Prevalence and Significance of Impaired Microvascular Tissue Reperfusion Despite Macrovascular Angiographic Reperfusion (No-Reflow)

The benefit of favorable venous outflow profile is mediated through reduced microvascular dysfunction in acute ischemic stroke

INTRODUCTIONS

Venous outflow (VO) is emerging as a marker of microvascular integrity in acute ischemic stroke. Using hemorrhagic transformation (HT) and infarct growth as mediators, we tested whether a favorable VO profile benefited functional outcome by reducing consequences of microvascular dysfunction.

PATIENTS AND METHODS

Patients receiving thrombectomy in three comprehensive stroke centers due to acute anterior circulation occlusion were included. VO was assessed semi-quantitatively by the opacification of ipsilateral vein of Labbé, Trolard and superficial middle cerebral vein. HT was graded on follow-up CT. Infarct growth volume (IGV) was the difference of final infarct volume and baseline core volume. The association of VO and functional independence (90-day modified Rankin Scale ⩽ 2) was examined by logistic regression. Mediation analysis was performed among VO, HT or IGV, and functional outcome in patients with or without recanalization, respectively.

RESULTS

In 242 patients analyzed, VO was strongly correlated with functional independence and VO ⩾ 4 was defined favorable. In 175 patients recanalized, favorable VO was associated with a reduced risk of HT (OR = 0.82, 95% CI 0.71-0.95, p = 0.008), which accounted for 13.1% of the association between VO and favorable outcome. In 67 patients without recanalization, favorable VO was associated with decreased IGV (β = -0.07, 95% CI -0.11 to -0.02, p = 0.007). The association of favorable VO and functional independence was no longer significant (aOR = 4.84, 95% CI 0.87-38.87, p = 0.089) after including IGV in the model, suggesting a complete mediation.

DISCUSSION AND CONCLUSION

In patients with acute anterior large vessel occlusion, the clinical benefit of VO may be mediated through reduced microvascular dysfunction.

No-reflow after recanalization in ischemic stroke: From pathomechanisms to therapeutic strategies

Endovascular reperfusion therapy is the primary strategy for acute ischemic stroke. No-reflow is a common phenomenon, which is defined as the failure of microcirculatory reperfusion despite clot removal by thrombolysis or mechanical embolization. It has been reported that up to 25% of ischemic strokes suffer from no-reflow, which strongly contributes to an increased risk of poor clinical outcomes. No-reflow is associated with functional and structural alterations of cerebrovascular microcirculation, and the injury to the microcirculation seriously hinders the neural functional recovery following macrovascular reperfusion. Accumulated evidence indicates that pathology of no-reflow is linked to adhesion, aggregation, and rolling of blood components along the endothelium, capillary stagnation with neutrophils, astrocytes end-feet, and endothelial cell edema, pericyte contraction, and vasoconstriction. Prevention or treatment strategies aim to alleviate or reverse these pathological changes, including targeted therapies such as cilostazol, adhesion molecule blocking antibodies, peroxisome proliferator-activated receptors (PPARs) activator, adenosine, pericyte regulators, as well as adjunctive therapies, such as extracorporeal counterpulsation, ischemic preconditioning, and alternative or complementary therapies. Herein, we provide an overview of pathomechanisms, predictive factors, diagnosis, and intervention strategies for no-reflow, and attempt to convey a new perspective on the clinical management of no-reflow post-ischemic stroke.

Early automated cerebral edema assessment following endovascular therapy: impact on stroke outcome

BACKGROUND

Cerebral edema (CED) is associated with poorer outcome in patients with acute ischemic stroke (AIS). The aim of the study was to investigate the factors contributing to greater early CED formation in patients with AIS who underwent endovascular therapy (EVT) and its association with functional outcome.

METHODS

We conducted a multicenter cohort study of patients with an anterior circulation AIS undergoing EVT. The volume of cerebrospinal fluid (CSF) was extracted from baseline and 24-hour follow-up CT using an automated algorithm. The severity of CED was quantified by the percentage reduction in CSF volume between CT scans (∆CSF). The primary endpoint was a shift towards an unfavorable outcome, assessed by modified Rankin Scale (mRS) score at 3 months. Multivariable ordinal logistic regression analyses were performed. The ∆CSF threshold that predicted unfavorable outcome was selected using receiver operating characteristic curve analysis.

RESULTS

We analyzed 201 patients (mean age 72.7 years, 47.8% women) in whom CED was assessable for 85.6%. Higher systolic blood pressure during EVT and failure to achieve modified Thrombolysis In Cerebral Infarction (mTICI) 3 were found to be independent predictors of greater CED. ∆CSF was independently associated with the probability of a one-point worsening in the mRS score (common odds ratio (cOR) 1.05, 95% CI 1.03 to 1.08) after adjusting for age, baseline mRS, National Institutes of Health Stroke Scale (NIHSS), and number of passes. Displacement of more than 25% of CSF was associated with an unfavorable outcome (OR 6.09, 95% CI 3.01 to 12.33) and mortality (OR 6.72, 95% CI 2.94 to 15.32).

CONCLUSIONS

Early CED formation in patients undergoing EVT was affected by higher blood pressure and incomplete reperfusion. The extent of early CED, measured by automated ∆CSF, was associated with worse outcomes.

Deviation From Personalized Blood Pressure Targets Correlates With Worse Outcome After Successful Recanalization

BACKGROUND

Personalized blood pressure (BP) management for patients with acute ischemic stroke after successful endovascular thrombectomy lacks evidence. We aimed to investigate whether the deviation of BP from cerebral autoregulation limits is associated with worse outcomes.

METHODS AND RESULTS

We determined autoregulation by measuring mean velocity index and calculated the percentage of time and the burden (defined as the time-BP area) with BP outside the autoregulatory limits of each subject within 48 hours after endovascular thrombectomy. In total, 91 patients with large vessel occlusion stroke who had achieved successful recanalization were prospectively enrolled between May 2020 and February 2022. The burden with BP outside the autoregulatory limits was associated with poor outcome (modified Rankin Scale score 3-6) at 90 days (adjusted odds ratio, 1.28 [95% CI, 1.03-1.59]). The percentage of time with BP out of the autoregulatory limits was correlated with early neurological deterioration (National Institute of Health Stroke Scale scores increased ≥2 at 7 days) (adjusted odds ratio, 1.38 [95% CI, 1.04-1.83]). The burden of BP that decreased below the autoregulatory lower limit was associated with significant infarct growth (volume of infarct growth >11.6 mL) at 7 days (adjusted odds ratio, 1.21 [95% CI, 1.01-1.44]). The percentage of time that BP exceeded the autoregulatory upper limit was associated with symptomatic intracranial hemorrhage within 48 hours (adjusted odds ratio, 1.55 [95% CI, 1.02-2.34]).

CONCLUSIONS

Both the percentage of time and the burden of BP that deviates from the autoregulation-preserved range are associated with unfavorable clinical outcomes. This study highlights the potential benefits of autoregulation-guided BP management strategy after successful recanalization.

Intravenous Thrombolysis before Complete Angiographic Reperfusion: Beyond Angiographic Assessment to Target Microvascular Obstruction?

OBJECTIVE

Recent data have suggested that ineffective tissue reperfusion despite successful angiographic reperfusion was partly responsible for unfavorable outcomes after endovascular therapy (EVT) and might be modulated by intravenous thrombolysis (IVT) use before EVT. To specifically decipher the effect played by IVT before EVT, we compared the clinical and safety outcomes of patients who experienced a complete reperfusion at the end of EVT according to IVT use before EVT.

METHODS

The Endovascular Treatment in Ischemic Stroke (ETIS) registry is an ongoing, prospective, observational study at 21 centers that perform EVT in France. Patients were included if they had an anterior large vessel occlusion of the intracranial internal carotid artery or middle cerebral artery (M1/M2 segments) and complete reperfusion (expanded Thrombolysis in Cerebral Infarction score = 3) with EVT within 6 hours, between January 2015 and December 2021. The cohort was divided into two groups according to IVT use before EVT, and propensity score matching (PSM) was used to balance the two groups. Primary outcome was the shift in the degree of disability as measured by the modified Rankin Scale (mRS) at 90 days. Secondary outcomes included favorable outcome (mRS 0-2) at 90 days. Safety outcomes included symptomatic intracranial hemorrhage and 90-day mortality. Outcomes were estimated with multivariate logistic models adjusted for age, National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, and time from symptom onset to puncture.

RESULTS

Among 5,429 patients included in the ETIS registry, 1,093 were included in the study, including 651 patients with complete recanalization treated with IVT before EVT. After PSM, 488 patients treated with IVT before EVT were compared to 337 patients without IVT. In the matched cohort analysis, the IVT+EVT group had a favorable shift in the overall mRS score distribution (adjusted odds ratio [aOR] = 1.41, 95% confidence interval [CI] = 1.04-1.91, p = 0.023) and higher rates of favorable outcome (61.1% vs 48.7%, aOR = 1.49, 95% CI = 1.02-2.20, p = 0.041) at 90 days compared with the EVT alone group. Rates of symptomatic intracerebral hemorrhage were comparable between both groups (6.0% vs 4.3%, aOR = 1.16, 95% CI = 0.53-2.54, p = 0.709).

INTERPRETATION

In clinical practice, even after complete angiographic reperfusion by EVT, prior IVT use improves clinical outcomes of patients without increasing bleeding risk. ANN NEUROL 2024;95:762-773.

Evolution pattern estimated by computed tomography perfusion post-thrombectomy predicts outcome in acute ischemic stroke

OBJECTIVES

Computed tomography perfusion (CTP) and computed tomography angiography (CTA) have been recommended to select acute ischemic stroke (AIS) patients for endovascular thrombectomy (EVT) but are not widely used for post-treatment evaluation. We aimed to observe abnormalities in CTP and CTA before and after EVT and evaluate post-EVT CTP and CTA as potential tools for improving clinical outcome prediction.

METHODS

Patients with AIS who underwent EVT and received CTP and CTA before and after EVT were retrospectively evaluated. The ischemic core was defined as the volume of relative cerebral blood flow <30% and hypoperfusion as the volume of Tmax >6 s. A reduction in hypoperfusion volume >90% between baseline and post-EVT CTP was defined as tissue optimal reperfusion (TOR). The 90-day modified Rankin scale was used to evaluate the clinical outcome.

