Impact of Retrievable Stents on Acute Ischemic Stroke Treatment

Retrievable stents combine the high recanalization rate of stents and the capability of removing the thrombus offered by mechanical thrombectomy devices. We hypothesized that retrievable stents shorten time to recanalization in the multimodal approach for endovascular stroke treatment.

Vertical bias in neglect: A question of time?

Neglect is defined as the failure to attend and to orient to the contralesional side of space. A horizontal bias towards the right visual field is a classical finding in patients who suffered from a right-hemispheric stroke. The vertical dimension of spatial attention orienting has only sparsely been investigated so far. The aim of this study was to investigate the specificity of this vertical bias by means of a search task, which taps a more pronounced top-down attentional component. Eye movements and behavioural search performance were measured in thirteen patients with left-sided neglect after right hemispheric stroke and in thirteen age-matched controls. Concerning behavioural performance, patients found significantly less targets than healthy controls in both the upper and lower left quadrant. However, when targets were located in the lower left quadrant, patients needed more visual fixations (and therefore longer search time) to find them, suggesting a time-dependent vertical bias.

The incidence and health economic burden of ischemic amputation in Minnesota, 2005-2008

Critical limb ischemia (CLI) is the most severe manifestation of peripheral artery disease (PAD), is associated with high rates of myocardial infarction, stroke, and amputation, and has a high health economic cost. The objective of this study was to estimate the incidence of lower limb amputation, the most serious consequence of CLI, and to create a surveillance methodology for the incidence of ischemic amputation in Minnesota.

Delayed diagnosis of acute ischemic stroke in children - a registry-based study in Switzerland

QUESTIONS UNDER STUDY/PRINCIPLES: After arterial ischemic stroke (AIS) an early diagnosis helps preserve treatment options that are no longer available later. Paediatric AIS is difficult to diagnose and often the time to diagnosis exceeds the time window of 6 hours defined for thrombolysis in adults. We investigated the delay from the onset of symptoms to AIS diagnosis in children and potential contributing factors.

[Mechanical Thrombectomy for Acute Ischemic Stroke.]

The therapy of acute ischemic stroke aims at fast recanalization of the occluded brain vessel. In contrast to intravenous thrombolysis (IVT), endovascular approaches yield higher recanalization rates especially in large vessel occlusions. Mechanical thrombectomy with the Merci Retriever received FDA approval in 2004 as an adjunct to IVT or in the case of failed recanalization after IVT. The time window for treatment is 8 h from stroke onset. However, the recanalization rate was 55 %, still leaving space for further improvement. In addition to the Merci Retriever, the Penumbra System received FDA approval in 2008. The newest endovascular approach comprising retrievable intracranial stents results in an increased recanalization rate exceeding 90 % and has markedly reduced the time to recanalization. On the other hand, the complication rate has not increased yet. These promising results suggest a combined therapy for acute ischemic stroke. In a first step IVT can be started independently of the size of the treating hospital and in a next step the patient is transferred to a neuroradiological center. If vessel occlusion persists, additional endovascular recanalization is performed (bridging concept). Patients who don't qualify for IVT are candidates for mechanical thrombectomy up to 8 h after stroke onset.

Experimental Evaluation of Immediate Recanalization Effect and Recanalization Efficacy of a New Thrombus Retriever for Acute Stroke Treatment In Vivo

BACKGROUND AND PURPOSE: Currently, several new stent retriever devices for acute stroke treatment are under development and early clinical evaluation. Preclinical testing under standardized conditions is an important first step to evaluate the technical performance and potential of these devices. The aim of this study was to evaluate the immediate recanalization effect, recanalization efficacy, thrombus-device interaction, and safety of a new stent retriever intended for thrombectomy in patients with acute stroke. MATERIAL AND METHODS: The pREset thrombectomy device (4 × 20 mm) was evaluated in 16 vessel occlusions in an established swine model. Radiopaque thrombi (10-mm length) were used for visualization of thrombus-device interaction during application and retrieval. Flow-restoration effect immediately after deployment and after 5-minute embedding time before retrieval, recanalization rate after retrieval, thromboembolic events, and complications were assessed. High-resolution FPCT was performed to illustrate thrombus-device interaction during the embedding time. RESULTS: Immediate flow restoration was achieved in 75% of occlusions. An increase or stable percentage of recanalizations during embedding time before retrieval was seen in 56.3%; a decrease, in 12.5%; reocclusion of a previously recanalized vessel, in 18.8%; and no recanalization effect at all, in 12.5%. Complete recanalization (TICI 3) after retrieval was achieved in 93.8%; partial recanalization (TICI 2b), in 6.2%. No distal thromboembolic events were observed. High-resolution FPCT illustrated entrapment of the thrombus between the stent struts and compression against the contralateral vessel wall, leading to partial flow restoration. During retrieval, the thrombus was retained in a straight position within the stent struts. CONCLUSIONS: In this experimental study, the pREset thrombus retriever showed a high recanalization rate in vivo. High-resolution FPCT allows detailed illustration of the thrombus-device interaction during embedding time and is advocated as an add-on tool to the animal model used in this study.

