American Heart Association

Using Post-Thrombectomy CT Perfusion to Improve Tissue Reperfusion Assessments

Vignan Yogendrakumar, MD, MSc

Tan Z, Parsons M, Bivard A, Sharma G, Mitchell P, Dowling R, Bush S, Xu A, Yan B. Optimal Tissue Reperfusion Estimation by Computed Tomography Perfusion Post-Thrombectomy in Acute Ischemic Stroke. Stroke. 2021.

In the thrombectomy era of acute stroke care, it is commonplace to utilize mTICI scores as one of the primary measures of assessing reperfusion status immediately post-procedure. In many studies, it is common to see a measure of mTICI scores 2b-3 as a representation of a good study outcome. However, registry data shows us that mTICI 2b scores are associated with an independent functional state in only 40% of patients. While the surrogate use of mTICI status to represent tissue reperfusion status is certainly a reasonable approach, the association between mTICI score and actual tissue status remains unclear.

In this study by Tan and colleagues, acute stroke patients treated at the Royal Melbourne Hospital with endovascular clot retrieval underwent CT or MRI perfusion at 24-36 hours post procedure. Comparing the baseline and follow-up perfusion scans, the authors defined optimal tissue reperfusion (TOR) as a >90% reduction of penumbra (using TMax>6s) volume. In 82 patients, those who had higher mTICI scores were more likely to achieve TOR at follow-up. Notably, achieving mTICI scores of 2c or 3 were more likely to be associated with TOR compared to mTICI 2b. Clinically, TOR was associated with improved clinical outcomes in multivariable logistic regression models.

By |November 9th, 2021|clinical|0 Comments

World Stroke Congress: “Stroke in Low to Middle Income Countries”

Ericka Samantha Teleg, MD

World Stroke Congress
October 28–29, 2021

Plenary Session: “Stroke in Low to Middle Income Countries”

While the landscape of stroke changes in terms of innovations, pathways and technology, there is a continuing increase of stroke burden in the low to middle income countries (LMICs). This session was moderated by Dr. Norlinah Ibrahim and Dr. Mayowa Owolabi.

Dr. Owolabi opened the discussion by giving an overview of the Lancet Commission in giving evidence-based recommendations that are pragmatic in nature extending to primary, secondary, and tertiary prevention, keeping in mind that these regions bear a burden due to limited resources. He emphasized the Stroke Quadrangle that includes epidemiological surveillance, acute care, rehabilitation, palliative care, health promotion, and disease prevention. He set the stage by reiterating that there is scarcity of funding for primary stroke prevention, particularly in LMICs. There is indeed an absence of an integrative approach. Regional and national differences in policymaking are also a variable. 

ASPECTS Score as a Biomarker to Predict Clinical Outcome

Arooshi Kumar, MD

Liebeskind DS, Saber H, Bhuva P, Xiang B, Yoo AJ, Jadhav AP, Haussen DC, Budzik RF, Bonafe A, Yavagal DR, et al. Serial ASPECTS in the DAWN Trial: Infarct Evolution and Clinical Impact. Stroke. 2021;52:3318–3324.

With the rapid adoption of endovascular therapy (EVT) for selected ischemic stroke patients, there remains a need to identify practical biomarkers to help predict treatment efficacy and clinical outcomes. The Alberta Stroke Program Early CT Score (ASPECTS) grading system is a well-accepted method to capture the degree of brain injury following stroke in the anterior circulation.1,2 While it has emerged as one standard method to quantify degree of ischemia and select candidates for endovascular treatment (EVT), the utility of post-intervention ASPECTS scores remains unclear.

To that end, a secondary SWIFT analysis demonstrated that post-treatment ASPECTS score was a reliable predictor of 90-day clinical function after stroke for presenting in the early intervention window (< 6hours).3 This study aimed at investigating the relevance of post-treatment ASPECTS score for later presenting window (6-24 hours) patients with ischemic stroke using the DAWN trial results. In this study, the ASPECTS score, initial and after 24 hours, was tabulated from 81 CT-CT pairs, 56 CT-MRI pairs, and 66 MRI-MRI pairs.

Article Commentary: “d-dimer Level as a Predictor of Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source”

Meghana Srinivas, MD

Choi KH, Kim JH, Kim JM, Kang KW, Lee C, Kim JT, Choi SM, Park MS, Cho KH. d-dimer Level as a Predictor of Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source. Stroke. 2021;52:2292–2301.

