The yield of genetic workup for middle-aged and elderly patients with neurological disorders in a real-world setting.

Genetic workup is becoming increasingly common in the clinical assessment of neurological disorders. We evaluated its yield among middle-aged and elderly neurological patients, in a real-world context. This retrospective study included 368 consecutive Israeli patients aged 50 years and older (202 [54.9%] males), who were referred to a single neurogenetics clinic between 2017 and mid-2023. All had neurological disorders, without a previous molecular diagnosis. Demographic, clinical and genetic data were collected from medical records. The mean age at first genetic counseling at the clinic was 62.3 ± 7.8 years (range 50-85 years), and the main indications for referral were neuromuscular, movement and cerebrovascular disorders, as well as cognitive impairment and dementia. Out of the 368 patients, 245 (66.6%) underwent genetic testing that included exome sequencing (ES), analysis of nucleotide repeat expansions, detection of specific mutations, targeted gene panel sequencing or chromosomal microarray analysis. Overall, 80 patients (21.7%) received a molecular diagnosis due to 36 conditions, accounting for 32.7% of the patients who performed genetic testing. The diagnostic rates were highest for neuromuscular (58/186 patients [31.2%] in this group, 39.2% of 148 tested individuals) and movement disorders (14/79 [17.7%] patients, 29.2% of 48 tested), but lower for other disorders. Testing of nucleotide repeat expansions and ES provided a diagnosis to 28/73 (38.4%) and 19/132 (14.4%) individuals, respectively. Based on our findings, genetic workup and testing are useful in the diagnostic process of neurological patients aged ≥50 years, in particular for those with neuromuscular and movement disorders.

Efficacy and safety of Apixaban in the treatment of cerebral venous sinus thrombosis: a multi-center study.

Background: Information regarding the safety and efficacy of specific direct oral anticoagulants (DOAC) in the treatment of cerebral sinus and venous thrombosis (CSVT) is scarce. Apixaban is one of the most frequently prescribed DOACs. Therefore, we aimed to compare the safety and efficacy of Apixaban with those of vitamin k antagonists (VKA) in patients with CSVT. Methods: Prospective CSVT databases from seven academic medical centers were retrospectively analyzed. Patients treated with Apixaban were compared to those treated with VKA. Data on demographics, clinical presentations, risk factors, radiological and outcome parameters were studied. Results: Overall, 403 patients were included in the analysis. Of them, 48 (12%) were treated with Apixaban, and 355 (88%) were treated with VKA. Rates of coagulopathies were significantly higher in the VKA-treated patients but no other differences between the groups were found in baseline characteristics and underlying etiology. No significant differences were found between groups in efficacy or safety parameters including the rates of recanalization, favorable outcomes, one-year mortality, seizures, intracranial hemorrhage or CSVT recurrences. Conclusion: Our data suggests that Apixaban may be safe and effective for patients with CSVT. These results should be tested in prospective randomized clinical studies.

Levetiracetam Interaction with Direct Oral Anticoagulants: A Pharmacovigilance Study.

BACKGROUND: Levetiracetam is widely used in post-stroke epilepsy. However, it is suspected to possess P-glycoprotein (P-gp) induction properties, and therefore, a potentially significant interaction with direct oral anticoagulants (DOACs). We aimed to search for ischemic stroke signals with levetiracetam and the DOACs. METHODS: In this retrospective pharmacovigilance study, we used the FAERS database to identify ischemic stroke events associated with DOACs and concomitant use of levetiracetam. We evaluated disproportionate reporting by the adjusted reporting odds ratio (adjROR) and the lower bound of the shrinkage 95% confidence interval. When shrinkage is positive, an increased risk of a specific adverse event occurrence is emphasized over the sum of the individual risks when these same drugs are used separately. RESULTS: We identified 1841 (1.5%), 3731 (5.3%), 338 (4.9%), and 1723 (1.3%) ischemic stroke reports with apixaban, dabigatran, edoxaban, and rivaroxaban, respectively. The adjROR of the interaction effect was 3.57 (95% CI 2.81-4.58) between DOACs and levetiracetam. The shrinkage analysis detected an interaction between each of the DOACs and levetiracetam. The logistic model and shrinkage analysis failed to detect an interaction when queried for hemorrhagic stroke. A significant signal in the classical enzyme inducer, carbamazepine, strengthened our results (adjROR; 8.47, 95% CI 5.37-13.36). CONCLUSIONS: Our study shows a strong signal for the levetiracetam interaction with the DOACs. Our findings suggest implementation of a drug monitoring strategy.