RESULTS

Eighty-three patients were included. Patients with an absent ischemic core or with TOR after EVT had a higher rate of modified Thrombolysis in Cerebral Ischemia score 2c-3 and recanalization of post-treatment vessel condition based on follow-up CTA. Multivariable logistic regression revealed that the baseline ischemic core volume (OR:0.934, p=0.009), TOR (OR:8.322, p=0.029) and immediate NIHSS score after EVT (OR:0.761, p=0.012) were factors significantly associated with good clinical outcome. Combining baseline ischemic core volume and TOR with immediate NIHSS score after EVT showed greatest performance for good outcome prediction after EVT(AUC=0.921).

CONCLUSIONS

The addition of pretreatment and post-treatment CTP information to purely clinical NIHSS scores might help to improve the efficacy for good outcome prediction after EVT.

Shexiang Tongxin dropping pills protect against ischemic stroke-induced cerebral microvascular dysfunction via suppressing TXNIP/NLRP3 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Patients with ischemic stroke (IS) often continue to exhibit cerebral microcirculatory dysfunction even after receiving thrombolytic therapy. Enhancing the function of cerebral microvascular endothelia represents a pivotal advancement in the therapeutic strategy for ischemic microcirculatory disturbances. A traditional Chinese medicinal formulation named Shexiang Tongxin Dropping Pills (STDP), has been clinically employed to ameliorate microcirculatory abnormalities. Existing literature attests to the beneficial role of STDP on endothelial cells (ECs). Nevertheless, specific impacts and underlying mechanisms of STDP in rectifying IS-induced cerebral microvascular dysfunction warrant further exploration.

AIM OF THE STUDY

This investigation seeks to delineate the effects of STDP on cerebral microvascular endothelial damage induced by ischemic stroke and to elucidate the underlying mechanism involved.

MATERIALS AND METHODS

Middle cerebral artery occlusion and reperfusion (MCAO/R) technique was employed to established ischemic stroke model in mice. The therapeutic efficacy of STDP on cerebral microvascular function was assessed through laser speckle contrast imaging, behavioral assays, and histological evaluations. Biochemical markers in the brain tissue, including GSH, SOD, MDA, and ROS, were quantified using specific assay kits. In vitro study, oxygen-glucose deprivation and reperfusion (OGD/R) was performed in bEnd.3 cells. The cytoprotective potential of STDP was then evaluated by measuring cell viability, LDH activity, endothelial permeability, and oxidative stress parameters. Important targets in critical pathway were verified by immunoblotting and immunofluorescence both in mice brain slices and bEnd.3 cells.

RESULTS

STDP decrease brain infarct size, repaired microvascular cerebral blood flow and attenuated neurological deficiency in MCAO/R mice. Moreover, STDP abolished MCAO/R-induced oxidative stress which was reflected by rescuing GSH content, restoration of SOD activity and T-AOC, reduction of MDA and ROS. Ex vivo, STDP increased cerebral microvascular endothelial cells viability, abolished oxidative stress and decreased their permeability after ODG/R. Mechanistically, STDP significantly suppressed endothelial ROS-TXNIP mediated the activation of NLRP3 inflammasome in vivo and in vitro.

CONCLUSION

STDP improves ischemic stroke-induced cerebral microcirculatory deficits by regulating cerebral microvascular endothelial ROS/TXNIP/NLRP3 signaling pathway.

Comparing Low- or Standard-Dose Alteplase in Endovascular Thrombectomy: Insights From a Nationwide Registry

BACKGROUND

Timely intravenous thrombolysis and endovascular thrombectomy are the standard reperfusion treatments for large vessel occlusion stroke. Currently, it is unknown whether a low-dose thrombolytic agent (0.6 mg/kg alteplase) can offer similar efficacy to the standard dose (0.9 mg/kg alteplase).

METHODS

We enrolled consecutive patients in the multicenter Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke who had received combined thrombolysis (within 4.5 hours of onset) and thrombectomy treatment from January 2019 to April 2023. The choice of low- or standard-dose alteplase was based on the physician's discretion. The outcomes included successful reperfusion (modified Thrombolysis in Cerebral Infarction score, 2b-3), symptomatic intracerebral hemorrhage, 90-day modified Rankin Scale score, and 90-day mortality. The outcomes between the 2 groups were compared using multivariable logistic regression and inverse probability of treatment weighting-adjusted analysis.

RESULTS

Among the 2242 patients in the Taiwan Registry of Endovascular Thrombectomy for Acute Ischemic Stroke, 734 (33%) received intravenous alteplase. Patients in the low-dose group (n=360) were older, had more women, more atrial fibrillation, and longer onset-to-needle time compared with the standard-dose group (n=374). In comparison to low-dose alteplase, standard-dose alteplase was associated with a lower rate of successful reperfusion (81% versus 87%; adjusted odds ratio, 0.63 [95% CI, 0.40-0.98]), a numerically higher incidence of symptomatic intracerebral hemorrhage (6.7% versus 3.9%; adjusted odds ratio, 1.81 [95% CI, 0.88-3.69]), but better 90-day modified Rankin Scale score (functional independence [modified Rankin Scale score, 0-2], 47% versus 31%; adjusted odds ratio, 1.91 [95% CI, 1.28-2.86]), and a numerically lower mortality rate (9% versus 15%; adjusted odds ratio, 0.73 [95% CI, 0.43-1.25]) after adjusting for covariates. Similar results were observed in the inverse probability of treatment weighting-adjusted models. The results were consistent across predefined subgroups and age strata.

CONCLUSIONS

Despite the lower rate of successful reperfusion and higher risk of symptomatic intracerebral hemorrhage with standard-dose alteplase, standard-dose alteplase was associated with a better functional outcome in patients receiving combined thrombolysis and thrombectomy.

Value of Immediate Flat Panel Perfusion Imaging after Endovascular Therapy (AFTERMATH): A Proof of Concept Study

BACKGROUND AND PURPOSE

Potential utility of flat panel CT perfusion imaging (FPCT-PI) performed immediately after mechanical thrombectomy (MT) is unknown. We aimed to assess whether FPCT-PI obtained directly post-MT could provide additional potentially relevant information on tissue reperfusion status.

MATERIALS AND METHODS

This was a single-center analysis of all patients with consecutive acute stroke admitted between June 2019 and March 2021 who underwent MT and postinterventional FPCT-PI (n = 26). A core lab blinded to technical details and clinical data performed TICI grading on postinterventional DSA images and qualitatively assessed reperfusion on time-sensitive FPCT-PI maps. According to agreement between DSA and FPCT-PI, all patients were classified into 4 groups: hypoperfusion findings perfectly matched by location (group 1), hypoperfusion findings mismatched by location (group 2), complete reperfusion on DSA with hypoperfusion on FPCT-PI (group 3), and hypoperfusion on DSA with complete reperfusion on FPCT-PI (group 4).

RESULTS

Detection of hypoperfusion (present/absent) concurred in 21/26 patients. Of these, reperfusion findings showed perfect agreement on location and size in 16 patients (group 1), while in 5 patients there was a mismatch by location (group 2). Of the remaining 5 patients with disagreement regarding the presence or absence of hypoperfusion, 3 were classified into group 3 and 2 into group 4. FPCT-PI findings could have avoided TICI overestimation in all false-positive operator-rated TICI 3 cases (10/26).

CONCLUSIONS

FPCT-PI may provide additional clinically relevant information in a considerable proportion of patients undergoing MT. Hence, FPCT-PI may complement the evaluation of reperfusion efficacy and potentially inform decision-making in the angiography suite.

Systemic Immune-Inflammation Response is Associated with Futile Recanalization After Endovascular Treatment

BACKGROUND

Frequent incidence of futile recanalization decreases the benefit of endovascular treatment (EVT) in acute ischemic stroke. We hypothesized that the inflammation and immune response after ischemic are associated with futile recanalization. We aimed to investigate the correlation of admission systemic immune-inflammation index (SII) with futile recanalization post EVT.

METHODS

Patients with successful recanalization (modified Thrombolysis in Cerebral Ischemia angiographic score 2b-3) and maintained artery recanalized after 24 h of EVT were chosen from a prospective nationwide registry study. Futile recanalization was defined as a poor functional outcome (modified Rankin Scale score 3-6) at 90 days, irrespective of a successful recanalization. At admission, SII was calculated as (platelet count × neutrophil count)/lymphocyte count/100. Logistic regression analysis helped to test the relationship of SII with futile recanalization.

RESULTS

Among the 1,002 patients included, futile recanalization occurred in 508 (50.70%). No matter whether tested as quartiles or continuous variables, SII was significantly associated with futile recanalization (P < 0.05), and for every one standard deviation increase of SII, the risk of futile recanalization elevated by 22.3% (odds ratio 1.223, 95% confidence interval 1.053-1.444, P = 0.0093). Moreover, no significant interactions could be observed between SII or SII quartiles and age, baseline National Institutes of Health Stroke Scale scores, onset-to-recanalization time, and modified Thrombolysis in Cerebral Ischemia angiographic scores (all P for interaction > 0.05).

CONCLUSIONS

Early SII elevation was associated with an increased risk of futile recanalization among patients with EVT. Our results indicated that therapeutic drug targeting hyperreactive immune-inflammation response might be helpful for reducing the incidence of futile recanalization.

Hyperperfusion profiles after recanalization differentially associate with outcomes in a rat ischemic stroke model

Futile recanalization hampers prognoses of ischemic stroke after successful mechanical thrombectomy, hypothetically through post-recanalization perfusion deficits, onset-to-groin delays and sex effects. Clinically, acute multiparametric imaging studies remain challenging. We assessed possible relationships between these factors and disease outcome after experimental cerebral ischemia-reperfusion, using translational MRI, behavioral testing and multi-model inference analyses. Male and female rats (N = 60) were subjected to 45-/90-min filament-induced transient middle cerebral artery occlusion. Diffusion, T2- and perfusion-weighted MRI at occlusion, 0.5 h and four days after recanalization, enabled tracking of tissue fate, and relative regional cerebral blood flow (rrCBF) and -volume (rrCBV). Lesion areas were parcellated into core, salvageable tissue and delayed injury, verified by histology. Recanalization resulted in acute-to-subacute lesion volume reductions, most apparently in females (n = 19). Hyperacute normo-to-hyperperfusion in the post-ischemic lesion augmented towards day four, particularly in males (n = 23). Tissue suffering delayed injury contained higher ratios of hypoperfused voxels early after recanalization. Regressed against acute-to-subacute lesion volume change, increased rrCBF associated with lesion growth, but increased rrCBV with lesion reduction. Similar relationships were detected for behavioral outcome. Post-ischemic hyperperfusion may develop differentially in males and females, and can be beneficial or detrimental to disease outcome, depending on which perfusion parameter is used as explanatory variable.

