Transient Attack Research Articles

Isochronous Gaussian Sampling and its applying to the Falcon Signature Scheme

This paper describes a block framework for generating discrete Gaussian components with arbitrary center and standard deviation. Simplicity makes it easy to implement secure, portable, effective, and time-resistant. This sampler is a good candidate for any sample analysis. Most importantly, it was recently introduced into the Falcon Signature Scheme. Gaussian sampling over integers is a central element of algebraic lattice cryptography, which is difficult to perform efficiently and safely. Given the vast number of uses of sampling processes, it is important to select Gaussian samplers that are effective provably secure, resistant to transient attacks, and generally easy to implement. Sampling with other distributions, other than Gaussian, is yet an open question.

Recurrent Transient Ischemic Attack Followed By Stroke Due To Stretched Patent Foramen Ovale – A Rare Entity

A Patent Foramen Ovale (PFO) is not a true deficiency of atrial septal tissue but rather a potential space or separation between the septum primum and septum secundum located in the anterosuperior portion of the atrial septum. It is not considered a true Atrial Septal Defect (ASD), because no structural deficiency of the atrial septal tissue is present. We are describing a unique case of recurrent transient attacks followed by stroke associated with finding of a large stretched PFO on echocardiography.

Characteristic Features of the Kernel-level Rootkit for Learning-based Detection Model Training

The core part of the operating system is the kernel, and it plays an important role in managing critical data structure resources for correct operations. The kernel-level rootkits are the most elusive type of malware that can modify the running OS kernel in order to hide its presence and perform many malicious activities such as process hiding, module hiding, network communication hiding, and many more. In the past years, many approaches have been proposed to detect kernel-level rootkit. Still, it is challenging to detect new attacks and properly categorize the kernel-level rootkits. Memory forensic approaches showed efficient results with the limitation against transient attacks. Cross-view-based and integrity monitoring-based approaches have their own weaknesses. A learning-based detection approach is an excellent way to solve these problems. In this paper, we give an insight into the kernel-level rootkit characteristic features and how the features can be represented to train learning-based models in order to detect known and unknown attacks. Our feature set combined the memory forensic, cross-view, and integrity features to train learning-based detection models. We also suggest useful tools that can be used to collect the characteristics features of the kernel-level rootkit.

Periorbital injections of botulinum toxin a: a novel therapeutic option for convergence spasm in neuropsychiatric disorders

PurposeConvergence spasm (CS, spasm of near reflex) is characterized by transient attacks of convergence, miosis and accommodation, often associated with functional neurological disorders. To date, no simple and efficient treatment option is available for CS. This study investigates whether periorbital botulinum toxin injections as used in essential blepharospasm are also a treatment option in these patients.MethodsAll patients with convergence spasm having been treated with periorbital BoNTA injections in the department of neuro-ophthalmology were identified. Data were extracted from patient files concerning details and subjective effectiveness of botulinum toxin injections and relation to psychiatric or neurological disorders. Patients reporting with a history of closed-head trauma or organic neurologic pathologies possibly causing CS were excluded. A telephone assessment with a standardized questionnaire was performed to evaluate mental health issues as a trigger, as well as the long-term effect and satisfaction with periorbital injections.ResultsOf 16 patients treated with periorbital botulinum toxin injections for convergence spasm, 9 patients reported depression and/or anxiety disorders ongoing or in the past. A median number of 3 injections (range 1–13) was administered with a variable effect (relief of symptoms) between no effect and effect of up to more than 12 weeks. A longitudinal follow-up revealed ongoing symptoms in five patients.ConclusionsPeriorbital botulinum toxin injections are less invasive than injections in the medial rectus muscle and can be a bridging therapeutic option in patients with CS. Mental health exploration is important due to psychiatric comorbidity.

