Local tirofiban infusion for remnant stenosis in large vessel occlusion: tirofiban ASSIST study

Endovascular Thrombectomy for Acute Ischemic Stroke : Current Concept in Management

Endovascular thrombectomy (EVT) has been established as the standard of care in the treatment of acute ischemic stroke (AIS) based on landmark randomized controlled trials. Nevertheless, while the strict eligibility of EVT for AIS patients restrict the wide application of EVT, a considerable population still undergoes off-label EVT. Besides, it is important to acknowledge that recanalization is not achieved in approximately 20% of procedures, and more than 50% of patients who undergo EVT still do not experience a favorable outcome. This article reviews the brief history of EVT trials and recent progressions in the treatment of AIS, with focusing on the expanding eligibility criteria, new target for EVT, and the evolution of EVT techniques.

Development and validation of a SCORing systEm for pre-thrombectomy diagnosis of IntraCranial Atherosclerotic Disease (Score-ICAD)

BACKGROUND

Early identification of intracranial atherosclerotic disease (ICAD) may impact the management of patients undergoing mechanical thrombectomy (MT). We sought to develop and validate a scoring system for pre-thrombectomy diagnosis of ICAD in anterior circulation large vessel/distal medium vessel occlusion strokes (LVOs/DMVOs).

METHODS

Retrospective analysis of two prospectively maintained comprehensive stroke center databases including patients with anterior circulation occlusions spanning 2010-22 (development cohort) and 2018-22 (validation cohort). ICAD cases were matched for age and sex (1:1) to non-ICAD controls.

RESULTS

Of 2870 MTs within the study period, 348 patients were included in the development cohort: 174 anterior circulation ICAD (6% of 2870 MTs) and 174 controls. Multivariable analysis β coefficients led to a 20 point scale: absence of atrial fibrillation (5); vascular risk factor burden (1) for each of hypertension, diabetes, smoking, and hyperlipidemia; multifocal single artery stenoses on CT angiography (3); absence of territorial cortical infarct (3); presence of borderzone infarct (3); or ipsilateral carotid siphon calcification (2). The validation cohort comprised 56 ICAD patients (4.1% of 1359 MTs): 56 controls. Area under the receiver operating characteristic curve was 0.88 (0.84-0.91) and 0.82 (0.73-0.89) in the development and validation cohorts, respectively. Calibration slope and intercept showed a good fit for the development cohort although with overestimated risk for the validation cohort. After intercept adjustment, the overestimation was corrected (intercept 0, 95% CI -0.5 to -0.5; slope 0.8, 95% CI 0.5 to 1.1). In the full cohort (n=414), ≥11 points showed the best performance for distinguishing ICAD from non-ICAD, with 0.71 (95% CI 0.65 to 0.78) sensitivity and 0.82 (95% CI 0.77 to 0.87) specificity, and 3.92 (95% CI 2.92 to 5.28) positive and 0.35 (95% CI 0.28 to 0.44) negative likelihood ratio. Scores ≥12 showed 90% specificity and 63% sensitivity.

CONCLUSION

The proposed scoring system for preprocedural diagnosis of ICAD LVOs and DMVOs presented satisfactory discrimination and calibration based on clinical and non-invasive radiological data.

Balloon angioplasty as first-choice recanalization strategy for intracranial atherosclerosis-related emergent large vessel occlusion with small clot burden

PURPOSE

The optimal primary recanalization strategy for intracranial atherosclerosis-related emergent large vessel occlusion (ICAS-ELVO) remains controversial. We aimed to explore the safety and efficacy of balloon angioplasty as the first-choice recanalization strategy for ICAS-ELVO with small clot burden.

METHODS

Consecutive ICAS-ELVO patients presenting with microcatheter "first-pass effect" during endovascular treatment (EVT) were retrospectively analyzed. Patients were divided into preferred balloon angioplasty (PBA) and preferred mechanical thrombectomy (PMT) groups based on the first-choice recanalization strategy. The reperfusion and clinical outcomes between the two groups were compared.

RESULTS

Seventy-six patients with ICAS-ELVO involving the microcatheter "first-pass effect" during EVT were enrolled. Compared with patients in the PMT group, those in the PBA group were associated with (i) a higher rate of first-pass recanalization (54.0% vs. 28.9%, p = .010) and complete reperfusion (expanded thrombolysis in cerebral ischemia ≥ 2c; 76.0% vs. 53.8%, p = .049), (ii) shorter puncture-to-recanalization time (49.5 min vs. 89.0 min, p < .001), (iii) lower operation costs (¥48,499.5 vs. ¥ 99,086.0, p < .001), and (iv) better 90-day functional outcomes (modified Rankin scale:0-1; 44.0% vs. 19.2%, p = .032). Logistic regression analysis revealed that balloon angioplasty as the first-choice recanalization strategy was an independent predictor of 90-day excellent functional outcomes for ICAS-ELVO patients with microcatheter "first-pass effect" (adjusted odds ratio = 6.01, 95% confidence interval: 1.15-31.51, p = .034).

CONCLUSION

Direct balloon angioplasty potentially improves 90-day functional outcomes for ICAS-ELVO patients with small clot burden, and may be a more appropriate first-choice recanalization strategy than mechanical thrombectomy for these patients.

The impact of intraarterial, intravenous, and combined tirofiban on endovascular treatment for acute intracranial atherosclerotic occlusion

Background and purpose

Adjunctive tirofiban administration in patients undergoing endovascular treatment (EVT) for acute large vessel occlusion (LVO) has been investigated in several studies. However, the findings are conflict. This study aimed to compare the effect of different administration pathways of tirofiban on patients undergoing EVT for acute LVO with intracranial atherosclerotic disease (ICAD).

Methods

Patients were selected from the ANGEL-ACT Registry (Endovascular Treatment Key Technique and Emergency Workflow Improvement of Acute Ischemic Stroke: A Prospective Multicenter Registry Study) and divided into four groups: intra-arterial (IA), intravenous (IV), and intra-arterial plus intravenous (IA+IV) and non-tirofiban. The primary outcome was 90-day ordinal modified Rankin Scale (mRS) score, and the secondary outcomes included the rates of mRS 0-1, 0-2, and 0-3 at 90-day, successful recanalization. The safety outcomes were symptomatic intracranial hemorrhage (sICH) and other safety endpoints. The multivariable logistic regression models adjusting for potential baseline confounders were performed to compare the outcomes. A propensity score matching (PSM) with a 1:1:1:1 ratio was conducted among four groups, and the outcomes were then compared in the post-matched population.