National institutes of health stroke scale score and vessel occlusion in 2152 patients with acute ischemic stroke

Background and Purpose—There is some controversy on the association of the National Institutes of Health Stroke Scale (NIHSS) score to predict arterial occlusion on MR arteriography and CT arteriography in acute stroke. Methods—We analyzed NIHSS scores and arteriographic findings in 2152 patients (35.4% women, mean age 66±14 years) with acute anterior or posterior circulation strokes. Results—The study included 1603 patients examined with MR arteriography and 549 with CT arteriography. Of those, 1043 patients (48.5%; median NIHSS score 5, median time to clinical assessment 179 minutes) showed an occlusion, 887 in the anterior (median NIHSS score 7/0–31), and 156 in the posterior circulation (median NIHSS score 3/0–32). Eight hundred sixty visualized occlusions (82.5%) were located centrally (ie, in the basilar, intracranial vertebral, internal carotid artery, or M1/M2 segment of the middle cerebral artery). NIHSS scores turned out to be predictive for any vessel occlusions in the anterior circulation. Best cut-off values within 3 hours after symptom onset were NIHSS scores ≥9 (positive predictive value 86.4%) and NIHSS scores ≥7 within >3 to 6 hours (positive predictive value 84.4%). Patients with central occlusions presenting within 3 hours had NIHSS scores <4 in only 5%. In the posterior circulation and in patients presenting after 6 hours, the predictive value of the NIHSS score for vessel occlusion was poor. Conclusions—There is a significant association of NIHSS scores and vessel occlusions in patients with anterior circulation strokes. This association is best within the first hours after symptom onset. Thereafter and in the posterior circulation the association is poor.

Safety of endovascular treatment beyond the 6-h time window in 205 patients

Background and purpose Intra-arterial treatment (IAT) is effective when performed within 6 h of symptom onset in selected stroke patients (‘T < 6H’). Its safety and efficacy is unclear when the patient has had symptoms for more than 6 h (‘T > 6H’) or for an unknown time (unclear-onset stroke, UOS), or woke up with a stroke (wake-up stroke, WUS). In this study we compared the safety of IAT in these four patient groups. Methods Eight-hundred and fifty-nine patients treated with IAT were enrolled. The main outcome parameters were clinical outcome [excellent: modified Rankin Scale (mRS) 0 or 1; or favorable: mRS 0–2] or mortality 3 months after treatment. Further outcome parameters were the rates of vessel recanalization, and cerebral and systemic hemorrhage. Results Six-hundred and fifty-four patients were treated before (T < 6H) and 205 after 6 h or an unknown time (128 T > 6H, 55 WUS and 22 UOS). NIHSS scores were higher in UOS patients than in T < 6H patients, vertebrobasilar occlusion was more common in T > 6H and UOS patients, and middle cerebral artery occlusions less common in T > 6H than in T < 6H patients. Other baseline characteristics were similar. There was no significant difference in clinical outcome and the rate of hemorrhage in multivariable regression analysis. Conclusions Clinical outcome of our four groups of patients was similar with no increase of hemorrhage rates in patients treated after awakening, after an unknown time or more than 6 h. Our preliminary data suggest that treatment of such patients may be performed safely. If confirmed in randomized trials, this would have major clinical implications.

