Shorter Door-to-Needle Times Are Associated With Better Outcomes After Intravenous Thrombolytic Therapy and Endovascular Thrombectomy for Acute Ischemic Stroke.

BACKGROUND: Existing data and clinical trials could not determine whether faster intravenous thrombolytic therapy (IVT) translates into better long-term functional outcomes after acute ischemic stroke among those treated with endovascular thrombectomy (EVT). Patient-level national data can provide the required large population to study the associations between earlier IVT, versus later, with longitudinal functional outcomes and mortality in patients receiving IVT+EVT combined treatment. METHODS: This cohort study included older US patients (age ≥65 years) who received IVT within 4.5 hours or EVT within 7 hours after acute ischemic stroke using the linked 2015 to 2018 Get With The Guidelines-Stroke and Medicare database (38 913 treated with IVT only and 3946 with IVT+EVT). Primary outcome was home time, a patient-prioritized functional outcome. Secondary outcomes included all-cause mortality in 1 year. Multivariate logistic regression and Cox proportional hazards models were used to evaluate the associations between door-to-needle (DTN) times and outcomes. RESULTS: Among patients treated with IVT+EVT, after adjusting for patient and hospital factors, including onset-to-EVT times, each 15-minute increase in DTN times for IVT was associated with significantly higher odds of zero home time in a year (never discharged to home) (adjusted odds ratio, 1.12 [95% CI, 1.06-1.19]), less home time among those discharged to home (adjusted odds ratio, 0.93 per 1% of 365 days [95% CI, 0.89-0.98]), and higher all-cause mortality (adjusted hazard ratio, 1.07 [95% CI, 1.02-1.11]). These associations were also statistically significant among patients treated with IVT but at a modest degree (adjusted odds ratio, 1.04 for zero home time, 0.96 per 1% home time for those discharged to home, and adjusted hazard ratio 1.03 for mortality). In the secondary analysis where the IVT+EVT group was compared with 3704 patients treated with EVT only, shorter DTN times (≤60, 45, and 30 minutes) achieved incrementally more home time in a year, and more modified Rankin Scale 0 to 2 at discharge (22.3%, 23.4%, and 25.0%, respectively) versus EVT only (16.4%, P<0.001 for each). The benefit dissipated with DTN>60 minutes. CONCLUSIONS: Among older patients with stroke treated with either IVT only or IVT+EVT, shorter DTN times are associated with better long-term functional outcomes and lower mortality. These findings support further efforts to accelerate thrombolytic administration in all eligible patients, including EVT candidates.

Intravenous Thrombolysis Before Endovascular Treatment in Posterior Circulation Occlusions: A MR CLEAN Registry Study.

BACKGROUND: The effectiveness of intravenous thrombolysis (IVT) before endovascular treatment (EVT) has been investigated in randomized trials and meta-analyses. These studies mainly concerned anterior circulation occlusions. We aimed to investigate clinical, technical, and safety outcomes of IVT before EVT in posterior circulation occlusions in a nationwide registry. METHODS: Patients were included from the MR CLEAN Registry (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands), a nationwide, prospective, multicenter registry of patients with acute ischemic stroke due to a large intracranial vessel occlusion receiving EVT between 2014 and 2019. All patients with a posterior circulation occlusion were included. Primary outcome was a shift toward better functional outcome on the modified Rankin Scale at 90 days. Secondary outcomes were favorable functional outcome (modified Rankin Scale scores, 0-3), occurrence of symptomatic intracranial hemorrhages, successful reperfusion (extended Thrombolysis in Cerebral Ischemia ≥2B), first-attempt successful reperfusion, and mortality at 90 days. Regression analyses with adjustments based on univariable analyses and literature were applied. RESULTS: A total of 248 patients were included, who received either IVT (n=125) or no IVT (n=123) before EVT. Results show no differences in a shift on the modified Rankin Scale (adjusted common odds ratio, 1.04 [95% CI, 0.61-1.76]). Although symptomatic intracranial hemorrhages occurred more often in the IVT group (4.8% versus 2.4%), regression analysis did not show a significant difference (adjusted odds ratio, 1.65 [95% CI, 0.33-8.35]). Successful reperfusion, favorable functional outcome, first-attempt successful reperfusion, and mortality did not differ between patients treated with and without IVT. CONCLUSIONS: We found no significant differences in clinical, technical, and safety outcomes between patients with a large vessel occlusion in the posterior circulation treated with or without IVT before EVT. Our results are in line with the literature on the anterior circulation.

How Clot Composition Influences Fibrinolysis in the Acute Phase of Stroke: A Proteomic Study of Cerebral Thrombi.