Progressive microvascular failure in acute ischemic stroke: A systematic review, meta-analysis, and time-course analysis

This systematic review, meta-analysis, and novel time course analysis examines microvascular failure in the treatment of acute ischemic stroke (AIS) patients undergoing endovascular therapy (EVT) and/or thrombolytic administration for stroke management. A systematic review and meta-analysis following PRIMSA-2020 guidelines was conducted along with a novel curve-of-best fit analysis to elucidate the time-course of microvascular failure. Scopus and PubMed were searched using relevant keywords to identify studies that examine recanalization and reperfusion assessment of AIS patients following large vessel occlusion. Meta-analysis was conducted using a random-effects model. Curve-of-best-fit analysis of microvascular failure rate was performed with a negative exponential model. Twenty-seven studies with 1151 patients were included. Fourteen studies evaluated patients within a standard stroke onset-to-treatment time window (≤6 hours after last known normal) and thirteen studies had an extended time window (>6 hours). Our analysis yields a 22% event rate of microvascular failure following successful recanalization (95% CI: 16-30%). A negative exponential curve modeled a microvascular failure rate asymptote of 28.5% for standard time window studies, with no convergence of the model for extended time window studies. Progressive microvascular failure is a phenomenon that is increasingly identified in clinical studies of AIS patients undergoing revascularization treatment.

Implications of Post-recanalization Perfusion Deficit After Acute Ischemic Stroke: a Scoping Review of Clinical and Preclinical Imaging Studies

The goal of reperfusion therapy for acute ischemic stroke (AIS) is to restore cerebral blood flow through recanalization of the occluded vessel. Unfortunately, successful recanalization does not always result in favorable clinical outcome. Post-recanalization perfusion deficits (PRPDs), constituted by cerebral hypo- or hyperperfusion, may contribute to lagging patient recovery rates, but its clinical significance remains unclear. This scoping review provides an overview of clinical and preclinical findings on post-ischemic reperfusion, aiming to elucidate the pattern and consequences of PRPD from a translational perspective. The MEDLINE database was searched for quantitative clinical and preclinical studies of AIS reporting PRPD based on cerebral circulation parameters acquired by translational tomographic imaging methods. PRPD and stroke outcome were mapped on a charting table, creating an overview of PRPD after AIS. Twenty-two clinical and twenty-two preclinical studies were included. Post-recanalization hypoperfusion is rarely reported in clinical studies (4/22) but unequivocally associated with detrimental outcome. Post-recanalization hyperperfusion is more commonly reported (18/22 clinical studies) and may be associated with positive or negative outcome. PRPD has been replicated in animal studies, offering mechanistic insights into causes and consequences of PRPD and allowing delineation of possible courses of PRPD. Complex relationships exist between PRPD and stroke outcome. Diversity in methods and lack of standardized definitions in reperfusion studies complicate the characterization of reperfusion patterns. Recommendations are made to advance the understanding of PRPD mechanisms and to further disentangle the relation between PRPD and disease outcome.

Predictive role of neutrophil-to-platelet ratio in futile recanalization of patients after endovascular therapy

Aim: To explore the association between the neutrophil-to-platelet ratio (NPR) and futile recanalization (FR) in patients with acute ischemic stroke due to large vascular occlusions after endovascular therapy (EVT). Methods: FR after EVT was defined as a poor 90-day prognosis (modified Rankin scale [mRS] score ≥3) despite successful reperfusion (modified thrombolysis in cerebral infarction grade 2b-3). Patients were divided into high NPR (>35; n = 115) and low NPR (≤35; n = 81) groups. Results: The FR rate was significantly higher in the high NPR group than low NPR group (81.74 vs 55.56%; p = 0.000). NPR was independently associated with FR (odds ratio: 2.107; 95% CI: 1.017-4.364; p = 0.045). Conclusion: High NPR was associated with the risk of FR in patients with acute ischemic stroke due to large vascular occlusions.

Safety and efficacy of adjunctive intra-arterial antithrombotic therapy during endovascular thrombectomy for acute ischemic stroke: a systematic review and meta-analysis

BACKGROUND

Half of patients who achieve successful recanalization following endovascular thrombectomy (EVT) for acute ischemic stroke experience poor functional outcome. We aim to investigate whether the use of adjunctive intra-arterial antithrombotic therapy (AAT) during EVT is safe and efficacious compared with standard therapy (ST) of EVT with or without prior intravenous thrombolysis.

METHODS

Electronic databases were searched (PubMed/MEDLINE, Embase, Cochrane Library) from 2010 until October 2023. Data were pooled using a random-effects model and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Risk of bias was assessed using ROBINS-I and ROB-2. The primary outcome was functional independence (modified Rankin Scale (mRS) 0-2) at 3 months. Secondary outcomes were successful recanalization (modified Thrombolysis In Cerebral Infarction (TICI) 2b-3), symptomatic intracranial hemorrhage (sICH), and 90-day mortality.

RESULTS

41 randomized and non-randomized studies met the eligibility criteria. Overall, 15 316 patients were included; 3296 patients were treated with AAT during EVT and 12 020 were treated with ST alone. Compared with ST, patients treated with AAT demonstrated higher odds of functional independence (46.5% AAT vs 42.6% ST; OR 1.22, 95% CI 1.07 to 1.40, P=0.004, I2=48%) and a lower likelihood of 90-day mortality (OR 0.71, 95% CI 0.61 to 0.83, P<0.0001, I2=20%). The rates of sICH (OR 1.00, 95% CI 0.82 to 1.22,P=0.97, I2=13%) and successful recanalization (OR 1.09, 95% CI 0.84 to 1.42, P=0.52, I2=76%) were not significantly different.

CONCLUSION

The use of AAT during EVT may improve functional outcomes and reduce mortality rates compared with ST alone, without an increased risk of sICH. These findings should be interpreted with caution pending the results from ongoing phase III trials to establish the efficacy and safety of AAT during EVT.

No-reflow phenomenon in stroke patients: A systematic literature review and meta-analysis of clinical data

BACKGROUND

The no-reflow phenomenon refers to the absence of microvascular reperfusion despite macrovascular reperfusion.

AIM

The aim of this analysis was to summarize the available clinical evidence on no-reflow in patients with acute ischemic stroke.

METHODS

A systematic literature review and a meta-analysis of clinical data on definition, rates, and impact of the no-reflow phenomenon after reperfusion therapy was carried out. A predefined research strategy was formulated according to the Population, Intervention, Comparison, and Outcome (PICO) model and was used to screen for articles in PubMed, MEDLINE, and Embase up to 8 September 2022. Whenever possible, quantitative data were summarized using a random-effects model.

RESULTS

Thirteen studies with a total of 719 patients were included in the final analysis. Most studies (n = 10/13) used variations of the Thrombolysis in Cerebral Infarction scale to evaluate macrovascular reperfusion, whereas microvascular reperfusion and no-reflow were mostly assessed on perfusion maps (n = 9/13). In one-third of stroke patients with successful macrovascular reperfusion (29%, 95% confidence interval (CI), 21-37%), the no-reflow phenomenon was observed. Pooled analysis showed that no-reflow was consistently associated with reduced rates of functional independence (odds ratio (OR), 0.21, 95% CI, 0.15-0.31).

CONCLUSION

The definition of no-reflow varied substantially across studies, but it appears to be a common phenomenon. Some of the no-reflow cases may simply represent remaining vessel occlusions, and it remains unclear whether no-reflow is an epiphenomenon of the infarcted parenchyma or causes infarction. Future studies should focus on standardizing the definition of no-reflow with more consistent definitions of successful macrovascular reperfusion and experimental set-ups that could detect the causality of the observed findings.

Incidence, severity and impact on functional outcome of persistent hypoperfusion despite large-vessel recanalization, a potential marker of impaired microvascular reperfusion: Systematic review of the clinical literature

The reported incidence of persistent hypoperfusion despite complete recanalization as surrogate for impaired microvascular reperfusion (IMR) has varied widely among clinical studies, possibly due to differences in i) definition of complete recanalization, with only recent Thrombolysis in Cerebral Infarction (TICI) grading schemes allowing distinction between complete (TICI3) and partial recanalization with distal occlusions (TICI2c); ii) operational definition of IMR; and iii) consideration of potential alternative causes for hypoperfusion, notably carotid stenosis, re-occlusion and post-thrombectomy hemorrhage. We performed a systematic review to identify clinical studies that carried out brain perfusion imaging within 72 hrs post-thrombectomy for anterior circulation stroke and reported hypoperfusion rates separately for TICI3 and TICI2c grades. Authors were contacted if this data was missing. We identified eight eligible articles, altogether reporting 636 patients. The incidence of IMR after complete recanalization (i.e., TICI3) tended to decrease with the number of considered alternative causes of hypoperfusion: range 12.5-42.9%, 0-31.6% and 0-9.1% in articles that considered none, two or all three causes, respectively. No study reported the impact of IMR on functional outcome separately for TICI-3 patients. Based on this systematic review, IMR in true complete recanalization appears relatively rare, and reported incidence highly depends on definition used and consideration of confounding factors.

