Endovascular treatment strategies for acute ischemic stroke

Stroke Treatment With PAR-1 Agents to Decrease Hemorrhagic Transformation

Ischemic stroke is the most widespread cause of disability and a leading cause of death in developed countries. To date, the most potent approved treatment for acute stroke is recanalization therapy with thrombolytic drugs such as tissue plasminogen activator (rt-PA or tPA) or endovascular mechanical thrombectomy. Although tPA and thrombectomy are widely available in the United States, it is currently estimated that only 10-20% of stroke patients get tPA treatment, in part due to restrictive selection criteria. Recently, however, tPA and thrombectomy selection criteria have loosened, potentially allowing more patients to qualify. The relatively low rate of treatment may also reflect the perceived risk of brain hemorrhage following treatment with tPA. In translational research and a single patient study, protease activated receptor 1 (PAR-1) targeted therapies given along with thrombolysis and thrombectomy appear to reduce hemorrhagic transformation after recanalization. Such adjuncts may likely enhance the availability of recanalization and encourage more physicians to use the recently expanded selection criteria for applying recanalization therapies. This narrative review discusses stroke therapies, the role of hemorrhagic transformation in producing poor outcomes, and presents the data suggesting that PAR-1 acting agents show promise for decreasing hemorrhagic transformation and improving outcomes.

Acute ischaemic stroke: a systematic review of the cost-effectiveness of emergency endovascular therapy using mechanical thrombectomy

PURPOSE

Although good evidence exists regarding the clinical effectiveness of mechanical thrombectomy for people with acute ischaemic stroke, cost-effectiveness should also be considered. The aim of this study was to systematically review the evidence of cost-effectiveness of emergency endovascular therapy using mechanical thrombectomy in the management of acute ischaemic stroke.

METHODS

The search was carried out in PubMed, EMBASE, Cochrane Library, and a grey literature search. Studies were included if they compared the costs and consequences of mechanical thrombectomy added to usual medical care compared to usual care alone for people with acute ischaemic stroke in the anterior and/or posterior region. Study quality was assessed using two appraisal tools tailored to economic evaluations.

FINDINGS

Thirteen studies were identified including twelve cost-utility analyses and one cost-benefit analysis. Studies could be dichotomised into those that evaluated first-generation (n = 4) and second-generation (n = 9) mechanical thrombectomy devices. Six studies had low applicability, six had moderate applicability, and one had high applicability to other settings. All cost-utility studies reported incremental cost-effectiveness ratios that would be considered cost-effective under typical willingness-to-pay thresholds.

CONCLUSIONS

If the outcomes of the trials underpinning the evidence of clinical effectiveness can be replicated, then mechanical thrombectomy is likely to be cost-effective by typical willingness-to-pay thresholds. This finding holds under the assumption that no investment is required to develop stroke centres to the standard required to provide a safe emergency endovascular service and that additional expenditure on timely patient transport is not required.

Limitations of Current Near-Infrared Spectroscopy Configuration in Detecting Focal Cerebral Ischemia During Cardiac Surgery: An Observational Case-Series Study

Cerebral oximetry using near-infrared spectroscopy (NIRS) allows for continuous monitoring of cerebral perfusion and immediate treatment of hemodynamic perturbations. In configurations used in current clinical practice, NIRS optodes are placed on the patient`s forehead and cerebral oxygen saturation (ScO₂ ) is determined in bilateral frontal cortical samples. However, focal cerebral ischemic lesions outside of the NIRS field of view may remain undetected. The objective of this observational case-series study was to investigate ScO₂ measurements in patients with acute iatrogenic stroke not located in the frontal cortical region. Adult patients undergoing cardiac surgery with cardiopulmonary bypass or interventional cardiology procedures and suffering stroke in the early postoperative period were identified from the Bernese Stroke Registry and analyzed for their intraoperative ScO₂ values and brain imaging data. Main outcome measures were the ScO₂ values, computed tomography and magnetic resonance imaging findings. In six patients, the infarct areas were localized in the vascular territories of the posterior and/or dorsal middle cerebral arteries. One patient had watershed stroke and another one excellent collaterals resulting in normal cerebral blood volume and only subtle decrease of cerebral blood flow in initially critically perfused watershed brain areas. Intraoperative ScO₂ values were entirely unremarkable or nonindicative for brain damage. Our results indicate that uneventful intraoperative NIRS monitoring does not exclude severe cerebral ischemia due to the limited field of view of commercially available NIRS devices. False negative NIRS may occur as a consequence of stroke localized outside the frontal cortex.