Survey of Transient Execution Attacks and Their Mitigations

Transient execution attacks, also known as speculative execution attacks, have drawn much interest in the last few years as they can cause critical data leakage. Since the first disclosure of Spectre and Meltdown attacks in January 2018, a number of new transient execution attack types have been demonstrated targeting different processors. A transient execution attack consists of two main components: transient execution itself and a covert channel that is used to actually exfiltrate the information.Transient execution is a result of the fundamental features of modern processors that are designed to boost performance and efficiency, while covert channels are unintended information leakage channels that result from temporal and spatial sharing of the micro-architectural components. Given the severity of the transient execution attacks, they have motivated computer architects in both industry and academia to rethink the design of the processors and to propose hardware defenses. To help understand the transient execution attacks, this survey summarizes the phases of the attacks and the security boundaries across which the information is leaked in different attacks.This survey further analyzes the causes of transient execution as well as the different types of covert channels and presents a taxonomy of the attacks based on the causes and types. This survey in addition presents metrics for comparing different aspects of the transient execution attacks and uses them to evaluate the feasibility of the different attacks. This survey especially considers both existing attacks and potential new attacks suggested by our analysis. This survey finishes by discussing different mitigations that have so far been proposed at the micro-architecture level and discusses their benefits and limitations.

Multicenter global early feasibility study to evaluate total endovascular arch repair using three-vessel inner branch stent-grafts for aneurysms and dissections

ObjectiveWe evaluated the outcomes of total endovascular aortic arch repair using three-vessel inner branch stent-grafts for aneurysms and chronic dissections. MethodsWe reviewed the clinical data and outcomes of consecutive patients treated by total endovascular aortic arch repair at eight academic centers using three-vessel inner branch stent-grafts (William Cook Europe, Bjaeverskov, Denmark) from 2016 to 2019. All patients received three-vessel designs with two antegrade and one retrograde inner branch, which was used to incorporate the innominate, left common carotid, and left subclavian arteries. The antegrade inner branches were accessed via a carotid or an upper extremity approach. A preloaded catheter was used for access to the retrograde left subclavian artery branch via a transfemoral approach. The endpoints were technical success, mortality, major adverse events, any stroke (minor or major) or transient ischemia attack, secondary interventions, target vessel patency, target vessel instability, aneurysm-related mortality, and patient survival. ResultsA total of 39 patients (31 men [79%]; mean age, 70 ± 7 years) had undergone treatment of 14 degenerative (36%) and 25 chronic (64%) postdissection arch aneurysms. The clinical characteristics included American Society of Anesthesiologists class ≥III in 28 patients (95%) and previous median sternotomy for ascending aortic repair in 28 patients (72%). The technical success rate was 100%. Two patients had died in-hospital or within 30 days (5%), and two patients had experienced a stroke (one minor). The combined mortality and any stroke rate was 8% (n = 3). Major adverse events occurred in 10 patients (26%), including respiratory failure in 4 (10%) and estimated blood loss >1 L, myocardial infarction, and acute kidney injury in 2 patients each (5%). The median follow-up was 3.2 months (interquartile range, 1-14 months). Of the 39 patients, 12 (31%) required secondary interventions to treat vascular access complications in 5, endoleak in 6 (three type II, one type Ic, one type Ia/Ib, one type IIIa), and target vessel stenosis in 1 patient. At 1 year, the primary and secondary patency rates and freedom from target vessel instability were 95% ± 5%, 100%, and 91% ± 5%, respectively. Freedom from aortic-related mortality and patient survival was 94% ± 4% and 90% ± 6%, respectively. ConclusionsThe findings from the present multicenter global experience have demonstrated the technical feasibility and safety of total endovascular aortic arch repair for aneurysms and chronic dissections using three-vessel inner branch stent-grafts. The mortality and stroke rates compare favorably with those after open surgical repair in a higher risk group of patients. However, the rate of secondary interventions was high (31%), emphasizing need for greater experience and longer follow-up.

Morphine overinfusion of intrathecal drug administration system under magnetic resonance evaluation for the diagnosis of stroke: a case report