The impact on clinical outcomes after 1 year of implementation of an artificial intelligence solution for the detection of intracranial hemorrhage.

BACKGROUND: To assess the effect of a commercial artificial intelligence (AI) solution implementation in the emergency department on clinical outcomes in a single level 1 trauma center. METHODS: A retrospective cohort study for two time periods-pre-AI (1.1.2017-1.1.2018) and post-AI (1.1.2019-1.1.2020)-in a level 1 trauma center was performed. The ICH algorithm was applied to 587 consecutive patients with a confirmed diagnosis of ICH on head CT upon admission to the emergency department. Study variables included demographics, patient outcomes, and imaging data. Participants admitted to the emergency department during the same time periods for other acute diagnoses (ischemic stroke (IS) and myocardial infarction (MI)) served as control groups. Primary outcomes were 30- and 120-day all-cause mortality. The secondary outcome was morbidity based on Modified Rankin Scale for Neurologic Disability (mRS) at discharge. RESULTS: Five hundred eighty-seven participants (289 pre-AI-age 71 ± 1, 169 men; 298 post-AI-age 69 ± 1, 187 men) with ICH were eligible for the analyzed period. Demographics, comorbidities, Emergency Severity Score, type of ICH, and length of stay were not significantly different between the two time periods. The 30- and 120-day all-cause mortality were significantly reduced in the post-AI group when compared to the pre-AI group (27.7% vs 17.5%; p = 0.004 and 31.8% vs 21.7%; p = 0.017, respectively). Modified Rankin Scale (mRS) at discharge was significantly reduced post-AI implementation (3.2 vs 2.8; p = 0.044). CONCLUSION: The added value of this study emphasizes the introduction of artificial intelligence (AI) computer-aided triage and prioritization software in an emergent care setting that demonstrated a significant reduction in a 30- and 120-day all-cause mortality and morbidity for patients diagnosed with intracranial hemorrhage (ICH). Along with mortality rates, the AI software was associated with a significant reduction in the Modified Ranking Scale (mRs).

Does Malignancy Status Effect Outcomes in Patients With Large Vessel Occlusion Stroke and Cancer Who Underwent Endovascular Thrombectomy?

Background Cancer is associated with an increased risk of acute ischemic stroke, including large vessel occlusions. Whether cancer status affects outcomes in patients with large vessel occlusions that undergo endovascular thrombectomy remains unknown. Methods and Results All consecutive patients undergoing endovascular thrombectomy for large vessel occlusions were recruited into a prospective ongoing multicenter database, and the data were retrospectively analyzed. Patients with active cancer were compared with patients with cancer in remission. Association of cancer status with 90-day functional outcome and mortality were calculated in multivariable analyses. We identified 154 patients with cancer and large vessel occlusions that underwent endovascular thrombectomy (mean age, 74±11; 43% men; median National Institutes of Health Stroke Scale 15). Of the included patients, 70 (46%) had a remote history of cancer or cancer in remission, and 84 (54%) had active disease. Outcome data at 90 days poststroke were available for 138 patients (90%) and was classified as favorable in 53 (38%). Patients with active cancer were younger and more often smoked but did not significantly differ from those without malignancy in other risk factors, stroke severity, stroke subtype, or procedural variables. Favorable outcome rates among patients with active cancer did not significantly differ compared with those seen in patients without active cancer, but mortality rates were significantly higher among patients with active cancer on univariate and multivariable analyses. Conclusions Our study suggests that endovascular thrombectomy is safe and efficacious in patients with history of malignancy as well as in those with active cancer at the time of stroke onset, although mortality rates are higher among patients with active cancer.