Thrombectomy using Trevo ProVue Stent Retriever Devices after Recombinant Tissue Plasminogen Activator Thrombolysis for Acute Basilar Artery Occlusion during Vertebral Artery Dissection

A 41-year-old woman was admitted due to a sudden-onset severe headache, left hemiparesis and dysarthria. Diffusion-weighted magnetic resonance imaging showed an acute infarct in the bilateral pons, and magnetic resonance angiography revealed basilar artery (BA) occlusion resulting from dissection of the right vertebral artery (VA). She was treated with intravenous recombinant tissue plasminogen activator (rt-PA) 110 minutes after symptom onset. Subsequently, brain angiography was performed along with mechanical thrombolysis using Trevo ProVue retriever devices. The BA was successfully recanalized 240 minutes after the onset of symptoms. Thrombectomy is a promising treatment strategy for cases of VA dissection resistant to intravenous rt-PA thrombolysis.

Paediatric arterial ischemic stroke: acute management, recent advances and remaining issues

Stroke is a rare disease in childhood with an estimated incidence of 1-6/100.000. It has an increasingly recognised impact on child mortality along with its outcomes and effects on quality of life of patients and their families. Clinical presentation and risk factors of paediatric stroke are different to those of adults therefore it can be considered as an independent nosological entity. The relative rarity, the age-related peculiarities and the variety of manifested symptoms makes the diagnosis of paediatric stroke extremely difficult and often delayed. History and clinical examination should investigate underlying diseases or predisposing factors and should take into account the potential territoriality of neurological deficits and the spectrum of differential diagnosis of acute neurological accidents in childhood. Neuroimaging (in particular diffusion weighted magnetic resonance) is the keystone for diagnosis of paediatric stroke and other investigations might be considered according to the clinical condition. Despite substantial advances in paediatric stroke research and clinical care, many unanswered questions remain concerning both its acute treatment and its secondary prevention and rehabilitation so that treatment recommendations are mainly extrapolated from studies on adult population. We have tried to summarize the pathophysiological and clinical characteristics of arterial ischemic stroke in children and the most recent international guidelines and practical directions on how to recognise and manage it in paediatric emergency.

Spatio-temporal assessment of the neuroprotective effects of neuregulin-1 on ischemic stroke lesions using MRI

The neuroprotective effects of neuregulin-1 (NRG-1) on stroke lesions were assessed longitudinally in rats with middle cerebral artery occlusion (MCAo) using MRI. Sprague-Dawley rats (n=16, 250±20g) underwent permanent MCAo surgery with cerebral blood flow (CBF) monitored by laser doppler flowmetry at ipsilateral side of bregma for 20min post-occlusion. A single 50μl bolus dose of NRG-1 or vehicle was administered into the left internal carotid artery immediately prior to MCAo. The expansion of the ischemic lesion into the cortex was attenuated by NRG-1 over a 48-hour (h) time span as measured by diffusion weighted imaging (DWI). The final infarct volumes of NRG-1 treated rats were significantly smaller than those of the vehicle treated rats at 48h (264.8±192.1 vs. 533.4±175.5mm(3), p<0.05). The NRG-1 treated rats were further subdivided into 2 subgroups according to their CBF reduction during stroke surgery: mild ischemia (<70% CBF reduction) or severe ischemia (>70% CBF reduction). In particular, ischemic infarction was not usually observed in the cortex of NRG-1 treated rats with mild ischemia at 3 and 48h post-occlusion. Histological results validated the imaging findings and demonstrated that NRG-1 treated rats had fewer injured neurons in peri-infarct areas 48h post-ischemia. In summary, the neuroprotective effect of NRG-1 in the pMCAo stroke model was demonstrated by prevention of ischemic lesion expansion, reduced infarct volume and protection of neurons from ischemic damage.

