Diffusion-Weighted Imaging Fluid-Attenuated Inversion Recovery Mismatch on Portable, Low-Field Magnetic Resonance Imaging Among Acute Stroke Patients.

OBJECTIVE: For stroke patients with unknown time of onset, mismatch between diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) can guide thrombolytic intervention. However, access to MRI for hyperacute stroke is limited. Here, we sought to evaluate whether a portable, low-field (LF)-MRI scanner can identify DWI-FLAIR mismatch in acute ischemic stroke. METHODS: Eligible patients with a diagnosis of acute ischemic stroke underwent LF-MRI acquisition on a 0.064-T scanner within 24 h of last known well. Qualitative and quantitative metrics were evaluated. Two trained assessors determined the visibility of stroke lesions on LF-FLAIR. An image coregistration pipeline was developed, and the LF-FLAIR signal intensity ratio (SIR) was derived. RESULTS: The study included 71 patients aged 71 ± 14 years and a National Institutes of Health Stroke Scale of 6 (interquartile range 3-14). The interobserver agreement for identifying visible FLAIR hyperintensities was high (κ = 0.85, 95% CI 0.70-0.99). Visual DWI-FLAIR mismatch had a 60% sensitivity and 82% specificity for stroke patients <4.5 h, with a negative predictive value of 93%. LF-FLAIR SIR had a mean value of 1.18 ± 0.18 <4.5 h, 1.24 ± 0.39 4.5-6 h, and 1.40 ± 0.23 >6 h of stroke onset. The optimal cut-point for LF-FLAIR SIR was 1.15, with 85% sensitivity and 70% specificity. A cut-point of 6.6 h was established for a FLAIR SIR <1.15, with an 89% sensitivity and 62% specificity. INTERPRETATION: A 0.064-T portable LF-MRI can identify DWI-FLAIR mismatch among patients with acute ischemic stroke. Future research is needed to prospectively validate thresholds and evaluate a role of LF-MRI in guiding thrombolysis among stroke patients with uncertain time of onset. ANN NEUROL 2024.

Caspase-4/11 exacerbates disease severity in SARS-CoV-2 infection by promoting inflammation and immunothrombosis.

Severe acute respiratory syndrome coronavirus 2 (SARS­CoV-2) is a worldwide health concern, and new treatment strategies are needed. Targeting inflammatory innate immunity pathways holds therapeutic promise, but effective molecular targets remain elusive. Here, we show that human caspase-4 (CASP4) and its mouse homolog, caspase-11 (CASP11), are up-regulated in SARS­CoV-2 infections and that CASP4 expression correlates with severity of SARS­CoV-2 infection in humans. SARS­CoV-2­infected Casp11−/− mice were protected from severe weight loss and lung pathology, including blood vessel damage, compared to wild-type (WT) mice and mice lacking the caspase downstream effector gasdermin-D (Gsdmd−/−). Notably, viral titers were similar regardless of CASP11 knockout. Global transcriptomics of SARS­CoV-2­infected WT, Casp11−/−, and Gsdmd−/− lungs identified restrained expression of inflammatory molecules and altered neutrophil gene signatures in Casp11−/− mice. We confirmed that protein levels of inflammatory mediators interleukin (IL)-1ß, IL-6, and CXCL1, as well as neutrophil functions, were reduced in Casp11−/− lungs. Additionally, Casp11−/− lungs accumulated less von Willebrand factor, a marker for endothelial damage, but expressed more Kruppel-Like Factor 2, a transcription factor that maintains vascular integrity. Overall, our results demonstrate that CASP4/11 promotes detrimental SARS­CoV-2­induced inflammation and coagulopathy, largely independently of GSDMD, identifying CASP4/11 as a promising drug target for treatment and prevention of severe COVID-19.

Direct Versus Indirect Revascularization for Moyamoya: a Large Multicenter Study.

