M. Shazam Hussain

Embolectomy for stroke with emergent large vessel occlusion (ELVO): report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery

Stroke is the leading cause of adult disability in North America and is the fifth most common cause of death.1 ,2 The natural history of patients with acute ischemic stroke and occlusion of a major intracranial vessel such as the internal carotid artery (ICA), middle cerebral artery (MCA), or basilar artery is dismal, with high rates of mortality and low rates of disability-free survival.3 ,4 We introduce the term ‘Emergent Large Vessel Occlusion (ELVO)’ to describe this clinical scenario. Among acute ischemic stroke, ELVO accounts for the greatest proportion of patients with long-term disability. For the past two decades the use of endovascular therapy has been performed in many centers across the world. The therapies have spanned from infusion of thrombolytic agents5 ,6 to mechanical embolectomy with the introduction of first-generation devices,7 ,8 aspiration-based embolectomy techniques,9 ,10 and the use of stent-retriever based procedures.11 ,12 However, these embolectomy trials were single-arm trials demonstrating safety of the procedure and technique or superiority over another, without direct comparison with standard medical therapy alone. In the past 3 years, several major trials have been published comparing endovascular therapy with standard medical therapy alone. The purpose of this document is to summarize the results of these trials and synthesize the level of evidence supporting the use of embolectomy in patients with ELVO. This document was prepared by the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery, a multidisciplinary society representing the leaders in the field of endovascular therapy for neurovascular disease. The strength of the evidence supporting each recommendation was summarized using a scale previously described by the American Heart Association. ### Role of intravenous thrombolysis In 1996 the FDA approved the use of recombinant tissue plasminogen activator (tPA) for the treatment of acute ischemic stroke …

Initial hospital management of patients with emergent large vessel occlusion (ELVO): report of the standards and guidelines committee of the Society of NeuroInterventional Surgery

Objective To summarize the current literature regarding the initial hospital management of patients with acute ischemic stroke (AIS) secondary to emergent large vessel occlusion (ELVO), and to offer recommendations designed to decrease the time to endovascular treatment (EVT) for appropriately selected patients with stroke. Methods Using guidelines for evidenced-based medicine proposed by the Stroke Council of the American Heart Association, a critical review of all available medical literature supporting best initial medical management of patients with AIS secondary to ELVO was performed. The purpose was to identify processes of care that most expeditiously determine the eligibility of a patient with an acute stroke for interventions including intravenous fibrinolysis with recombinant tissue plasminogen activator (IV tPA) and EVT using mechanical embolectomy. Results This review identifies four elements that are required to achieve timely revascularization in ELVO. (1) In addition to non-contrast CT (NCCT) brain scan, CT angiography should be performed in all patients who meet an institutional threshold for clinical stroke severity. The use of any advanced imaging beyond NCCT should not delay the administration of IV tPA in eligible patients. (2) Activation of the neurointerventional team should occur as soon as possible, based on either confirmation of large vessel occlusion or a prespecified clinical severity threshold. (3) Additional imaging techniques, particularly those intended to physiologically select patients for EVT (CT perfusion and diffusion–perfusion mismatch imaging), may provide additional value, but should not delay EVT. (4) Routine use of general anesthesia during EVT procedures, should be avoided if possible. These workflow recommendations apply to both primary and comprehensive stroke centers and should be tailored to meet the needs of individual institutions. Conclusions Patients with ELVO are at risk for severe neurologic morbidity and mortality. To achieve the best possible clinical outcomes stroke centers must optimize their triage strategies. Strategies that provide patients with ELVO with the fastest access to reperfusion depend upon detail-oriented process improvement.

Posterior circulation flow diversion: a single-center experience and literature review