Results

A total of 502 patients were included, 80 of which were in the IA-tirofiban group, 73 in IV-tirofiban, 181 in (IA+IV)-tirofiban group, and 168 in the non-tirofiban group. The median (IQR) 90-day mRS score in the four groups of IA, IV, IA+IV, and non-tirofiban was, respectively 3(0-5) vs. 1(0-4) vs. 1(0-4) vs. 3(0-5). The adjusted common odds ratio (OR) for 90-day ordinal modified Rankin Scale distribution with IA-tirofiban vs. non-tirofiban was 0.77 (95% CI, 0.45-1.30, P = 0.330), with IV-tirofiban vs. non-tirofiban was 1.36 (95% CI, 0.78-2.36, P = 0.276), and with (IA+IV)-tirofiban vs. non-tirofiban was 1.03 (95% CI, 0.64-1.64, P = 0.912). The adjusted OR for mRS 0-1 and mRS 0-2 at 90-day with IA-tirofiban vs. non-tirofiban was, respectively 0.51 (95% CI, 0.27-0.98, P = 0.042) and 0.50 (95% CI, 0.26-0.94, P = 0.033). The other outcomes of each group were similar with non-tirofiban group, all P was >0.05. After PSM, the common odds ratio (OR) for 90-day ordinal modified Rankin Scale distribution with IA-tirofiban vs. non-tirofiban was 0.41 (95% CI, 0.18-0.94, P = 0.036), and the OR for mRS 0-1 and mRS 0-2 at 90-day with IA-tirofiban vs. non-tirofiban was, respectively 0.28 (95% CI, 0.11-0.74, P = 0.011) and 0.25 (95% CI, 0.09-0.67, P = 0.006).

Conclusions

Intra-arterial administration of tirofiban was associated with worse outcome than non-tirofiban, which suggested that intra-arterial tirofiban had a harmful effect on patients undergoing EVT for ICAD-LVO.

Clinical trial registration

http://www.clinicaltrials.gov, Unique identifier: NCT03370939.

Glycoprotein inhibitors as a first line rescue treatment after unsuccessful recanalization of endovascular thrombectomy: A systematic review and meta-analysis

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is a major cause of stroke with a high rate of re-occlusion following mechanical thrombectomy (MT). Among the available rescue options, glycoprotein IIb/IIIa inhibitors (GPI) have shown promise as a potential therapeutic strategy. This systematic review and meta-analysis examine studies exploring the use of glycoprotein inhibitors as a first-line treatment for refractory occlusion or high-grade stenosis following EVT in the setting of ICAD.

METHODS

A systematic review and meta-analysis were performed. Studies using GPI as the first-line rescue treatment (GPI-rt) after failed thrombectomy or in the setting with high-grade stenosis (>50%) were included. The primary outcome of interest was good clinical outcomes (defined as a modified Rankin Scale (mRS) score of 0-2 at 90 days). Secondary outcomes of interest were successful recanalization (TICI 2b-3), symptomatic intracranial hemorrhage (sICH), and mortality by 90 days.

RESULTS

Our study processed 2111 articles, which yielded eight relevant studies for review, four single and four double arm. These studies comprised 763 patients, divided into GPI-rt (535 patients) and non-GPI-rt (228 patients) cohorts. The GPI-rt group had higher rates of mRS ≤ 2 at 90 days (58.5% vs 38.9%, p = 0.002) and lower mortality rates (7.8% vs 17.5%, p = 0.04) compared to the non-GPI-rt cohort. mTICI 2b-3 rates and rates of sICH were not significantly different between the cohorts.

CONCLUSIONS

First line GPI-rt demonstrates significant clinical benefit and significantly lower mortality without a rise in rates of sICH. GPI are a potential first line rescue treatment of ICAD.

Subtyping treatment response of tirofiban in acute ischemic stroke based on neuroimaging features

In a previously published clinical trial, we demonstrated that tirofiban was effective and safe in acute ischemic stroke (AIS) patients who did not undergo early recanalization treatments. We aimed to evaluate neuroimaging characteristics and their clinical significance to guide tirofiban treatment. In this post hoc analysis, location of infarcts (anterior circulation stroke [ACS] vs. posterior circulation stroke [PCS]), degree of cerebral artery stenosis (≤69% vs. ≥70% or occlusion), total infarct volume, and ASPECTS were used to predict the treatment effects of tirofiban, defined as the proportions of excellent and favorable functional outcome (modified Rankin Scale [mRS] score of 0-1, 0-2) at 90 days. ACS patients were more likely to achieve excellent (OR 2.08; 95% CI 1.25-3.45; p = 0.004) and favorable functional outcome (OR 2.28; 95% CI 1.24-4.22; p = 0.008) when treated with tirofiban. However, there was no significant difference in PCS patients between tirofiban and the control group. For patients with severe stenosis (≥70% or occlusion), tirofiban treatment improved the proportion of good outcomes (OR 2.84; 95% CI 1.44-5.60; p = 0.002 for mRS 0-1; OR 2.42; 95% CI 1.22-4.77; p = 0.011 for mRS 0-2). Meanwhile, we found that tirofiban improved outcome in patients with ASPECTS 8-10 and was independent of total infarct volume. These findings support the hypothesis that patients with ACS and severe stenosis may be recommended for tirofiban treatment, which can be predicted independent of total infarct volume.

Acute Vertebrobasilar Artery Occlusion with Underlying Atherosclerosis: Balloon Angioplasty Combined with Tirofiban as Initial Salvage Therapy

OBJECTIVE

The optimal rescue endovascular treatment for patients with intracranial atherosclerotic stenosis in acute vertebrobasilar artery occlusion is not well established. We investigated the safety and efficacy of balloon angioplasty combined with tirofiban as the initial rescue strategy in these patients.

METHODS

We retrospectively analyzed the records of 41 patients admitted between January 2014 and September 2022, with vertebrobasilar artery atherosclerotic occlusion. Balloon angioplasty in combination with tirofiban was used as the first-line salvage therapy after the failure of mechanical thrombectomy. The technical success rate, recanalization outcome, procedure-related complications, symptomatic intracranial hemorrhage, and functional outcome at 90 days were reviewed.

