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Transcranial Doppler Helps with Understanding of Cerebral Hemodynamics After Endovascular Recanalization

Victor J. Del Brutto, MD

Kneihsl M, Niederkorn K, Deutschmann H, Enzinger C, Poltrum B, Horner S, et al. Abnormal Blood Flow on Transcranial Duplex Sonography Predicts Poor Outcome After Stroke Thrombectomy. Stroke. 2018

Early recanalization with mechanical thrombectomy gives stroke patients with large vessel occlusion the best chance to achieve a good functional outcome. Successful angiographic reperfusion as determined by a good TICI score implies restoration of cerebral blood flow to ischemic tissue, thus preventing neuronal death, which result in a better functional recovery after stroke. However, this happy ending story could be distorted in the post interventional course by abnormal cerebral hemodynamics including no-reflow phenomena, vessel reocclusion, focal vessel stenosis, or hyperperfusion with high risk of hemorrhagic conversion.

By |December 10th, 2018|clinical|0 Comments

When More Isn’t More: Increasing Stent Retriever Passes Associated with Futile Recanalization

Kat Dakay, DO

Baek J-H, Kim BM, Heo JH, Nam HS, Kim YD, Park H, et al. Number of Stent Retriever Passes Associated With Futile Recanalization in Acute Stroke. Stroke. 2018

Mechanical thrombectomy has been recognized as the standard of care in acute ischemic stroke due to proximal large vessel occlusion. However, despite best efforts, it is not always successful: According to the authors, about 20-30% of clots are refractory to stent retriever thrombectomy. However, even if the vessel is eventually recanalized, the patient may still not necessarily have a favorable outcome, often termed “futile recanalization”; rates of futile recanalization vary widely depending on the definition used. Additionally, there are risks to a long and complex thrombectomy procedure in cases with refractory clots. In this article, the authors examine the number of stent retriever attempts, or passes, as a marker for futile recanalization.

In this multicenter, retrospective study [1], patients with a proximal anterior circulation large vessel occlusion treated with stent retriever thrombectomy were included. Additionally, patients needed to have an NIHSS of 4 or greater and be treated within 10 hours of last known well. The number of stent retriever passes required to achieve successful recanalization of TICI 2b or 3 was measured. A total of 467 patients were included in the study, with a median age of 67.3 years, median NIHSS of 15, and median ASPECTS of 8. The median number of stent retriever passes was 2, although rates ranged from 1 to 7.

Transthoracic Echocardiography: Can We Eliminate Unnecessary Testing?

Robert W. Regenhardt, MD, PhD
@rwregen

Yaghi S, Chang AD, Cutting S, Jayaraman M, McTaggart RA, Ricci BA, et al. Troponin Improves the Yield of Transthoracic Echocardiography in Ischemic Stroke Patients of Determined Stroke Subtype. Stroke. 2018

Throughout my training, I have had several mentors dissuade me from ordering tests that are unlikely to change management during the admission of patients with ischemic stroke. Transthoracic echocardiography (TTE) is one of the studies that is not uncommonly cut, especially if the stroke etiology is clear without it. Indeed, the recent 2018 American Heart Association guidelines do not mandate TTE, but recommend the clinician use his or her judgement. This recent article in Stroke by Yaghi et al. set out to test the yield of TTE in these patients and the utility of troponin levels to improve its yield. They examined 578 patients (mean age 74) admitted to their single center over an 18-month period with ischemic stroke “whose etiologic subtype could be obtained without the need for TTE.” Of these patients, TTE changed clinical management in 11.1%, but identified intracardiac thrombus in only 0.7%. The authors also identified an association between positive troponin levels and TTE changing management (adjusted OR 4.26, 95% CI 2.17-8.34, P<0.001).

By |December 5th, 2018|clinical|0 Comments

In Search of an IV-tPA Biomarker for LVO

Richard Jackson, MD

Yoo J, Baek J-H, Park H, Song D, Kim K, Hwang IG, et al. Thrombus Volume as a Predictor of Nonrecanalization After Intravenous Thrombolysis in Acute Stroke. Stroke. 2018

Now that endovascular thrombectomy has been shown to be beneficial in large vessel occlusions, there is a question of distribution of resources and triage of patients. Yoo et al. recognized this need and began to look at a possible imaging biomarker for response to IV-tPA.