"No-reflow" phenomenon in acute ischemic stroke

Acute ischemic stroke (AIS) afflicts millions of individuals worldwide. Despite the advancements in thrombolysis and thrombectomy facilitating proximal large artery recanalization, the resultant distal hypoperfusion, referred to "no-reflow" phenomenon, often impedes the neurological function restoration in patients. Over half a century of scientific inquiry has validated the existence of cerebral "no-reflow" in both animal models and human subjects. Furthermore, the correlation between "no-reflow" and adverse clinical outcomes underscores the necessity to address this phenomenon as a pivotal strategy for enhancing AIS prognoses. The underlying mechanisms of "no-reflow" are multifaceted, encompassing the formation of microemboli, microvascular compression and contraction. Moreover, a myriad of complex mechanisms warrant further investigation. Insights gleaned from mechanistic exploration have prompted advancements in "no-reflow" treatment, including microthrombosis therapy, which has demonstrated clinical efficacy in improving patient prognoses. The stagnation in current "no-reflow" diagnostic methods imposes limitations on the timely application of combined therapy on "no-reflow" post-recanalization. This narrative review will traverse the historical journey of the "no-reflow" phenomenon, delve into its underpinnings in AIS, and elucidate potential therapeutic and diagnostic strategies. Our aim is to equip readers with a swift comprehension of the "no-reflow" phenomenon and highlight critical points for future research endeavors.

Compromised dynamic cerebral autoregulation is a hemodynamic marker for predicting poor prognosis even with good recanalization after endovascular thrombectomy

PURPOSE

In patients undergoing endovascular thrombectomy (EVT) with acute ischemic stroke (AIS), dynamic cerebral autoregulation (dCA) may minimize neurological injury from blood pressure fluctuations. This study set out to investigate the function of dCA in predicting clinical outcomes following EVT.

METHODS

43 AIS of the middle cerebral or internal carotid artery patients underwent with EVT, and 43 healthy individuals (controls) were enrolled in this case control research. The dCA was evaluated using transcranial Doppler 12 h and five days after EVT. The transfer function analysis was used to derive the dCA parameters, such as phase, gain, and coherence. The modified Rankin scale (mRS) at 3 months after EVT was used to assess the clinical outcomes. Thefavorable outcome group was defined with mRS ≤2 and the unfavorable outcome group was defined with mRS score of 3-6. Logistic regression analysis was performed to determine the risk factors of clinical outcomes.

RESULTS

A significant impairment in dCA was observed on the ipsilateral side after EVT, particularly in patients with unfavorable outcomes. After 5 days, the ipsilateral phase was associated with poor functional outcomes (adjusted odds ratio [OR] = 0.911, 95% confidence interval [CI]: 0.854-0.972; P = 0.005) and the area under the curve (AUC) (AUC, 0.878, [95% CI: 0.756-1.000] P < 0.001) (optimal cutoff, 35.0°). Phase change was an independent predictor of clinical outcomes from 12 h to 5 days after EVT (adjusted OR = 1.061, 95% CI: 1.016-1.109, P = 0.008).

CONCLUSIONS

dCA is impaired in patients with AIS after EVT. Change in dCA could be an independent factor related to the clinical outcomes.

Postoperative fibrinogen-to-albumin ratio acting as an indicator of futile recanalization in patients with successful thrombectomy

BACKGROUND

Timely recognition of futile recanalization might enable a prompter response and thus improve outcomes in patients receiving successful thrombectomy. This study aims to evaluate whether postoperative fibrinogen-to-albumin ratio (FAR) could act as an indicator of futile recanalization.

METHODS

This is a single-center, retrospective analysis of patients with acute anterior circulation large-vessel occlusion and successful thrombectomy between May 2019 and June 2022. FAR was defined as postoperative blood levels of fibrinogen divided by those of albumin, and dichotomized into high and low levels based on the Youden index. Futile recanalization was defined as patients achieving a successful recanalization with a modified Rankin Scale score of 3-6 at 90 days. Multivariable logistic regression was used to assess the association of FAR with futile recanalization.

RESULTS

A total of 255 patients were enrolled, amongst which 87 patients (34.1%) had high postoperative FAR. Futile recanalization was more prevalent among patients with high FAR compared to those with low FAR (74.7% vs. 53.0%, p = .001). After adjusting for potential confounders, high postoperative FAR was found to independently correspond with the occurrence of futile recanalization (adjusted OR 2.40, 95%CI 1.18-4.87, p = .015). This association was consistently observed regardless of prior antithrombotic therapy, treatment of intravenous thrombolysis, occlusion site, time from symptom onset to groin puncture, and reperfusion status.

CONCLUSION

Our findings support high postoperative FAR serving as an indicator of futile recanalization in patients with anterior circulation large-vessel occlusion and successful thrombectomy.

Risk Factors, Pathophysiologic Mechanisms, and Potential Treatment Strategies of Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Endovascular therapy is the first-line treatment for acute ischemic stroke. However, studies have shown that, even with the timely opening of occluded blood vessels, nearly half of all patients treated with endovascular therapy for acute ischemic stroke still have poor functional recovery, a phenomenon called "futile recanalization.". The pathophysiology of futile recanalization is complex and may include tissue no-reflow (microcirculation reperfusion failure despite recanalization of the occluded large artery), early arterial reocclusion (reocclusion of the recanalized artery 24-48 hours post endovascular therapy), poor collateral circulation, hemorrhagic transformation (cerebral bleeding following primary ischemic stroke), impaired cerebrovascular autoregulation, and large hypoperfusion volume. Therapeutic strategies targeting these mechanisms have been attempted in preclinical research; however, translation to the bedside remains to be explored. This review summarizes the risk factors, pathophysiological mechanisms, and targeted therapy strategies of futile recanalization, focusing on the mechanisms and targeted therapy strategies of no-reflow to deepen the understanding of this phenomenon and provide new translational research ideas and potential intervention targets for improving the efficacy of endovascular therapy for acute ischemic stroke.

Role of intravenous alteplase on late lesion growth and clinical outcome after stroke treatment

Several acute ischemic stroke mechanisms that cause lesion growth continue after treatment which is detrimental to long-term clinical outcome. The potential role of intravenous alteplase treatment (IVT), a standard in stroke care, in cessing the physiological processes causing post-treatment lesion development is understudied. We analyzed patients from the MR CLEAN-NO IV trial with good quality 24-hour and 1-week follow-up Non-Contrast CT scans. We delineated hypo- and hyper-dense regions on the scans as lesion. We performed univariable logistic and linear regression to estimate the influence of IVT on the presence (growth > 0 ml) and extent of late lesion growth. The association between late lesion growth and mRS was assessed using ordinal logistic regression. Interaction analysis was performed to evaluate the influence of IVT on this association. Of the 63/116 were randomized to included patients, IVT. Median growth was 8.4(-0.88-26) ml. IVT was not significantly associated with the presence (OR: 1.24 (0.57-2.74, p = 0.59) or extent (β = 5.1(-8.8-19), p = 0.47) of growth. Late lesion growth was associated with worse clinical outcome (aOR: 0.85(0.76-0.95), p < 0.01; per 10 ml). IVT did not influence this association (p = 0.18). We did not find evidence that IVT influences late lesion growth or the relationship between growth and worse clinical outcome. Therapies to reduce lesion development are necessary.

Restoring microcirculatory perfusion in a preclinical model of severe hemorrhagic shock: The role of microcirculatory function

BACKGROUND

No reflow in capillaries (no reflow) is the lack of tissue perfusion that occurs once central hemodynamics are restored. This prevents oxygen transfer and debt repayment to vital tissues after shock resuscitation. Since metabolic swelling of cells and tissues can cause no reflow, it is a target for study in shock. We hypothesize no reflow secondary to metabolic cell swelling causes the problem not addressed by current strategies that increase central hemodynamics alone.

METHODS

Anesthetized swine were bled until plasma lactate reached 7.5 mM to 9 mM. Intravenous low volume resuscitation solutions were administered (6.8 mL/kg over 5 minutes) consisting of; (1) lactated Ringer (LR), (2) autologous whole blood, (3) high-dose vitamin C (200 mg/kg), or (4) 10% PEG-20k, a polymer-based cell impermeant that corrects metabolic cell swelling. Outcomes were macrohemodynamics (MAP), plasma lactate, capillary flow in the gut and tongue mucosa using orthogonal polarization spectral imaging (OPSI), and survival to 4 hours.

RESULTS

All PEG-20k resuscitated swine survived 240 minutes with MAP above 60 mm Hg compared with 50% and 0% of the whole blood and LR groups, respectively. The vitamin C group died at just over 2 hours with MAPs below 40 and high lactate. The LR swine only survived 30 minutes and died with low MAP and high lactate. Capillary flow positively correlated ( p < 0.05) with survival and MAP. Sublingual OPSI correlated with intestinal OPSI and OPSI was validated with a histological technique.

DISCUSSION

Targeting micro-hemodynamics in resuscitation may be more important than macrohemodynamics. Fixing both is optimal. Sublingual OPSI is clinically achievable to assess micro-hemodynamic status. Targeting tissue cell swelling that occurs during ATP depletion in shock using optimized osmotically active cell impermeants in crystalloid low volume resuscitation solutions improves perfusion in shocked tissues, which leverages a primary mechanism of injury.

No-reflow phenomenon in acute ischemic stroke: an angiographic evaluation

BACKGROUND

Futile recanalization (FR) is de fined as a poor 90-day outcome or lack of neurological improvement at 24 h despite successful recanalization in acute ischemic stroke (AIS) with large vessel occlusion (LVO) treated by mechanical throbectomy (MT). The No-reflow phenomenon (NRP) could be a possible cause of FR, but its evidence in AIS patients is scarce.

METHODS

We retrospectively analyzed 185 digital subtraction angiographies (DSA) of AIS patients with anterior circulation LVO after endovascular treatment. To better define NRP, we designed a score called the modified capillary index score (mCIS). The score is obtained by dividing the middle cerebral artery territory in three segments. For each segment, we gave 2 points if the capillary blush was present without any delay, 1 if delayed, and 0 if absent. The primary endpoint was to use mCIS to identify NRP on post-interventional DSA and to test whether this marker may predict FR and failure of early neurological improvement (fENI). The secondary endpoint was to search for a correlation between NRP, lesion volume, and hemorrhagic transformation. We used the ROC curve to define mCIS ≤ 3 as the cut-off and marker of NRP.

RESULTS

NRP was present in 35.1% of patients. NRP predicted fENI at 24 h (aOR 2.825, 95% CI 1.265-6.308, P = 0.011) and at 7 days (aOR 2.191, 95% CI 1.008-4.762, P = 0.048), but not 90-day FR. Moreover, NRP predicted hemorrhagic transformation (aOR 2.444, 95% CI 1.266-4.717, P = 0.008).