Background Flow diverters have been used predominantly for large anterior circulation aneurysms. Data on the safety and efficacy of this treatment for posterior circulation aneurysms are limited. Objective To present our posterior circulation flow diverter experience, outcomes and morbidity in comparison with recent studies. Methods A retrospective chart and imaging review of six patients with seven aneurysms in posterior circulation vessels, treated with flow diverter technology was carried out. A literature review was performed using standard online search tools. Results We included five saccular and two fusiform posterior circulation aneurysms. An average of two flow diverters was placed for each patient. Adjunctive coiling was used in three cases. Follow-up at an average of 14.5 months showed complete angiographic occlusion in 4 (57.1%) cases, including one patient with in-stent thrombosis and major brainstem stroke at 4.5 months, a week after self-discontinuing dual antiplatelet therapy. Two other patients developed small periprocedural strokes but had excellent recovery. One death occurred 18 months after the initial procedure. No aneurysm rupture or parenchymal hemorrhage was seen. Overall, 5 (71%) cases, all with saccular aneurysms, had good clinical outcome (modified Rankin score (mRS) 0–1). Fusiform basilar aneurysms had markedly worse outcomes (mRS 5 and 6). Our literature review yielded six other studies with 100 additional patients. Overall, good outcome was seen in 74.3%, with a 12.3% average mortality and 11% permanent neurologic deficit rate. Complete occlusion varied from 43% to 100%. Conclusions Flow diversion may be a possible treatment in carefully selected patients with high-risk atypical posterior circulation aneurysms, with poor natural history and no optimal treatment strategy. Symptomatic and fusiform large aneurysms appear to carry the highest risk. Further studies are necessary to assess the role of flow diversion in the posterior circulation.

Door‐to‐Puncture: A Practical Metric for Capturing and Enhancing System Processes Associated With Endovascular Stroke Care, Preliminary Results From the Rapid Reperfusion Registry

Background In 2011, the Brain Attack Coalition proposed door‐to‐treatment times of 2 hours as a benchmark for patients undergoing intra‐arterial therapy (IAT). We designed the Rapid Reperfusion Registry to capture the percentage of stroke patients who meet the target and its impact on outcomes. Methods and Results This is a retrospective analysis of anterior circulation patients treated with IAT within 9 hours of symptom onset. Data was collected from December 31, 2011 to December 31, 2012 at 2 centers and from July 1, 2012 to December 31, 2012 at 7 centers. Short “Door‐to‐Puncture” (D2P) time was hypothesized to be associated with good patient outcomes. A total of 478 patients with a mean age of 68±14 years and median National Institutes of Health Stroke Scale (NIHSS) of 18 (IQR 14 to 21) were analyzed. The median times for IAT delivery were 234 minutes (IQR 163 to 304) for “last known normal‐to‐groin puncture” time (LKN‐to‐GP) and 112 minutes (IQR 68 to 176) for D2P time. The overall good outcome rate was 39.7% for the entire cohort. In a multivariable model adjusting for age, NIHSS, hypertension, diabetes, reperfusion status, and symptomatic hemorrhage, both short LKN‐to‐GP (OR 0.996; 95% CI [0.993 to 0.998]; P<0.001) and short D2P times (OR 0.993, 95% CI [0.990 to 0.996]; P<0.001) were associated with good outcomes. Only 52% of all patients in the registry achieved the targeted D2P time of 2 hours. Conclusions The time interval of D2P presents a clinically relevant time frame by which system processes can be targeted to streamline the delivery of IAT care nationally. At present, there is much opportunity to enhance outcomes through reducing D2P.

Platelet function inhibitors and platelet function testing in neurointerventional procedures

Over the past decade there has been a growing use of intracranial stents for the treatment of both ischemic and hemorrhagic cerebrovascular disease, including stents to assist in the remodeling of the neck of aneurysms as well as the use of flow diverting devices for aneurysm treatment. With this increase in stent usage has come a growing need for the neurointerventional (NI) community to understand the pharmacology of medications used for modifying platelet function, as well as the testing methodologies available. Platelet function testing in NI procedures remains controversial. While pre-procedural antiplatelet assays might lead to a reduced rate of thromboembolic complications, little evidence exists to support this as a standard of care practice. Despite the routine use of dual antiplatelet therapy (DAT) with aspirin and a P2Y12 receptor antagonist (such as clopidogrel, prasugrel, or ticagrelor) in most neuroembolization procedures necessitating intraluminal reconstruction devices, thromboembolic complications are still encountered.1–3 Moreover, DAT carries the risk of hemorrhagic complications, with intracerebral hemorrhage (ICH) being the most potentially devastating.4 ,5 Light transmission aggregometry (LTA) is the gold standard to test for platelet reactivity, but it is usually expensive and may not be easily obtainable at many centers. This has led to the development of point-of-care assays, such as the VerifyNow (Accumetrics, San Diego, California, USA), which correlates strongly with LTA and can reliably measure the degree of P2Y12 receptor inhibition.6–9 VerifyNow results are reported in P2Y12 reaction units (PRUs), with a lower PRU value corresponding to a higher level of P2Y12 receptor inhibition and, presumably, a lower probability of platelet aggregation, and a higher PRU value corresponding to a lower level of P2Y12 receptor inhibition and, hence, a higher chance of platelet activation and aggregation. While aspirin resistance is perhaps less common, clopidogrel resistance may be more challenging as …