BACKGROUND: The dramatic clinical improvement offered by mechanical thrombectomy raised questions about the relevance of prior intravenous thrombolysis in large-vessel occlusion strokes. Hence, studying intravenous thrombolysis susceptibility and its dependence on thrombus composition is crucial. We used an observational proteomic study of whole thrombi retrieved by mechanical thrombectomy to identify factors associated with fibrin content and fibrinolytic activity (FA). METHODS: In 104 stroke patients, the thrombi proteome was established by mass spectrometry coupled to liquid chromatography. FA was estimated in clots both outside (FAout) by measuring D-dimer levels at the blood-thrombus interface and inside (FAin) by evaluating the ratio of fibrinogen α to its plasmin-cleaved forms using proteomics coupled with protein electrophoresis. The factors associated with fibrin content, FAin, and FAout were determined by intravenous thrombolysis-adjusted linear regression. RESULTS: FAout (P<0.0001) and FAin (P=0.0147) were driven by recombinant tissue-type plasminogen activator (r-tPA) administration (47/104) and thrombus composition. Indeed, FAout was greater with fibrin-rich than erythrocyte-rich thrombi, presumably because of more (r)tPA substrates. Thus, FAout was increased with cardioembolic thrombi (72/104), which are rich in fibrin (P=0.0300). Opposite results were found inside the thrombus, suggesting that (r)tPA penetrability was hampered by the density of the fibrinous cap. Moreover, blood cells had a strong impact on thrombus structure and susceptibility to (r)tPA. Indeed, fibrin content was negatively associated with erythrocyte-specific proteins in the thrombus, admission hematocrit (P=0.0139), and hemoglobin level (P=0.0080), which underlines the key role of erythrocytes in thrombus composition. Also, an increased number of neutrophils impaired FAout (P=0.0225), which suggests that their aggregation around the thrombus prevented the (r)tPA attack. Only FAout was significantly associated with reduced thrombus weight (P=0.0310), increased recanalization rate (P=0.0150), good clinical outcome (P=0.0480), and reduced mortality (P=0.0080). CONCLUSIONS: Proteomics can offer new insights into the close relationship between thrombus composition and susceptibility to fibrinolysis, paving the way for new adjuvant therapies.

Intravenous Tirofiban Versus Alteplase Before Endovascular Treatment in Acute Ischemic Stroke: A Pooled Analysis of the DEVT and RESCUE BT Trials.

BACKGROUND: The present study aimed to evaluate the efficacy and safety of intravenous tirofiban versus alteplase before endovascular treatment (EVT) in acute ischemic stroke patients with intracranial large vessel occlusion. METHODS: This was a post hoc analysis using data from 2 multicenter, randomized trials: the DEVT trial (Direct Endovascular Treatment for Large Vessel Occlusion Stroke) from May 2018 to May 2020 and the RESCUE BT trial (Intravenous Tirofiban Before Endovascular Thrombectomy for Acute Ischemic Stroke) from October 2018 to October 2021. Patients with acute intracranial large vessel occlusion within 4.5 hours from last known well were dichotomized into 2 groups: tirofiban plus EVT versus alteplase bridging with EVT. The primary outcome was functional independence (modified Rankin Scale score of 0-2) at 90 days. Safety outcomes included symptomatic intracranial hemorrhage and 3-month mortality. Multivariable logistic regression (adjusting for baseline systolic blood pressure, occlusion site, onset-to-puncture time, anesthesia, and first choice of EVT) and propensity score overlap weighting (balance in demographic covariates, stroke characteristics, and initial management between groups) were performed. RESULTS: One-hundred and eighteen alteplase-treated patients in the DEVT trial and 98 tirofiban-treated patients in the RESCUE BT trial were included (median age, 70 years; 115 [53.2%] men). The rate of functional independence was 60.2% in the tirofiban group compared with 46.6% in the alteplase group (adjusted odds ratio, 1.25 [95% CI, 0.60-2.63]). Compared with alteplase, tirofiban was not associated with increased risk of symptomatic intracranial hemorrhage (6.8% versus 9.2%; P=0.51) and mortality (17.8% versus 19.4%; P=0.76). The propensity score overlap weighting analyses showed consistent outcomes. CONCLUSIONS: Among patients with intracranial large vessel occlusion within 4.5 hours of onset, tirofiban plus EVT was comparable to alteplase bridging with EVT regarding the efficacy and safety outcomes. These findings should be interpreted as preliminary and require confirmation in a randomized trial. REGISTRATION: URL: https://www.chictr.org.cn; Unique identifiers: ChiCTR-IOR-17013568 and ChiCTR-INR-17014167.

Endovascular Treatment of Medium Vessel Occlusion Stroke.

Approximately one-third of acute ischemic strokes with an identifiable vessel occlusion are caused by medium vessel occlusion (MeVO), that is, nonlarge vessel occlusions that are potentially amenable to endovascular treatment (EVT). Management of patients with MeVO is challenging in many ways: detecting MeVOs can be challenging, particularly for inexperienced physicians, and in busy clinical routine, MeVOs, therefore, remain sometimes undiagnosed. While the clinical course of MeVO stroke with medical management, including intravenous thrombolysis, is by no means, benign, it is more favorable compared with large vessel occlusion. At the same time, EVT complication rates are higher, and thus, the marginal benefit of EVT beyond best medical management is expected to be smaller and more challenging to detect if it were present. Several randomized controlled trials are currently underway to investigate whether and to what degree patients with MeVO may benefit from EVT and will soon provide robust data for evidence-based MeVO EVT decision-making. In this review, we discuss different ways of defining MeVOs, strategies to optimize MeVO detection on imaging, and considerations for EVT decision-making in the setting of MeVO stroke. We discuss the technical challenges related to MeVO EVT and conclude with an overview of currently ongoing MeVO EVT trials.