Value of Utilizing Both Aspects and CT Angiography Collateral Score for Outcome Prediction in Acute Ischemic Stroke

Background

Alberta Stroke Program Early CT Score (ASPECTS) represents the extent of irreversibly damaged tissue; while CT angiography collateral score (CTA-CS) denotes the degree of collaterals.

Aims

We investigated whether there is cumulative value in using both ASPECTS and CTA-CS for outcome prediction and attempted to determine the specific subgroup of patients who could benefit from successful reperfusion using these scores.

Methods

This is a retrospective observational study of stroke patients treated with intra-arterial reperfusion therapy for unilateral arterial occlusion in the anterior circulation. A favorable outcome was defined as modified Rankin Scale ≤ 2 at three-months. Receiver operating characteristic comparison analysis was performed to decide whether outcome predictability increases when ASPECTS and CTA-CS are used together. Classification and regression tree (CART) analysis was done to identify the variables that best predict outcome and define the specific subgroup of patients who could benefit from successful reperfusion.

Results

A total of 91 consecutive patients were included. Outcome predictability of ASPECTS with CTA-CS was better than that of ASPECTS ( P = 0·088) or that of CTA-CS ( P = 0·049). CART analysis revealed that ASPECTS > 5 was the primary determinant of favorable outcome, followed by CTA-CS > 1. Among 19 patients with ASPECTS ≤ 5, none had a favorable outcome. Successful reperfusion was associated significantly with favorable outcome in the 51 patients with ASPECTS > 5 and CTA-CS > 1, but not in the 21 patients with ASPECTS > 5 and CTA-CS ≤ 1.

Conclusions

Outcome predictability improves when using ASPECTS and CTA-CS together.

Impact of temporary opening using a stent retriever on clinical outcome in acute ischemic stroke

Background

Stent retriever has a distinct ability to restore blood flow temporarily before achieving final reperfusion. There has been a limited report regarding the clinical impact of it. We investigated if temporary opening of occluded vessels using a stent retriever before final reperfusion might improve clinical outcome in acute ischemic stroke patients who received the endovascular reperfusion treatment.

Methods

We enrolled consecutive ischemic stroke patients who had an initial occlusive lesion in the anterior circulation and achieved final reperfusion (Thrombolysis In Cerebral Infarction [TICI] ≥2) by endovascular treatment. Temporary opening was defined as the presence of ante grade flow (TICI≥2) during deployment of a stent retriever. Favorable outcome was defined as a modified Rankin scale score≤2 at 90 day.

Results

A total of 98 patients were included in the study and temporary opening was achieved in 49 (50%). Temporary opening was associated with favorable outcome (odds ratio, 7.825; 95% confidence interval, 1.592–38.461; p = 0.011) in the multivariate analysis. The probability of having a favorable outcome tended to decrease as time from onset to final reperfusion increased in patients without temporary opening. However, this trend was not evident in the patient with temporary opening. The beneficial effect of temporary opening on clinical outcome seemed to be present in patients with good collaterals but not in patients with poor collaterals.

Conclusions

Temporary opening of occluded vessel using a stent retriever may be beneficial for improving clinical outcome in acute ischemic stroke patients.

Endovascular thrombectomy following acute ischemic stroke: a single-center case series and critical review of the literature

Acute ischemic stroke (AIS) due to thrombo-embolic occlusion in the cerebral vasculature is a major cause of morbidity and mortality in the United States and throughout the world. Although the prognosis is poor for many patients with AIS, a variety of strategies and devices are now available for achieving recanalization in patients with this disease. Here, we review the treatment options for cerebrovascular thromboembolic occlusion with a focus on the evolution of strategies and devices that are utilized for achieving endovascular clot extraction. In order to demonstrate the progression of this treatment strategy over the past decade, we will also present a single-center case series of AIS patients treated with endovascular thrombectomy.