Prehospital care delivery and triage of stroke with emergent large vessel occlusion (ELVO): report of the Standards and Guidelines Committee of the Society of Neurointerventional Surgery

Recent randomized clinical trials1–5 established the superiority of endovascular recanalization techniques, specifically mechanical embolectomy, compared with best medical therapy alone for the treatment of patients with emergent large vessel occlusion (ELVO) stroke. ELVO stroke is defined as a stroke secondary to anterior circulation large vessel occlusion (LVO) of the internal carotid, middle cerebral (M1 segments) arteries documented by imaging, without large completed infarct and presenting within 6 hours of symptom onset.6 Given the overwhelming clinical evidence provided by these trials, recent American Heart Association (AHA) guidelines concluded that “embolectomy needs to be performed as rapidly as possible for the greatest clinical benefit, and is best when performed within 6 h from onset of symptoms” (AHA class I, level of evidence A).6 In addition, cost modeling derived from trial outcomes data and claims databases in the USA strongly suggests that cost-effectiveness and an overall societal benefit is associated with investment in access to these endovascular techniques.7 Rapid access to endovascular services depends upon optimization of prehospital stroke care and transport within stroke systems of care, focusing on the unique needs of patients with ELVO through their diagnostic investigation and treatment pathway. The Society of NeuroInterventional Surgery (SNIS) proposed process time metrics for ELVO stroke treatment, including door to IV tissue plasminogen activator (t-PA) of <30 min, comprehensive stroke center (CSC) door to puncture of <60 min, CSC door to recanalization of <90 min and primary stroke certification (PSC) picture to CSC puncture of <90 min.8 Early team awareness of the patient with potential ELVO, coupled with efficient interdisciplinary communication, triage and transport assist in meeting these ideal time metrics, and also contribute to improved clinical outcomes through efficiency gains and maximization of endovascular care delivery. The Standards and Guidelines Committee of the SNIS, a multidisciplinary society representing leaders in the field of …

Vertebral augmentation: report of the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery

Vertebroplasty and kyphoplasty are minimally invasive image-guided procedures that involve the injection of cement (typically polymethylmethacrylate (PMMA)) into a vertebral body. Kyphoplasty involves inflation of a balloon tamp to create a cavity within the vertebral body into which cement is subsequently injected. The majority of these vertebral augmentation procedures are performed to relieve back pain from osteoporotic or cancer-related vertebral compression fractures and to reinforce the vertebral body with neoplasm or vascular tumor. The primary goal of vertebroplasty and kyphoplasty is to reduce back pain and to improve patients functional status, and the secondary goal is stabilization of a vertebra weakened by fracture or neoplasia. ### Osteoporotic vertebral fractures Osteoporosis is a common disease that causes significant morbidity and incurs a significant healthcare cost to the community. The major osteoporotic fractures involve the hip, vertebra, proximal humerus and distal forearm; the lifetime osteoporotic fracture risk at age 50 is approximately one in two women and one in five men.1 The lifetime incidence of symptomatic osteoporotic vertebral fractures in women at age 50 is estimated at 10–15%1; once a vertebral fracture occurs, there is a 20% risk of another vertebral fracture within 12 months.2 Most osteoporotic vertebral compression fractures are asymptomatic or result in minimal pain; only a third of vertebral fractures result in medical attention.3 Conservative medical therapy is therefore appropriate for the vast majority of vertebral compression fractures since most acute back pain symptoms are mild and subside over a period of 6–8 weeks as the fracture heals. The goals of conservative therapy are pain reduction (with analgesics and/or bed rest), improvement in functional status (with orthotic devices and physical therapy) and prevention of future fractures (with vitamin D, calcium supplementation and antiresorptive agents). However, conservative treatment for those with severe pain or limitation of function is not benign. It …

Standard of practice: endovascular treatment of intracranial atherosclerosis.