BackgroundUntil recently, it is generally considered safe to perform magnetic resonance imaging (MRI) in patients with an intrathecal drug administration system (ITDAS) device. In this study, we presented a case of morphine overdose due to ITDAS malfunction during MRI evaluation for the diagnosis of stroke.Case presentationA 58-year-old woman was referred to the emergency department for left-sided hemiparesis and dysarthria. She had undergone ITDAS implantation 4 years ago because of intractable back pain. Her brain MRI examination did not show any abnormalities except an old hemorrhagic infarction in the right basal ganglia. After MRI was performed, her symptoms completely resolved. Approximately 3 h after the MRI scan, the patient showed progressive stuporous consciousness and decreased respiration with decreased peripheral oxygen saturation of 80%. Initial arterial blood gas analysis revealed respiratory acidosis with hypoxia and hypercapnia. We suspected the opioid overdose for her unconciousness, small and sluggish pupils, and slow respiration. The patient regained consciousness within 3 min after the administration of naloxone with severe anxiety and irritability, without any respiratory symptoms or focal neurological deficits. In the pump interrogation and actual reservoir checks performed 6 h after the MRI scan, there was no significant difference between the expected reservoir volume and actual reservoir volume. Follow-up MRI performed to rule out posterior circulation infarction showed no structural lesions. The patient was eventually discharged without further neurologic or functional deterioration, with diagnosis of transient ischemia attack for initial symptoms of focal neurologic deficits.ConclusionAlthough both ex vivo and in vivo studies have provided evidence that ITDAS devices are MRI-compatible, the pump is made of titanium and has ferromagnetic components. Since misdiagnosis of overinfusion could lead to mortality, early awareness of overinfusion of the intrathecal drug is needed to all clinicians in case of performing MRI in ITDAS implanted patients.

Differential Diagnosis of Recurrent Hypersomnia: A Case Report of Primary Narcolepsy and Acute Transient Psychotic Attack

Differential Diagnosis of Recurrent Hypersomnia: A Case Report of Primary Narcolepsy and Acute Transient Psychotic Attack

Comparison of Carotid Plaque Characteristics Between Men and Women Using Magnetic Resonance Vessel Wall Imaging: A Chinese Atherosclerosis Risk Evaluation Study.

Carotid vulnerable plaque is a major cause of stroke and differs between men and women. Few studies have investigated the differences in carotid plaque features between sexes in a Chinese population. To compare carotid atherosclerotic plaque features between men and women in a Chinese population using magnetic resonance imaging. Cross-sectional. A total of 567 patients (mean age: 61.5 ± 10.1 years; 404 men) who had recent stroke or transient ischemia attack and atherosclerotic plaque in at least one carotid artery. A 3.0 T. T1- and T2-weighted turbo spin echo, three-dimensional time-of-flight (TOF) fast field echo and magnetization-prepared rapid acquisition gradient echo sequences. Plaque characteristics including lumen area (LA), wall area (WA), total vessel area (TVA), mean wall thickness (MWT), and mean normalized wall index (NWI); presence of calcification, lipid-rich necrotic core (LRNC), intraplaque hemorrhage (IPH), and fibrous cap rupture (FCR); and percent composition area (%area) were evaluated and compared between men and women. Independent-sample t test, Mann-Whitney U test, chi-square test, and multiple linear and logistic regressions. In symptomatic arteries, men had significantly greater LA (46.2 ± 15.6 mm2 vs. 40.7 ± 12.9 mm2 , P < 0.05), WA (33.9 ± 11.5 mm2 vs. 26.3 ± 7.5 mm2 , P < 0.05), and TVA (80.1 ± 20.4 mm2 vs. 67.0 ± 18.0 mm2 , P < 0.05); higher MWT (1.2 ± 0.4 mm vs. 1.0 ± 0.2 mm, P < 0.05); and higher prevalence of LRNC (72.3% vs. 46.0%, P < 0.05) and IPH (18.6% vs. 4.9%, P < 0.05) compared with women. In asymptomatic arteries, men had significantly greater LA (48.3 ± 16.9 mm2 vs. 42.1 ± 12.6 mm2 , P < 0.05), WA (32.9 ± 11.0 mm2 vs. 25.8 ± 6.1 mm2 , P < 0.05), and TVA (81.2 ± 22.1 mm2 vs. 67.9 ± 16.5 mm2 , P < 0.05); higher MWT (1.2 ± 0.3 mm vs. 1.0 ± 0.2 mm, P < 0.05); higher prevalence of LRNC (67.8% vs. 42.9%, P < 0.05), IPH (14.9% vs. 1.2%, P < 0.05), and FCR (6.4% vs. 1.2%, P < 0.05); and higher %LRNC area (24.8 ± 17.2% vs. 17.8 ± 14.1%, P < 0.05) compared with women. Men have similar plaque burden but more vulnerable atherosclerotic plaques compared with women in both symptomatic and asymptomatic carotid arteries in a Chinese population. 4 TECHNICAL EFFICACY: Stage 3.