RESULTS

Recanalization with a modified Thrombolysis in Cerebral Infarction grade of 2b-3 was achieved in 38 of the 41 patients (92.7%). Acute stents were deployed in 5 patients who did not achieve successful reperfusion after balloon angioplasty. Six patients (14.6%, 6/41) underwent stent angioplasty in the stable stage for severe residual stenosis detected on follow-up imaging. There was no procedure-related complication. Hemorrhagic transformation was detected on follow-up imaging in 11 patients (26.8%), while no symptomatic intracranial hemorrhage was recorded. Good functional outcome rate was 31.7% (13/41).

CONCLUSIONS

Balloon angioplasty combined with intravenous tirofiban administration is a safe and effective salvage therapy in patients with acute atherosclerotic occlusion of the vertebrobasilar artery.

Rescue therapy after thrombectomy for large vessel occlusion due to underlying atherosclerosis: review of literature

In this review article, we summarized the current advances in rescue management for reperfusion therapy of acute ischemic stroke from large vessel occlusion due to underlying intracranial atherosclerotic stenosis (ICAS). It is estimated that 24-47% of patients with acute vertebrobasilar artery occlusion have underlying ICAS and superimposed in situ thrombosis. These patients have been found to have longer procedure times, lower recanalization rates, higher rates of reocclusion and lower rates of favorable outcomes than patients with embolic occlusion. Here, we discuss the most recent literature regarding the use of glycoprotein IIb/IIIa inhibitors, angioplasty alone, or angioplasty with stenting for rescue therapy in the setting of failed recanalization or instant/imminent reocclusion during thrombectomy. We also present a case of rescue therapy post intravenous tPA and thrombectomy with intra-arterial tirofiban and balloon angioplasty followed by oral dual antiplatelet therapy in a patient with dominant vertebral artery occlusion due to ICAS. Based on the available literature data, we conclude that glycoprotein IIb/IIIa is a reasonably safe and effective rescue therapy for patients who have had a failed thrombectomy or have residual severe intracranial stenosis. Balloon angioplasty and/or stenting may be helpful as a rescue treatment for patients who have had a failed thrombectomy or are at risk of reocclusion. The effectiveness of immediate stenting for residual stenosis after successful thrombectomy is still uncertain. Rescue therapy does not appear to increase the risk of sICH. Randomized controlled trials are warranted to prove the efficacy of rescue therapy.

Endovascular Treatment for Acute Large Vessel Occlusion Due to Underlying Intracranial Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of acute ischemic stroke worldwide. Patients with acute large vessel occlusion due to underlying ICAD (ICAD-LVO) often do not achieve successful recanalization when undergoing mechanical thrombectomy (MT) alone, requiring rescue treatment, including intra-arterial thrombolysis, balloon angioplasty, and stenting. Therefore, early detection of ICAD-LVO before the procedure is important to enable physicians to select the optimal treatment strategy for ICAD-LVO to improve clinical outcomes. Early diagnosis of ICAD-LVO is challenging in the absence of consensus diagnostic criteria on noninvasive imaging and early digital subtraction angiography. In this review, we summarize the clinical and diagnostic criteria, prediction of ICAD-LVO prior to the procedure, and EVT strategy of ICAD-LVO and provide recommendations according to the current literature.

Antiplatelet Therapy in Neurointervention

The aim of this review is to provide an overview of the use of antiplatelet medication in neurointervention, with a focus on the clinical indications for antiplatelet use in both preventing and reducing platelet aggregation. This review will cover current antiplatelet medications, pharmacokinetics, and pharmacodynamics. We will provide an overview of different endovascular devices and discuss the antiplatelet regimes in neurointervention, highlighting gaps in evidence and scope for future studies.Two randomized controlled trials have evaluated antiplatelet use in the setting of acute large vessel occlusion stroke, with neither demonstrating benefit in their overall cohorts. Evidence on antiplatelet medication for both acute and elective stenting for acute stroke and treatment of cerebral aneurysms is currently based on large case series, and practice in neurointervention has increasingly utilized dual antiplatelet regimes with clopidogrel and second-line agents like prasugrel and ticagrelor. Clopidogrel function testing has an increasing role in neurointerventional procedures, particularly for high metal surface area stents such as the braided flow diverter type stents. Intravenous glycoprotein IIB/IIIA inhibitors have been utilized for both acute bridging and rescue therapy.Antiplatelet decision making is complex, and there are few randomized control trials to guide clinical practice. Comparative trials to guide decision making remain important in both the acute and elective settings. Standardised protocols incorporating platelet function testing may play a role in assisting decision making until more robust clinical evidence is available, particularly in the context of acute neurointerventional stenting for stroke and ruptured cerebral aneurysms.

Association of Tirofiban With Functional Outcomes After Thrombectomy in Acute Ischemic Stroke Due to Intracranial Atherosclerotic Disease

BACKGROUND AND OBJECTIVE

To investigate the efficacy and safety of IV infusion of tirofiban before endovascular thrombectomy for patients with large vessel occlusion due to intracranial atherosclerotic disease. The secondary objective was to identify potential mediators for the clinical effect of tirofiban.

METHODS

Post hoc exploratory analysis of the Endovascular Treatment With versus Without Tirofiban for Patients with Large Vessel Occlusion Stroke (RESCUE BT) trial, which was a randomized, double-blinded, placebo-controlled trial at 55 centers in China from October 2018 to October 2021. Patients with occlusion of the internal carotid artery or middle cerebral artery due to intracranial atherosclerosis were included. The primary efficacy outcome was the proportion of patients achieving functional independence (defined as modified Rankin scale 0-2) at 90 days. Binary logistic regression and causal mediation analyses were used to estimate the treatment effect of tirofiban and the potential mediators.

RESULTS

This study included 435 patients, of whom 71.5% were men. The median age was 65 (interquartile range [IQR] 56-72) years, with a median NIH Stroke Scale of 14 (IQR 10-19). Patients in the tirofiban group had higher rates of functional independence at 90 days than patients in the placebo group (adjusted odds ratio 1.68; 95% CI 1.11-2.56, p = 0.02) without an increased risk of mortality or symptomatic intracranial hemorrhage. Tirofiban was associated with fewer thrombectomy passes (median [IQR] 1 [1-2] vs 1 [1-2], p = 0.004), which was an independent predictor of functional independence. Mediation analysis showed tirofiban-reduced thrombectomy passes explained 20.0% (95% CI 4.1%-76.0%) of the effect of tirofiban on functional independence.