R-tPA Resistance Is Specific for Platelet-Rich Stroke Thrombi and Can Be Overcome by Targeting Nonfibrin Components.

BACKGROUND: Resistance to r-tPA (recombinant tissue-type plasminogen activator) is a well-known but poorly understood phenomenon that hampers successful recanalization in patients with acute ischemic stroke. Using clinically relevant thrombi from patients with acute ischemic stroke, we investigated if and how thrombus composition impacts r-tPA-mediated lysis. In addition, we explored strategies to overcome r-tPA resistance. METHODS: Thrombi were split into 2 parts, 1 of which was used for thrombolysis and the other for detailed histological analysis. Thrombolysis was performed in normal human plasma using r-tPA alone, using r-tPA in combination with DNase-1 or using r-tPA in combination with N,N'-diacetyl-l-cystine. Thrombus lysis was calculated as the percentage of residual thrombus weight compared with its initial weight and the degree of lysis was linked to thrombus composition determined via histology. RESULTS: Interestingly, we found that the efficacy of r-tPA-mediated thrombolysis was strongly correlated with the composition of the thrombi. Thrombi containing high amounts of red blood cells and low amounts of DNA and von Willebrand Factor were efficiently degraded by r-tPA, whereas thrombi containing low amounts of red blood cells and higher amounts of DNA and von Willebrand Factor were resistant to r-tPA. Importantly, combination of r-tPA with DNase-1 or N,N'-diacetyl-l-cystine significantly and specifically improved the lysis of these r-tPA-resistant thrombi. CONCLUSIONS: Using patient thrombus material, our results for the first time show that the composition of stroke thrombi largely determines their susceptibility to r-tPA-mediated thrombolysis. Red blood cell-poor thrombi have a specific resistance to r-tPA, which can be overcome by targeting nonfibrin components using DNase-1 or N,N'-diacetyl-l-cystine.

Outcomes of Bridging Intravenous Thrombolysis Versus Endovascular Therapy Alone in Late-Window Acute Ischemic Stroke.

BACKGROUND: Studies comparing bridging intravenous thrombolysis (IVT) with direct endovascular therapy (EVT) in patients with acute ischemic stroke who present late are limited. We aimed to compare the clinical outcomes and safety of bridging IVT in patients with acute ischemic stroke due to anterior circulation large vessel occlusion who underwent EVT 6 to 24 hours after time last known well. METHODS: We enrolled patients with anterior circulation large vessel occlusion stroke and a National Institutes of Health Stroke Scale score of ≥6 from 20 centers across 10 countries in the multicenter retrospective CLEAR study (CT for Late Endovascular Reperfusion) between January 2014 and May 2022. We used inverse probability of treatment weighting modeling adjusted for clinical and imaging confounders to compare functional outcomes, reperfusion success, symptomatic intracranial hemorrhage, and mortality between EVT patients with and without prior IVT. RESULTS: Of 5098 patients screened for eligibility, we included 2749 patients, of whom 549 received bridging IVT before EVT. The timing of IVT was not recorded. Witnessed stroke onset and transfer rates were higher in the bridging IVT group (25% versus 12% and 77% versus 55%, respectively, P value for both <0.0001), and time intervals between stroke onset and treatment were shorter (time last known well-start of EVT median 560 minutes [interquartile range, 432-791] versus 724 minutes [interquartile range, 544-912]; P<0.0001). After adjustment for confounders, there was no difference in functional outcome at 3 months (adjusted common odds ratio for modified Rankin Scale shift, 1.03 [95% CI, 0.89-1.19]; P=0.72) or successful reperfusion (adjusted odds ratio, 1.19 [95% CI, 0.81-1.75]; P=0.39). There were no safety concerns associated with bridging IVT versus direct EVT (symptomatic intracranial hemorrhage: adjusted odds ratio, 0.75 [95% CI, 0.38-1.48]; P=0.40; mortality: adjusted odds ratio, 1.14 [95% CI, 0.89-1.46]; P=0.31). Results were unchanged when the analysis was limited to patients who received IVT >6 hours after last known well. CONCLUSIONS: In patients with an anterior circulation large vessel occlusion stroke who underwent EVT 6 to 24 hours from last known well, bridging IVT was not associated with a difference in outcomes compared with direct EVT. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04096248.

Arterial Recanalization During Interhospital Transfer for Thrombectomy.