Secondary stroke prevention: patent foramen ovale, aortic plaque, and carotid stenosis

Stroke is the most debilitating cardiovascular event. It has a variety of causes that may be present simultaneously. In young or otherwise healthy people, the search for a patent foramen ovale (PFO) has become standard. In stroke of the elderly, atherosclerosis and atrial fibrillation are in the foreground but the PFO should not be ignored. The risk of a PFO-related stroke over time is controversial and so is its prevention by device closure. The association of proximal aortic plaques in arteries subtending the brain and stroke is considered strong, ignoring that it is as putative as that of the PFO. Statins can prevent progression of such plaques. Antiplatelet agents in asymptomatic and surgical endarterectomy in symptomatic patients or highly ulcerated lesions are the treatment of choice. Stenting with protection devices was shown competitive in selected patients.

Different pattern of clinical deficits in stroke mimics treated with intravenous thrombolysis

Guidelines recommend intravenous thrombolysis (IVT) to be applied as early as possible in ischemic stroke (IS), while clinical presentation is often assessed by using the National Institutes of Health Stroke Scale (NIHSS). However, diagnostic workup under time pressure bears the risk of misdiagnosis. Little is known about whether NIHSS could help to differentiate between IS and stroke mimics (SM) in patients being evaluated for IVT.

Sleep deprivation before stroke is neuroprotective: A pre-ischemic conditioning related to sleep rebound

BACKGROUND AND AIM: We have previously shown in a rat model of focal cerebral ischemia that sleep deprivation after stroke onset aggravates brain damage. Others reported that sleep deprivation prior to stroke is neuroprotective. The main aim of this study was to test the hypothesis that the neuroprotection may be related to an increase in sleep (sleep rebound) during the acute phase of stroke. METHODS: Male Sprague Dawley rats (n=36) were subjected to continuous polygraphic recordings for baseline, total sleep deprivation (TSD), and 24h after ischemia. TSD for 6h was performed by gentle handling and immediately followed by ischemia. Focal cerebral ischemia was induced by permanent occlusion of distal branches of the middle cerebral artery. Control experiments included ischemia without SD (nSD) and sham surgery with TSD (n=6/group). RESULTS: Shortly after stroke, the amount of slow wave sleep (SWS) and paradoxical sleep (PS) increased significantly (p<0.05) in the TSD/ischemia, resulting in an increase in the total sleep time by 30% compared to baseline, or by 20% compared with the nSD/ischemia group. The infarct volume decreased significantly by 50% in the TSD/ischemia compared to nSD group (p<0.02). Removal of sleep rebound by allowing TSD-rats sleep for 24h before ischemia eliminated the reduction in the infarct size. CONCLUSION PRESTROKE: Sleep deprivation results in sleep rebound and reduces brain damage. Sleep rebound may be causally related to the neuroprotection.

[Arterial-ischaemic stroke in childhood]

The risk to have a stroke during childhood is at least as frequent as to suffer from a brain tumour. Unlike adults, in whom ischaemic strokes overweigh haemorrhagic strokes, ischaemic and haemorrhagic strokes are equally frequent in children, occurring with an incidence of 2 - 3/100'000 children/year. Even though the clinical presentation of arterial-ischaemic stroke in children (pedAIS) is similar to adults, time to diagnosis is longer. The delay to diagnosis is mainly explained by the low index of suspicion of both the general population and the medical personnel, a broad range of differential diagnoses, and the fact that diagnostic imaging in children often requires sedation, which is not always readily available. PedAIS is a multiple risk problem, usually occurring due to a combination of risk factors, such as infectious diseases, dehydration, trauma or an underlying condition such as congenital heart disease. Still little is known about the appropriate management of pedAIS. Supportive measures are considered to be the mainstay of therapy. The use of antithrombotic medication depends on pedAIS aetiology. In an ongoing multicenter trial, the safety and effectiveness of thrombolysis are currently being investigated. PedAIS carries an important mortality and morbidity, with neurological and neuropsychological deficits persisting in two thirds of the affected children.

