. with those with visible lesions on baseline CT using binary logistic regression (controlled for age, NIHSS, time from stroke onset to CT).

Results

From 2,961 patients (median age 81 years, median 2.6 h from stroke onset, 1,534 [51.8%] female, 1,484 [50.1%] allocated alteplase), NIHSS>11 best identified those with medium-large ischaemic lesions (area under curve = 0.79, sensitivity = 72.3%, specificity = 71.9%). In IST-3, 1,404/2,961 (47.4%) patients had baseline CT and NIHSS>11. Of these, 745/1,404 (53.1%) had visible baseline ischaemic lesions, 659/1,404 (46.9%) did not (NAIBT). Adjusted odds ratio for favorable outcome after alteplase was 1.54 (95% confidence interval, 1.01-2.36), p = 0.045 among patients with NAIBT vs. 1.61 (0.97-2.67), p = 0.066 for patients with visible lesions, with no evidence of an alteplase-NAIBT interaction (p-value = 0.895).

Conclusions

Patients with ischaemic stroke and NIHSS >11 commonly develop sizeable ischaemic brain lesions by 48 h that may not be visible within 6 h of stroke onset. Invisible ischaemic lesions may indicate tissue viability. In IST-3, patients with this clinical-radiological mismatch allocated to alteplase achieved more favorable outcome than those allocated to control.

Intravenous thrombolysis for acute ischemic stroke: why not?

PURPOSE OF REVIEW

The aim of this study was to summarize available evidence regarding the safety and efficacy of intravenous thrombolysis (IVT) using recombinant tissue-plasminogen activator (rt-PA) in acute ischemic stroke (AIS) patients with specific comorbidities and potential contraindications to systemic reperfusion therapy. Recent advances in IVT implementation in wake-up stroke and in extended time window using advanced neuroimaging will also be highlighted.

RECENT FINDINGS

Despite theoretical concerns of a higher bleeding risk with IVT, there are no data showing increased risk of symptomatic intracerebral haemorrhage (sICH) in patients with stroke mimics, including seizures, increasing age and dual antiplatelet pretreatment. In addition, recent randomized evidence allows us to expand the time window of IVT for AIS using advanced neuroimaging both in wake-up stroke patients and in patients presenting within 4.5-9 h from symptom onset fulfilling certain neuroimaging criteria (based on DWI/FLAIR mismatch or perfusion mismatch).

SUMMARY

IVT is a highly effective systemic reperfusion therapy that counts 25 years of everyday clinical experience but still presents several challenges in its application. Appropriate patient selection and adherence to rt-PA protocol is paramount in terms of safety. The effort to simplify the indications, expand the therapeutic time window and eliminate specific initial contraindications is continuously evolving.

Imaging Acute Stroke: From One-Size-Fit-All to Biomarkers

In acute stroke management, time window has been rigidly used as a guide for decades and the reperfusion treatment is only available in the first few limited hours. Recently, imaging-based selection of patients has successfully expanded the treatment window out to 16 and even 24 h in the DEFUSE 3 and DAWN trials, respectively. Recent guidelines recommend the use of imaging techniques to guide therapeutic decision-making and expanded eligibility in acute ischemic stroke. A tissue window is proposed to replace the time window and serve as the surrogate marker for potentially salvageable tissue. This article reviews the evolution of time window, addresses the advantage of a tissue window in precision medicine for ischemic stroke, and discusses both the established and emerging techniques of neuroimaging and their roles in defining a tissue window. We also emphasize the metabolic imaging and molecular imaging of brain pathophysiology, and highlight its potential in patient selection and treatment response prediction in ischemic stroke.

Acute reperfusion therapies for acute ischemic stroke patients with unknown time of symptom onset or in extended time windows: an individualized approach

Recent randomized controlled clinical trials (RCTs) have revolutionized acute ischemic stroke care by extending the use of intravenous thrombolysis and endovascular reperfusion therapies in time windows that have been originally considered futile or even unsafe. Both systemic and endovascular reperfusion therapies have been shown to improve outcome in patients with wake-up strokes or symptom onset beyond 4.5 h for intravenous thrombolysis and beyond 6 h for endovascular treatment; however, they require advanced neuroimaging to select stroke patients safely. Experts have proposed simpler imaging algorithms but high-quality data on safety and efficacy are currently missing. RCTs used diverse imaging and clinical inclusion criteria for patient selection during the dawn of this novel stroke treatment paradigm. After taking into consideration the dismal prognosis of nonrecanalized ischemic stroke patients and the substantial clinical benefit of reperfusion therapies in selected late presenters, we propose rescue reperfusion therapies for acute ischemic stroke patients not fulfilling all clinical and imaging inclusion criteria as an option in a subgroup of patients with clinical and radiological profiles suggesting low risk for complications, notably hemorrhagic transformation as well as local or remote parenchymal hemorrhage. Incorporating new data to treatment algorithms may seem perplexing to stroke physicians, since treatment and imaging capabilities of each stroke center may dictate diverse treatment pathways. This narrative review will summarize current data that will assist clinicians in the selection of those late presenters that will most likely benefit from acute reperfusion therapies. Different treatment algorithms are provided according to available neuroimaging and endovascular treatment capabilities.