Clinical experience with the Bendit steerable microcatheter: a new paradigm for endovascular treatment.

BACKGROUND: Vessel tortuosity poses a challenge during endovascular treatment of neurovascular lesions. Bendit Technologies (Petah Tikva, Israel) has developed flexible, steerable microcatheters designed with unique bending and torquing capabilities. OBJECTIVE: To describe our first-in-human trial of Bendit21. METHODS: Bendit21 was used in our exploratory, prospective, multicenter, open-label, single-arm clinical study, and in two compassionate use cases. Procedures were conducted at four centers in Austria, Germany, Israel, and the United States between May 2021 and March 2022, in patients with neurovascular conditions. The primary endpoints were device-related safety events, successful navigation through the neurovasculature, and, when intended, successful delivery of contrast or therapy. RESULTS: Two patients with giant aneurysms were treated successfully under compassionate use approval. The clinical study included 25 patients (mean age: 63.4±11.8 years; 32.0% female). Fourteen patients (56.0%) had aneurysms, two had arteriovenous malformations/fistulas (8.0%), one had a stroke (4.0%), four (16.0%) had intracranial stenosis, and four (16.0%) had other conditions. Bendit21 was used without a guidewire in 12/25 (48.0%) procedures. Bendit21 was successfully navigated through the vasculature without delays or spasms in all cases (100%). Contrast was delivered as intended in 7/7 (100%) cases. Therapeutic devices were delivered successfully with Bendit as intended in 14/18 (77.8%) cases; four deficiencies occurred in three patients with aneurysms, in whom delivery of coils, an intrasaccular device, or a flow diverter was attempted. There were no device-related safety events or mortalities. CONCLUSIONS: Our initial clinical experience with the Bendit21 microcatheter demonstrates its usefulness in achieving technical success in patients with challenging neurovascular conditions.

Progressive enhancement of kinetic proofreading in T cell antigen discrimination from receptor activation to DAG generation.

T cells use kinetic proofreading to discriminate antigens by converting small changes in antigen-binding lifetime into large differences in cell activation, but where in the signaling cascade this computation is performed is unknown. Previously, we developed a light-gated immune receptor to probe the role of ligand kinetics in T cell antigen signaling. We found significant kinetic proofreading at the level of the signaling lipid diacylglycerol (DAG) but lacked the ability to determine where the multiple signaling steps required for kinetic discrimination originate in the upstream signaling cascade (Tiseher and Weiner, 2019). Here, we uncover where kinetic proofreading is executed by adapting our optogenetic system for robust activation of early signaling events. We find the strength of kinetic proofreading progressively increases from Zap70 recruitment to LAT clustering to downstream DAG generation. Leveraging the ability of our system to rapidly disengage ligand binding, we also measure slower reset rates for downstream signaling events. These data suggest a distributed kinetic proofreading mechanism, with proofreading steps both at the receptor and at slower resetting downstream signaling complexes that could help balance antigen sensitivity and discrimination.

Janus Kinase-2 V617F Mutation and Antiphospholipid Syndrome in Cerebral Sinus Venous Thrombosis: Natural History and Retrospective Bicenter Analysis.

