High-Frequency versus Low-Frequency Spinal Cord Stimulation in Treatment of Chronic Limb-Threatening Ischemia: Short-Term Results of a Randomized Trial

INTRODUCTION

The objective of the study is to determine if high-frequency (1 kHz) spinal cord stimulation (SCS) is better than low-frequency SCS for pain relief in chronic limb-threatening ischemia (CLTI).

METHODS

HEAL-SCS trial was designed as an open-label, parallel-group, single-center randomized study with a 1:1 allocation ratio. The trial was conducted in Meshalkin National Medical Research Center between August 2018 and February 2020. Total 56 patients underwent screening, 50 were enrolled, 6 were rejected. The participants were randomized into 2 cohorts of 25 patients each by an external coordinator using an online tool. A neurosurgeon and a vascular surgeon both examined all patients and estimated the pain intensity using visual analog scale (VAS), quality of life with short-form-36 health survey (SF-36), and functional status by walking impairment questionnaire (WIQ) at 3 and 12 months. Tissue perfusion was evaluated for 34 patients using transcutaneous oxygen tension measurement (TcPO2) at baseline and in 12 months.

RESULTS

All 50 patients (84% men, median age 66.5 y.o) were available for primary outcome assessment 3 and 12 months after implantation. Intention-to-treat analysis demonstrated comparative advantage of HF-SCS over LF-SCS at 3 months with mean VAS score 2.8 (95% CI, 2.4; 3.2) and 3.3 (95% CI, 3.0; 3.6), respectively (p = 0.031). Clinical superiority of HF-SCS persisted at 12-month follow-up (p < 0.001). HF-SCS produced significantly greater pain relief by WIQ at 3 (p < 0.001) and 12 months (p = 0.009). Despite stair-climbing ability was better in HF-SCS group (p = 0.02), no significant difference between groups was found at 1-year post-op in terms of speed (p = 0.92) and distance scores (p = 0.68). Accordingly, the general and mental health domains of SF-36 were significantly better in HF-SCS at 12 months. Despite a tendency toward better resting oxygen pressure in HF-SCS group, there was no intergroup difference by TcPO2 (p = 0.076). Only 1 patient (2%) required above-the-knee amputation at 10 months after LF-SCS implantation.

CONCLUSION

High-frequency SCS provides better pain relief, life quality, and functional performance in patients with CLTI during short-term follow-up. The lack of perfusion difference between high-frequency and conventional SCS requires further examination to the possible long-term advantages of the method.

Huge cerebral pial arteriovenous fistula in a newborn: illustrative case

BACKGROUND

Pediatric arteriovenous malformations (AVMs) and pial/dural arteriovenous fistulas (AVFs) are rare but life-threatening complications that can lead to congestive heart failure and hemorrhagic stroke in newborns and pediatric patients. The pronounced shunting in these conditions is associated with early complications and necessitates aggressive surgical management. Here, the authors describe endovascular treatment of an atypical cerebral pial AVF in a newborn.

OBSERVATIONS

This AVF formed direct communication between a major cerebral artery (basilar artery) and a large draining vein (dilated deep cerebral vein). The authors performed earlier subtotal embolization of the AVF using 0.020-inch coils, which led to progressive thrombosis of the fistula with restoration of normal arterial blood flow. The patient was discharged 18 days after surgery, examination at 1.5 and 6 months showed magnetic resonance imaging signs of blood flow absence through the fistula and satisfactory condition of the infant without physical and mental developmental delay.

LESSONS

Subtotal coiling of a high-flow pial AVF in a newborn can result in a good clinical outcome.

Numerical Assessment of the Risk of Abnormal Endothelialization for Diverter Devices: Clinical Data Driven Numerical Study

Numerical modeling is an effective tool for preoperative planning. The present work is devoted to a retrospective analysis of neurosurgical treatments for the occlusion of cerebral aneurysms using flow-diverters and hemodynamic factors affecting stent endothelization. Several different geometric approaches have been considered for virtual flow-diverters deployment. A comparative analysis of hemodynamic parameters as a result of computational modeling has been carried out basing on the four clinical cases: one successful treatment, one with no occlusion and two with in stent stenosis. For the first time, a quantitative assessment of both: the limiting magnitude of shear stresses that are necessary for the occurrence of in stent stenosis (MaxWSS > 1.23) and for conditions in which endothelialization is insufficiently active and occlusion of the cervical part of the aneurysm does not occur (MaxWSS < 1.68)—has been statistacally proven (p < 0.01).

Middle Cerebral Artery Aneurysm Trial (MCAAT): A randomized care trial comparing surgical and endovascular management of MCA aneurysm patients

BACKGROUND

Whether the best management of middle cerebral artery (MCA) aneurysm patients is surgical or endovascular remains uncertain, with little evidence to guide decision-making. A randomized care trial offering MCA aneurysm patients a 50% chance of surgical and a 50% chance of endovascular management may optimize outcomes in the presence of uncertainty.