A clinical approach to arterial ischemic childhood stroke: increasing knowledge over the last decade

Childhood stroke is increasingly being recognized as an important burden not only for affected children and families, but also for socioeconomic reasons. A primary problem is delayed diagnosis, due to the many mimics of childhood stroke, and the variety of manifesting symptoms. The most important is hemiparesis (with/without dysphasia or facial palsy), but ataxia, seizures, and many more are also possible. Suspicion of stroke has to be ascertained by neuroimaging, gold standard being (diffusion weighted) magnetic resonance. Risk factors are multiple, but their presence might help to increase the suspicion of stroke. The most important factors are infectious/parainfectious etiologies, frequently possibly manifesting by transient focal cerebral arteriopathy (FCA). Cardiological underlying problems are the second most important. Arteriopathies can be detected in about half of the children, besides FCA and dissection and MoyaMoya disease are the most important. Hereditary coagulopathies increase the risk of stroke. There is still a controversy on best treatment in children: platelet antiaggregation and heparinization are used about equally. Thrombolysis is being discussed increasingly. Severity of symptoms at manifestation and on follow-up are not less significant in children than in young adults. About two-third of the children have significant residual neurological problems and a majority cognitive and behavior problems.

A dedicated animal model for mechanical thrombectomy in acute stroke

BACKGROUND: Recent studies have focused on mechanical thrombectomy as a means to reduce the time required for revascularization and increase the revascularization rate in acute stroke. To date no systematic evaluation has been made of the different mechanical devices in this novel and fast-developing field of endovascular interventions. To facilitate such evaluations, we developed a specific in vivo model for mechanical thrombectomy that allows visualization of dislocation or fragmentation of the thrombus during angiographic manipulation. METHODS: Angiography and embolization with a preformed thrombus was performed in 8 swine. The thrombus was generated by mixing 25 IU bovine thrombin and 10 mL autologous blood. For visualization during angiography, 1 g barium sulfate was added. RESULTS: The preformed thrombus exhibited mechanical stability, reproducibility, and high radiographic absorption, providing excellent visibility during angiography. The setting allowed selective embolization of targeted vessels without thrombus fragmentation. Despite the application of barium sulfate no local or systemic reaction occurred. Histologic evaluation revealed no intimal damage caused by the thrombus or contrast agent washout. CONCLUSION: The model presented here allows selective and reliable thromboembolization of vessels that reproduce the anatomic and hemodynamic situation in acute cerebrovascular stroke. It permits visualization of the thrombus during angiography and intervention, providing unique insight into the behavior of both thrombus and device, which is potentially useful in the development and evaluation of mechanical clot retrieval in acute cerebrovascular stroke.

Sleep-disordered breathing and acute ischemic stroke: diagnosis, risk factors, treatment, evolution, and long-term clinical outcome

BACKGROUND AND PURPOSE: Sleep-disordered breathing (SDB) is frequent in stroke patients. Risk factors, treatment response, short-term and long-term outcome of SDB in stroke patients are poorly known. METHODS: We prospectively studied 152 patients (mean age 56+/-13 years) with acute ischemic stroke. Cardiovascular risk factors, Epworth sleepiness score (ESS), stroke severity/etiology, and time of stroke onset were assessed. The apnea-hypopnea index (AHI) was determined 3+/-2 days after stroke onset and 6 months later (subacute phase). Continuous positive airway pressure (CPAP) treatment was started acutely in patients with SDB (AHI > or =15 or AHI > or =10+ESS >10). CPAP compliance, incidence of vascular events, and stroke outcome were assessed 60+/-16 months later (chronic phase). RESULTS: Initial AHI was 18+/-16 (> or =10 in 58%, > or =30 in 17% of patients) and decreased in the subacute phase (P<0.001). Age, diabetes, and nighttime stroke onset were independent predictors of AHI (r2=0.34). In patients with AHI > or =30, age, male gender, body mass index, diabetes, hypertension, coronary heart disease, ESS, and macroangiopathic etiology of stroke were significantly higher/more common than in patients with AHI <10. Long-term incidence of vascular events and stroke outcome were similar in both groups. CPAP was started in 51% and continued chronically in 15% of SDB pts. Long-term stroke mortality was associated with initial AHI, age, hypertension, diabetes, and coronary heart disease. CONCLUSIONS: SDB is common particularly in elderly stroke male patients with diabetes, nighttime stroke onset, and macroangiopathy as cause of stroke; it improves after the acute phase, is associated with an increased poststroke mortality, and can be treated with CPAP in a small percentage of patients.