BACKGROUND: Moyamoya is a chronic occlusive cerebrovascular disease of unknown etiology causing neovascularization of the lenticulostriate collaterals at the base of the brain. Although revascularization surgery is the most effective treatment for moyamoya, there is still no consensus on the best surgical treatment modality as different studies provide different outcomes. OBJECTIVE: In this large case series, we compare the outcomes of direct (DR) and indirect revascularisation (IR) and compare our results to the literature in order to reflect on the best revascularization modality for moyamoya. METHODS: We conducted a multicenter retrospective study in accordance with the Strengthening the Reporting of Observational studies in Epidemiology guidelines of moyamoya affected hemispheres treated with DR and IR surgeries across 13 academic institutions predominantly in North America. All patients who underwent surgical revascularization of their moyamoya-affected hemispheres were included in the study. The primary outcome of the study was the rate of symptomatic strokes. RESULTS: The rates of symptomatic strokes across 515 disease-affected hemispheres were comparable between the two cohorts (11.6% in the DR cohort vs 9.6% in the IR cohort, OR 1.238 (95% CI 0.651 to 2.354), p=0.514). The rate of total perioperative strokes was slightly higher in the DR cohort (6.1% for DR vs 2.0% for IR, OR 3.129 (95% CI 0.991 to 9.875), p=0.052). The rate of total follow-up strokes was slightly higher in the IR cohort (8.1% vs 6.6%, OR 0.799 (95% CI 0.374 to 1.709) p=0.563). CONCLUSION: Since both modalities showed comparable rates of overall total strokes, both modalities of revascularization can be performed depending on the patient's risk assessment.

The Brain Injury Guidelines (BIG) and emergency department observation and admission rates: A retrospective cohort study.

BACKGROUND: Emergency Department (ED) Observation Units (OU) can provide safe, effective care for low risk patients with intracranial hemorrhages. We compared current ED OU use for patients with subdural hematomas (SDH) to the validated Brain Injury Guidelines (BIG) to evaluate the potential impact of implementing this risk stratification tool. METHODS: Retrospective cohort of patients ≥18 years old with SDH of any cause from 2014 to 2020 to evaluate for potential missed OU cases. Missed OU cases were defined as patients with an initial Glasgow Coma Score (GCS) of 15 with hospital length of stays (LOS) <2 days, who did not meet the composite outcome and were not cared for in the OU or discharged from the ED. Composite outcome included in-hospital death or transition to hospice care, neurosurgical intervention, GCS decline, and worsening SDH size. Secondary outcomes were whether application of BIG would increase ED OU use or reduce CT use. RESULTS: 264 patients met inclusion criteria over 5.3 year study timeframe. Mean age was 61 years (range 19-93) and 61.4% were male. SDH were traumatic in 76.9% and 60.2% of the cohort had additional injuries. The admission rate was 81.4% (n = 215). Fourteen (6.5%) missed OU cases were identified (2.6/year). Retrospective application of BIG resulted in 82.6% (n = 217) at BIG 3, 10.2% (n = 27) at BIG 2 and 7.6% (n = 20) at BIG 1. Application of BIG would not have decreased admission rates (82.6% BIG 3) and BIG 1 and 2 admissions were often for medical co-morbidities. The composite outcome was met in 50% of BIG 3, 22% of BIG 2, and no BIG 1 patients. CONCLUSION: In a level 1 trauma center with an established observation unit, current clinical care processes missed very few patients who could be discharged or placed in ED OU for SDH. Hospital admissions in BIG 1/2 were driven by co-morbidities and/or injuries, limiting applicability of BIG to this population.

Harnessing cortical plasticity via gabapentinoid administration promotes recovery after stroke.