CONCLUSIONS

The modified capillary index score (mCIS) seems useful in identifying NRP in AIS. In addition, mCIS was able to predict NRP that correlated with early clinical outcome and hemorrhagic transformation of the ischemic lesion. An external validation of the score is warranted.

Intravenous tirofiban following successful reperfusion in intracranial large artery atherosclerotic stroke: A secondary analysis of a randomized clinical trial

OBJECTIVE

This study aimed to investigate whether treatment with adjunct intravenous tirofiban is associated with improved outcomes following successful reperfusion in patients with intracranial atherosclerotic stroke.

METHODS

Patients with intracranial large artery atherosclerotic (LAA) stroke and an expanded Treatment in Cerebral Ischemia angiographic score of 2b50 to 3 from the Effect of Intravenous Tirofiban versus Placebo Before Endovascular Thrombectomy on Functional Outcomes in Large Vessel Occlusion Stroke (RESCUE BT) trial were included. The primary outcome was the difference in proportion of independent functional outcome (modified Rankin score of 0-2 at 90 days). Safety outcomes included the rates of symptomatic intracranial hemorrhage (sICH) and 90-day mortality.

RESULTS

Among the 382 patients with intracranial LAA stroke and successful reperfusion, 175 patients (45.8%) were treated with intravenous tirofiban and 207 (54.2%) with placebo. The proportion of patients with independent functional outcome at 90 days was 54.3% (95 out of 175) with tirofiban and 44.0% (91 out of 207) with placebo (adjusted odds ratio [aOR], 1.58; 95% CI, 1.02-2.44; p = 0.04). Intravenous tirofiban was not significantly associated with an increased risk of sICH (12/175 [6.9%] vs. 11/207 [5.3%]; aOR, 1.41; 95% CI, 0.59-3.34; p = 0.44) or 90-day mortality (21/175 [12.0%] vs. 34/207 [16.4%]; aOR, 0.71; 95% CI, 0.38-1.31; p = 0.27).

INTERPRETATION

Among patients with acute intracranial LAA stroke and successful reperfusion following endovascular thrombectomy, adjunct intravenous tirofiban was associated with a higher rate of independent functional outcome, without higher rates of sICH or mortality. Confirmatory randomized trials in these patients are desirable.

Effect of prolonged microcirculation time after thrombectomy on the outcome of acute stroke

BACKGROUND

Although recanalization can be successful, microcirculatory dysfunction is common in acute large vessel occlusive stroke (LVOS). We assessed the microcirculation time by postprocessing software and analyzed its impact on prognosis in patients treated with mechanical thrombectomy (MT).

METHODS

Patients with acute LVOS treated with MT were retrospectively enrolled consecutively. We measured the time to peak (TTP) and cerebral circulation time (CCT) in regions of interest on digital subtraction angiography using syngo iFlow software (Siemens Healthineers, Forchheim, Germany). A modified Rankin score ≤2 at 90 days was defined as a favorable outcome. Logistic regression was used to analyze the effect of each time parameter on prognosis. Then, we included time parameters in the baseline model to construct receiver operating characteristic (ROC) curves to assess the predictive ability for prognosis.

RESULTS

A total of 215 patients were finally included. Of them, 118 (54.9%) had a favourable outcome at 90 days. Multivariate analysis showed that the microvascular cerebral circulation time (mCCT) was significantly associated with poor outcomes (odds ratio (OR) 2.061, 95% confidence interval (CI) 1.414 to 3.005 p<0.001). The area under the ROC curve was significantly enhanced by including mCCT in the baseline model (0.859 vs 0.829, p=0.016, DeLong test).

CONCLUSIONS

The mCCT immediately after recanalization is a powerful predictive factor for 90-day functional prognosis.

The vascular Na,K-ATPase: clinical implications in stroke, migraine, and hypertension

In the vascular wall, the Na,K-ATPase plays an important role in the control of arterial tone. Through cSrc signaling, it contributes to the modulation of Ca2+ sensitivity in vascular smooth muscle cells. This review focuses on the potential implication of Na,K-ATPase-dependent intracellular signaling pathways in severe vascular disorders; ischemic stroke, familial migraine, and arterial hypertension. We propose similarity in the detrimental Na,K-ATPase-dependent signaling seen in these pathological conditions. The review includes a retrospective proteomics analysis investigating temporal changes after ischemic stroke. The analysis revealed that the expression of Na,K-ATPase α isoforms is down-regulated in the days and weeks following reperfusion, while downstream Na,K-ATPase-dependent cSrc kinase is up-regulated. These results are important since previous studies have linked the Na,K-ATPase-dependent cSrc signaling to futile recanalization and vasospasm after stroke. The review also explores a link between the Na,K-ATPase and migraine with aura, as reduced expression or pharmacological inhibition of the Na,K-ATPase leads to cSrc kinase signaling up-regulation and cerebral hypoperfusion. The review discusses the role of an endogenous cardiotonic steroid-like compound, ouabain, which binds to the Na,K-ATPase and initiates the intracellular cSrc signaling, in the pathophysiology of arterial hypertension. Currently, our understanding of the precise control mechanisms governing the Na,K-ATPase/cSrc kinase regulation in the vascular wall is limited. Understanding the role of vascular Na,K-ATPase signaling is essential for developing targeted treatments for cerebrovascular disorders and hypertension, as the Na,K-ATPase is implicated in the pathogenesis of these conditions and may contribute to their comorbidity.

Microvascular reperfusion during endovascular therapy: the balance of supply and demand

BACKGROUND

Endovascular therapy (EVT) has revolutionized the treatment of acute stroke, but large vessel recanalization does not always result in tissue-level reperfusion. Cerebral blood flow (CBF) is not routinely monitored during EVT. We aimed to leverage diffuse correlation spectroscopy (DCS), a novel transcranial optical imaging technique, to assess the relationship between microvascular CBF and post-EVT outcomes.

METHODS

Frontal lobe CBF was monitored by DCS in 40 patients undergoing EVT. Baseline CBF deficit was calculated as the percentage of CBF impairment on pre-EVT CT perfusion. Microvascular reperfusion was calculated as the percentage increase in DCS-derived CBF that occurred with recanalization. The adequacy of reperfusion was defined by persistent CBF deficit, calculated as: baseline CBF deficit - microvascular reperfusion. A good functional outcome was defined as 90-day modified Rankin Scale score ≤2.

RESULTS

Thirty-six of 40 patients achieved successful recanalization, in whom microvascular reperfusion in itself was not associated with infarct volume or functional outcome. However, patients with good functional outcomes had a smaller persistent CBF deficit (median 1% (IQR -11%-16%)) than patients with poor outcomes (median 28% (IQR 2-50%)) (p=0.02). Smaller persistent CBF deficit was also associated with smaller infarct volume (p=0.004). Multivariate models confirmed that persistent CBF deficit was independently associated with infarct volume and functional outcome.

CONCLUSIONS

CBF augmentation alone does not predict post-EVT outcomes, but when microvascular reperfusion closely matches the baseline CBF deficit, patients experience favorable clinical and radiographic outcomes. By recognizing inadequate reperfusion, bedside CBF monitoring may provide opportunities to personalize post-EVT care aimed at CBF optimization.

Evolving Clinical-Translational Investigations of Cerebroprotection in Ischemic Stroke

Ischemic stroke is a highly morbid disease, with over 50% of large vessel stroke (middle cerebral artery or internal carotid artery terminus occlusion) patients suffering disability despite maximal acute reperfusion therapy with thrombolysis and thrombectomy. The discovery of the ischemic penumbra in the 1980s laid the foundation for a salvageable territory in ischemic stroke. Since then, the concept of neuroprotection has been a focus of post-stroke care to (1) minimize the conversion from penumbra to core irreversible infarct, (2) limit secondary damage from ischemia-reperfusion injury, inflammation, and excitotoxicity and (3) to encourage tissue repair. However, despite multiple studies, the preclinical-clinical research enterprise has not yet created an agent that mitigates post-stroke outcomes beyond thrombolysis and mechanical clot retrieval. These translational gaps have not deterred the scientific community as agents are under continuous investigation. The NIH has recently promoted the concept of cerebroprotection to consider the whole brain post-stroke rather than just the neurons. This review will briefly outline the translational science of past, current, and emerging breakthroughs in cerebroprotection and use of these foundational ideas to develop a novel paradigm for optimizing stroke outcomes.

Efficacy and safety of early anticoagulation after endovascular treatment in patients with atrial fibrillation

BACKGROUND

The timing for initiating anticoagulant therapy in acute ischaemic stroke (AIS) patients with atrial fibrillation who recanalised after endovascular treatment (EVT) is unclear. The objective of this study was to evaluate the effect of early anticoagulation after successful recanalisation in AIS patients with atrial fibrillation.

METHODS

Patients with anterior circulation large vessel occlusion and atrial fibrillation who were successfully recanalised by EVT within 24 hours after stroke in the Registration Study for Critical Care of Acute Ischemic Stroke after Recanalization registry were analysed. Early anticoagulation was defined as the initiation of unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) within 72 hours after EVT. Ultra-early anticoagulation was defined if it was initiated within 24 hours. The primary efficacy outcome was the score on the modified Rankin Scale (mRS) at day 90, and the primary safety outcome was symptomatic intracranial haemorrhage within 90 days.

RESULTS

Overall, 257 patients were enrolled, of whom 141 (54.9%) initiated anticoagulation within 72 hours after EVT, including 111 within 24 hours. A significant shift towards better mRS scores at day 90 was associated with early anticoagulation (adjusted common OR 2.08 (95% CI 1.27 to 3.41)). Symptomatic intracranial haemorrhage was comparable between patients treated with early and routine anticoagulation (adjusted OR 0.20 (95% CI 0.02 to 2.18)). Comparison of different early anticoagulation regimens showed that ultra-early anticoagulation was more significantly associated with favourable functional outcomes (adjusted common OR 2.03 (95% CI 1.20 to 3.44)) and reduced the incidence of asymptomatic intracranial haemorrhage (OR 0.37 (95% CI 0.14 to 0.94)).

CONCLUSIONS

In AIS patients with atrial fibrillation, early anticoagulation with UFH or LMWH after successful recanalisation is associated with favourable functional outcomes without increasing the risk of symptomatic intracranial haemorrhages.