Background: Cerebral sinus venous thrombosis (CSVT) is a rare neurovascular entity, usually associated with acquired or genetic hypercoagulable states. In up to 30% of the cases it remains idiopathic. Bone marrow proliferation disorders that are associated with Janus Kinase 2 V617F mutation (JAK-2) are known causes of the systemic and cerebral thrombosis-at times despite normal blood counts-for which hematologic treatment exists. However, JAK-2 prevalence in the CSVT cases is not clear. Methods: In this retrospective analysis, data of 236 patients with CSVT admitted to two tertiary centers between 2010 and 2020 were analyzed, with emphasis on laboratory and imaging data and clinical and interventional outcomes. Results: A total of 236 patients were included in the analysis. The patients' median age was 42 years and the average age was 44 years (±19 years), with 59% female patients. JAK-2 positivity rate was 18% (among 77 patients tested for the mutation). Patients with normal blood counts on presentation comprised 36% of the JAK-2 positive cases. Other hypercoagulability states were also investigated, with the antiphospholipid syndrome (APLA) showing the highest prevalence (11%) followed by other etiologies including oral contraceptive use, Factor V Leiden, prothrombin mutation, and malignancy. Selected JAK-2, APLA, and prothrombin mutation cases showed a more severe clinical course. Conclusion: JAK-2 mutation is underdiagnosed and its screening may be warranted in the cases of idiopathic CSVT, even despite normal blood counts, to allow disease-modifying treatment and blood cell count monitoring. JAK-2, APLA, and prothrombin mutation may be associated with a more complicated clinical course.

In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

Endovascularly retrieved clots may be a potential resource for diagnosing stroke etiology. This method may influence secondary prevention treatment. We measure thrombin activity eluted by serially washing clots. We concluded that an assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.

Reduction in Acute Stroke Admissions during the COVID-19 Pandemic: Data from a National Stroke Registry.

INTRODUCTION: The COVID-19 pandemic overwhelmed health-care systems worldwide, and medical care for other acute diseases was negatively impacted. We aimed to investigate the effect of the COVID-19 outbreak on admission rates and in-hospital care for acute stroke and transient ischemic attack (TIA) in Israel, shortly after the start of the pandemic. METHODS: We conducted a retrospective observational study, based on data reported to the Israeli National Stroke Registry from 7 tertiary hospitals. All hospital admissions for acute stroke or TIA that occurred between January 1 and April 30, 2020 were included. Data were stratified into 2 periods according to the timing of COVID-19 restrictions as follows: (1) "pre-pandemic" - January 1 to March 7, 2020 and (2) "pandemic" - March 8 to April 30, 2020. We compared the weekly counts of hospitalizations between the 2 periods. We further investigated changes in demographic characteristics and in some key parameters of stroke care, including the percentage of reperfusion therapies performed, time from hospital arrival to brain imaging and to thrombolysis, length of hospital stay, and in-hospital mortality. RESULTS: 2,260 cases were included: 1,469 in the pre-COVID-19 period and 791 in the COVID-19 period. Hospital admissions significantly declined between the 2 periods, by 48% for TIA (rate ratio [RR] = 0.52; 95% CI 0.43-0.64) and by 29% for stroke (RR = 0.71; 95% CI 0.64-0.78). No significant changes were detected in demographic characteristics and in most parameters of stroke management. While the percentage of reperfusion therapies performed remained unchanged, the absolute number of patients treated with reperfusion therapies seemed to decrease. Higher in-hospital mortality was observed only for hemorrhagic stroke. CONCLUSION: The marked decrease in admissions for acute stroke and TIA, occurring at a time of a relatively low burden of COVID-19, is of great concern. Public awareness campaigns are needed as patients reluctant to seek urgent stroke care are deprived of lifesaving procedures and secondary prevention treatments.

Can other coronavirus infections cause a cryptogenic stroke in a young patient?

We present a challenging case of a young patient who presented with focal neurological signs following a course of OC-43 coronavirus-related pneumonia almost 8 months before the COVID-19 outbreak.

The Pandemic's impacts on patients without Covid-19 on multidisciplinary aspects in emergency medicine care.