DISCUSSION

In this post hoc analysis of the RESCUE BT trial, tirofiban was an effective and well-tolerated adjuvant medication of endovascular thrombectomy for patients with large vessel occlusion due to intracranial atherosclerosis. These findings need to be confirmed in future trials.

TRIAL REGISTRATION INFORMATION

The RESCUE BT trial was registered on the Chinese Clinical Trial Registry: chictr.org.cn, ChiCTR-INR-17014167.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that tirofiban plus endovascular therapy improves 90-day outcome for patients with large vessel occlusion due to intracranial atherosclerosis.

Antithrombotic therapies for neurointerventional surgery: a 2021 French comprehensive national survey

BACKGROUND

Neurointerventionists lack guidelines for the use of antithrombotic therapies in their clinical practice; consequently, there is likely to be significant heterogeneity in antithrombotic use between centers. Through a nationwide survey, we aimed to obtain an exhaustive cross-sectional overview of antithrombotic use in neurointerventional procedures in France.

METHODS

In April 2021, French neurointerventional surgery centers were invited to participate in a nationwide 51-question survey disseminated through an active trainee-led research collaborative network (the JENI-RC).

RESULTS

All 40 centers answered the survey. Fifty-one percent of centers reported using ticagrelor and 43% used clopidogrel as premedication before intracranial stenting. For flow diversion treatment, dual antiplatelet therapy was maintained for 3 or 6 months in 39% and 53% of centers, respectively, and aspirin was prescribed for 12 months or more than 12 months in 63% and 26% of centers, respectively. For unruptured aneurysms, the most common heparin bolus dose was 50 IU/kg (59%), and only 35% of centers monitored heparin activity for dose adjustment. Tirofiban was used in 64% of centers to treat thromboembolic complications. Fifteen percent of these comprehensive stroke centers reported using tenecteplase to treat acute ischemic strokes. Cangrelor appeared as an emergent drug in specific indications.

CONCLUSION

This nationwide survey highlights the important heterogeneity in clinical practices across centers. There is a pressing need for trials and guidelines to further evaluate and harmonize antithrombotic regimens in the neurointerventional field.

Effects of Antecedent Intravenous Thrombolysis on Endovascular Treatment of Acute Stroke Using Tirofiban

PURPOSE

To investigate whether preceding intravenous thrombolysis combined with tirofiban in patients with acute ischemic stroke undergoing endovascular treatment is safe and effective.

MATERIALS AND METHODS

Consecutive data were identified for patients who experienced acute ischemic stroke and were admitted to 2 comprehensive stroke centers from January 2015 to August 2021. All patients were divided into 2 groups-a thrombolytic with tirofiban group and a tirofiban-alone group-on the basis of whether intravenous thrombolysis before emergency endovascular angioplasty was used. Multivariate regression and propensity adjustment analyses were performed to characterize differences in safety and clinical outcomes between the 2 groups.

RESULTS

Of 373 eligible patients, 111 (29.7%) were treated with thrombolysis with tirofiban. There was a significant difference in the rate of any intracerebral hemorrhage (35.1% vs 24.8%; P = .04) but not in the rates of symptomatic intracerebral hemorrhage (16.2% vs 11.5%; P = .23) and reocclusion at 24 hours (5.4% vs 7.6%; P = .51) between the 2 groups. Multivariate regression analysis revealed that intravenous thrombolysis was not associated with any or symptomatic intracerebral hemorrhage, artery occlusion, functional outcome, or death at the 3-month follow-up (all adjusted P > .05). After propensity adjustment, the thrombolytic with tirofiban group showed nonsignificant rates of clinical and safety outcomes compared with those of the tirofiban-alone group (all P > .05).

CONCLUSIONS

Tirofiban may be used without increasing the risk of adverse events in selected patients who experienced ischemic stroke and were treated with intravenous thrombolysis and endovascular therapy.

Anaesthetic and peri-operative management for thrombectomy procedures in stroke patients

PURPOSE

To provide recommendations for the anaesthetic and peri-operative management for thrombectomy procedure in stroke patients DESIGN: A consensus committee of 15 experts issued from the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation, SFAR), the Association of French-language Neuro-Anaesthetists (Association des Neuro-Anesthésistes Réanimateurs de Langue Francaise, ANARLF), the French Neuro-Vascular Society (Société Francaise de Neuro-Vasculaire, SFNV), the French Neuro-Radiology Society (Société Francaise de Neuro-Radiologie, SFNR) and the French Study Group on Haemostasis and Thrombosis (Groupe Français d'Études sur l'Hémostase et la Thrombose, GFHT) was convened, under the supervision of two expert coordinators from the SFAR and the ANARLF. A formal conflict-of-interest policy was developed at the outset of the process and enforced throughout. The entire guideline elaboration process was conducted independently of any industry funding. The authors were required to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide their assessment of quality of evidence.

METHODS

Four fields were defined prior to the literature search: (1) Peri-procedural management, (2) Prevention and management of secondary brain injuries, (3) Management of antiplatelet and anticoagulant treatments, (4) Post-procedural management and orientation of the patient. Questions were formulated using the PICO format (Population, Intervention, Comparison, and Outcomes) and updated as needed. Analysis of the literature was then conducted and the recommendations were formulated according to the GRADE methodology.

RESULTS

The SFAR/ANARLF/SFNV/SFNR/GFHT guideline panel drew up 18 recommendations regarding anaesthetic management of mechanical thrombectomy procedures. Due to a lack of data in the literature allowing to conclude with high certainty on relevant clinical outcomes, the experts decided to formulate these guidelines as "Professional Practice Recommendations" (PPR) rather than "Formalized Expert Recommendations". After two rounds of rating and several amendments, a strong agreement was reached on 100% of the recommendations. No recommendation could be formulated for two questions.

CONCLUSIONS

Strong agreement among experts was reached to provide a sizable number of recommendations aimed at optimising anaesthetic management for thrombectomy in patients suffering from stroke.

Emergency Angioplasty or Stenting for Stroke Patients with Intracranial Atherosclerotic Large Vessel Occlusion

AIM

Mechanical thrombectomy (MT) has become the gold standard for the treatment of large vessel occlusion (LVO) in acute ischemic stroke. However, it remains controversial whether emergency angioplasty or stenting in patients with intracranial atherosclerotic stenosis (ICAS) should be adopted. Thus, we performed a retrospective analysis of clinical data to determine whether emergency angioplasty or stenting is necessary.