Endovascular treatment of extracranial carotid artery aneurysms using self-expandable covered stent grafts: A single center retrospective study.

This study was aimed to evaluate the safety and efficacy of endovascular treatment of extracranial carotid artery aneurysms (ECAAs) using self-expandable covered stent grafts. All patients with ECAA at a single institution were reviewed from February 2014 to February 2020. Eight consecutive patients (three men, mean age 64.5 years) treated with endovascular repair with self-expandable covered stent graft were retrospectively reviewed. Patient characteristics, angiographic results, and follow-up outcomes were retrospectively recorded. Access to ECAA was gained via a femoral approach or a direct puncture of common carotid artery after surgical exposure because of kinking of the aortic arch and common carotid artery. A self-expandable covered stent graft (Viabahn; W. L. Gore, Flagstaff, AZ) was deployed to exclude the aneurysm. Based on imaging features, there were five peudoaneurysms and three true aneurysms. The technical success rate was 100%. Cerebral protection devices were not used in all the patients during the procedures. Immediate absolute obliteration of the ECAA with no endoleak was documented in all the patients. Perioperative complications included one internal carotid-cavernous sinus fistula, one bleeding at the puncture site, and one stroke. The mean follow-up period was 35.5 months (range, 9-72 months). All the patients were alive, with an obligation rate of 100%. No transient ischemia attack, stroke, or reoccurrence of symptoms was identified during the follow-up period. Radiological examinations identified patency of the stent grafts and revealed no endoleaks, stent fracture, stent migration, or aneurysm rupture. Endovascular treatment of ECAAs with self-expandable covered stent grafts appears to be a safe and feasible alternative for traditional open surgery, especially in the challenging anatomy and instable physical conditions. Although cerebrovascular accidents can occur as the result of hemodynamic changes during the perioperative period, the minimal alternative can yield satisfactory midterm follow-up clinical outcomes.

A Persistent Fault-Based Collision Analysis Against the Advanced Encryption Standard

A transient fault-based collision attack always requires to inject fault multiple times. We present the first attack that uses collision information caused by a persistent fault in the substitution box (S-box) to recover the entire 128-bit key of the advanced encryption standard (AES). Moreover, a relatively relaxed fault model is required; i.e., the attacker does not know any information about the position, the length (i.e., the number of bytes), or the value of the injected fault. At most, 4096 chosen plaintexts are required for a persistent fault-based collision attack (PFCA), and the computational complexity is O(2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">23</sup> ) in the worst case in the single-byte fault setting. A filtering algorithm is presented in the multibyte fault setting, and we theoretically prove that the complexity can be reduced to O(2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> ) in more than half of cases if the number of collision ciphertexts follows a uniform distribution. In addition, PFCAs against a software implementation of AES are simulated on a laptop, and the results show that the success probability of the attack either with online key searching or with offline key searching approaches 100%. In particular, more than 97% of all experiments output the right key with complexity O(2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> ) in the multibyte fault setting. Therefore, the attack is more efficient in this scenario. Furthermore, the attack works on an AES implementation protected by Boolean masking. Finally, PFCAs against AES implementations separately protected by two widely used countermeasures-the inverse S-box and the parity-1 matrix-are performed. The experimental results illustrate that only a 10-round protection using the first method can completely defeat the attack.