Treatment of acute vertebrobasilar occlusion using thrombectomy with stent retrievers: initial experience with 18 patients

BACKGROUND AND PURPOSE

Acute vertebrobasilar occlusion is an ominous disease with few proved effective treatments. Experience with stent retrievers is scarce and limited to combined therapies (stent retrievers associated with previous intravenous fibrinolysis, intra-arterial thrombolysis, or other mechanical devices). We present our experience with 18 patients treated with direct thrombectomy by using stent retrievers.

MATERIALS AND METHODS

Eighteen patients with vertebrobasilar occlusion were treated with direct thrombectomy by using stent retrievers at our hospital. The mean age was 67.5 years. Clinical presentation was sudden deterioration in consciousness level in 61.2% and progressive or fluctuating brain stem symptoms in 38.8%. Stroke subtype (TOAST) was atherothrombotic (33.3%), undetermined (33.3%), cardioembolic (27.7%), and of unusual etiology (5.5%).

RESULTS

The occlusion site was the vertebral artery in 1 case, proximal basilar artery in 4, middle basilar artery in 6, distal basilar artery in 5, and unilateral posterior cerebral artery in 2 cases. SRs included the Solitaire AB in 8 cases, Solitaire FR in 5 cases, and Trevo Pro in 5 cases. An 8F Merci balloon guide catheter was used in 15 patients, and a Neuron 6F, in 3 patients. Post-clot retrieval definitive intracranial stents were used in 5 patients (27.7%). Postprocedural TICI ≥ 2b was achieved in 17 patients (94.4%). Clinically, 72.2% of patients experienced an improved NIHSS score at discharge, 22.2% died, and in 5.5% the NIHSS scores did not change. The mRS score at 3 months was 0-2 in 9 patients (50%) and 3-5 in 5 patients (27.7%).

CONCLUSIONS

Thrombectomy with stent retrievers is feasible in the treatment of vertebrobasilar occlusion. These initial results must be confirmed by further prospective studies with a larger number of cases.

Intravenous alteplase versus rescue endovascular procedure in patients with proximal middle cerebral artery occlusion

OBJECTIVES

To compare outcome of ischaemic stroke patients undergoing rescue endovascular procedure for proximal middle cerebral artery occlusion with matched patients without endovascular procedure after unsuccessful intravenous thrombolysis.

METHODS

Endovascularly treated patients with middle cerebral artery occlusion (n = 41) were matched by propensity score with similar patients treated by intravenous thrombolysis and having a considerable post-thrombolysis neurological deficit (n = 82). We compared their three-month outcome (modified Rankin Scale) and frequency of symptomatic intracerebral haemorrhage. For the endovascular group, we report onset-to-puncture time, onset-to-recanalization time, and recanalization rates.

RESULTS

In age, gender, time from onset, admission National Institutes of Health Stroke Scale, systolic and diastolic blood pressure, blood glucose, history of hypertension, diabetes mellitus, hyperlipidaemia, atrial fibrillation, and congestive heart failure, and in aetiology, the groups were similar. Endovascular group patients had a recanalization rate of 90%, and more often reached three-month modified Rankin Scale 0-2 (36.6% vs. 18.3%, P = 0.03). Mortality was equally common (19.5%) in both groups, and frequency of symptomatic intracerebral haemorrhage was 9.8% vs. 14.6% (P = 0.45). The endovascular group's median onset-to-puncture time was four-hours and six-minutes and onset-to-recanalization time was five-hours and 12 min. The latter time was more than one-hour longer in patients treated under general anaesthesia compared with patients treated under conscious sedation (median four-hours 50 min vs. five-hours 58 min; P < 0.01).

CONCLUSIONS

Rescue endovascular approach increases likelihood of recanalization and may improve functional outcome in acute ischaemic stroke patients with proximal middle cerebral artery occlusion who did not respond to intravenous thrombolysis.