The emergence of Covid-19 has caused a pandemic and is a major public health concern. Covid-19 has fundamentally challenged the global health care system in all aspects. However, there is a growing concern for the subsequent detrimental effects of continuing delays or adjustments on time-dependent treatments for Covid-19 negative patients. Patients arriving to the ED with STEMIs and acute CVA are currently presumed to have delays due to Covid-19 related concerns. The objective of this paper is to evaluate the implications of the Covid-19 pandemic on non-Covid19 patients in emergency care settings. We conducted a retrospective study from February 2020 to April 2020 and compared this to a parallel period in 2019 to assess the impact of the Covid-19 pandemic on three distinct non-Covid-19 ED diagnosis that require immediate intervention. Our primary outcome measures were time to primary PCI in acute STEMI, time to fibrinolysis in acute CVA, and time to femoral hip fracture correction surgery. Our secondary outcome measure included a composite outcome of length of stay in hospital and mortality. From 1 February 2020 to 30 April 2020, the total referrals to ED diagnosed with STEMI, Hip fracture and CVA of which required intervention were 197 within Covid-19 group 2020 compared to 250 in the control group 2019. Mean duration to intervention (PCI, surgery and tPA, respectively) did not differ between COVID-19 group and 2019 group. Among femoral hip fracture patients', the referral numbers to ED were significantly lower in Covid-19 era (p = 0.040) and the hospitalization stay was significantly shorter (p = 0.003). Among CVA patients', we found statistical differences among the number of referrals and the patients' age. Coping with the Covid-19 pandemic presents a challenge for the general healthcare system. Our results suggest that with proper management, despite the obstacles of isolation policies and social distancing, any negative impact on the quality of health care for the non-Covid-19 patients can be minimized in the emergency department setting.

Are there disparities in acute stroke treatment between the Jewish and Arab populations in Israel? Results from the National Acute Stroke Israeli registry.

BACKGROUND: According to the latest reported data from the National Acute Stroke Israeli Survey (NASIS), around 18,000 strokes occur annually in Israel. Data regarding disparities in stroke care between the Jewish and the Arab populations in Israel are lacking. AIMS: We wished to compare demographics, comorbidities, stroke characteristics and outcomes between Jewish and Arab stroke patients in Israel that were acutely treated with intravenous thrombolysis (IVT) and/or endovascular thrombectomy (EVT), in order to test if there are disparities or any ethnic-specific parameters. METHODS: The National Acute Stroke Israeli registry of patients undergoing revascularization (NASIS-REVASC) prospectively enrolled patients in six comprehensive stroke centers between 1/2014 and 3/2016. In this observational research, we compared demographics, comorbidities, time metrics, stroke characteristics and outcomes between Jewish and Arab patients enrolled. RESULTS: NASIS-REVASC included 1432 patients out of which 143 (10%) were of Arab ethnicity and 1289 (90%) of Jewish ethnicity. Arab patients were significantly younger (66 ± 14 vs. 73 ± 29, p = 0·004), exhibited higher rates of smoking and diabetes (31% vs. 18% and 57% vs. 34%, p < 0·001 for both), and were less often treated with systemic thrombolysis (48% vs. 59%, p = 0·012). However, the rates of any interventional treatment with either intravenous thrombolysis or endovascular thrombectomy as well as the rates of favorable outcomes and mortality were comparable between groups. CONCLUSIONS: Despite several baseline differences between Arab and Jewish Israeli stroke patients, treatment allocations, survival and functional outcomes were similar indicating lack of disparity in stroke care among patients treated acutely with IVT and/or EVT in Israel. DATA ACCESS STATEMENT: Full data is available following a formal request to the NASIS-REVASC registry at the Israeli Health Ministry.

Autoantibodies to Annexin A2 and cerebral thrombosis: Insights from a mouse model.