METHODS

The Middle Cerebral Artery Aneurysm Trial (MCAAT) is an investigator-initiated, multi-center, parallel group, prospective, 1:1 randomized controlled clinical trial. All adult patients with MCA aneurysms, ruptured or unruptured, amenable to surgical and endovascular treatment can be included. The composite primary outcome is 'Treatment Success': i) occlusion or exclusion of the aneurysm using the allocated treatment modality; ii) no intracranial hemorrhage during follow-up; iii) no retreatment of the target aneurysm during follow-up, iv) no residual aneurysm on angiographic follow-up and v) independence (mRS <3) at 1 year. The trial tests two versions of the same hypothesis (one for ruptured and one for unruptured MCA aneurysm patients): Surgical management will lead to a 15% absolute increase in the proportion of patients reaching Treatment Success from 55% to 70% (ruptured) or from 75% to 90% (unruptured aneurysm patients) compared to endovascular treatment (any method). In this pragmatic trial, outcome evaluations are by treating physicians, except for 1 year angiographic results which will be core lab assessed. The trial will be monitored by an independent data safety monitoring committee to assure safety of participants. MCAAT is registered at clinicaltrials.gov: NCT05161377.

CONCLUSION

Patients with MCA aneurysms can be optimally managed within a care trial protocol.

Silent EEG-Speech Recognition Using Convolutional and Recurrent Neural Network with 85% Accuracy of 9 Words Classification

In this work, we focus on silent speech recognition in electroencephalography (EEG) data of healthy individuals to advance brain–computer interface (BCI) development to include people with neurodegeneration and movement and communication difficulties in society. Our dataset was recorded from 270 healthy subjects during silent speech of eight different Russia words (commands): ‘forward’, ‘backward’, ‘up’, ‘down’, ‘help’, ‘take’, ‘stop’, and ‘release’, and one pseudoword. We began by demonstrating that silent word distributions can be very close statistically and that there are words describing directed movements that share similar patterns of brain activity. However, after training one individual, we achieved 85% accuracy performing 9 words (including pseudoword) classification and 88% accuracy on binary classification on average. We show that a smaller dataset collected on one participant allows for building a more accurate classifier for a given subject than a larger dataset collected on a group of people. At the same time, we show that the learning outcomes on a limited sample of EEG-data are transferable to the general population. Thus, we demonstrate the possibility of using selected command-words to create an EEG-based input device for people on whom the neural network classifier has not been trained, which is particularly important for people with disabilities.

Temporary spinal cord stimulation to prevent postoperative atrial fibrillation after coronary surgery. First results of the feasibility study

Background

Atrial fibrillation (AF) is the most common arrhythmia after cardiac surgery with typical appearance at early days after operation and leads to increase morbidity and mortality in the short and long term follow up. Spinal cord stimulation (SCS) was proven to be effective in chronic pain and intractable angina pectoris treatment. Recently, animal studies demonstrated that spinal cord stimulation could suppress AF and reduce AF burden.

Aim

To test safety and efficacy of the temporary SCS in early postoperative period in patients undergoing coronary artery bypass grafting

Methods

Fifteen patients (10 men, mean age 61±7.5 years) with indications for coronary artery bypass grafting (CABG) and history of paroxysmal AF underwent percutaneous lead placement for temporary SCS. Under local anesthesia and fluoroscopic guidance, the leads were placed at C7-Th4 level according to patient's sense of paresthesia and connected with spinal cord stimulator externally fixed on patient's chest. Temporary SCS was performed 3 days before CABG and turned off during surgery. At the end of CABG, the SCS was turned on in the intensive care unit and continued for 7 days. After that the temporary leads were removed. The primary safety objective was to test safety of the temporary SCS in early postoperative period, including 30 days occurrence of MACE (Death, stroke or TIA, myocardial infarction), acute spinal cord and kidney injury. The efficacy endpoint included occurrence of AF or any atrial tachyarrhythmias lasting ≥30 seconds during 30 days after surgery. All patients had continuous external ECG monitoring for 30 days after surgery.

Results

In all (100%) patients temporary leads for SCS were implanted successfully and standard on-pump elective CABG was performed thereafter. There were no any adverse events related to temporary SCS in either patient till the end of follow up. There were no significant differences in CK-MB and creatinine levels as compared with baseline data (p=0.2 and 0.3, respectively). No patients developed AF or atrial tachyarrhythmias during follow up according 30-days ECG monitoring.

Conclusions

The first results of the temporary spinal cord stimulation to prevent AF after coronary surgery demonstrated safety and efficacy of this therapy. The parallel group randomizes study is under way (NCT 03539354)

Funding Acknowledgement

Type of funding source: None

Considerations for Antiplatelet Management of Carotid Stenting in the Setting of Mechanical Thrombectomy: A Delphi Consensus Statement

BACKGROUND AND PURPOSE

There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement.

MATERIALS AND METHODS

We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback.

RESULTS

A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period.

CONCLUSIONS

More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement

BACKGROUND AND PURPOSE

There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies.

MATERIALS AND METHODS

The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society.

RESULTS

Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure.