Embolic stroke of underdetermined source is used to identify patients with nonlacunar embolic cryptogenic strokes with a more restrictive inclusion criteria for strokes of cryptogenic origin and complete diagnostic workup in comparison to classic cryptogenic strokes.

Patients with a diagnosis of ESUS at the time of their index stroke carry a high risk of recurrent strokes, which is approximately twice as compared to cryptogenic stroke other than ESUS. Given this incidence, it is important to identify the underlying mechanism and cause of strokes for secondary stroke prevention. Although the most common mechanism in ESUS is embolism with covert atrial fibrillation being the most common cause, recent randomized control trials have shown that non-vitamin antagonist oral anticoagulants (OACs) are not superior to aspirin in preventing recurrence of strokes in patients with ESUS. This can be explained by the heterogeneity among the potential causes of ESUS, which can be covert AF and hidden malignancy to patients with ipsilateral carotid stenosis of less than 50% and aortic arch atherosclerosis. As in the name, it is unknown at least at the time of initial presentation. It is important to identify factors which can predict the risk of recurrent stroke in patients with ESUS and use the right secondary preventative measures.

Post-Stroke Epilepsy in Children

Kevin O’Connor, M.D.

Sundelin HEK, Tomson T, Zelano J, Söderling J, Bang P, Ludvigsson JF. Pediatric Ischemic Stroke and Epilepsy: A Nationwide Cohort Study. Stroke. 2021.

Post-stroke epilepsy is a well-known entity, particularly in adults. To explore post-stroke epilepsy in children, Sundelin et al. used the Swedish National Registers to identify 1220 children with ischemic stroke (including cerebral venous sinus thrombosis, which could not be differentiated in the Register) and 12155 comparators between 1969-2016; they excluded patients with previously known epilepsy.

Of the 1220 children with ischemic stroke, 219 (18%) developed post-stroke epilepsy compared to 91 comparators (0.7%). The epilepsy risk was highest in the six months following stroke (HR, 119.4 [95% CI, 48.0–297.4]) and remained elevated even at 20 years post-stroke (HR, 7.9 [95% CI, 3.3–19.0]). The cumulative incidence of post-stroke epilepsy increased with longer follow-up periods: 11.9% at 5 years (95% CI, 10.1%–14.0%), 21.6% (95% CI, 19.0%–24.6%), and 26.4% at 30 years (95% CI, 23.0%–30.1%).

Article Commentary: “Deep Learning–Based Automated Thrombolysis in Cerebral Infarction Scoring”

Tolga D. Dittrich, MD

Nielsen M, Waldmann M, Frölich AM, Flottmann F, Hristova E, Bendszus M, Seker F, Fiehler J, Sentker T, Werner R. Deep Learning-Based Automated Thrombolysis in Cerebral Infarction Scoring: A Timely Proof-of-Principle Study. Stroke. 2021.

The success of mechanical thrombectomy is commonly measured by the TICI (Thrombolysis in Cerebral Infarction) score. The score is determined by the visual assessment of the digital subtraction angiography (DSA) images during the intervention by the treating interventionalist. Despite modifications of the original scale (e.g., modified TICI [mTICI]) that have become established in the meantime, a relatively high inter- and intraobserver variability of TICI scores can be observed. This investigator dependency poses a challenge, particularly regarding clinical studies, as it may affect the comparability of results.

In the present study, based on occlusions of the middle cerebral artery in the M1 segment, Nielsen and colleagues sought to develop an automated and thus more objective TICI assessment using a deep learning (DL) approach. Agreement between DL and expert-based assessment (gold standard) was evaluated, and a comparison with corresponding published numbers on expert assessment variability was performed.

By |October 29th, 2021|clinical|0 Comments

Efficacy of Tenecteplase as a Reperfusion Therapy for Acute Ischemic Stroke

Farah Aleisa, MD

Burgos AM, Saver JL. Evidence that Tenecteplase Is Noninferior to Alteplase for Acute Ischemic Stroke: Meta-Analysis of 5 Randomized Trials. Stroke. 2019;50:2156–2162.