METHODS

We retrospectively analyzed data from patients undergoing MT with ICAS-related LVO of the acute anterior circulation between 2017 and 2019. Eligible patients were divided into two treatment groups: those who received rescue angioplasty or stenting [Patients treated with rescue angioplasty or stenting (PTAS) group] and those who received thrombectomy alone (non-PTAS group). The primary outcomes were good prognosis at 90 days (mRS: 0-2). Mortality, symptomatic intracranial hemorrhage, and reocclusion rate were evaluated as secondary outcomes.

RESULTS

A total of 184 patients with severe stenosis after MT were enrolled, including 64 patients receiving rescue angioplasty or stenting and 120 patients without rescue angioplasty or stenting. Compared with the non-PTAS group, a better functional outcome (mRS0-2) (51.6% vs. 35.0%, adjusted odds ratio: 2.11, 95% confidence interval [CI]: 1.22-4.29; P=0.02), lower 7-day National Institutes of Health Stroke Scale [6 (3-12.75) vs. 10 (4-16); P=0.04], lower 24-h neurological deterioration rate (7.8% vs. 21.7%, P=0.02), and lower 24-h reocclusion rate were observed in the PTAS group (6.3% vs. 17.5%, P=0.03). There were no significant differences in mortality or incidence of symptomatic intracerebral hemorrhage.

CONCLUSION

Emergency angioplasty or stenting could be a safe and feasible therapeutic option with better outcomes for stroke patients with ICAS-related LVO.

Balloon Angioplasty Combined with Tirofiban as a First-Line Rescue Treatment After Failed Mechanical Thrombectomy for Middle Cerebral Artery Occlusion with Underlying Atherosclerosis

OBJECTIVE

The standard rescue modality for patients with intracranial atherosclerotic stenosis after failed mechanical thrombectomy (MT) is not well established. We evaluated the safety and efficacy of balloon dilation in combination with tirofiban as the first-line salvage therapy when MT failed in these patients.

METHODS

We retrospectively analyzed the records of 47 patients admitted between January 2018 and June 2021, with middle cerebral artery atherosclerotic occlusion, who underwent balloon angioplasty in combination with tirofiban as the first-line salvage therapy after the failure of MT. The recanalization outcome, procedure-related complications, symptomatic intracranial hemorrhage, and functional outcome at 90 days were reviewed.

RESULTS

Recanalization with a modified Thrombolysis in Cerebral Infarction grade of 2b-3 was achieved in 41 (87.2%) of the 47 patients. Acute stents were deployed in another 6 patients who did not achieve successful re-perfusion after balloon angioplasty. Successful recanalization was achieved in 3 of them. One patient (2.1%, 1/47) experienced re-occlusion several days later due to the withdrawal of antiplatelet therapy for parenchymal hematoma. Seven patients (14.9%, 7/47) underwent stent angioplasty in the stable stage (range: 1-2 months) because severe residual stenosis was detected on follow-up imaging. There was only one event of periprocedural complication, namely ectopic migration of emboli. The good functional outcome rate was 55.3% (26/47), without the events of symptomatic intracranial hemorrhage and mortality.

CONCLUSIONS

Balloon angioplasty in combination with tirofiban is safe and effective for middle cerebral artery atherosclerotic occlusion after the failure of MT.

Endovascular Recanalization for Acute Internal Carotid Artery Terminus Occlusion: A Subgroup Analysis From the Direct-MT Trial

BACKGROUND

The efficacy of endovascular recanalization for internal carotid artery (ICA) terminus occlusion has not been completely evaluated.

OBJECTIVE

To investigate the efficacy of endovascular recanalization for ICA terminus occlusion.

METHODS

Data from Direct-MT, a randomized controlled trial, were applied. ICA terminus occlusions were diagnosed with preprocedure computed tomography angiography by the core laboratory. We dichotomized the ICA terminus occlusions into 2 groups (non-T and T) and analyzed the differences between them. Single-factor analysis and multiple logistic regression were applied to detect independent factors for clinical outcomes and futile recanalization.

RESULTS

The rates of first-pass effect, successful recanalization, good clinical outcome, mortality, and futile recanalization were 22.3% (50 of 224), 83.0% (181 of 224), 24.6% (55 of 224), 26.7% (60 of 224), and 69.6% (126 of 181), respectively. Baseline National Institutes of Health Stroke Scale (negative factor; odds ratio [OR] 0.89; 95% CI 0.84-0.95; P &lt; .001), hypertension (negative factor; OR 0.38; 95% CI 0.18-0.80; P = .010), Alberta Stroke Program Early CT Score ≥ 6 (OR 3.68; 95% CI 1.29-10.5; P = .014), tirofiban use (OR 2.46; 95% CI 1.16-5.19; P = .018), first-pass effect (OR 2.87; 95% CI 1.28-6.41; P = .010), and final extended thrombolysis in cerebral infarction ≥ 2b (OR, 3.50; 95% CI 1.17-10.4; P = .024) were independent factors for good clinical outcome. Baseline National Institutes of Health Stroke Scale (OR 1.12; 95% CI 1.05-1.20; P = .004), Alberta Stroke Program Early CT Score &lt; 6 (OR 4.68; 95% CI 1.51-14.5; P = .007), tirofiban use (negative factor; OR 0.39; 95% CI 0.18-0.86; P = .020), and first-pass effect (negative factor; OR 0.44; 95% CI 0.19-0.99; P = .047) were independent factors for futile recanalization.

CONCLUSION

More efforts in modifiable factors should be made to improve the efficacy of endovascular recanalization for better clinical outcomes and less futile recanalization in ICA terminus occlusions.