They began with a retrospective analysis of a CT-based thrombus cohort of 214 patients from three university hospitals between 2006 and 2009. Mean thrombus volume was found to be 129mm3 and density 53.5 HU with a median time to tPA of 52 minutes. Of the 214 patients, 162 (76%) failed to re-canalize, which was defined as TICI grade 1-2a. Using statistical analysis, the upper range of the calculated reference range was 181.9 mm3 thrombus volume, and, therefore, a cut-off volume of 200mm3 was determined to be optimal to predict non-recanalization.

Are Aphasia and Visual Neglect Good Prehospital Predictors for Large Vessel Occlusion in Acute Stroke?

Kara Jo Swafford, MD

Beume L-A, Hieber M, Kaller CP, Nitschke K, Bardutzky J, Urbach H, et al. Large Vessel Occlusion in Acute Stroke: Cortical Symptoms Are More Sensitive Prehospital Indicators Than Motor Deficits. Stroke. 2018

A simple yet sensitive tool that can be applied in the prehospital setting to identify patients with an acute stroke due to large vessel occlusion (LVO) would be a helpful aid to optimize selection of candidates for mechanical thrombectomy (MT) who would benefit from direct transport to a Comprehensive Stroke Center (CSC). Most screening assessments focus on motor deficits, which can be related to lesions in the internal capsule, motor cortex or brainstem and be due to either small vessel disease or LVO. Cortical symptoms, such as aphasia and visuo-spatial neglect, may be better predictors of LVO.

Beume et al. performed a single-center retrospective analysis of patients arriving within 4.5 hours of stroke symptom onset. To represent the prehospital setting, those with acute ischemic stroke, transient ischemic attack, intracranial hemorrhage and stroke mimics were included. Aphasia was assessed by asking patients to name an object, follow verbal commands and produce spontaneous speech. Visuo-spatial neglect was evaluated by testing of conjugate horizontal eye movements and presence of gaze and/or head deviation. Patients had cerebrovascular imaging to screen for presence of LVO.

By |December 3rd, 2018|clinical|0 Comments

Mechanical Thrombectomy in Patients with Minor Strokes and Large Vessel Occlusion: The “Too Good to Intervene” Dilemma

Victor J. Del Brutto, MD

Nagel S, Bouslama M, Krause LU, Küpper C, Messer M, Petersen M, et al. Mechanical Thrombectomy in Patients With Milder Strokes and Large Vessel Occlusions: A Multicenter Matched Analysis. Stroke. 2018

Over half of acute ischemic strokes in the U.S. present with mild deficits as defined by an initial NIHSS score of 5 or less. Despite having deficits perceived as “minor”, around 30% of these patients will not achieve a good functional outcome at follow-up. Large vessel occlusion (LVO) is found in 10 to 20% of patients with minor strokes. Presence of LVO has been associated with early neurological deterioration, as well as decreased likelihood of good recovery. Minor symptoms in the setting of a major occluded vessel pictures good collateral flow maintaining tissue perfusion. On the other hand, frequent early clinical deterioration and worse functional outcomes expose the potential failure of aforementioned collaterals and infarct expansion.

Mechanical thrombectomy  (MT) is the current standard of care for selected patients with LVO and initial NIHSS score ≥6; however, the benefit of MT in patients with milder symptoms remains uncertain. Recanalization is an appealing solution to prevent clinical deterioration and improve long-term functional outcome in these patients. Nonetheless, the treatment effect might not provide a significant benefit and could add potential risk for complications related to the procedure, such as hemorrhagic conversion, emboli to new vascular territories, failure of collaterals due to transient hypotension related to anesthesia, etc.

By |November 30th, 2018|clinical|0 Comments

The Modified Treatment in Cerebral Ischemia Score: Does It Matter Who is Scoring It?

Mohammad Anadani, MD

Zhang G, Treurniet KM, Jansen IGH, Emmer BJ, van den Berg R, Marquering HA, et al. Operator Versus Core Lab Adjudication of Reperfusion After Endovascular Treatment of Acute Ischemic Stroke. Stroke. 2018

Mechanical thrombectomy (MT) is the standard of care for acute ischemic stroke treatment. The goal of MT is to restore perfusion to the affected area. Hence, its efficiency is evaluated by the degree of reperfusion at the end of the procedure. The Modified Treatment in Cerebral Ischemia (mTICI) score is the most widely used reperfusion score, and it was used in most of the recent intra-arterial treatment landmark trials to assess the efficacy of mechanical thrombectomy. It was also used to compare different thrombectomy techniques, especially contact aspiration and stent retriever techniques. The mTICI score ranges from 0-3, where 0 means no perfusion and 3 means complete perfusion. In the randomized trial settings, mTICI is usually assessed by core laboratories to avoid overestimation. However, this notion of overestimation by local operators has not been supported by research studies.