Leaking Secrets through Modern Branch Predictor in the Speculative World

Transient execution attacks that exploit speculation have raised significant concerns in computer systems. Typically, branch predictors are leveraged to trigger mis-speculation in transient execution attacks. In this work, we demonstrate a new class of speculation-based attack that targets branch prediction unit (BPU). We find that speculative resolution of conditional branches (i.e., in nested speculation) alter the states of pattern history table (PHT) in modern processors, which are not restored after the corresponding branches are later squashed. Such characteristic allows attackers to exploit BPU as the secret transmitting medium in transient execution attacks. To evaluate the discovered vulnerability, we build a novel attack framework, BranchSpectre, that enables exfiltration of unintended secrets through observing speculative PHT updates (in the form of covert and side channels). We further investigate PHT collision mechanism in the history-based predictor as well as the branch prediction mode transitions in Intel processors. Built upon such knowledge, we implement an ultra high-speed covert channel (BranchSpectre-cc) as well as two side channels (i.e., BranchSpectre-v1 and BranchSpectre-v2) that merely rely on BPU for mis-speculation trigger and secret inference in the speculative domain. Notably, BranchSpectre side channels can take advantage of much simpler code patterns than the ones used in Spectre attacks. We present an extensive BranchSpectre code gadget analysis on a set of popular real-world application code bases followed by a demonstration of real-world side channel attack on OpenSSL. The evaluation results show substantial wider existence and higher exploitability of BranchSpectre code patterns in real-world software. Finally, we discuss several secure branch prediction mechanisms that can mitigate transient execution attacks exploiting modern branch predictors.

De-risking primary prevention: role of imaging.

Atherosclerotic cardiovascular disease (ASCVD) is a common disease among the general population, and includes four major areas: (1) coronary heart disease (CHD), manifested by stable angina, unstable angina, myocardial infarction (MI), heart failure, and coronary death; (2) cerebrovascular disease, manifested by transient ischemia attack and stroke; (3) peripheral vascular disease, manifested by claudication and critical limb ischemia; and (4) aortic atherosclerosis and aortic aneurysm (thoracic and abdominal). CHD remains the leading cause of death for both men and women in the United States. So, it is imperative to identify people at risk of CHD and provide appropriate medical treatment or intervention to prevent serious complications and outcomes including sudden cardiac death. Coronary artery calcification (CAC) is a marker of subclinical coronary artery disease. Therefore, coronary artery calcium score is an important screening method for Coronary artery disease (CAD). In this article, we performed a comprehensive review of current literatures and studies assessing the prognostic value of CAC for future cardiovascular disease (CVD) events. We searched PubMed, MEDLINE, Google Scholar, and Cochrane library. We also reviewed the 2018 American College of Cardiology (ACC)/American Heart Association (AHA) guideline on the assessment of CVD risk. A CAC score of zero corresponds to very low CVD event rates (∼1% per year) and hence a potent negative risk marker. This has been referred to as the ‘power of zero’ and affords the lowest risk of any method of risk calculation. It is now indicated in the 2018 ACC/AHA Cholesterol guidelines to be used to avoid statins for 5–10 years after a score of zero, and then re-assess the patient.

Involvement of the Peripheral Nervous System in Episodic Ataxias.

Episodic ataxias comprise a group of inherited disorders, which have a common hallmark—transient attacks of ataxia. The genetic background is heterogeneous and the causative genes are not always identified. Furthermore, the clinical presentation, including intraictal and interictal symptoms, as well as the retention and progression of neurological deficits, is heterogeneous. Spells of ataxia can be accompanied by other symptoms—mostly from the central nervous system. However, in some of episodic ataxias involvement of peripheral nervous system is a part of typical clinical picture. This review intends to provide an insight into involvement of peripheral nervous system in episodic ataxias.

Endovascular techniques in the treatment of extracranial carotid artery aneurysms

ObjectiveCarotid artery aneurysms and pseudoaneurysms (extracranial carotid artery aneurysm [ECCAs]) are relatively rare. The gold standard treatment has historically been open repair; however, there is increasing evidence of successful treatment of ECCAs with endovascular techniques. Our study examines the evolving experience with endovascular management of ECCAs at a tertiary care center. MethodsWe performed a retrospective analysis of patients with ECCAs who underwent endovascular interventions at a single institution from 2010 to 2020. With increasing experience, the techniques evolved from covered stents to stent-assisted coil embolization and finally to braided stents and overlapping closed cell stents. ResultsThere were 18 ECCAs in 17 patients treated with endovascular modalities. The average age was 65.9 years. There were 11 males (64.7%). Seven aneurysms (38.9%) were symptomatic: three patients had painless pulsatile masses, three patients had painful pulsatile masses, and one had transient ischemia attacks. Two (11.1%) were treated with covered stents, 2 (11.1%) were treated with stent-assisted embolization, 2 (11.1%) were treated with flow-diverting braided stents, 10 (55.6%) were treated with overlapping bare metal stents, and 2 (11.1%) were treated with embolization or ligation alone. Technical success was achieved in all patients. The mean duration of follow up was 338 days (range, 8-3039 days). No perioperative or postoperative complications were encountered, including no neurologic deficits and no embolic events. All patients were discharged on postoperative day 1 or 2. All 16 stents (100%) retained vessel patency on follow-up imaging and exclusion of ECCAs was confirmed on postprocedure surveillance imaging. ConclusionsEndovascular modalities for the management of ECCAs have evolved with experience. Our study suggests that endovascular management is technically feasible as well as clinically effective and suggests an algorithm for navigating the various treatment modalities.