BACKGROUND: Patients with acute ischemic stroke harboring a large vessel occlusion admitted to nonendovascular-capable centers often require interhospital transfer for thrombectomy. We evaluated the incidence and predictors of arterial recanalization during transfer, as well as the relationship between interhospital recanalization and clinical outcomes. METHODS: We analyzed data from 2 cohorts of patients with an anterior circulation large vessel occlusion transferred for consideration of thrombectomy to a comprehensive center, with arterial imaging at the referring hospital and on comprehensive stroke center arrival. Interhospital recanalization was determined by comparison of the baseline and posttransfer arterial imaging and was defined as revised arterial occlusive lesion (rAOL) score 2b to 3. Pretransfer variables independently associated with interhospital recanalization were studied using multivariable logistic regression analysis. RESULTS: Of the 520 included patients (Montpellier, France, n=237; Stanford, United States, n=283), 111 (21%) experienced interhospital recanalization (partial [rAOL=2b] in 77% and complete [rAOL=3] in 23%). Pretransfer variables independently associated with recanalization were intravenous thrombolysis (adjusted odds ratio, 6.8 [95% CI, 4.0-11.6]), more distal occlusions (intracranial carotid occlusion as reference: adjusted odds ratio, 2.0 [95% CI, 0.9-4.5] for proximal first segment of the middle cerebral artery, 5.1 [95% CI, 2.3-11.5] for distal first segment of the middle cerebral artery, and 5.0 [95% CI, 2.1-11.8] for second segment of the middle cerebral artery), and smaller clot burden (clot burden score 0-4 as reference: adjusted odds ratio, 3.4 [95% CI, 1.5-7.6] for 5-7 and 5.6 [95% CI, 2.4-12.7] for 8-9). Recanalization on arrival at the comprehensive center was associated with less interhospital infarct growth (rAOL, 0-2a: 11.6 mL; rAOL, 2b: 2.2 mL; rAOL, 3: 0.6 mL; Ptrend<0.001) and greater interhospital National Institutes of Health Stroke Scale score improvement (0 versus -5 versus -6; Ptrend<0.001). Interhospital recanalization was associated with reduced 3-month disability (adjusted common odds ratio, 2.51 [95% CI, 1.68-3.77]) with greater benefit from complete than partial recanalization. CONCLUSIONS: Recanalization is frequently observed during interhospital transfer for thrombectomy and is strongly associated with favorable outcomes, even when partial. Broadening thrombolysis indications in primary centers, and developing therapies that increase recanalization during transfer, will likely improve clinical outcomes.

Comparing Outcomes of Thrombectomy Versus Intravenous Thrombolysis Based on Middle Cerebral Artery M2 Occlusion Features.

BACKGROUND: Current evidence provides limited support for the superiority of endovascular thrombectomy (EVT) in patients with M2 segment middle cerebral artery occlusion. We aim to investigate whether imaging features of M2 segment occlusion impact the effectiveness of EVT. METHODS: We conducted a retrospective cohort study from January 2017 to January 2022, drawing data from the CASE II registry (Computer-Based Online Database of Acute Stroke Patients for Stroke Management Quality Evaluation), which specifically documented patients with acute ischemic stroke presenting with M2 segment occlusion undergoing reperfusion therapy. Patients were stratified into the intravenous thrombolysis (IVT) group (IVT alone) and EVT group (IVT plus EVT or EVT alone). The primary outcome was a modified Rankin Scale score 0 to 2 at 90 days. Secondary outcomes included additional thresholds and distribution of modified Rankin Scale scores, 24-hour recanalization, early neurological deterioration, and relevant complications during hospitalization. Safety outcomes encompassed intracranial hemorrhagic events at 24 hours and mortality at 90 days. Binary logistic regression analyses with propensity score matching were used. Subgroup analyses were performed based on the anatomic site of occlusion, including right versus left, proximal versus distal, dominant/co-dominant versus nondominant, single versus double/triple branch(es), and anterior versus central/posterior branch. RESULTS: Among 734 patients (43.3% were females; median age, 73 years) with M2 segment occlusion, 342 (46.6%) were in the EVT group. Propensity score matching analysis revealed no statistical difference in the primary outcome (odds ratio, 0.860 [95% CI, 0.611-1.209]; P=0.385) between the EVT group and IVT group. However, EVT was associated with a higher incidence of subarachnoid hemorrhage (odds ratio, 6.655 [95% CI, 1.487-29.788]; P=0.004) and pneumonia (odds ratio, 2.015 [95% CI, 1.364-2.977]; P<0.001). Subgroup analyses indicated that patients in the IVT group achieved better outcomes when presenting with right, distal, or nondominant branch occlusion (Pall interaction<0.05). CONCLUSIONS: Our study showed similar efficiency of EVT versus IVT alone in acute M2 segment middle cerebral artery occlusion. This suggested that only specific patient subpopulations might have a potentially higher benefit of EVT over IVT alone. REGISTRATION: URL: https://clinicaltrials.gov; Unique identifier: NCT04487340.

