BACKGROUND: Endovascular treatment (EVT) for acute ischemic stroke (AIS) patients presenting with National Institutes of Health Stroke Scale score of 0 to 5 is common in clinical practice but has not yet been proven safe and effective. Our objective is to assess whether EVT on top of best medical treatment (BMT) in AIS patients with large-vessel occlusion of the anterior circulation presenting with mild symptoms is beneficial compared with BMT. METHODS: We searched MEDLINE, SCOPUS, and reference lists of retrieved articles published until December 28, 2022. A systematic literature search was conducted to identify clinical trials or observational cohort studies evaluating patients with AIS due to anterior circulation large-vessel occlusion and admission National Institutes of Health Stroke Scale score ≤5 treated with EVT versus BMT alone. The primary outcome was excellent functional outcome (modified Rankin Scale score 0–1) at 3 months. The protocol had been registered before data collection (PROSPERO). RESULTS: Eleven observational eligible studies were included in the meta-analysis, comprising a total of 2019 AIS patients with National Institutes of Health Stroke Scale score ≤5 treated with EVT versus 3171 patients treated with BMT. EVT was not associated with excellent functional outcome (risk ratio, 1.10 [95% CI, 0.93–1.31]). When stratified for different study design (per-protocol versus intention-to-treat), there were no significant subgroup differences. EVT was not associated with good functional outcome (modified Rankin Scale score 0–2; risk ratio, 1.01 [95% CI, 0.89–1.16]) or reduced disability at 3 months (common odds ratio, 0.92 [95% CI, 0.60–1.41]). Symptomatic intracranial hemorrhage was more common in the patients receiving EVT (risk ratio, 3.53 [95% CI, 2.35–5.31]). No correlation was found between EVT and mortality at 3 months (risk ratio, 1.34 [95% CI, 0.83–2.18]). The same overall associations were confirmed in the sensitivity analysis of studies that performed propensity score matching. CONCLUSIONS: EVT appears equivalent to BMT for patients with anterior circulation large-vessel occlusion AIS with low baseline National Institutes of Health Stroke Scale, despite the increased risk for symptomatic intracranial hemorrhage. REGISTRATION: URL: https://www.crd.york.ac.uk/PROSPERO/ ; Unique identifier: CRD42022334417.

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.

Tenecteplase has recently emerged as an alternative thrombolytic agent in acute ischemic stroke (AIS) patients with large vessel occlusion (LVO), possibly superior in achieving early reperfusion compared with alteplase. We aimed to compare the safety and efficacy of intravenous tenecteplase with intravenous alteplase for AIS patients with LVO in everyday clinical practice settings. We prospectively evaluated patients with AIS due to LVO, treated with intravenous thrombolysis (IVT) with or without mechanical thrombectomy in two tertiary stroke centers. Patients were treated with standard-dose alteplase (0.9 mg/kg) or 0.25 mg/kg tenecteplase. Safety outcomes included prevalence of symptomatic intracranial hemorrhage (sICH) and mortality. Efficacy outcomes included averted thrombectomy, major neurological improvement at 24 h (defined as decrease in baseline NIHSS score of 8 points or greater) and functional status on discharge and on 3 months assessed by modified Rankin Scale (mRS). Nineteen AIS patients with LVO received tenecteplase and 39 received alteplase. We observed a non-significant higher rate of averted thrombectomies (32% versus 18%, p = 0.243) and a non-significant higher rate of sICH (16% versus 5%, p = 0.201) in the tenecteplase group. The rate of 24 h major neurological improvement was higher in the tenecteplase group (64% versus 33%, p = 0.046) but this was marginally attenuated in multivariable analyses (adjusted OR 10.22, 95% CI: 0.73–142.98; p = 0.084). Discharge mRS, 3-months mRS, and 3-month functional independence (mRS scores of 0–2) did not differ (p > 0.2) between the two groups. The rates of 3-month mortality (11% versus 18%, p = 0.703) were similar in the two groups. No independent association between thrombolytic agent and safety or efficacy outcomes emerged in multivariable regression analyses. The present pilot observational study highlights that AIS patients with LVO treated with 0.25 mg/kg bolus administration of tenecteplase had increased likelihood to achieve early neurological improvement compared with AIS patients treated with alteplase, but this association was attenuated after adjustment for potential confounders. There were no significant differences in 3-month functional or safety outcomes between the two groups. This preliminary real-world observation requires independent confirmation in larger, multicenter studies.

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.

Most clots retrieved from patients with acute ischemic stroke are 'red' in color. 'White' clots represent a less common entity and their histological composition is less known. Our aim was to investigate the composition, imaging and procedural characteristics of 'white' clots retrieved by mechanical thrombectomy. Seventy five 'white' thrombi were selected by visual inspection from a cohort of 760 clots collected as part of the RESTORE registry. Clots were evaluated histopathologically. Quantification of Martius Scarlett Blue stain identified platelets/other as the major component in 'white' clots' (mean of 55% of clot overall composition) followed by fibrin (31%), red blood cells (6%) and white blood cells (3%). 'White' clots contained significantly more platelets/other (p<0.001*) and collagen/calcification (p<0.001*) and less red blood cells (p<0.001*) and white blood cells (p=0.018*) than 'red' clots. The mean platelet and von Willebrand Factor expression was 43% and 24%, respectively. Adipocytes were found in four cases. 'White' clots were significantly smaller (p=0.016*), less hyperdense (p=0.005*) on computed tomography angiography/non-contrast CT and were associated with a smaller extracted clot area (p<0.001*) than 'red' clots. They primarily caused the occlusion of middle cerebral artery, were less likely to be removed by aspiration and more likely to require rescue-therapy for retrieval. 'White' clots represented 14% of our cohort and were platelet, von Willebrand Factor and collagen/calcification-rich. 'White' clots were smaller, less hyperdense, were associated with significantly more distal occlusions and were less successfully removed by aspiration alone than 'red' clots.

There is a paucity of knowledge in the literature relating to the extent of clot burden and stroke etiology. In this study, we measured the Extracted Clot Area (ECA) retrieved during endovascular treatment (EVT) and investigated relationships with suspected etiology, administration of intravenous thrombolysis and recanalization. As part of the multi-institutional RESTORE registry, the ECA retrieved during mechanical thrombectomy was quantified using ImageJ. The effect of stroke etiology (Large-artery atherosclerosis (LAA), Cardioembolism, Cryptogenic and other) and recombinant tissue plasminogen activator (rtPA) on ECA and recanalization outcome (mTICI) was assessed. Successful recanalization was described as mTICI 2c-3. A total of 550 patients who underwent EVT with any clot retrieved were included in the study. The ECA was significantly larger in the LAA group compared to all other etiologies. The average ECA size of each etiology was; LAA=109 mm², Cardioembolic=52 mm², Cryptogenic=47 mm² and Other=52 mm² (p=0.014*). LAA patients also had a significantly poorer rate of successful recanalization (mTICI 2c-3) compared to all other etiologies (p=0.003*). The administration of tPA was associated with a smaller ECA in both LAA (p=0.007*) and cardioembolic (p=0.035*) groups. The ECA of LAA clots was double the size of all other etiologies and this is associated with a lower rate of successful recanalization in LAA stroke subtype. rtPA administration prior to thrombectomy was associated with reduced ECA in LAA and CE clots.