TRIAL REGISTRATION NUMBER

ChiCTR1900022154.

Post-reperfusion hyperperfusion after endovascular stroke treatment: a prospective comparative study of TCD versus MRI

BACKGROUND

Increased middle cerebral artery (MCA) blood flow velocities on transcranial duplex sonography (TCD) were recently reported in individual patients after successful mechanical thrombectomy (MT) and were related to intracranial hemorrhage and poor outcome. However, the retrospective study design of prior studies precluded elucidation of the underlying pathomechanisms, and the relationship between TCD and brain parenchymal perfusion still remains to be determined.

METHODS

We prospectively investigated consecutive patients with stroke successfully recanalized by MT with TCD and MRI including contrast-enhanced perfusion sequences within 48 hours post-intervention. Increased MCA flow on TCD was defined as >30% mean blood flow velocity in the treated MCA compared with the contralateral MCA. MRI blood flow maps served to assess hyperperfusion rated by neuroradiologists blinded to TCD.

RESULTS

A total of 226 patients recanalized by MT underwent post-interventional TCD and 92 patients additionally had perfusion MRI. 85 patients (38%) had increased post-interventional MCA flow on TCD. Of these, 10 patients (12%) had an underlying focal stenosis. Increased TCD blood flow in the recanalized MCA was associated with larger infarct size, vasogenic edema, intracranial hemorrhage and poor 90-day outcome (all p≤0.005). In the subgroup for which both TCD and perfusion MRI were available, 29 patients (31%) had increased ipsilateral MCA flow velocities on TCD. Of these, 25 patients also showed parenchymal hyperperfusion on MRI (sensitivity 85%; specificity 62%). Hyperperfusion severity on MRI correlated with MCA flow velocities on TCD (rs=0.379, p<0.001).

CONCLUSIONS

TCD is a reliable bedside tool to identify post-reperfusion hyperperfusion, correlates well with perfusion MRI, and indicates risk of reperfusion injury after MT.

No-reflow phenomenon following stroke recanalization therapy: Clinical assessment advances: A narrative review

The no-reflow phenomenon (NRP) after successful vascular recanalization in acute ischemic stroke (AIS) has become a major cause of poor clinical prognosis and ineffective recanalization. However, there is currently no clear definition or unified clinical assessment method for the NRP. Therefore, it is urgent to clarify the clinical evaluation criteria for the NRP and develop new no-reflow evaluation techniques so that remedial treatment can be applied to AIS patients suffering from the NRP. In this brief review, a variety of NRP assessment methods and defining criteria for clinical practice are presented.

Neutrophil-derived cathelicidin promotes cerebral angiogenesis after ischemic stroke

Neutrophils play critical roles in the evolving of brain injuries following ischemic stroke. However, how they impact the brain repair in the late phase after stroke remain uncertain. Using a prospective clinical stroke patient cohort, we found significantly increased cathelicidin antimicrobial peptide (CAMP) in the peripheral blood of stroke patients compared to that of healthy controls. While in the mouse stroke model, CAMP was present in the peripheral blood, brain ischemic core and significantly increased at day 1, 3, 7, 14 after middle cerebral artery occlusion (MCAO). CAMP-/- mice exhibited significantly increased infarct volume, exacerbated neurological outcome, reduced cerebral endothelial cell proliferation and vascular density at 7 and 14 days after MCAO. Using bEND3 cells subjected to oxygen-glucose deprivation (OGD), we found significantly increased angiogenesis-related gene expression with the treatment of recombinant CAMP peptide (rCAMP) after reoxygenation. Intracerebroventricular injection (ICV) of AZD-5069, the antagonist of CAMP receptor CXCR2, or knockdown of CXCR2 by shCXCR2 recombinant adeno-associated virus (rAAV) impeded angiogenesis and neurological recovery after MCAO. Administration of rCAMP promoted endothelial proliferation and angiogenesis and attenuated neurological deficits 14 days after MCAO. In conclusion, neutrophil derived CAMP represents an important mediator that could promote post-stroke angiogenesis and neurological recovery in the late phase after stroke.

Preceding transient ischemic attack was associated with functional outcome after stroke thrombectomy: A propensity score matching study

Whether preceding transient ischemic attack (TIA) can provide neuroprotective benefits in subsequent acute ischemic stroke (AIS) caused by large vessel occlusion remains unclarified. This study aimed to investigate the association between preceding TIA and functional outcomes in AIS patients with endovascular therapy (EVT). Eligible patients were divided into TIA and non-TIA groups according to whether they experienced TIA within 96 hours prior to stroke. Two groups were balanced using propensity score matching (PSM) analysis at a 1:3 ratio. Onset stroke severity and 3-month functional independence were evaluated. A total of 887 patients were included. After PSM, 73 patients with and 217 patients without preceding TIA were well matched. Onset stroke severity was not different between the groups (p > 0.05). However, the TIA group had a lower systemic immune-inflammation index (SII) (median, 1091 versus 1358, p < 0.05). Preceding TIA was significantly associated with 3-month functional independence (adjusted odds ratio, 2.852; 95% confidence interval [CI], 1.481-5.495; adjusted p < 0.01). The effects of preceding TIA on functional independence were partially mediated by SII (average causal mediation effects 0.02; 95% CI, 0.001-0.06, p < 0.05). In AIS patients treated by EVT, preceding TIA within 96 hours was associated with three-month functional independence but not with reduced onset stroke severity.

Clinical Significance and Influencing Factors of Microvascular Tissue Reperfusion After Macrovascular Recanalization

The relevance of impaired microvascular tissue reperfusion despite successful macrovascular angiographic reperfusion (no-reflow) in acute ischemic stroke (AIS) remains controversial. In this study, we aimed to investigate the impact of tissue optimal reperfusion (TOR) and its influencing factors. From December 1, 2020 to December 1, 2021, AIS patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score [mTICI] ≥ 2b) after mechanical thrombectomy (MT) were retrospectively reviewed. Computed tomography perfusion was performed before and after MT. Successful reperfusion was assessed by TOR, defined as > 90% reduction of the Tmax > 6 s lesion volumes between baseline and early follow-up perfusion profiles. The impact of TOR on functional outcomes after successful recanalization and influencing factors for TOR were both investigated. Sixty-three patients were included, including 44 cases in the TOR group and 19 cases in the non-TOR group. The TOR group had a higher rate of favorable outcome (aOR 4.366, 95%CI 1.159-16.445, p = 0.030) and NIHSS improvement (aOR 5.089, 95%CI 1.340-19.322, p = 0.017) than the non-TOR group. Multivariable logistic regression showed baseline glucose (OR 0.648, 95%CI 0.492-0.854, p = 0.002) and mTICI 2c/3 (OR 10.984, 95%CI 2.220-54.343, p = 0.003) predicted TOR in model 1; in model 2, postoperative glucose (OR 0.468, 95%CI 0.278-0.787, p = 0.004) and mTICI 2c/3 (OR 9.436, 95%CI 1.889-47.144, p = 0.006) were predictive. TOR was strongly associated with good functional outcomes after successful recanalization of MT. Higher mTICI grade and lower perioperative glucose level may predict microvascular tissue reperfusion.

A systematic observation of vasodynamics from different segments along the cerebral vasculature in the penumbra zone of awake mice following cerebral ischemia and recanalization

Different segments of the cerebral vascular network may react distinctly to brain ischemia and recanalization. However, there are limited systematic observations of these vascular responses in mice under a physiological state following ischemic stroke. Herein, we aimed to investigate the vasodynamics among several segments along the cerebral vessels in awake mice following cerebral ischemia/recanalization via two-photon imaging. Plasma in the blood vessels were labelled with fluorescein isothiocyanate dextran. Smooth muscle cells and pericytes were labelled via a genetic mouse line (PDGFRβ-tdTomato). We observed a no-reflow phenomenon in downstream microcirculation, and the vasodynamics of different segments of larger cerebral vessels varied in the penumbra area following cerebral ischemia-reperfusion. Despite obtaining reperfusion from the middle cerebral artery, there were significant constrictions of the downstream blood vessels in the ischemic penumbra zone. Interestingly, we observed an extensive constriction of the capillaries 3 hours following recanalization, both at the site covered by pericyte soma and by the pericyte process alone. In addition, we did not observe a significant positive correlation between the changed capillary diameter and pericyte coverage along the capillary. Taken together, abnormal constrictions and vasodynamics of cerebral large and small vessels may directly contribute to microcirculation failure following recanalization in ischemic stroke.

Super resolution imaging reconstruction reveals that gold standard methods may not correctly conclude neural/brain functional recovery

The status of cerebral perfusion and its restoration level play a vital role in the prognosis and clinical decision making of many neurosurgical diseases. As such, gold standard methods including CT, MR and ICP monitoring, which can indicate and measure cerebral perfusion and restoration, have been widely adopted to evaluate whether or not a patient has recovered from neurofunctional disabilities. This robust combination of methods, however, is confronted with a growing number of contradictions in recent years due to its inability to measure the status of cerebral reperfusion in microvasculature level, even though this has been shown to determine neurofunctional restoration as well or even better. To this date, nevertheless, we have very limited imaging methods that could evaluate human cerebral microperfusion both safely and accurately under most neurosurgical conditions. We herein report a new method of acquiring a patient's cerebral microperfusion status noninvasively which could display the precise distribution of microvasculature in deep cerebral regions with a resolution of ∼30 µm, using everyday bed-side ultrasonography combined with a computerized super-resolution reconstruction algorithm. Using this imaging modality, we found that a patient's cerebral microperfusion might not be improved by some routine administrations even though the gold standard method had yielded the opposite conclusions. Our imaging modality retains the safe, portable feature of ordinary ultrasonography while possesses the extraordinary super-resolution nature, which enables an efficient, precise diagnosis of cerebral perfusion. Most importantly, the super resolution nature of this method may also facilitate early-stage evaluation of a patient's neurofunctional restoration level and avoid overoptimistic conclusions from conventional angiography or ICP monitoring.

Reperfusion measurements, treatment time, and outcomes in patients receiving endovascular treatment within 24 hours of last known well

AIMS

The aim of this study was to explore the interaction between reperfusion and treatment time on the outcomes of patients undergoing endovascular treatment presenting within 24 h of last known well, and to compare the predictive ability of different reperfusion measurements on outcomes.