By |November 28th, 2018|clinical|0 Comments

Observational Study Data on the Utility of EVT for Acute Ischemic Stroke Patients with LVO and Mild Neurological Deficits: Shivering Lights Through the Mist!

Aristeidis H. Katsanos, MD, PhD

Nagel S, Bouslama M, Krause LU, Küpper C, Messer M, Petersen M, et al. Mechanical Thrombectomy in Patients With Milder Strokes and Large Vessel Occlusions: A Multicenter Matched Analysis. Stroke. 2018

Sarraj A, Hassan A, Savitz SI, Grotta JC, Cai C, Parsha KN, et al. Endovascular Thrombectomy for Mild Strokes: How Low Should We Go? A Multicenter Cohort Study. Stroke. 2018

According to the current guidelines from the American Heart Association/American Stroke Association, endovascular thrombectomy (EVT) should be implemented in the treatment of acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) who have a measurable neurological deficit of at least 6 points in the National Institutes of Health Stroke Scale (NIHSS) on admission, providing however weak support for the use of EVT in AIS patients with internal carotid artery (ICA) or proximal middle cerebral artery (MCA-M1) occlusion and a baseline NIHSS score less than 6. In the October issue of Stroke, two independent multicenter study groups aimed to answer the question on the utility of EVT in patients with LVO and mild AIS severity (NIHSS <6).

By |November 27th, 2018|clinical|0 Comments

How Long Should We Give Dual Antiplatelet Therapy After Minor Acute Ischemic Stroke?

World Stroke Congress
October 17-20, 2018

Danielle de Sa Boasquevisque, MD

Following a Transient Ischemic Attack (TIA) or minor ischemic stroke, the risk of having another ischemic stroke or vascular events within the next three months is 10-20%. The Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial was a randomized, double-blind study designed to evaluate the benefit of dual antiplatelet therapy (DAPT) compared to aspirin alone during the first 90 days after a minor ischemic stroke or transient ischemic attack. The primary efficacy outcome was major ischemic events, and the primary safety outcome was major hemorrhage.

The POINT Trial was halted after 84% of the anticipated number of participants had been enrolled. They found that patients enrolled in 3 months of DAPT had fewer major ischemic events than patients given aspirin alone (5% versus 6.5%, respectively; hazard ratio, 0.75; 95% confidence interval [CI], 0.59 to 0.95; p=0.02). However, the DAPT also seemed to increase chances of major hemorrhage compared to the aspirin controls (0.9% versus 0.4%, respectively; hazard ratio 2.32; 95% CI, 1.10-4.87; p=0.02).

A secondary analysis of POINT Trial data was presented by Jordan J. Elm at the World Stroke Congress in October in Montreal. It aimed to identify the time course of risks versus benefits of clopidogrel and aspirin in acute minor ischemic stroke and high-risk TIA patients and determine if there is an optimal time when patients would benefit most from using both aspirin and clopidogrel.

Article Commentary: “Resting-State Functional Connectivity Magnetic Resonance Imaging and Outcome after Acute Stroke”

Alexis N. Simpkins, MD, PhD

Puig J, Blasco G, Alberich-Bayarri A, Schlaug G, Deco G, Biarnes C, et al. Resting-State Functional Connectivity Magnetic Resonance Imaging and Outcome After Acute Stroke. Stroke. 2018

Many ischemic stroke patients will have residual disability from their stroke even if they receive thrombolysis or endovascular therapy. In fact, stroke is and is projected to continue to be one of the leading causes of long-term disability in adults. Identifying tools that can be used to accurately predict expected stroke recovery can change the way the patient is medically managed and can be used as an outcome measure in clinical trials. Changes in NIHSS, infarct volume, and stroke lesion have been shown to predict early neurologic outcome, but there are still limitations with each of these predictors. As a result, there are continued efforts to provide more sensitive and specific predictive models. Here, the authors assessed whether resting state-functional MRI (rs-fMRI) is associated with projected neurologic outcome at 90 days and can be combined with other frequently used predictors to improve accuracy. The selection of rs-fMRI was supported by previous studies that demonstrated an association between resting state and task-oriented functional connectivity and previous reports of the role of interhemispheric connectivity in stroke recovery.