Safety of intravenous thrombolysis in stroke of unknown time of onset: A systematic review and meta-analysis

The safety of intravenous tissue plasminogen activator (IV-tPA) in patients with stroke of unknown time of onset (SUTO) was unclear and mostly concerned. We sought to investigate the safety in terms of symptomatic intracranial hemorrhage (sICH) and death in SUTO patients treated with IV-tPA. We searched PubMed and EMBASE from inception to 2 December 2020 for eligible studies reporting IV-tPA in SUTO patients compared to conservative medical therapy, or to stroke of known onset time (SKOT) treated with IV-tPA within standard time window. We pooled relative risk (RR) with 95% confidence interval (95%CI) with random-effects model. Twenty-four studies were included, enrolling 77,398 patients. SUTO patients with IV-tPA had higher incidence of sICH than that in SUTO patients without IV-tPA (3.8% versus 0.96%; RR = 3.75, 95%CI: 2.69-5.22) but comparable to that in SKOT patients with IV-tPA (3.8% versus 4.1%; RR = 1.16, 95%CI: 0.94-1.44). There was no significant difference in death risk in SUTO patients with IV-tPA versus SUTO patients without IV-tPA (RR = 1.34, 95%CI: 0.60-3.01) and versus SKOT patients with IV-tPA (RR = 1.19, 95%CI: 0.95-1.50). Compared with SUTO patients without IV-tPA, SUTO patients with IV-tPA had higher likelihood of favorable functional outcome (adjusted RR = 1.28, 95%CI: 1.03-1.60) and functional independence (adjusted RR = 1.95, 95%CI: 1.24-3.06), comparable to that in SKOT patients with IV-tPA in favorable functional outcome (adjusted RR = 0.67, 95%CI: 0.38-1.20) and functional independence (adjusted RR = 0.84, 95%CI: 0.59-1.18). SUTO patients could be treated safely and effectively with IV-tPA under the guidance of imaging evaluation.

Thrombolytic therapy for wake-up stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

According to evidence-based clinical practice guidelines, patients presenting with disabling stroke symptoms should be treated with intravenous tissue plasminogen activator (IV tPA) within 4.5 h of time last known well. However, 25% of strokes are detected upon awakening (i.e., wake-up stroke [WUS]), which renders patients ineligible for IV tPA administered via time-based treatment algorithms, because it is impossible to establish a reliable time of symptom onset. We performed a systematic review and meta-analysis of the efficacy and safety of IV tPA compared with normal saline, placebo, or no treatment in patients with WUS using imaging-based treatment algorithms.

METHODS

We searched MEDLINE, Web of Science, and Scopus between January 1, 2006 and April 30, 2020. We included controlled trials (randomized or nonrandomized), observational cohort studies (prospective or retrospective), and single-arm studies in which adults with WUS were administered IV tPA after magnetic resonance imaging (MRI)- or computed tomography (CT)-based imaging. Our primary outcome was recovery at 90 days (defined as a modified Rankin Scale [mRS] score of 0-2), and our secondary outcomes were symptomatic intracranial hemorrhage (sICH) within 36 h, mortality, and other adverse effects.

RESULTS

We included 16 studies that enrolled a total of 14,017 patients. Most studies were conducted in Europe (37.5%) or North America (37.5%), and 1757 patients (12.5%) received IV tPA. All studies used MRI-based (five studies) or CT-based (10 studies) imaging selection, and one study used a combination of modalities. Sixty-one percent of patients receiving IV tPA achieved an mRS score of 0 to 2 at 90 days (95% confidence interval [CI]: 51%-70%, 12 studies), with a relative risk (RR) of 1.21 compared with patients not receiving IV tPA (95% CI: 1.01-1.46, four studies). Three percent of patients receiving IV tPA experienced sICH within 36 h (95% CI: 2.5%-4.1%; 16 studies), which is an RR of 4.00 compared with patients not receiving IV tPA (95% CI: 2.85-5.61, seven studies).