One-stop hybrid procedure combining catheter ablation and left atrial appendage closure increases long-term risk for adverse events in patients with atrial fibrillation.

Combined catheter ablation (CA) and left atrial appendage closure (LAAC) have proven to be a feasible and safe strategy in treating patients with nonvalvular atrial fibrillation (AF). However, the interactions between CA and LAAC have not been systematically explored. We analyzed the impact of CA on long-term outcomes of LAAC in patients with AF treated with the hybrid procedure. A total of 107 consecutive patients with AF who underwent LAAC were divided into two groups: group A (n=61) included patients who underwent CA followed by LAAC during the same procedure and group B (n=46) included patients who underwent LAAC only. All patients underwent systematic transesophageal echocardiography (TEE) follow-up. In group A, CA resulted in severe edema of the left atrial ridge (LAR), which manifested as an increase in LAR thickness from 4.6 ± 0.4mm before CA to 6.8 ± 0.6mm (P<.01) after CA. TEE at 45 days showed that the incidence of peri-device leakage was significantly higher in group A than in group B (45.9%vs 4.3%, P<.001). At the 12-month follow-up, the peri-device leakage rate remained higher in group A than in group B (14.8%vs 2.2%, P<.01). Three (4.9%) patients in group A experienced transient ischemia attacks; no events were reported in group B during the 1-year follow-up. Edema of LAR with the single-stage procedure that consists of CA followed by LAAC could result in increased peri-device leakage and decreased compression rate over time, which may be also associated with elevated risk profiles when compared with an LAAC-only procedure.

Advances in sleep-related hypermotor epilepsy

Sleep-related hypermotor epilepsy (SHE), formerly known as nocturnal frontal epilepsy, is characterized by asymmetrical tonic or complex hypermotor seizures during sleep, with transient, frequent and clustering attack. The accurate incidence is not known but somehow low, which is estimated about 1.8/100 000. The differential diagnosis between SHE and parasomnias may be challenging due to possible similarities between the two sleep-related manifestations. In a majority of patients, the etiology is unknown. Identified etiologies are heterogeneous and structural abnormalities,which are involved in the severity and prognosis of SHE. In terms of treatment, it mainly includes pharmacological therapy and surgery. Carbamazepine seems to be the drug of choice in SHE patients, and epilepsy surgery provides excellent results in selected drug-resistant SHE cases. This review will focus on diagnosis, pathogenesis, treatment and prognosis of SHE, aiming to promote its early diagnosis and appropriate treatment.

Intravenous Nimodipine Treatment for Severe Episode of ATP1A2 Hemiplegic Migraine

Abstract Hemiplegic migraine (HM) is a rare, genetically heterogenous migraine subtype with aura presenting as recurrent transient attacks of hemicrania and hemiparesis. There are no established evidence-based guidelines for the emergency management of HM, and acute therapy therefore remains empiric. We report for the first time a successful treatment of a prolonged Na+-K+-ATPase subunit gene ATP1A2 -linked HM attack in a pediatric case with the calcium antagonist nimodipine. Nimodipine treatment is currently established only for management of HM involving calcium channels. Our results suggest that nimodipine can be an effective emergency treatment option for HM devoid of calcium channel pathologies, arguing for suggested effects of nimodipine such as the inhibition of cerebral vasoconstriction.

Rapid Decline in Telestroke Consults in the Setting of COVID-19.