Stroke causes devastating sensory-motor deficits and long-term disability due to disruption of descending motor pathways. Restoration of these functions enables independent living and therefore represents a high priority for those afflicted by stroke. Here, we report that daily administration of gabapentin, a clinically approved drug already used to treat various neurological disorders, promotes structural and functional plasticity of the corticospinal pathway after photothrombotic cortical stroke in adult mice. We found that gabapentin administration had no effects on vascular occlusion, haemodynamic changes nor survival of corticospinal neurons within the ipsilateral sensory-motor cortex in the acute stages of stroke. Instead, using a combination of tract tracing, electrical stimulation and functional connectivity mapping, we demonstrated that corticospinal axons originating from the contralateral side of the brain in mice administered gabapentin extend numerous collaterals, form new synaptic contacts and better integrate within spinal circuits that control forelimb muscles. Not only does gabapentin daily administration promote neuroplasticity, but it also dampens maladaptive plasticity by reducing the excitability of spinal motor circuitry. In turn, mice administered gabapentin starting 1 h or 1 day after stroke recovered skilled upper extremity function. Functional recovery persists even after stopping the treatment at 6 weeks following a stroke. Finally, chemogenetic silencing of cortical projections originating from the contralateral side of the brain transiently abrogated recovery in mice administered gabapentin, further supporting the conclusion that gabapentin-dependent reorganization of spared cortical pathways drives functional recovery after stroke. These observations highlight the strong potential for repurposing gabapentinoids as a promising treatment strategy for stroke repair.

Sex differences in thrombosis as it affects acute ischemic stroke.

Ischemic stroke is a devastating health problem, affecting approximately 800,000 patients in the US every year, making it the leading cause of combined death and disability in the country. Stroke has historically been thought of as predominantly impacting men, however it is becoming increasingly clear that stroke affects women to a greater degree than men. Indeed, women have worse outcomes compared to men following ischemic stroke. Recent clinical advances have shown great promise in acute stroke therapy, with the use of mechanical endovascular thrombectomy (with and without recombinant tissue plasminogen activator; rtPA) greatly improving outcomes. This observation makes it clear that removal of clots and reperfusion, either mechanically or pharmacologically, is critical for improving outcomes of patients following acute ischemic stroke. Despite these promising advances, long-term neurological sequelae persist in the post-stroke population. This review focuses on mechanisms of thrombosis (clot formation) as it pertains to stroke and important sex differences in thrombosis and responses to treatment. Finally, we describe recent data related to new therapeutic approaches to thrombolysis, with a particular focus on von Willebrand Factor (vWF).

Suppression of Fibrinolysis and Hypercoagulability, Severity of Hypoxemia, and Mortality in COVID-19 Patients: A Retrospective Cohort Study.

BACKGROUND: COVID-19 causes hypercoagulability, but the association between coagulopathy and hypoxemia in critically ill patients has not been thoroughly explored. This study hypothesized that severity of coagulopathy would be associated with acute respiratory distress syndrome severity, major thrombotic events, and mortality in patients requiring intensive care unit-level care. METHODS: Viscoelastic testing by rotational thromboelastometry and coagulation factor biomarker analyses were performed in this prospective observational cohort study of critically ill COVID-19 patients from April 2020 to October 2020. Statistical analyses were performed to identify significant coagulopathic biomarkers such as fibrinolysis-inhibiting plasminogen activator inhibitor 1 and their associations with clinical outcomes such as mortality, extracorporeal membrane oxygenation requirement, occurrence of major thrombotic events, and severity of hypoxemia (arterial partial pressure of oxygen/fraction of inspired oxygen categorized into mild, moderate, and severe per the Berlin criteria). RESULTS: In total, 53 of 55 (96%) of the cohort required mechanical ventilation and 9 of 55 (16%) required extracorporeal membrane oxygenation. Extracorporeal membrane oxygenation-naïve patients demonstrated lysis indices at 30 min indicative of fibrinolytic suppression on rotational thromboelastometry. Survivors demonstrated fewer procoagulate acute phase reactants, such as microparticle-bound tissue factor levels (odds ratio, 0.14 [0.02, 0.99]; P = 0.049). Those who did not experience significant bleeding events had smaller changes in ADAMTS13 levels compared to those who did (odds ratio, 0.05 [0, 0.7]; P = 0.026). Elevations in plasminogen activator inhibitor 1 (odds ratio, 1.95 [1.21, 3.14]; P = 0.006), d-dimer (odds ratio, 3.52 [0.99, 12.48]; P = 0.05), and factor VIII (no clot, 1.15 ± 0.28 vs. clot, 1.42 ± 0.31; P = 0.003) were also demonstrated in extracorporeal membrane oxygenation-naïve patients who experienced major thrombotic events. Plasminogen activator inhibitor 1 levels were significantly elevated during periods of severe compared to mild and moderate acute respiratory distress syndrome (severe, 44.2 ± 14.9 ng/ml vs. mild, 31.8 ± 14.7 ng/ml and moderate, 33.1 ± 15.9 ng/ml; P = 0.029 and 0.039, respectively). CONCLUSIONS: Increased inflammatory and procoagulant markers such as plasminogen activator inhibitor 1, microparticle-bound tissue factor, and von Willebrand factor levels are associated with severe hypoxemia and major thrombotic events, implicating fibrinolytic suppression in the microcirculatory system and subsequent micro- and macrovascular thrombosis in severe COVID-19.