Tenecteplase (TNK) is a tissue-type plasminogen activator modified by 3 amino acids from alteplase, and it has the potential to reperfuse brain tissue in case of blocked brain vessels. It has greater fibrin specificity resulting in lower bleeding risks,1 and it has initial serum half-life of 20 minutes and a mean terminal half-life of 100 minutes, such that it can be given as a bolus dose on a weight-adjusted basis,2 being given even in the pre-hospital setting, which allows faster time to reperfusion and less delay for endovascular therapy if needed.

There are 5 independent randomized trials that have studied the efficacy of TNK in comparison to altelplase (ALT) in acute ischemic stroke.3-7 These trials enrolled a total of 1585 patients (828 TNK, 757 ALT), mean National Institutes of Health Stroke Scale (NIHSS) at baseline was 7, and mean time from last known well to treatment start was 148 minutes. All patients with ALT received standard 0.9 mg/kg dosing; TNK dosing was one-time bolus only, at doses of 0.1 mg/kg in 6.8% of patients, 0.25 mg/kg in 24.6%, and 0.4 mg/kg in 68.6%.

By |October 26th, 2021|clinical|0 Comments

Chasing the D-Dimer Level in Patients With ESUS

Muhammad Rizwan Husain, MD

Choi KH, Kim JH, Kim JM, Kang KW, Lee C, Kim JT, Choi SM, Park MS, Cho KH. d-dimer Level as a Predictor of Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source. Stroke. 2021;52:2292–2301.

D-dimer levels are known to be a marker for underlying hypercoagulable state in several studies reporting raised D-dimer levels in patients with cardioembolic stroke, underling malignancy, and venous thromboembolism. However, the role of D-dimer levels to predict recurrent stroke in patients with ESUS (Embolic Stroke of Undetermined Source) is unknown.

The authors in this study evaluated the role of plasma D-dimer levels to help predict recurrent stroke (ischemic or hemorrhagic) within 1 year in patients with ESUS, as well as to evaluate possible etiologies of recurrent strokes based on D-dimer levels.

Article Commentary: “Rescue of Neglect and Language Impairment After Stroke Thrombectomy”

Hannah Roeder, MD, MPH

Desai SM, Malhotra K, Ramaiah G, Tonetti DA, Haq W, Jovin TG, Jadhav AP. Rescue of Neglect and Language Impairment After Stroke Thrombectomy. Stroke. 2021.

The presence of cortical signs, such as aphasia and neglect, on a stroke code examination prompts neurologists to investigate for the presence of a large vessel occlusion (LVO) and to determine if the patient may benefit from thrombectomy. Can the rescue or persistence of cortical signs following mechanical thrombectomy (MT) help us predict outcomes among stroke patients?

The authors performed a retrospective analysis of the stroke database at a single Comprehensive Stroke Center to assess the impact of neglect and aphasia on clinical outcomes for patients with right and left anterior LVO, respectively. They found that a significant majority of patients with right-sided LVOs presented with neglect (71%) and patients with left-sided LVOs presented with language impairment (93%). MT resulted in “rescue of neglect” (31%) and “rescue of language impairment” (23%) in a minority of cases but was an independent and better predictor of functional independence (mRS 0-2) and survival even after adjustment for NIHSS and infarct volume.

By |October 22nd, 2021|clinical|0 Comments

Activation of T Lymphocytes After Stroke: An Antigen-Specific or Antigen-Independent Mechanism?

Aurora Semerano, MD

Schulze J, Gellrich J, Kirsch M, Dressel A, Vogelgesang A. Central Nervous System-Infiltrating T Lymphocytes in Stroke Are Activated via Their TCR (T-Cell Receptor) but Lack CD25 Expression. Stroke. 2021;52:2939–2947.

Leukocytes from peripheral circulation infiltrate the ischemic brain within hours to days after stroke, and they can contribute to secondary tissue damage, as well as to the subsequent processes of repair and recovery. T lymphocytes are also implied in this response. However, it remains unclear which mechanism of lymphocyte activation plays the most relevant role after stroke: Indeed, both antigen-specific T lymphocytes (reacting against brain antigens) and antigen-independent mechanisms (driven by pro-inflammatory mediators) have been described. These previous studies were mostly conducted with ablative approaches, that’s to say in T-cell-deficient experimental models or upon inhibition of lymphocyte infiltration into the brain.