European Stroke Organisation guidelines on treatment of patients with intracranial atherosclerotic disease

The aim of the present European Stroke Organisation guideline is to provide clinically useful evidence-based recommendations on the management of patients with intracranial atherosclerotic disease (ICAD). The guidelines were prepared following the Standard Operational Procedure of the European Stroke Organisation guidelines and according to GRADE methodology. ICAD represents a major cause of ischemic stroke worldwide, and patients affected by this condition are exposed to a high risk for future strokes and other major cardiovascular events, despite best medical therapy available. We identified 11 relevant clinical problems affecting ICAD patients and formulated the corresponding Population Intervention Comparator Outcomes (PICO) questions. The first two questions refer to the asymptomatic stage of the disease, which is being increasingly detected thanks to the routine use of noninvasive vascular imaging. We were not able to provide evidence-based recommendations regarding the optimal detection strategy and management of asymptomatic ICAD, and further research in the field is encouraged as subclinical ICAD may represent a big opportunity to improve primary stroke prevention. The second block of PICOs (3-5) is dedicated to the management of acute large vessel occlusion (LVO) ischemic stroke caused by ICAD, a clinical presentation of this disease that is becoming increasingly relevant and problematic, since it is associated with more refractory endovascular reperfusion procedures. An operational definition of probable ICAD-related LVO is proposed in the guideline. Despite the challenging context, no dedicated randomized clinical trials (RCTs) were identified, and therefore the guideline can only provide with suggestions derived from observational studies and our expert consensus, such as the escalated use of glycoprotein IIb-IIIa inhibitors and angioplasty/stenting in cases of refractory thrombectomies due to underlying ICAD. The last block of PICOs is devoted to the secondary prevention of patients with symptomatic ICAD. Moderate-level evidence was found to recommend against the use of oral anticoagulation as preferred antithrombotic drug, in favor of antiplatelets. Low-level evidence based our recommendation in favor of double antiplatelet as the antithrombotic treatment of choice in symptomatic ICAD patients, which we suggest to maintain during 90 days as per our expert consensus. Endovascular therapy with intracranial angioplasty and or stenting is not recommended as a treatment of first choice in high-grade symptomatic ICAD (moderate-level evidence). Regarding neurosurgical interventions, the available evidence does not support their use as front line therapies in patients with high-grade ICAD. There is not enough evidence as to provide any specific recommendation regarding the use of remote ischemic conditioning in ICAD patients, and further RCTs are needed to shed light on the utility of this promising therapy. Finally, we dedicate the last PICO to the importance of aggressive vascular risk factor management in ICAD, although the evidence derived from RCTs specifically addressing this question is still scarce.

Long-Term Outcomes of Local Tirofiban Infusion for Intracranial Atherosclerosis-Related Occlusion

Local tirofiban infusion has been reported as a rescue strategy for intracranial atherosclerotic stenosis (ICAS)-related stroke. However, the long-term outcomes of local tirofiban infusion during endovascular reperfusion therapy (ERT) for ICAS-related stroke are still uncertain. This study aimed to investigate the long-term outcomes of local tirofiban infusion during ERT. We retrospectively analyzed acute patients with ICAS-related stroke who were treated with local tirofiban as a rescue strategy during ERT. The primary outcomes were ischemic stroke, transient ischemic stroke (TIA), and stroke-related death within 30 days. Secondary outcomes included ischemic stroke and TIA beyond 30 days and up to 2 years after ERT in the corresponding treated vessel, symptomatic brain hemorrhage, any stroke, and non-stroke-related death. During a median follow-up of 24.0 months, 12 patients developed an ischemic stroke and TIA (4 within 30 days and 8 afterward). The 1-year risk of stroke and TIA was 9.2% (95% confidence interval, 8.0–18.6%). This study demonstrates that 1-year outcomes of local tirofiban infusion were comparable to the results of intracranial stenting in patients with symptomatic ICAS. Local tirofiban infusion for ICAS-related stroke may be a feasible rescue strategy that can have a bridging role until the maximum effect of antiplatelet agents is achieved.

Efficacy and Safety of Tirofiban in Clinical Patients With Acute Ischemic Stroke

Background

Intravenous thrombolysis and endovascular thrombectomy have been approved for acute ischemic stroke (AIS). However, only a minority of patients received these treatments in China. We aimed to evaluate the efficacy and safety of tirofiban in patients with AIS who were not undergoing early recanalization treatments.

Methods

Patients with mild-to-moderate stroke [National Institutes of Health Stroke Scale (NIHSS) score, 4–15] were enrolled in this study. Patients due to cardiogenic embolism were excluded. Eligible patients within 12 h from symptom onset were randomly assigned (1:1) to receive tirofiban (a loading dose of 0.4 μg/kg/min over 30 min and a maintenance dose of 0.1 μg/kg/min up to 48 h) followed by regular treatment or to receive regular treatment (aspirin at a dose of 100 mg per day for 90 days) (control). The primary outcome was the proportion of favorable functional outcomes at 90 days [defined as the modified Rankin Scale (mRS) score of 0–2]. The secondary outcomes included a shift in the distribution of the mRS scores at 90 days and the NIHSS score at 24 h and 7 days. The primary safety outcome was symptomatic intracranial hemorrhage (sICH) within 7 days after tirofiban treatment.

Results

A total of 380 eligible patients were randomly assigned to the tirofiban group (n = 190) or the control group (n = 190). The proportion of favorable functional outcomes was higher in the tirofiban group (79.1%) than that in the control group (67.8%) at 90 days [odds ratio (OR), 1.80; 95% CI, 1.12–2.90; p = 0.0155]. An improvement was also observed in the overall distribution of the 90-day mRS scores (adjusted common OR, 2.31; 95% CI, 1.58–3.39; p < 0.0001). Additionally, the median NIHSS score was lower in the tirofiban group than in the control group at 7 days (3 vs. 5, p < 0.0001). Next, we observed that the occurrence of sICH did not differ between the two groups.

Conclusion

Our trial supports that tirofiban was safe and effective and might be a remedial treatment for patients with AIS who did not receive recanalization treatments.

Clinical Trial Registration

http://www.chictr.org.cn/, identifier: ChiCTR2000031297.

Endovascular Treatment of Large Vessel Occlusion Strokes Due to Intracranial Atherosclerotic Disease

Mechanical thrombectomy (MT) has become the gold-standard for patients with acute large vessel occlusion strokes (LVOS). MT is highly effective in the treatment of embolic occlusions; however, underlying intracranial atherosclerotic disease (ICAD) represents a therapeutic challenge, often requiring pharmacological and/or mechanical rescue treatment. Glycoprotein IIb/IIIa inhibitors have been suggested as the best initial approach, if reperfusion can be achieved after thrombectomy, with angioplasty and/or stenting being reserved for the more refractory cases. In this review, we focus on the therapeutic considerations surrounding the endovascular treatment of ICAD-related acute LVOS.