INTRODUCTION: Antiphospholipid syndrome (APS) is an autoimmune disorder manifested by thromboembolic events, recurrent spontaneous abortions and elevated titers of circulating antiphospholipid antibodies. In addition, the presence of antiphospholipid antibodies seems to confer a fivefold higher risk for stroke or transient ischemic attack. Although the major antigen of APS is ß2 glycoprotein I, it is now well established that antiphospholipid antibodies are heterogeneous and bind to various targets. Recently, antibodies to Annexin A2 (ANXA2) have been reported in APS. This is of special interest since data indicated ANXA2 as a key player in fibrinolysis. Therefore, in the present study we assessed whether anti-ANXA2 antibodies play a pathological role in thrombosis associated disease. MATERIALS AND METHODS: Mice were induced to produce anti-ANXA2 antibodies by immunization with ANXA2 (iANXA2) and control mice were immunized with adjuvant only. A middle cerebral artery occlusion stroke model was applied to the mice. The outcome of stroke severity was assessed and compared between the two groups. RESULTS: Our results indicate that antibodies to ANXA2 lead to a more severe stroke as demonstrated by a significant larger stroke infarct volume (iANXA2 133.9 ± 3.3 mm3 and control 113.7 ± 7.4 mm3; p = 0.017) and a more severe neurological outcome (iANXA2 2.2 ± 0.2, and control 1.5 ± 0.18; p = 0.03). CONCLUSIONS: This study supports the hypothesis that auto-antibodies to ANXA2 are an independent risk factor for cerebral thrombosis. Consequently, we propose screening for anti-ANXA2 antibodies should be more widely used and patients that exhibit the manifestations of APS should be closely monitored by physicians.

Patent Foramen Ovale Closure among Patients with Hypercoagulable States Maintained on Antithrombotic Therapy.

BACKGROUND: Percutaneous device closure was shown to effectively prevent recurrent strokes in patients with patent foramen ovale (PFO). Whether this protective effect is relevant for patients with hypercoagulable states (HCSs) is unknown as they were not represented in prior studies. METHODS: Data on 136 consecutive patients with a PFO and clinically significant HCS were retrospectively collected. PFO closure and antithrombotic regimen were decided on an individual basis by the treating physicians, and adherence to therapy was routinely evaluated. The outcome was the occurrence of cerebrovascular accident (CVA) or transient ischemic attack (TIA). RESULTS: HCS types consisted of antiphospholipid syndrome (31%), factor-5 Leiden mutation (22%), prothrombin mutation (18%), protein S deficiency (15%), protein C deficiency (7%), methyl-tetra-hydro folate reductase mutation (5%), and essential thrombocytosis (2%). 102 patients (75%) were maintained on anticoagulants and the remaining on antiplatelet therapy. PFO closure was undertaken in 85 (63%); antithrombotic therapy was not interrupted prior to or after the procedures. At a mean follow-up of 46 ± 8 months, 23 patients (17%; 95% confidence interval, 9.3-22%) experienced an outcome event, mainly in the form of CVAs (n = 15, 65%). In multivariable analysis, PFO closure was associated with a 5-fold decrease in the risk of CVA/TIA (p = 0.02). This effect was independent of the type of HCS or antithrombotic therapy. CONCLUSIONS: Among patients with HCSs maintained on anticoagulant or antiplatelet therapies, PFO closure was associated with a significantly lower risk of CVA or TIA.

Surgical Management of Failed Endovascular Treatment for Spinal Dural Arteriovenous Fistulas.

BACKGROUND: Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular malformations. Digital subtraction angiography is the modality of choice to demonstrate the malformation before endovascular embolization or open surgical repair. Angiographically occult SDAVFs have been previously reported. Surgical considerations in SDAVFs with misleading angiography findings have not yet been assessed. METHODS: A retrospective evaluation of charts and imaging files of patients operated on for SDAVF in 2018-2019 at a single institution was performed. All patients were referred to surgery following failure of endovascular embolization or owing to clinical and radiographic deterioration in the presence of an angiographically occult lesion. Cases were comprehensively reviewed and evaluated for surgical considerations in these lesions. RESULTS: This case series included 4 cases. Two patients underwent embolization before surgical repair but continued to deteriorate neurologically, and 2 patients had a failed embolization attempt owing to a torturous vascular network. In all 4 patients, exploration was successful, yielding either improvement or stabilization of neurological status. Indocyanine green injection for microscopically integrated fluorescent angiography contributed to the identification of the supplying vessels and confirmed the SDAVF closure. CONCLUSIONS: SDAVFs should be treated promptly after diagnosis. In cases with high suspicion for SDAVF with occult or misleading angiography findings, spinal exploration should be pursued with no delay. Indocyanine green-assisted microscopic angiography may contribute to exploratory spine surgery for SDAVF closure.