Safety and Efficacy of Reteplase Versus Alteplase for Acute Ischemic Stroke: A Phase 2 Randomized Controlled Trial.

BACKGROUND: Reteplase is a more affordable new-generation thrombolytic with a prolonged half-life. We aimed to determine the safety dose range of reteplase for patients with acute ischemic stroke within 4.5 hours of onset. METHODS: This is a multicenter, prospective, randomized controlled, open-label, blinded-end point phase 2 clinical trial. Patients with acute ischemic stroke aged between 18 and 80 years who were eligible for standard intravenous thrombolysis were enrolled from 17 centers in China and randomly assigned (1:1:1) to receive intravenous reteplase 12+12 mg, intravenous reteplase 18+18 mg, or intravenous alteplase 0.9 mg/kg. The primary safety outcome was symptomatic intracranial hemorrhage (SITS definition) within 36 hours. The primary efficacy outcome was the proportion of patients with the National Institutes of Health Stroke Scale score of no more than 1 or a decrease of at least 4 points from the baseline at 14 days after thrombolysis. RESULTS: Between August 2019 and May 2021, 180 patients were randomly assigned to reteplase 12+12 mg (n=61), reteplase 18+18 mg (n=67), or alteplase (n=52). Four patients did not receive the study agent. Symptomatic intracranial hemorrhage occurred in 3 of 60 (5.0%) in the reteplase 12+12 mg group, 1 of 66 (1.5%) in the reteplase 18+18 mg group, and 1 of 50 (2.0%) in the alteplase group (P=0.53). The primary efficacy outcome in the modified intention-to-treat population occurred in 45 of 60 (75.0%) in the reteplase 12+12 mg group (odds ratio, 0.85 [95% CI, 0.35-2.06]), 48 of 66 (72.7%) in the reteplase 18+18 mg group (odds ratio, 0.75 [95% CI, 0.32-1.78]), and 39 of 50 (78.0%) in alteplase group. CONCLUSIONS: Reteplase was well tolerated in patients with acute ischemic stroke within 4.5 hours of onset in China with a similar efficacy profile to alteplase. The efficacy and appropriate dosage of reteplase for patients with acute ischemic stroke need prospective validation. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04028518.

Lack of Interactions Between Alteplase/Tenecteplase and the Adenosine A1R/A3R Agonist AST-004.

BACKGROUND: AST-004, a small molecule agonist of the adenosine A1 and A3 receptors, is a potential cerebroprotectant for patients with acute stroke and is currently in clinical trials. Drug-drug interactions are critically important to assess in the context of acute stroke care. Lytic therapy with tPA (tissue-type plasminogen activator)-induced plasmin formation (alteplase) is the only available pharmacotherapy for acute stroke. Consequently, it is imperative to evaluate potential interactions between AST-004 and tPAs such as alteplase and tenecteplase. METHODS: The interactions between AST-004 and tPAs were evaluated in 3 ways in preparation for AST-004 phase II trials. First, the metabolic stability of AST-004 was determined in the presence of alteplase and plasmin. Second, the potential for AST-004 to influence the thrombolytic efficacy of alteplase and tenecteplase was evaluated with an in vitro assay system utilizing a fluorogenic substrate of plasmin. Finally, the potential for AST-004 to influence the thrombolytic efficacy of alteplase was also determined with an in vitro thrombolysis assay of human blood thrombi. RESULTS: Neither alteplase nor plasmin affected the stability of AST-004 in vitro. In 2 different in vitro systems, AST-004 had no effect on the ability of alteplase or tenecteplase to generate plasmin, and AST-004 had no effect on the thrombolytic efficacy of alteplase to lyse blood clots in human blood. CONCLUSIONS: These studies indicate that there will be no interactions between AST-004 and tPAs such as alteplase or tenecteplase in patients with stroke undergoing thrombolytic therapy.

Endovascular Thrombectomy with or without Bridging Thrombolysis in Acute Ischemic Stroke: A Cost-Effectiveness Analysis.

BACKGROUND: There is unclear added benefit of intravenous thrombolysis (IVT) with endovascular thrombectomy (EVT). We performed a cost-effectiveness analysis to assess the cost-effectiveness of comparing EVT with IVT versus EVT alone. METHODS: We used a decision tree to examine the short-term costs and outcomes at 90 days after the occurrence of index stroke to compare the cost-effectiveness of EVT alone with EVT plus IVT for patients with stroke. Subsequently, we developed a Markov state transition model to assess the costs and outcomes over 1-year, 5-year, and 20-year time horizons. We estimated total and incremental cost, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio. RESULTS: The average costs per patient were estimated to be $47,304, $49,510, $59,770, and $76,561 for EVT-only strategy and $55,482, $57,751, $68,314, and $85,611 for EVT with IVT over 90 days, 1 year, 5 years, and 20 years, respectively. The cost saving of EVT-only strategy was driven by the avoided medication costs of IVT (ranging from $8,178 to $9,050). The additional IVT led to a slight decrease in QALY estimate during the 90-day time horizon (loss of 0.002 QALY), but a small gain over 1-year and 5-year time horizons (0.011 and 0.0636 QALY). At a willingness-to-pay threshold of $50,000 per QALY gained, the probabilities of EVT only being cost-effective were 100%, 100%, and 99.3% over 90-day, 1-year, and 5-year time horizons. CONCLUSION: Our cost-effectiveness model suggested that EVT only may be cost-effective for patients with acute ischemic stroke secondary to large vessel occlusion.