2022 Update of the Korean Clinical Practice Guidelines for Stroke: Antithrombotic Therapy for Patients with Acute Ischemic Stroke or Transient Ischemic Attack

Antithrombotic therapy is a cornerstone of acute ischemic stroke (AIS) management and secondary stroke prevention. Since the first version of the Korean Clinical Practice Guideline (CPG) for stroke was issued in 2009, significant progress has been made in antithrombotic therapy for patients with AIS, including dual antiplatelet therapy in acute minor ischemic stroke or high-risk transient ischemic stroke and early oral anticoagulation in AIS with atrial fibrillation. The evidence is widely accepted by stroke experts and has changed clinical practice. Accordingly, the CPG Committee of the Korean Stroke Society (KSS) decided to update the Korean Stroke CPG for antithrombotic therapy for AIS. The writing members of the CPG committee of the KSS reviewed recent evidence, including clinical trials and relevant literature, and revised recommendations. A total of 35 experts were invited from the KSS to reach a consensus on the revised recommendations. The current guideline update aims to assist healthcare providers in making well-informed decisions and improving the quality of acute stroke care. However, the ultimate treatment decision should be made using a holistic approach, considering the specific medical conditions of individual patients.

Can Tirofiban Improve the Outcome of Patients With Acute Ischemic Stroke: A Propensity Score Matching Analysis

Objective: To evaluate the efficacy and safety of tirofiban for patients with acute ischemic stroke (AIS), especially posterior circulation stroke (PCS).

Methods: We enrolled consecutive patients with AIS who suffered large artery occlusion (LAO) and underwent mechanical thrombectomy (MT) between January 2016 and May 2020. Patients were divided into two groups according to whether tirofiban was used during MT. The primary efficacy outcome was a favorable functional outcome, defined as a modified Rankin Scale (mRS) score of 0–2 at 3 months. The safety outcomes were the rate of mortality at 3 months and the presence of intracranial hemorrhage (ICH) and symptomatic intracranial hemorrhage (sICH). Cohorts were balanced using 1:1 propensity score matching (PSM). Subgroup analysis was further performed to compare the efficacy and safety of tirofiban between the anterior circulation stroke (ACS) and PCS groups.

Results: A total of 292 patients were eligible for this study and divided into the tirofiban group (n = 51) and the no-tirofiban group (n = 241). In the propensity-score-matched cohort, the tirofiban group had a higher rate of favorable outcomes than the no-tirofiban group (49.0 vs. 25.5%, p = 0.014), and the mortality at 3 months showed a greater downward trend in the tirofiban group than the no-tirofiban group (15.6 vs. 33.3% p = 0.064). The risk of sICH and ICH was the same between the tirofiban and control groups (17.6 vs. 27.4% p = 0.236, 31.3 vs. 45.1% p = 0.154, respectively). Tirofiban use was predictive of favorable outcomes [adjusted odds ratio (aOR) = 2.87, 95% confidence interval (CI) 1.52–6.44, p = 0.043] after multiple logistic regression analysis. Subgroup analysis revealed that tirofiban use was significantly associated with favorable outcomes in ACS (aOR = 3.66, 95% CI 1.24–5.22, p = 0.019) but not in PCS (aOR = 1.12, 95% CI 0.47–7.52, p = 0.570).

Conclusion: We demonstrated that tirofiban may be associated with improving favorable outcome for the AIS patients who underwent MT, without increasing ICH or sICH. Furthermore, our results indicated that for PCS patients tirofiban may not be associated with favorable outcome, and more comprehensive randomized controlled trials are needed to confirm this finding.

The Safety of Intra-arterial Tirofiban during Endovascular Therapy after Intravenous Thrombolysis

BACKGROUND AND PURPOSE

The safety and efficacy of tirofiban during endovascular therapy in patients undergoing intravenous thrombolysis with recombinant IV tPA remain unclear. This study aimed to investigate the safety and efficacy of intra-arterial tirofiban use during endovascular therapy in patients treated with IV tPA.

MATERIALS AND METHODS

Using a multicenter registry, we enrolled patients with acute ischemic stroke who underwent endovascular therapy. Safety outcomes included postprocedural parenchymal hematoma type 2 and/or thick subarachnoid hemorrhage, intraventricular hemorrhage, and 3-month mortality. Efficacy outcomes included the successful reperfusion rate, postprocedural reocclusion, and good outcomes at 3 months (mRS scores of 0-2). The tirofiban effect on the outcomes was evaluated using a multivariable analysis while adjusting for potential confounders.

RESULTS

Among enrolled patients, we identified 314 patients with stroke (279 and 35 patients in the no tirofiban and tirofiban groups, respectively) due to an intracranial artery occlusion who underwent endovascular therapy with intravenous thrombolysis. A multivariable analysis revealed no association of intra-arterial tirofiban with postprocedural parenchymal hematoma type and/or thick subarachnoid hemorrhage (adjusted OR, 1.07; 95% CI, 0.20-4.10; P = .918), intraventricular hemorrhage (adjusted OR, 0.43; 95% CI, 0.02-2.85; P = .467), and 3-month mortality (adjusted OR, 0.38; 95% CI, 0.04-1.87; P = .299). Intra-arterial tirofiban was not associated with good outcome (adjusted OR, 2.22; 95% CI, 0.89 -6.12; P = .099).

CONCLUSIONS

Using intra-arterial tirofiban during endovascular therapy after IV tPA could be safe.

Low-dose tirofiban is associated with reduced in-hospital mortality in cardioembolic stroke patients treated with endovascular thrombectomy

BACKGROUND AND PURPOSE

Whether tirofiban is safe and effective in cardioembolic stroke patients treated with endovascular thrombectomy (EVT) remains unknown; this study evaluated the safety and efficacy of low-dose tirofiban in this patients population.

METHODS

This study was a prospective registry study. Patients with cardioembolic stroke undergoing EVT from January 2013 to December 2020 were treated with EVT alone or EVT plus low-dose tirofiban. The primary outcome was symptomatic intracerebral hemorrhage (sICH) prior to discharge. The secondary outcomes included reocclusion, in-hospital mortality, and 3-month functional outcomes.