METHODS

Eligible patients from a single-center cohort were enrolled in this study. Reperfusion was assessed using reperfusion index (decreased volume of hypoperfusion lesion compared with baseline) measured by repeated perfusion imaging, and modified treatment in cerebral ischemia score measured by digital subtraction angiography, respectively. The interactions between reperfusion measurements and treatment time on outcomes were explored using multivariate-adjusted logistic and linear regression models. The predictive abilities of reperfusion measurements on outcomes were compared using area under the receiver operating characteristic curve (ROC-AUC) and values of R-square.

RESULTS

Reperfusion index and treatment time had significant interactions on 3-month modified Rankin Scale (mRS) 0-2 and infarct growth (p for interaction <0.05). Although the AUCs were statistically similar (AUCs of mRS 0-2 prediction, mTICI≥2b:0.63, mTICI≥2c:0.59, reperfusion index≥0.5:0.66, reperfusion index ≥0.9:0.73, P value of any of the two AUCs >0.05), reperfusion index≥0.9 showed the highest R-square values in outcome prediction (R-square values of 3-month mRS 0-2 and infarct growth = 0.21) among all the reperfusion measurements.

CONCLUSION

Treatment time mitigated the effect of reperfusion on outcomes of patients receiving endovascular treatment within 24 h of last known well. Reperfusion index≥0.9 might serve as a better proxy of good outcomes compared with other reperfusion measurements.

Advances in the management of acute ischemic stroke

PURPOSE OF REVIEW

This review aims to summarize the therapeutic advances and evidence in the medical management of acute ischemic stroke (AIS). Recent evidence comparing the efficacy and safety of tenecteplase (TNK) with alteplase for intravenous thrombolysis (IVT) in AIS will be highlighted. Recent advances and evidence on improving micro-circulation following endovascular procedures and neuroprotection will be reviewed.

RECENT FINDINGS

A significant number of randomized control studies now support the use of tenecteplase for IVT in AIS. TNK 0.25 mg/kg single bolus is as effective and well tolerated as alteplase 0.9 mg/kg infusion for IVT in AIS. Evidence from randomized control trials (RCTs) has shown effective and well tolerated expansion of the therapeutic window of IVT in the wake-up stroke and up to 9 h after last seen well, using advanced neuroimaging with computed tomography perfusion/MRI. Early evidence suggests that intra-arterial alteplase may help improve microcirculation in patients with large vessel occlusion following successful thrombectomy. However, more trials are required to confirm the results. Similarly, early evidence from a recent RCT showed that remote ischemic conditioning confers potential neuroprotection and improves outcomes in AIS.

SUMMARY

Converging evidence has demonstrated that for patients with ischemic stroke presenting at under 4.5 h from the onset, TNK is comparable to alteplase. These data along with the practical advantages of TNK have resulted in a shift to replace intravenous TNK as the standard for thrombolysis. Ongoing studies of IVT with TNK are focussed on defining the optimal dose, expanding the time window with multimodal imaging and defining the role of thrombolysis for bridging patients with stroke due to large vessel occlusion.

Incidence and predictors of poor functional outcome despite complete recanalisation following endovascular thrombectomy for acute ischaemic stroke

BACKGROUND

Numerous ischaemic stroke patients experience poor functional outcome despite successful recanalisation following endovascular thrombectomy (EVT). We aimed to identify the incidence and predictors of futile complete recanalisation (FCR) in a national stroke registry.

METHODS

Patients who achieved complete recanalisation (mTICI 3) following EVT, between October 2015 and March 2020, were included from a United Kingdom national stroke registry. Modified Rankin Scale of 4-6 at discharge was defined as a 'poor/futile outcome'. Backward stepwise multivariable logistic regression analysis was performed with FCR as the dependent variable, incorporating all baseline characteristics, procedural time metrics and post-procedural events.

RESULTS

We included 2132 of 4383 patients (48.8%) with complete recanalisation post-EVT, of which 948 patients (44.4%) developed FCR. Following multivariable regression analysis adjusted for potential confounders, patients with FCR were associated with multiple baseline patient, imaging and procedural factors: age (p=0.0001), admission NIHSS scores (p=0.0001), pre-stroke disability (p=0.007), onset-to-puncture (p=0.0001) and procedural times (p=0.0001), presence of diabetes (p=0.005), and use of general anaesthesia (p=0.0001). Although not predictive of outcome, post-procedural events including development of any intracranial haemorrhage (ICH) (p=0.0001), symptomatic ICH (sICH) (p=0.0001) and early neurological deterioration (END) (p=0.007) were associated with FCR.

CONCLUSION

Nearly half of patients in this national registry experienced FCR following EVT. Significant predictors of FCR included increasing age, admission NIHSS scores, pre-stroke disability, onset-to-puncture and procedural times, presence of diabetes, atrial fibrillation, and use of general anaesthesia. Post procedural development of any ICH, sICH, and END were associated with FCR.

Sex Difference in Capillary Reperfusion After Transient Middle Cerebral Artery Occlusion in Diabetic Mice

BACKGROUND

Type 2 diabetes (DM2) exacerbates stroke injury, reduces efficacy of endovascular therapy, and worsens long-term functional outcome. Sex differences exist in stroke incidence, response to therapy, poststroke microvascular dysfunction, and functional recovery. In this study, we tested the hypotheses that poor outcome after stroke in the setting of DM2 is linked to impaired microvascular tissue reperfusion and that male and female DM2 mice exhibit different microvascular reperfusion response after transient middle cerebral artery occlusion (MCAO).

METHODS

Transient MCAO was induced for 60 minutes using an intraluminal filament in young adult DM2 and nondiabetic control male and female mice. Capillary flux in deep cortical layers was assessed using optical coherence tomography-based optical microangiography (OMAG), and associated regional brain infarct size was evaluated by hematoxylin and eosin staining.

RESULTS

Compared to baseline, MCAO reduced absolute capillary red blood cell flux by 84% at 24 hours post-MCAO in male DM2 (P<0.001) but not male control mice. When normalized to pre-MCAO baseline, red blood cell flux 24 hours after stroke was 64% lower in male DM2 mice than male nondiabetic controls (P<0.01). In females, MCAO decreased capillary flux by 48% at 24 hours post-MCAO compared with baseline in DM2 (P<0.05) but not in control mice. Red blood cell flux of female DM2 mice did not differ from that of nondiabetic controls either before or 24 hours after MCAO. Furthermore, normalized capillary flux 24 hours after MCAO failed to differ between female DM2 mice and nondiabetic controls. Concomitantly, male but not female DM2 mice experienced 25% larger infarct in caudate-putamen versus respective nondiabetic controls (P<0.05).

CONCLUSIONS

DM2 impairs capillary perfusion and exacerbates ischemic deep brain injury in male but not female young adult mice. Premenopausal females appear to be protected against DM2-related capillary dysfunction and brain injury.

Intra-arterial thrombolytics during endovascular thrombectomy for acute ischaemic stroke in the MR CLEAN Registry

INTRODUCTION

The efficacy and safety of local intra-arterial (IA) thrombolytics during endovascular thrombectomy (EVT) for large-vessel occlusions is uncertain. We analysed how often IA thrombolytics were administered in the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry, whether it was associated with improved functional outcome and assessed technical and safety outcomes compared with EVT without IA thrombolytics.

METHODS

In this observational study, we included patients undergoing EVT for an acute ischaemic stroke in the anterior circulation from the MR CLEAN Registry (March 2014-November 2017). The primary endpoint was favourable functional outcome, defined as an modified Rankin Scale score ≤2 at 90 days. Secondary endpoints were reperfusion status, early neurological recovery and symptomatic intracranial haemorrhage (sICH). Subgroup analyses for IA thrombolytics as primary versus adjuvant revascularisation attempt were performed.

RESULTS

Of the 2263 included patients, 95 (4.2%) received IA thrombolytics during EVT. The IA thrombolytics administered were urokinase (median dose, 250 000 IU (IQR, 1 93 750-2 50 000)) or alteplase (median dose, 20 mg (IQR, 12-20)). No association was found between IA thrombolytics and favourable functional outcome (adjusted OR (aOR), 1.16; 95% CI 0.71 to 1.90). Successful reperfusion was less often observed in those patients treated with IA thrombolytics (aOR, 0.57; 95% CI 0.36 to 0.90). The odds of sICH (aOR, 0.82; 95% CI 0.32 to 2.10) and early neurological recovery were comparable between patients treated with and without IA thrombolytics. For primary and adjuvant revascularisation attempts, IA thrombolytics were more often administered for proximal than for distal occlusions. Functional outcomes were comparable for patients receiving IA thrombolytics as a primary versus adjuvant revascularisation attempt.

CONCLUSION

Local IA thrombolytics were rarely used in the MR CLEAN Registry. In the relatively small study sample, no statistical difference was observed between groups in the rate of favourable functional outcome or sICH. Patients whom required and underwent IA thrombolytics were patients less likely to achieve successful reperfusion, probably due to selection bias.

Spatial accuracy of computed tomography perfusion to estimate the follow-up infarct on diffusion-weighted imaging after successful mechanical thrombectomy

BACKGROUND

Volumetric accuracy of using computed tomography perfusion (CTP) to estimate the post-treatment infarct in stroke patients with successful recanalization after mechanical thrombectomy (MT) has been studied a lot, however the spatial accuracy and its influence factors has not been fully investigated.

METHODS

This retrospective study reviewed the data from consecutive anterior large vessel occlusion (LVO) patients who had baseline CTP, successful recanalization after MT, and post-treatment diffusion-weighed imaging (DWI). Ischemic core on baseline CTP was estimated using relative cerebral blood flood (CBF) of < 30%. The infarct area was outlined manually on post-treatment DWI, and registered to CTP. Spatial agreement was assessed using the Dice similarity coefficient (DSC) and average Hausdorff distance. According to the median DSC, the study population was dichotomized into high and low Dice groups. Univariable and multivariable regression analyses were used to determine the factors independently associated with the spatial agreement.