Heterologous expression, purification and single step efficient refolding of recombinant tissue plasminogen activator (Reteplase) from E. coli.

Reteplase (recombinant plasminogen activator, rPA) is a mutant non-glycosylated tissue-type plasminogen activator (tPA) containing 355 amino acids with longer half-life and promising thrombolytic activity than its original counterpart, full length tPA. In this study, we aimed to produce and optimize the purification process of recombinant tissue-type plasminogen activator (tPA) known as Reteplase (rPA). Reteplase cDNA synthesized from total mRNA isolated from human placenta was PCR amplified, cloned into a pET-28a(+) E. coli expression vector and expressed in Rosetta-gami 2 E. coli (NovagenⓇ) host. rPA was expressed as an inclusion body in E. coli and its biological activity was achieved after single step solubilization, purification and refolding. We exploited the strategy of Slow Refolding using Gradual Dialysis (SRGD) in which a refolding buffer containing glutathione oxidized (1 mM GSSG) and glutathione reduced (3 mM GSH) and pH 9.0 was used. Using the SRGD method, we were able to successfully obtain the protein in its active form. We obtained 4.26 mg of active refolded protein from a 50 mL culture that was scaled up in a bioreactor. The purity and homogeneity of rPA was evaluated by SDS-PAGE, Western blotting and mass spectrometry. Circular dichroism spectroscopy was conducted to evaluate the refolding and stability of the refolded rPA in comparison to reference standard rPA. The thrombolytic potential of rPA was assessed by fibrin plate assay and In Vitro clot lysis assay. The presented protocol offers a viable approach for enhancing both the yield and refolding efficiency of reteplase, potentially resulting in an increase in yield.

Radiomics using non-contrast CT to predict hemorrhagic transformation risk in stroke patients undergoing revascularization.

OBJECTIVES: This study explores whether textural features from initial non-contrast CT scans of infarcted brain tissue are linked to hemorrhagic transformation susceptibility. MATERIALS AND METHODS: Stroke patients undergoing thrombolysis or thrombectomy from Jan 2012 to Jan 2022 were analyzed retrospectively. Hemorrhagic transformation was defined using follow-up magnetic resonance imaging. A total of 94 radiomic features were extracted from the infarcted tissue on initial NCCT scans. Patients were divided into training and test sets (7:3 ratio). Two models were developed with fivefold cross-validation: one incorporating first-order and textural radiomic features, and another using only textural radiomic features. A clinical model was also constructed using logistic regression with clinical variables, and test set validation was performed. RESULTS: Among 362 patients, 218 had hemorrhagic transformations. The LightGBM model with all radiomics features had the best performance, with an area under the receiver operating characteristic curve (AUROC) of 0.986 (95% confidence interval [CI], 0.971-1.000) on the test dataset. The ExtraTrees model performed best when textural features were employed, with an AUROC of 0.845 (95% CI, 0.774-0.916). Minimum, maximum, and ten percentile values were significant predictors of hemorrhagic transformation. The clinical model showed an AUROC of 0.544 (95% CI, 0.431-0.658). The performance of the radiomics models was significantly better than that of the clinical model on the test dataset (p < 0.001). CONCLUSIONS: The radiomics model can predict hemorrhagic transformation using NCCT in stroke patients. Low Hounsfield unit was a strong predictor of hemorrhagic transformation, while textural features alone can predict hemorrhagic transformation. CLINICAL RELEVANCE STATEMENT: Using radiomic features extracted from initial non-contrast computed tomography, early prediction of hemorrhagic transformation has the potential to improve patient care and outcomes by aiding in personalized treatment decision-making and early identification of at-risk patients. KEY POINTS: • Predicting hemorrhagic transformation following thrombolysis in stroke is challenging since multiple factors are associated. • Radiomics features of infarcted tissue on initial non-contrast CT are associated with hemorrhagic transformation. • Textural features on non-contrast CT are associated with the frailty of the infarcted tissue.

Deep learning-based white matter lesion volume on CT is associated with outcome after acute ischemic stroke.