RESULTS

Overall, 288 patients were recruited and 117 received low-dose tirofiban; 137 patients (47.6%) experienced ICH, 42 patients (14.6%) were sICH, and 23 patients (8%) were fatal ICH. Thirteen patients (11.1%) receiving tirofiban and 29 patients (17.0%) not receiving tirofiban experienced sICH (p = 0.167). Reocclusion occurred in nine patients (7.7%) receiving tirofiban and 15 patients (8.8%) not receiving tirofiban (p = 0.745). The rates of hernia (6.8% versus 20.5%) and decompressive craniectomy (2.6% versus 11.7%) were significantly lower in patients receiving tirofiban (p < 0.01). At 3-month follow-up, functional independence was achieved in 39 patients(33.3%) receiving tirofiban and 43 patients (25.1%) not receiving tirofiban (p = 0.131). Tirofiban was associated with lower odds of in-hospital mortality (3.4% versus 12.3%; adjusted odds ratio, 0.16; 95% confidence interval, 0.03-0.81; adjusted p = 0.027).

CONCLUSIONS

In patients with cardioembolic stroke undergoing EVT, tirofiban is not associated with higher sICH, it seems to lead to lower odds of in-hospital death. Further investigations are needed to confirm these results and to determine the optimal treatment protocols of tirofiban.

Factors Contributing to an Efficacious Endovascular Treatment for Acute Ischemic Stroke in Asian Population

Although randomized control trials about endovascular treatment (EVT) of emergent large vessel occlusion (LVO) have demonstrated the success of mechanical thrombectomy as the choice of treatment, a wide range of caveats remain unaddressed. Asian patients were rarely included in the trials, thereby raising the question of whether the treatment could be generalized. In addition, there remains a concern on the feasibility of the method with respect to its application against intracranial atherosclerosis (ICAS)-related LVO, frequently observed in the Asian population. It is important to include evidence on ICAS LVO from Asian countries in the future for a comprehensive understanding of LVO etiology. Besides the issues with EVT, prognostic concerns in diabetes patients, acute kidney injury following EVT, neuroprotective management against reperfusion injury, and other peri-EVT issues should be considered in clinical practice. In the current article, we present an in-depth review of the literature that revises information pertaining to such concerns.

Etiological Approach to Understanding Recanalization Failure in Intracranial Large Vessel Occlusion and Thrombectomy: Close to Embolism but Distant From Atherosclerosis

Introduction: In patients with intracranial large vessel occlusion (LVO) who undergo endovascular treatment (EVT), recanalization failure may be related to intracranial atherosclerotic stenosis (ICAS). We evaluated whether the risk factors of recanalization failure could possibly be a marker of ICAS among various types of LVO.

Methods: From a multicenter registry, patients with middle cerebral artery M1 segment occlusions who underwent thrombectomy within 24 h were included. Based on the on-procedure and post-procedure angiographic findings, patients were classified into embolic, ICAS-related, tandem occlusion, and recanalization failure groups. Recanalization failure was defined if the occluded vessel could not be recanalized by stent retrieval, contact aspiration, or local lytics treatment. Risk factors, imaging markers, and EVT methods were compared between groups.

Results: Among 326 patients, 214 were classified as embolism, 76 as ICAS, 16 as tandem, and 20 as recanalization failure. The group with recanalization failure showed higher scores on the National Institutes of Health Stroke Scale (NIHSS) (median, 16.0 vs. 14.5 vs. 14.0 vs. 17.0, p = 0.097), frequent atrial fibrillation (59.3 vs. 18.4 vs. 0 vs. 40.0% p < 0.001), and elevation in erythrocyte sedimentation rate (ESR) (14.5 ± 15.7 vs. 15.0 ± 14.1 vs. 21.2 ± 19.5 vs. 36.0 ± 32.9, p < 0.001) among the groups. The rate of computed tomography angiography-based truncal-type occlusion in recanalization failure group was not as high as that in the ICAS group (8.1 vs. 37.5 vs. 0 vs. 16.7%, p < 0.001). Balloon guide catheters (BGC) were less frequently utilized in the recanalization failure group as compared to their use in the other groups (72.0 vs. 72.4 vs. 62.5 vs. 30.0%, p = 0.001). In the multivariable analysis, initial higher NIHSS [odds ratio (OR), 1.11 95% confidence interval (CI), 1.01–1.22 p = 0.027], higher ESR (OR, 1.03 CI, 1.01–1.05 p = 0.006), and non-use of BGCs (OR, 3.41 CI, 1.14–10.17 p = 0.028) were associated with recanalization failure. In M1 occlusions, the predominant mechanism of recanalization failure was presumed to be embolic in 80% and due to ICAS in 20%.

Conclusion: The analysis of recanalization failures does not suggest an underlying predominant ICAS mechanism. Sufficient utilization of thrombectomy devices and procedures may improve the rates of recanalization.

Prediction of Infarct Growth and Neurological Deterioration in Patients with Vertebrobasilar Artery Occlusions

We aimed to identify predictors of infarct growth and neurological deterioration (ND) in vertebrobasilar occlusions (VBOs) with a focus on clinical-core mismatch. From 2010 to 2018, VBO patients were selected from a university hospital registry. In total, 138 VBO patients were included. In these patients, a posterior circulation Alberta Stroke Program Early CT score (PC-ASPECTS) less than 6 was associated with futile outcome. Within patients with feasible cores, a decrease in PC-ASPECTS score of 2 or more on follow-up imaging was classified as infarct growth and could be predicted by a National Institutes of Health Stroke Scale (NIHSS) mental status subset of 1 or higher (odds ratio (OR): 3.34, 95% confidence interval (CI) (1.19-9.38), p = 0.022). Among the 73 patients who did not undergo reperfusion therapy, 13 patients experienced ND (increase in discharge NIHSS score of 4 or more compared to the initial presentation). Incomplete occlusion (vs. complete occlusion, OR 6.17, 95% CI (1.11-34.25), p = 0.037), poorer collateral status (BATMAN score, OR: 1.91, 95% CI (1.17-3.48), p = 0.009), and larger infarct cores (PC-ASPECTS, OR: 1.96, 95% CI (1.11-3.48), p = 0.021) were predictive of ND. In patients with VBO, an initial PC-ASPECTS of 6 or more, but with a decrease in the mental status subset of 1 or more can predict infarct growth, and may be used as a criterion for clinical-core mismatch. ND in VBO patients presenting with milder symptoms can be predicted by incomplete occlusion, poor collaterals, and larger infarct cores.