Background and Purpose: As coronavirus disease 2019 (COVID-19) continues to be a global pandemic, there is a growing body of evidence suggesting that incidence of diseases that require emergent care, particularly myocardial infarction and ischemic stroke, has declined rapidly. The objective of this study is to quantify our experience of telestroke (TS) consults at a large tertiary comprehensive stroke center during the COVID-19 pandemic. Methods: We retrospectively reviewed TS consults of patients presenting to our neuroscience network. Those with a confirmed diagnosis of acute ischemic stroke or transient ischemia attack were included. Data were compared from April 1, 2019, to June 30, 2020, which include consults prepandemic and during the crisis. Results: A total of 1,982 TS consults were provided in 1 year. Prepandemic, the mean monthly consults were 148. In April 2020, only 59 patients were seen (49% decline). Mobile stroke unit consults decreased by 72% in the same month. The 30-day moving average of patients seen per day was between five and six prepandemic declined to between two and three in April, and then began to uptrend during May. The mean percentage of patients receiving intravenous tissue plasminogen activator was 16% from April 2019 to March 2020 and increased to 31% in April 2020. The mean percentage of patients receiving endovascular therapy was 10% from April 2019 to March 2020 and increased to 19% in April 2020. Conclusions: At our large tertiary comprehensive stroke center, we observed a significant and rapid decline in TS consults during the COVID-19 pandemic. We cannot be certain of the reasons for the decline, but a fear of contracting coronavirus, social distancing, and isolation likely played a major role. Further research must be done to elucidate the etiology of this decline.

Multicenter Global Early Feasibility Study to Evaluate Total Endovascular Arch Repair Using Three-vessel Inner Branch Stent-grafts for Aneurysms and Dissections

To evaluate the outcomes of endovascular repair using three-vessel inner branch aortic arch stent-grafts for aneurysms and chronic dissections. We reviewed the clinical data and outcomes of consecutive patients treated by total endovascular aortic arch repair at eight academic centers using three-vessel inner branch stent grafts (William Cook Europe, Bjaeverskov, Denmark) between 2016 and 2019. All patients received patient-specific stent designs with two antegrade and one retrograde inner branch, which was used to incorporate the innominate, left common carotid, and left subclavian arteries. The antegrade inner branches were accessed via axillary or carotid artery access. A preloaded catheter was used for access to the retrograde left subclavian artery branch via femoral approach (Fig). End points were technical success, mortality, major adverse events, any stroke (minor or major) or transient ischemia attack, secondary interventions, target vessel patency, target vessel instability, aneurysm-related mortality and patient survival. There were 39 patients (31 male patients [79%], mean age 70 ± 7 years) treated for 14 (36%) degenerative and 25 (64%) chronic postdissection arch aneurysms. Clinical characteristics included American Society of Anesthesiologists classification of >3 in 37 patients (95%) and prior median sternotomy for ascending aortic repair in 33 patients (85%). Technical success rate was 100%. There were two in-hospital or 30-day deaths (5%) and two strokes (one minor). Combined mortality/any stroke rate was 8% (n = 3). Major adverse events occurred in 10 patients (26%), including respiratory failure in 4 patients (10%) and estimated blood loss of >1 L, myocardial infarction and acute kidney injury in two patients each (5%). Mean follow-up was 8 ± 10 months. Twelve patients (31%) required secondary interventions to treat vascular access complications in five patients, endoleak in six patients (three type II, one type IC, one type IB, one type IIIA) and target vessel stenosis in one patient. At 1 year, primary and secondary patency rates and freedom from target vessel instability were 95% ± 5%,100%, and 92% ± 5%, respectively. Freedom from aortic-related mortality and patient survival were 94% ± 4% and 90% ± 6%, respectively. This multicenter global experience demonstrates the technical feasibility and safety of total endovascular aortic arch repair for aneurysms and chronic dissections using three-vessel inner branch stent grafts. Mortality and stroke rates compare favorably to reported outcomes of total open surgical arch replacement, particularly among higher risk patients who had prior median sternotomies and ascending aortic repairs. A limitation remains the high rate of secondary reinterventions (31%), emphasizing need for larger experience and longer follow-up.