BACKGROUND: Intravenous thrombolysis (IVT) before endovascular treatment (EVT) for acute ischemic stroke might induce intracerebral hemorrhages which could negatively affect patient outcomes. Measuring white matter lesions size using deep learning (DL-WML) might help safely guide IVT administration. We aimed to develop, validate, and evaluate a DL-WML volume on CT compared to the Fazekas scale (WML-Faz) as a risk factor and IVT effect modifier in patients receiving EVT directly after IVT. METHODS: We developed a deep-learning model for WML segmentation on CT and validated with internal and external test sets. In a post hoc analysis of the MR CLEAN No-IV trial, we associated DL-WML volume and WML-Faz with symptomatic-intracerebral hemorrhage (sICH) and 90-day functional outcome according to the modified Rankin Scale (mRS). We used multiplicative interaction terms between WML measures and IVT administration to evaluate IVT treatment effect modification. Regression models were used to report unadjusted and adjusted common odds ratios (cOR/acOR). RESULTS: In total, 516 patients from the MR CLEAN No-IV trial (male/female, 291/225; age median, 71 [IQR, 62-79]) were analyzed. Both DL-WML volume and WML-Faz are associated with sICH (DL-WML volume acOR, 1.78 [95%CI, 1.17; 2.70]; WML-Faz acOR, 1.53 95%CI [1.02; 2.31]) and mRS (DL-WML volume acOR, 0.70 [95%CI, 0.55; 0.87], WML-Faz acOR, 0.73 [95%CI 0.60; 0.88]). Only in the unadjusted IVT effect modification analysis WML-Faz was associated with more sICH if IVT was given (p = 0.046). Neither WML measure was associated with worse mRS if IVT was given. CONCLUSION: DL-WML volume and WML-Faz had a similar relationship with functional outcome and sICH. Although more sICH might occur in patients with more severe WML-Faz receiving IVT, no worse functional outcome was observed. CLINICAL RELEVANCE STATEMENT: White matter lesion severity on baseline CT in acute ischemic stroke patients has a similar predictive value if measured with deep learning or the Fazekas scale. Safe administration of intravenous thrombolysis using white matter lesion severity should be further studied. KEY POINTS: White matter damage is a predisposing risk factor for intracranial hemorrhage in patients with acute ischemic stroke but remains difficult to measure on CT. White matter lesion volume on CT measured with deep learning had a similar association with symptomatic intracerebral hemorrhages and worse functional outcome as the Fazekas scale. A patient-level meta-analysis is required to study the benefit of white matter lesion severity-based selection for intravenous thrombolysis before endovascular treatment.

Evaluation of phytochemical, antibacterial, thrombolytic, anti-inflammatory, and cytotoxicity profile of Achyranthes aspera aerial part extracts.

This investigation was designed and performed to compare the phytochemical profiling, activities of antibacterial, thrombolytic, anti-inflammatory, and cytotoxicity of methanol extract (ME-E) and aqueous extract (AQ-E) of aerial parts of Achyranthes aspera through in-vitro approach. Also characterize the functional groups of bioactive compounds in the ME-E through Fourier-transform infrared (FTIR) spectroscopy analysis. Interestingly, qualitative phytochemical screening proved that the ME-E contain more number of vital phytochemicals such as phenolics. saponins, tannins, alkaloids, flavonoids, cardiac glycosides, steroids, and phlobatannins than AQ-E. Similarly, the ME-E showed notable antibacterial activity as dose dependent manner against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa at 1000 µg mL-1 concentration. ME-E also showed 75.2 ± 2% of clot lysis (thrombolytic activity) at 1000 µg mL-1 dosage and it followed by AQ-E 51.24 ± 3%. The ME-E showed moderate and AQ-E demonstrate poor anti-inflammatory activity evidenced by albumin denaturation inhibition and anti-lipoxygenase assays. Furthermore, the ME-E demonstrated a dose dependent cytotoxicity was noted against brine shrimp larvae. In support of this ME-E considerable activities, the Fourier transform infrared (FTIR) analysis confirmed that this extract contain more number peaks attributed to the stretch of various essential functional groups belongs to different bioactive compounds. Hence this ME-E of A. aspera can be considered for further in depth scientific investigations to validate their maximum biomedical potential.

Beyond silence: evolving ultrasound strategies in the battle against cardiovascular thrombotic challenges.

Cardiovascular thrombotic events have long been a perplexing factor in clinical settings, influencing patient prognoses significantly. Ultrasound-mediated acoustic therapy, an innovative thrombolytic treatment method known for its high efficiency, non-invasiveness, safety, and convenience, has demonstrated promising potential for clinical applications and has gradually become a focal point in cardiovascular thrombotic disease research. The current challenge lies in the technical complexities of preparing ultrasound-responsive carriers with thrombus-targeting capabilities and high thrombolytic efficiency. Additionally, optimizing the corresponding acoustic treatment mode is crucial to markedly enhance the thrombolytic effectiveness of ultrasound-mediated acoustic therapy. In light of the current status, this article provides a comprehensive review of the research progress in innovative ultrasound-mediated acoustic therapy for cardiovascular thrombotic diseases. It explores the impact of technical methods, therapeutic mechanisms, and influencing factors on the thrombolytic efficiency and clinical potential of ultrasound-mediated acoustic therapy. The review places particular emphasis on identifying solutions and key considerations in addressing the challenges associated with this cutting-edge therapeutic approach.