Background Symptomatic intracranial atherosclerotic disease (ICAD) worldwide represents one of the most prevalent causes of stroke. When severe, studies show that it has a very high risk for recurrent stroke, highlighting the need for effective preventative strategies. The mainstay of treatment has been medical therapy and is of critical importance in all patients with this disease. Endovascular therapy is also a possible therapeutic option but much remains to be defined in terms of best techniques and patient selection. This guideline will serve as recommendations for diagnosis and endovascular treatment of patients with ICAD. Methods A literature review was performed to extract published literature regarding ICAD, published from 2000 to 2011. Evidence was evaluated and classified according to American Heart Association (AHA)/American Stroke Association standard. Recommendations are made based on available evidence assessed by the Standards Committee of the Society of NeuroInterventional Surgery. The assessment was based on guidelines for evidence based medicine proposed by the American Academy of Neurology (AAN), the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Results 59 publications were identified. The SAMMPRIS study is the only prospective, randomized, controlled trial available and is given an AHA level B designation, AAN class II and CEBM level 1b. The Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial arteries (SSYLVIA) trial was a prospective, non-randomized study with the outcome assessment made by a non-operator study neurologist, allowing an AHA level B, AAN class III and CEBM level 2. The remaining studies were uncontrolled or did not have objective outcome measurement, and are thus classified as AHA level C, AAN class IV and CEBM level 4. Conclusion Medical management with combination aspirin and clopidogrel for 3 months and aggressive risk factor modification is the firstline therapy for patients with symptomatic ICAD. Endovascular angioplasty with or without stenting is a possible therapeutic option for selected patients with symptomatic ICAD. Further studies are necessary to define appropriate patient selection and the best therapeutic approach for various subsets of patients.

Early experience in high-resolution MRI for large vessel occlusions.

Background Large vessel occlusions are an important cause of ischemic stroke. Imaging goals center on identifying the site of occlusion, the size of the ischemic core and the size of the ischemic penumbra. The etiology of the occlusion is typically inferred by history and demographics, or subacutely during investigation for shunt, hypercoagulable state or other causes. Current generation vascular imaging is based primarily on lumenography. Contours of the vessel lumen on lumenography may suggest the presence of atherosclerosis, dissection or thrombus. High-resolution MRI (HRMRI) techniques can characterize wall morphology in the presence of an occlusion, which may affect clinical care by better definition of intra-occlusion wall characteristics as well as downstream vasculature normally confounded by the lack of antegrade flow. Methods The HRMRI databases of Cleveland Clinic and Beijing Tiantan Hospital were reviewed to identify patients with large vessel occlusions on lumenography, performed with a diagnostic quality HRMRI. Clinical data were reviewed for each patient and images were analyzed by experienced neuroradiologists at both institutions. Where possible, conventional angiography/lumenography was reviewed for comparison. Results Nine patients with large vessel cerebral artery occlusions were identified in whom HRMRI characteristics were reviewed and categorized. Images were correlated with demographics, risk factors and the working diagnosis of each case. Conclusions HRMRI of vascular occlusions can identify wall characteristics and characterize the course and caliber of the vasculature distal to the occluded segment. This information may be useful in determining preferred approaches for endovascular revascularization.

The PRE-hospital Stroke Treatment Organization:

Background The PRE-hospital Stroke Treatment Organization was formed in 2016 as an international consortium of medical practitioners involved in pre-hospital treatment of patients with acute stroke. Aims PRE-hospital Stroke Treatment Organization’s mission is to improve stroke outcomes by supporting research and advocacy for pre-hospital stroke treatment in Mobile Stroke Units. PRE-hospital Stroke Treatment Organization will provide a platform to enhance collaborative research across the spectrum of acute stroke management in the pre-hospital setting. PRE-hospital Stroke Treatment Organization will also facilitate the appropriate proliferation and distribution of Mobile Stroke Units by providing a forum for professional communication, resource for public education, and stimulus for government, industry, and philanthropic support. Summary of review In this “white paper”, we describe the evidence supporting pre-hospital stroke treatment, progress to date, practical issues such as application in various environments and staffing, planned research initiatives, and organizational structure. Conclusions PRE-hospital Stroke Treatment Organization is not-for-profit, with membership open to anyone involved (or hoping to become involved) in pre-hospital stroke care. PRE-hospital Stroke Treatment Organization has a Steering Committee comprised of members from Europe, U.S., Canada, Australia, and other regions having a Mobile Stroke Unit in operation. PRE-hospital Stroke Treatment Organization convenes satellite meetings for membership at the International Stroke Conference and European Stroke Congress each year to address the PRE-hospital Stroke Treatment Organization mission. The first research collaborations agreed upon are to: (1) develop a list of common data elements to be collected by all Mobile Stroke Unit programs and entered into a common research database, and (2) develop a protocol for investigating the natural history of hyper-acute Intracerebral Hemorrhage.