International controlled study of revascularization and outcomes following COVID-positive mechanical thrombectomy.

BACKGROUND AND PURPOSE: Previous studies suggest that mechanisms and outcomes in patients with COVID-19-associated stroke differ from those in patients with non-COVID-19-associated strokes, but there is limited comparative evidence focusing on these populations. The aim of this study, therefore, was to determine if a significant association exists between COVID-19 status with revascularization and functional outcomes following thrombectomy for large vessel occlusion (LVO), after adjustment for potential confounding factors. METHODS: A cross-sectional, international multicenter retrospective study was conducted in consecutively admitted COVID-19 patients with concomitant acute LVO, compared to a control group without COVID-19. Data collected included age, gender, comorbidities, clinical characteristics, details of the involved vessels, procedural technique, and various outcomes. A multivariable-adjusted analysis was conducted. RESULTS: In this cohort of 697 patients with acute LVO, 302 had COVID-19 while 395 patients did not. There was a significant difference (p < 0.001) in the mean age (in years) and gender of patients, with younger patients and more males in the COVID-19 group. In terms of favorable revascularization (modified Thrombolysis in Cerebral Infarction [mTICI] grade 3), COVID-19 was associated with lower odds of complete revascularization (odds ratio 0.33, 95% confidence interval [CI] 0.23-0.48; p < 0.001), which persisted on multivariable modeling with adjustment for other predictors (adjusted odds ratio 0.30, 95% CI 0.12-0.77; p = 0.012). Moreover, endovascular complications, in-hospital mortality, and length of hospital stay were significantly higher among COVID-19 patients (p < 0.001). CONCLUSION: COVID-19 was an independent predictor of incomplete revascularization and poor functional outcome in patients with stroke due to LVO. Furthermore, COVID-19 patients with LVO were more often younger and had higher morbidity/mortality rates.

Management of tandem occlusions in patients who receive rtPA.

BACKGROUND: Tandem occlusions exist in 17-32% of large vessel occlusion (LVO) strokes. A significant concern is bleeding when carotid stenting is performed in tandem with thrombectomy due the administration of antiplatelet agents such as glycoprotein IIb/IIIa inhibitors (GP2b3aI) after receiving rtPA, but data are limited in this setting. METHODS: A mutlicenter, retrospective chart review was conducted at two comprehensive stroke centers to assess the safety and efficacy of using GP2b3aI to facilitate carotid stent placement simultaneously with endovascular thrombectomy in patients who have received rtPA. RESULTS: Overall, 32 patients were included in this study, with average age of 66.3 ± 10.4 years and predominantly male (87.5%). The cause of stroke was mostly large artery atherosclerosis (59.4%) and the thrombectomy target vessels were typically first- or second segment middle cerebral artery (37.5% and 31.3%). Time from symptom onset to rtPA bolus was 1.8 h [interquartile range (IQR) 1.5-2.7], rtPA bolus to first pass was 2 h [IQR 1.5-3.1], rtPA bolus to GP2b3aI bolus was 2 h [IQR 1.6-3.5], and rtPA bolus to aspirin and clopidogrel administration was 4.3 h [IQR 2.6-8.9] and 6.6 h [IQR 4.5-11.6] respectively. No patients had acute in-stent thrombosis or post-op bleeding from the access site. Two patients (6.3%) had significant hemorrhagic conversion. CONCLUSION: The use of GP2b3aI in the setting of tandem occlusions that required emergent stent placement post-rtPA appears safe and effective. Given the small sample size, these findings should be interpreted cautiously, and need to be confirmed in a larger patient population.