Increased brain plasmin levels following experimental ischemic stroke in male mice.

Many coagulation factor proteases are increased in the brain during ischemic stroke. One of these proteases is plasmin. In this study we established a novel method for direct quantitative measurement of plasmin activity in male mouse brain slices using a sensitive fluorescent substrate in the presence of specific protease inhibitors. In both the ischemic and contralateral hemispheres, plasmin activity increased 3, 6, and 24 hr following stroke in comparison to healthy mice (F(3, 72) = 39.5, p < 0.0001, repeated measures ANOVA) after the induction of permanent middle cerebral artery occlusion (PMCAo). Plasmin activity was higher in the ischemic hemisphere (F(1,36) = 9.1, p = 0.005) and there was a significant interaction between time and ischemic hemisphere (F(3,36) = 4.4, p = 0.009). Plasmin activity was correlated with infarct volume (R2  = 0.5289, p = 0.0009 by Spearman). The specificity of the assay was verified utilizing tissue-type plasminogen activator (tPA)-deficient mice which, as expected, had significantly lower levels of plasmin 24 hr following ischemia compared to wild-type mice (ischemic (0.6 ± 0.23 and 1.94 ± 0.5, respectively), p = 0.049 and contralateral hemispheres (0.13 ± 0.14 and 0.75 ± 0.10, respectively), p = 0.018 by t test). There is a time-dependent increase in plasmin levels and an association of higher levels of plasmin with larger infarct volumes in an experimental stroke model. This suggests caution in the use of recombinant tPA (rtPA) and that plasmin inhibition in the brain may be a therapeutic target in acute ischemic stroke.

In-thrombus thrombin secretion: a new diagnostic marker of atrial fibrillation in cryptogenic stroke.

BACKGROUND: Endovascularly retrieved clots are a potential resource for diagnosing stroke etiology, which may influence secondary prevention treatment. In this study we measured thrombin activity eluted by serially washing clots. METHODS: Clots were retrieved from 68 patients with acute ischemic stroke, freshly frozen and classified by standard criteria into proven atrial fibrillation (AF, 18 patients), atherosclerotic origin (AS, 15 patients), cryptogenic stroke (Cr, 17 patients) and other known causes (18 patients). Thawed clot samples were washed by transferring them into 1 mL buffer in seven hourly cycles and a fluorescent substrate assay was used to measure secreted thrombin activity. The clots were also examined histologically. Artificial fibrin and red blood cell-rich clots were similarly assayed for wash-eluted thrombin activity as an external control. RESULTS: Thrombin activity eluted from clots of AF origin decreased significantly with time in contrast to steady levels eluted from AS origin thrombi (P<0.0001 by repeated measures ANOVA). The Cr stroke group was indistinguishable from the AF group and differed statistically from the AS group (P=0.017 by repeated measures ANOVA). In artificial clots we found a biphasic activity pattern, with initially decreasing levels of eluted thrombin (AF pattern) and then, with continuing washes, steady eluted thrombin levels (AS pattern). CONCLUSIONS: An assay measuring the change in thrombin in clots retrieved during acute stroke endovascular thrombectomy procedures may serve as a diagnostic marker of the origin of the clot. The suggested mechanism for these differences may be the clot location before its retrieval, with high blood flow causing thrombin washout in atherosclerotic clots, in contrast to atrium appendage low blood flow retaining high thrombin levels.