CONCLUSIONS

This systematic review and meta-analysis suggests that IV tPA is associated with a better functional outcome at 90 days despite the increased but acceptable risk of sICH. Based on these results, IV tPA should be offered as a treatment for WUS patients with favorable neuroimaging findings.

Non-contrast head CT-based thrombolysis for wake-up/unknown onset stroke is safe: A single-center study and meta-analysis

BACKGROUND

Recent studies have shown that tPA can be safely administered past the standard 4.5 h window with good outcomes when selected with multi-model imaging, which is often lacking outside of comprehensive stroke centers.

AIM

We aim to analyze the safety and outcomes of wake up/unknown onset (WUS/UNK) patients treated based on non-contrast head CT (NCCT) at our institution and in the literature.

METHODS

Suspected stroke patients from January 2015 to December 2018 receiving tPA within 4.5 h (standard window-SW) and with WUS/UNK based on NCCT and clinical-imaging mismatch were identified. We compared baseline characteristics, tPA metrics, and outcome data, with primary outcome as symptomatic intracerebral hemorrhage (sICH). A meta-analysis was performed evaluating NCCT-based treatment of WUS/UNK patients.

RESULTS

Of 1827 patients treated at our hub or through telestroke, 93 underwent WUS/UNK-based treatment. There was no statistical difference in sICH between WUS/UNK and SW: 1% vs. 4% (OR 0.3; 95% confidence interval 0.0-1.9). 90-day modified Rankin scale outcomes were similar between SW and WUS/UNK-treated patients. Seven studies encompassing 485 WUS/UNK patients were included in a pooled analysis with a 2.1% incidence of sICH. In our meta-analysis, three studies compared NCCT-based treated WUS/UNK patients with SW patients with no difference in rate of hemorrhage: 2.1% vs 3.4% (OR 1.01; 95% confidence interval 0.45-2.28).

INTERPRETATION

Our single-center analysis and meta-analysis suggest that tPA can be safely administered based on NCCT with comparable rates of sICH for select WUS/UNK stroke patients.

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.

Thrombolysis in Stroke With Unknown Onset Based on Non-Contrast Computerized Tomography (TRUST CT)

Background

Intravenous thrombolysis (IVT) in wake‐up stroke (WUS) or stroke with unknown onset (SUO) has been recently proven to be safe and effective using advanced neuroimaging (magnetic resonance imaging or computerized tomography‐perfusion) for patient selection. However, in most of the thrombolyzing centers advanced neuroimaging is not instantly available. We hypothesize that pragmatic non‐contrast computed tomography‐based IVT in WUS/SUO may be feasible and safe.

Methods and Results

TRUST‐CT (Thrombolysis in Stroke With Unknown Onset Based on Non‐Contrast Computerized Tomography) is an international multicenter registry‐based study. WUS/SUO patients undergoing non‐contrast computed tomography‐based IVT with National Institute of Health Stroke Scale ≥4 and initial Alberta Stroke Program Early Computerized Tomography score ≥7 were included and compared with propensity score matched non‐thrombolyzed WUS/SUO controls. Primary end point was the incidence of symptomatic intracranial hemorrhage; secondary end points included 24‐hour National Institute of Health Stroke Scale improvement of ≥4 and modified Rankin Scale at 90 days. One hundred and seventeen WUS/SUO patients treated with non‐contrast computed tomography‐based IVT were included. As compared with 112 controls, the median admission National Institute of Health Stroke Scale was 10 and the median Alberta Stroke Program Early Computerized Tomography score was 10 in both groups. Four (3.4%) IVT patients and one control patient (0.9%) suffered symptomatic intracranial hemorrhage (adjusted odds ratio 7.9, 95% CI 0.65–96, P=0.1). A decrease of ≥4 National Institute of Health Stroke Scale points was observed in 67 (57.3%) of IVT patients as compared with 25 (22.3%) in controls (adjusted odds ratio 5.8, CI 3.0–11.2, P<0.001). A months, 39 (33.3%) IVT patients reached a modified Rankin Scale score of 0 or 1 versus 23 (20.5%) controls (adjusted odds ratio 1.94, CI 1.0–3.76, P=0.05).

Conclusions

Non‐contrast computed tomography‐based thrombolysis in WUS/SUO seems feasible and safe and may be effective. Randomized prospective comparisons are warranted.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT03634748.