Aptamers as Therapeutics.

Aptamers are single-stranded nucleic acid molecules that bind to and inhibit proteins and are commonly produced by systematic evolution of ligands by exponential enrichment (SELEX). Aptamers undergo extensive pharmacological revision, which alters affinity, specificity, and therapeutic half-life, tailoring each drug for a specific clinical need. The first therapeutic aptamer was described 25 years ago. Thus far, one aptamer has been approved for clinical use, and numerous others are in preclinical or clinical development. This review presents a short history of aptamers and SELEX, describes their pharmacological development and optimization, and reviews potential treatment of diseases including visual disorders, thrombosis, and cancer.

Preclinical Development of a vWF Aptamer to Limit Thrombosis and Engender Arterial Recanalization of Occluded Vessels.

Endothelial surface and circulating glycoprotein von Willebrand factor (vWF) regulates platelet adhesion and is associated with thrombotic diseases, including ischemic stroke, myocardial infarction, and peripheral vascular disease. Thrombosis, as manifested in these diseases, is the leading cause of disability and death in the western world. Current parenteral antithrombotic and thrombolytic agents used to treat these conditions are limited by a short therapeutic window, irreversibility, and major risk of hemorrhage. To overcome these limitations, we developed a novel anti-vWF aptamer, called DTRI-031, that selectively binds and inhibits vWF-mediated platelet adhesion and arterial thrombosis while enabling rapid reversal of this antiplatelet activity by an antidote oligonucleotide (AO). Aptamer DTRI-031 exerts dose-dependent inhibition of platelet aggregation and thrombosis in whole blood and mice, respectively. Moreover, DTRI-031 can achieve potent vascular recanalization of platelet-rich thrombotic occlusions in murine and canine carotid arteries. Finally, DTRI-031 activity is rapidly (<5 min) and completely reversed by AO administration in a murine saphenous vein hemorrhage model, and murine toxicology studies indicate the aptamer is well tolerated. These findings suggest that targeting vWF with an antidote-controllable aptamer potentially represents an effective and safer treatment for thrombosis patients having platelet-rich arterial occlusions in the brain, heart, or periphery.

Inadvertent Arterial Placement of Central Venous Catheters: Systematic Review and Guidelines for Treatment.

Inadvertent arterial placement of central venous catheters carries serious sequelae, including pseudoaneurysm development and stroke. Although numerous strategies for therapeutic repair after arterial injury have been employed, no treatment provides a definitive standard of care. All articles published between January 2000 and July 2018 involving the placement of central venous catheters in the brachiocephalic or subclavian arteries, carotid artery, vertebral artery, and aortic arch and subsequent treatment were systematically reviewed. Arterial repair consisted of manual pressure, endovascular techniques (balloon tamponade, percutaneous closure devices, and covered stent placement), and open surgery. Success rates favored endovascular techniques and surgery over manual compression.

Pipeline embolization device for recurrence of previously treated aneurysms.