RESULTS

In 72 included patients, the median DSC was 0.26, and the median average Hausdorff distance was 1.77 mm. High Dice group showed significantly higher median ischemic core volume on baseline CTP (33.90 mL vs 3.40 mL, P < 0.001), lower proportion of moderate or severe leukoaraiosis [27.78% vs 52.78%, P = 0.031], and higher median infarct volume on follow-up DWI (51.17 mL vs 9.42 mL, P < 0.001) than low Dice group. Ischemic core volume on baseline CTP was found to be independently associated with the spatial agreement (OR, 1.092; P < 0.001).

CONCLUSIONS

CTP could help to spatially locate the post-treatment infarct in anterior LVO patients who achieving successful recanalization after MT. Ischemic core volume on baseline CTP was independently associated with the spatial agreement.

Intra-arterial tenecteplase is safe and may improve the first-pass recanalization for acute ischemic stroke with large-artery atherosclerosis: the BRETIS-TNK trial

Background and purpose

The first-pass recanalization of endovascular treatment (EVT) is closely correlated with clinical outcome of patients with large vessel occlusion (LVO) stroke. The aim of the study was to explore whether intra-arterial tenecteplase (TNK) during the first pass of EVT can increase first-pass successful reperfusion and improve the neurological outcome in AIS-LVO patients.

Materials and methods

The BRETIS-TNK trial (ClinicalTrials.gov Identifier: NCT04202458) was a prospective, single-arm, single center study. Twenty-six eligible AIS-LVO patients with large-artery atherosclerosis etiology were consecutively enrolled from December 2019 to November 2021. Intra-arterial TNK (4 mg) after microcatheter navigation through the clot was administered, followed by TNK (0.4  mg/min) given continuously for 20  min after the first retrieval attempt of EVT without confirmation of the reperfusion status by DSA. The 50 control patients comprised of a historical cohort before the BRETIS-TNK trial (from March 2015 to November 2019). Successful reperfusion was defined as modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b.

Results

The first-pass successful reperfusion rate was higher in the BRETIS-TNK vs. control group (53.8% vs. 36%, p = 0.14), and the difference became statistically significant after propensity score matching (53.8% vs. 23.1%, p = 0.03). There was no difference in symptomatic intracranial hemorrhage between the BRETIS-TNK and control groups (7.7% vs. 10.0%, p = 0.92). There was a trend toward higher proportion of functional independence at 90 days in the BRETIS-TNK comparing with the control group (50% vs. 32%, p = 0.11).

Conclusion

This is the first study to report that intra-arterial TNK during the first pass of EVT seems safe and feasible in AIS-LVO patients.

Safety and efficacy of adjunct tirofiban treatment following mechanical thrombectomy for acute ischemic stroke patients with large vessel occlusion (LVO) resulting in successful reperfusion

BACKGROUND AND PURPOSE

Tirofiban administration after mechanical thrombectomy (MT) remains controversial. This study aimed to investigate the efficacy and safety of adjunct tirofiban treatment following MT for acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) that resulted in successful reperfusion on digital subtraction angiography (DSA).

METHODS

This retrospective study was conducted in Zhengzhou University University People's Hospital, an advanced stroke center in China. Consecutive patients with AIS who underwent endovascular therapy (EVT) were enrolled from June 2018 to January 2022. The safety endpoints were symptomatic intracerebral hemorrhage (sICH), total intracranial hemorrhage (ICH), and 3-month mortality. The efficacy endpoints were 3-month modified Rankin scale (mRS) score and 24-h neurological improvement.

RESULTS

A total of 145 consecutive patients with AIS who underwent MT were analyzed, of whom 51 (35.2%) patients were in the tirofiban group. There were 30 (20.7%) patients with sICH, 50 (34.5%) patients suffered from ICH within 24-h post-MT, and 47 (32.4%) dead at 3-month. Besides, 31 (21.4%) patients achieved excellent clinical outcomes (mRS, 0-1), and 24-h neurological improvement was found in 29 (20.0%) patients. No statistically significant differences were found in safety outcomes on sICH, total ICH, and 3-month mortality, as well as efficacy outcomes on 3-month mRS scores (0-1) and 24-h neurological improvement between the two groups (P > 0.05 for all). Additionally, tirofiban was associated with 3-month mRS scores of 0-2 (adjusted odds ratio (OR), 3.75; 95% confidence interval (CI), 1.41-10.02, P = 0.008).

CONCLUSION

Adjunct tirofiban treatment following MT for AIS patients with LVO that resulted in successful reperfusion on DSA was not correlated with the increased risk of safety endpoints on sICH, ICH, and 3-month mortality, and it may be associated with a lower 3-month mRS score.

Adjunct Thrombolysis Enhances Brain Reperfusion following Successful Thrombectomy

OBJECTIVE

This study was undertaken to investigate whether adjunct alteplase improves brain reperfusion following successful thrombectomy.

METHODS

This single-center, randomized, double-blind, placebo-controlled study included 36 patients (mean [standard deviation] = 70.8 [13.5] years old, 18 [50%] women) with large vessel occlusion undergoing thrombectomy resulting in near-normal (expanded Thrombolysis in Cerebral Infarction [eTICI] b50/67/2c, n = 23, 64%) or normal angiographic reperfusion (eTICI 3, n = 13, 36%). Seventeen patients were randomized to intra-arterial alteplase (0.225mg/kg), and 19 received placebo. At 48 hours, patients had brain perfusion/diffusion-weighted magnetic resonance imaging (MRI) and MRI-spectroscopy. The primary outcome was the difference in the proportion of patients with areas of hypoperfusion on MRI. Secondary outcomes were the infarct expansion ratio (final to initial infarction volume), and the N-acetylaspartate (NAA) peak relative to total creatine as a marker of neuronal integrity.

RESULTS

The prevalence of hypoperfusion was 24% with intra-arterial alteplase, and 58% with placebo (adjusted odds ratio = 0.20, 95% confidence interval [CI] = 0.04-0.91, p = 0.03). Among 14 patients with final eTICI 3 scores, hypoperfusion was found in 1 of 7 (14%) in the alteplase group and 3 of 7 (43%) in the placebo group. Abnormal brain perfusion was associated with worse functional outcome at day 90. Alteplase significantly reduced the infarct expansion ratio compared with placebo (median [interquartile range (IQR)] = 0.7 [0.5-1.2] vs 3.2 [1.8-5.7], p = 0.01) and resulted in higher NAA peaks (median [IQR] = 1.13 [0.91-1.36] vs 1.00 [0.74-1.22], p < 0.0001).

INTERPRETATION

There is a high prevalence of areas of hypoperfusion following thrombectomy despite successful reperfusion on angiography. Adjunct alteplase enhances brain reperfusion, which results in reduced expansion of the infarction and improved neuronal integrity. ANN NEUROL 2022;92:860-870.

Duration of Ischemia Affects Outcomes Independent of Infarct Size in Stroke

BACKGROUND

Delays in endovascular reperfusion for patients with large vessel occlusion stroke are known to worsen outcomes, and the mechanism is believed to be time-dependent expansion of the ischemic infarction. In this study, we hypothesize that delays in onset to reperfusion (OTR) assert an effect on outcomes independent of effects of final infarct (FI).

METHODS

We performed a subgroup analysis from the prospective multicenter COMPLETE (International Acute Ischemic Stroke Registry With the Penumbra System Aspiration Including the 3D Revascularization Device; Penumbra, Inc) registry for 257 patients with anterior circulation large vessel occlusion who underwent endovascular therapy with successful reperfusion (modified treatment in cerebral infarction score 2b/3). FI was measured by Alberta Stroke Program Early CT score and volume on 24- to 48-hour computed tomography or magnetic resonance imaging. The likelihood of 90-day good functional outcome (modified Rankin scale 0-2) was assessed by OTR and absolute risk difference (ARD) was estimated using multivariable logistic regressions adjusting for patient characteristics including FI.

RESULTS

In univariable analysis, longer OTR was associated with a decreased likelihood of good functional outcome (ARD -3% [95% CI -4.5 to -1.0]/h delay). In multivariable analysis accounting for FI, the association between OTR and functional outcome remained significant (ARD -2% [95% CI -3.5 to -0.4]/h delay) with similar ARD. This finding was maintained in the subset of patients with FI imaging using CT only, using Alberta Stroke Program Early CT Score or volumetric FI measurements, and also in patients with larger versus smaller FIs.

CONCLUSIONS

The impact of OTR on outcomes appears to be mostly through a mechanism that is independent of FI. Our findings suggest that although the field has moved toward imaging infarct core definitions of eligibility for endovascular treatment, time remains an important predictor of outcome, independent of infarct core.

Safety and efficacy of periprocedural antithrombotics in patients with successful reperfusion after endovascular stroke treatment

OBJECTIVES

We aimed to evaluate whether the overall harmful effect of periprocedural treatment with aspirin or heparin during endovascular stroke treatment is different in patients with a successful reperfusion after the procedure.

MATERIALS AND METHODS

We performed a post-hoc analysis of the MR CLEAN-MED trial, including adult patients with a large vessel occlusion in the anterior circulation eligible for endovascular treatment (EVT). In this trial, patients were randomized for periprocedural intravenous treatment with aspirin or no aspirin (1:1 ratio), and for moderate-dose unfractionated heparin, low-dose unfractionated heparin or no unfractionated heparin (1:1:1 ratio). We tested for interaction between the post-EVT extended thrombolysis in cerebral infarction (eTICI) score and treatment with periprocedural medication with multivariable regression analyses. The primary outcome was the modified Rankin Scale score at 90 days. Secondary outcomes were final infarct volume, intracranial hemorrhage, and symptomatic intracranial hemorrhage.

RESULTS

Of 534 included patients, 93 (17%) had a post-EVT eTICI score of 0-2a, 115 (22%) a score of 2b, 73 (14%) a score of 2c, and 253 (47%) a score of 3. For both aspirin and heparin, we found no interaction between post-EVT eTICI score and treatment on the modified Rankin Scale score (p=0.76 and p=0.47, respectively). We found an interaction between post-EVT eTICI score and treatment with heparin on the final infarct volume (p=0.01). Of note, this interaction showed a biologically implausible distribution over the subgroups.

CONCLUSIONS

The overall harmful effect of periprocedural aspirin and unfractionated heparin is not different in patients with a successful reperfusion after EVT.