Evaluation of Post-thrombolytic Events to Determine Appropriate ICU Monitoring Duration for Patients with Ischemic Stroke.

BACKGROUND: Standard treatment for eligible patients presenting with acute ischemic stroke (AIS) is thrombolysis with tissue plasminogen activators alteplase or tenecteplase. Current guidelines recommend monitoring patients in an intensive care unit (ICU) for 24 h after thrombolytic therapy. However, recent studies have questioned the need for prolonged ICU monitoring. This retrospective cohort study aims to identify potential candidates for early transition to a lower level of care by assessing risk factors for neurological deterioration, symptomatic intracranial hemorrhage (sICH), or need for ICU intervention within 24 h post-thrombolysis. METHODS: This retrospective cohort study included adult patients 18 years and older with AIS who received thrombolysis. Patients were excluded if they were transferred to another facility, if they were transitioned to comfort care or hospice care within 24 h, or if they lacked imaging and National Institutes of Health Stroke Scale (NIHSS) score data. The primary end point was incidence of sICH between 0-12 and 12-24 h. Secondary end points included the need for ICU intervention and rates of neurological deterioration. RESULTS: The analysis included 204 patients who received the full dose of alteplase. Among them, ten patients (4.9%) developed sICH, with the majority (n = 7) occurring within 12 h post-thrombolysis. Sixty-two patients required ICU interventions within 12 h compared with four patients after 12 h. Twenty-four patients had neurological deterioration within 12 h, and seven patients had neurological deterioration after 12 h. Multivariable analysis identified mechanical thrombectomy and increased blood pressure at presentation as predictors of ICU need beyond 12 h post-thrombolysis. CONCLUSIONS: Our study demonstrates that sICH, neurological deterioration, and need for ICU intervention rarely occur beyond 12 h after thrombolytic administration. Patients presenting with blood pressures < 140/90 mm Hg, NIHSS scores < 10, and not undergoing mechanical thrombectomy may be best candidates for early de-escalation. Larger prospective studies are needed to more fully evaluate the safety, feasibility, and financial impact of early transition out of the ICU.

A qualitative study of barriers and facilitators to using tenecteplase to treat acute ischemic stroke.

BACKGROUND: Tenecteplase (TNK) is emerging as an alternative to alteplase (ALT) for thrombolytic treatment of acute ischemic stroke (AIS). Compared to ALT, TNK has a longer half-life, shorter administration time, lower cost, and similarly high efficacy in treating large vessel occlusion. Nevertheless, there are barriers to adopting TNK as a treatment for AIS. This study aimed to identify thematic barriers and facilitators to adopting TNK as an alternative to ALT as a thrombolytic for eligible AIS patients. METHODS: Qualitative research methodology using hermeneutic cycling and purposive sampling was used to interview four stroke clinicians in Texas. Interviews were recorded and transcribed verbatim. Enrollment was complete when saturation was reached. All members of the research team participated in content analysis during each cycle and in thematic analysis after saturation. RESULTS: Interviews were conducted between November 2022 and February 2023 with stroke center representatives from centers that either had successfully adopted TNK, or had not yet adopted TNK. Three themes and eight sub-themes were identified. The theme "Evidence" had three sub-themes: Pro-Con Balance, Fundamental Knowledge, and Pharmacotherapeutics. The theme "Process Flow" had four subthemes: Proactive, Reflective self-doubt, Change Process Barriers, and Parameter Barriers. The theme "Consensus" had one sub-theme: Getting Buy-In. CONCLUSION: Clinicians experience remarkably similar barriers and facilitators to adopting TNK. The results lead to a hypothesis that providing evidence to support a practice change, and identifying key change processes, will help clinicians achieve consensus across teams that need to 'buy in' to adopting TNK for AIS treatment.

Non-compliance with medical recommendations results in delayed hospitalization and poorer prognosis in patients with cerebral ischemic stroke in Poland: Non-compliance effects on post-ischemic stroke prognosis.

OBJECTIVES: This study aimed to reveal and analyze the causes of delays in reaching the hospital of patients with cerebral ischemic stroke and to assess their clinical picture. MATERIAL AND METHODS: The study group included 161 patients with stroke, who reported to the hospital beyond the thrombolytic treatment therapeutic window. The control group consisted of 85 patients recruited consecutively with stroke who received thrombolytic treatment per eligibility criteria. Laboratory and medical imaging tests essential for neurological condition assessment were conducted in the study group. Control group research was based on retrospective analysis of medical records. RESULTS: The rate of deaths during hospitalization was lower in the control group (4.7%) compared to the study group (14.9%). In the study group, more patients (16.8%) admitted to non-compliance with medical recommendations than in the control group (5.9%). There were no statistically significant differences in nicotinism and alcohol dependence syndrome frequency between both groups. CONCLUSIONS: Based on each group inclusion criteria, a lower mortality rate in the control group indicates a crucial role of the therapeutic window in cerebral stroke treatment. Analysis of reasons for delay points out that efficient prophylaxis is the education of patients with stroke risk factors and their families.