OBJECTIVE The utilization of the Pipeline embolization device (PED) has increased significantly since its inception and original approval for use in large, broad-necked aneurysms of the internal carotid artery. While microsurgical clipping and advances in endovascular techniques have improved overall efficacy in achieving complete occlusion, recurrences still occur, and the best modality for retreatment remains controversial. Despite its efficacy in this setting, the role of PED utilization in the setting of recurrent aneurysms has not yet been well defined. This study was designed to assess the safety and efficacy of PED in the recurrence of previously treated aneurysms. METHODS The authors reviewed a total of 13 cases in which patients underwent secondary placement of a PED for aneurysm recurrence following prior treatment with another modality. The PEDs were used to treat aneurysm recurrence or residual following endovascular coiling in 7 cases, flow diversion in 2, and microsurgical clipping in 4. The mean time between initial treatment and retreatment with a PED was 28.1 months, 12 months, and 88.7 months, respectively. Clinical outcomes, including complications and modified Rankin Scale (mRS) scores, and angiographic evidence of complete occlusion were tabulated for each treatment group. RESULTS All PEDs were successfully placed without periprocedural complications. The rate of complete occlusion was 80% at 6 months after PED placement and 100% at 12 months in these patients who underwent PED placement following failed endovascular coiling; there were no adverse clinical sequelae at a mean follow-up of 26.1 months. In the 2 cases in which PEDs were placed for treatment of residual aneurysms following prior flow diversion, 1 patient demonstrated asymptomatic vessel occlusion at 6 months, and the other exhibited complete aneurysm occlusion at 12 months. In patients with aneurysm recurrence following prior microsurgical clipping, the rate of complete occlusion was 100% at 6 and 12 months, with no adverse sequelae noted at a mean clinical follow-up of 27.7 months. CONCLUSIONS The treatment of recurrent aneurysms with the PED following previous endovascular coiling, flow diversion, or microsurgical clipping is associated with a high rate of complete occlusion and minimal morbidity.

Impact of subsidence on clinical outcomes and radiographic fusion rates in anterior cervical discectomy and fusion: a systematic review.

STUDY DESIGN: Systematic review. OBJECTIVE: To provide a systematic review of published literature on the impact of subsidence on clinical outcomes and radiographic fusion rates after anterior cervical discectomy and fusion with plates or without plates. BACKGROUND: Subsidence of interbody implants is common after anterior cervical spine fusions. The impact of subsidence on fusion rates and clinical outcomes is unknown. METHODS: Systematic literature review on published articles on anterior cervical discectomy and fusion, which objectively measured graft subsidence, radiographic fusion rates, and clinical outcomes between April 1966 and December 2010. RESULTS: A total of 35 articles that measured subsidence and provided fusion rates and/or clinical outcomes were selected for inclusion. The mean subsidence rate ranged from 19.3% to 42.5%. The rate of subsidence based on the type of implant ranged from 22.8% to 35.9%. The incidence of subsidence was not impacted by the type of implant (P=0.98). The overall fusion rate of the combined studies was 92.8% and was not impacted by subsidence irrespective of subsidence definition or the measurement technique used (P=0.19). Clinical outcomes were evaluated in 27 of 35 studies with all studies reporting an improvement in patient outcomes postoperatively. CONCLUSIONS: Subsidence irrespective of the measurement technique or definition does not appear to have an impact on successful fusion and/or clinical outcomes. A validated definition and standard measurement technique for subsidence is needed to determine the actual incidence of subsidence and its impact on radiographic and clinical outcomes.

Preoperative prescription opioid use as an independent predictor of 90-day mortality and adverse events in craniotomy and craniectomy patients.

OBJECTIVE: A growing body of literature suggests that preoperative opioid exposure is an independent predictor of poor outcomes in surgical patients. No outcomes data exist on preoperative opioid use and craniotomies/craniectomies. The objective of this study was to determine the impact of preoperative opioid use on 90-day adverse events after craniotomy or craniectomy. METHODS: A single-center retrospective cohort study of 2445 patients undergoing a craniotomy/craniectomy between January 1, 2013, and October 1, 2018, was conducted. Baseline demographics, pre- and postoperative opioid use (morphine milligram equivalents [MMEs]), and surgical metrics were recorded. Patients were categorized based on whether they took prescription opioids preoperatively, defined as within 1 month of surgery, or were opioid naive. The outcomes were mortality and adverse events 90 days after craniotomy/craniectomy. RESULTS: Overall, 26.6% of patients composed the preoperative opioid group. The median daily MME intake among this group was 34.6 (IQR 14.1-90) MMEs. Lower employment rates (p < 0.001), uninsured status (p = 0.016), and intravenous drug use (p = 0.006) were associated with preoperative opioid use. Preoperative opioid use was associated with increased venous thromboembolism (p = 0.001), acute kidney injury (p = 0.002), acute respiratory failure (p < 0.001), myocardial infarction (p = 0.002), delirium (p < 0.001), and infection (p < 0.001). Preoperative opioid use was an independent predictor of overall 90-day adverse events (OR 1.643, 95% CI 1.289-2.095; p < 0.001) and 90-day mortality (OR 1.690, 95% CI 1.254-2.277; p < 0.001). CONCLUSIONS: Preoperative opioid use was independently associated with 90-day postoperative adverse events and mortality. Opioid use increases vulnerability in craniotomy/craniectomy patients and necessitates close monitoring to improve outcomes.

Patients' perceptions on outcomes after mechanical thrombectomy in acute ischemic stroke.

BACKGROUND: The modified Rankin Scale (mRS) is a clinician-reported scale that measures the degree of disability in patients who suffered a stroke. Patients' perception of a meaningful recovery from severe stroke, expected value of a stroke intervention, and the effect of disparities are largely unknown. METHODS: We conducted a survey of patients, their family members, and accompanying visitors to understand their personal preferences and expectations for acute strokes potentially eligible for acute endovascular intervention using a hypothetical scenario of a severe stroke in a standardized questionnaire. RESULTS: Of 164 survey respondents, 65 (39.6%) were the patient involved, 93 (56.7%) were a family member, and six (3.7%) were accompanied visitors (friends, other). Minimally acceptable disability after a stroke intervention was considered as mRS 2 by 42 respondents (25.6%), as mRS 3 by 79 (48.2%), and as mRS 4 by 43 (26.2%) respondents. Race was associated with different views on this question (p < 0.001; Hispanic and Black patients being more likely to accept disability than Caucasian and Asian patients), while sex (p = 0.333) and age (p = 0.560) were not. Sixty-three respondents (38.4%) viewed minimally acceptable probability of improvement with an intervention as over 50%, 57 (34.8%) as 10-50%, and 44 (26.8%) as less than 10%. CONCLUSIONS: A wide range of acceptable outcomes were reported regardless of gender or age. However, race was associated with different acceptable outcome. This is an important finding to demonstrate because of the persistent racial and ethnic disparities in the utilization of endovascular therapy for acute stroke in the United States.

Rapidly regulating platelet activity in vivo with an antidote controlled platelet inhibitor.

Millions of individuals are prescribed platelet inhibitors, such as aspirin and clopidogrel, to reduce their risk of thrombosis-related clinical events. Unfortunately many platelet inhibitors are contraindicated in surgical settings because of their inherent bleeding risk complicating the treatment of patients who require surgery. We describe the development of a potent antiplatelet agent, an RNA aptamer-termed Ch-9.14-T10 that binds von Willebrand factor (VWF) with high affinity and inhibits thrombosis in a murine carotid artery damage model. As expected, when this potent antiplatelet agent is administered, it greatly increases bleeding from animals that are surgically challenged. To improve this antiplatelet agent's safety profile, we describe the generation of antidotes that can rapidly reverse the activity of Ch-9.14-T10 and limit blood loss from surgically challenged animals. Our work represents the first antidote controllable antiplatelet agent, which could conceivably lead to improved medical management of patients requiring antiplatelet medication who also need surgery.

Rapid molecular imaging of active thrombi in vivo using aptamer-antidote probes.

Pathological blood clotting, or thrombosis, limits vital blood flow to organs; such deprivation can lead to catastrophic events including myocardial infarction, pulmonary embolism, and ischemic stroke. Prompt restoration of blood flow greatly improves outcomes. We explored whether aptamers could serve as molecular imaging probes to rapidly detect thrombi. An aptamer targeting thrombin, Tog25t, was found to rapidly localize to and visualize pre-existing clots in the femoral and jugular veins of mice using fluorescence imaging and, when circulating, was able to image clots as they form. Since free aptamer is quickly cleared from circulation, contrast is rapidly developed, allowing clot visualization within minutes. Moreover, administration of an antidote oligonucleotide further enhanced contrast development, causing the unbound aptamer to clear within 5min while impacting the clot-bound aptamer more slowly. These findings suggest that aptamers can serve as imaging agents for rapid detection of thrombi in acute care and perioperative settings.