CONCLUSIONS

More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

Stent-assisted coiling of cerebral aneurysms: multi-center analysis of radiographic and clinical outcomes in 659 patients

INTRODUCTION

The endovascular stent-assisted coiling approach for the treatment of cerebral aneurysms is evolving rapidly with the availability of new stent devices. It remains unknown how each type of stent affects the safety and efficacy of the stent-coiling procedure.

METHODS

This study compared the outcomes of endovascular coiling of cerebral aneurysms using Neuroform (NEU), Enterprise (EP), and Low-profile Visualized Intraluminal Support (LVIS) stents. Patient characteristics, treatment details and angiographic results using the Raymond-Roy grade scale (RRGS), and procedural complications were analyzed in our study.

RESULTS

Our study included 659 patients with 670 cerebral aneurysms treated with stent-assisted coiling (NEU, n=182; EP, n=158; LVIS, n=330) that were retrospectively collected from six academic centers. Patient characteristics included mean age 56.3±12.1 years old, female prevalence 73.9%, and aneurysm rupture on initial presentation of 18.8%. We found differences in complete occlusion on baseline imaging, defined as RRGS I, among the three stents: LVIS 64.4%, 210/326; NEU 56.2%, 95/169; EP 47.6%, 68/143; P=0.008. The difference of complete occlusion on 10.5 months (mean) and 8 months (median) angiographic follow-up remained significant: LVIS 84%, 251/299; NEU 78%, 117/150; EP 67%, 83/123; P=0.004. There were 7% (47/670) intra-procedural complications and 11.5% (73/632) post-procedural-related complications in our cohort. Furthermore, procedure-related complications were higher in the braided-stents vs laser-cut, P=0.002.

CONCLUSIONS

There was a great variability in techniques and choice of stent type for stent-assisted coiling among the participating centers. The type of stent was associated with immediate and long-term angiographic outcomes. Randomized prospective trials comparing the different types of stents are warranted.

Posterior Fossa Dural Arteriovenous Fistulas with Subarachnoid Venous Drainage: Outcomes of Endovascular Treatment

BACKGROUND AND PURPOSE

Dural AVFs located in the posterior fossa are a rare entity. The objectives of the study were to analyze the anatomy of dural AVFs, their endovascular treatment strategies, and clinical outcomes.

MATERIALS AND METHODS

Two centers retrospectively selected patients treated between January 2009 and June 2018 having posterior fossa dural AVFs. We collected patient demographics, clinical presentation, arterial and venous outflow anatomy of the dural AVFs, and treatment outcomes.

RESULTS

Twenty-six patients treated endovascularly for posterior fossa dural AVFs, type III, IV, or V, were included. One hundred percent of the dural AVFs were occluded. A transarterial approach was performed in 23 dural AVFs (88.5%); a combined transarterial and transvenous approach, for 2 dural AVFs (7.7%); and a transvenous approach alone, for 1 dural AVF (3.8%). The middle meningeal artery was the most common artery chosen to inject embolic liquid (46%, 12/26). Procedure-related morbidity was 15.4% at 24 hours, 7.7% at discharge, and 0% at 6 months. Procedure-related mortality was 0%.

CONCLUSIONS

Endovascular treatment offers high occlusion rates for posterior fossa dural AVFs with low morbidity and mortality rates. The arterial approach is the first-line preferred approach, even if a transvenous or combined approach would be a safe and effective option for patients with favorable anatomy.

The Clinical Outcomes in Patients with Critical Limb Ischemia One Year after Spinal Cord Stimulation

BACKGROUND

The aim of this study was to evaluate the long-term outcomes of spinal cord stimulation in patients with critical limb ischemia and to test the hypothesis that the dynamics of clinical changes one year after therapy depend both on the clinical determinants associated with the underlying disease and on factors related to systemic atherosclerosis.

METHODS

This prospective cohort study included 56 patients with critical limb ischemia. All patients before and after spinal cord stimulation were examined in terms of the dynamics of their clinical changes using the Rutherford scale and transcutaneous oxygen tension (TcPO₂, mm Hg) in the affected foot. The active orthostatic test was used to assess the functional state of peripheral perfusion.

RESULTS

One year after spinal cord stimulation, 74% of patients showed positive clinical outcomes. No changes were observed in 9.3% of patients, whereas adverse clinical outcomes were revealed in 16.7% of cases. The TcPO₂ values were significantly reduced before spinal cord stimulation: 10.5 (6.4-16.0) mm Hg. The functional status of the peripheral microvasculature was also disturbed. One year after therapy, TcPO₂ significantly increased and the adaptive mechanisms of the microvasculature were improved in more than 70% of patients. Logistic regression analysis showed that the initially low TcPO₂ values (<10 mm Hg) with a lack of gain in TcPO₂ during the orthostatic test are associated with the negative clinical outcomes after spinal cord stimulation. The gain in TcPO₂ during the orthostatic test to >10 mm Hg is associated with the positive clinical outcomes after spinal cord stimulation. The age-adjusted Charlson Comorbidity Index >5 and duration of critical ischemic symptoms also had a negative effect on the clinical outcomes after spinal cord stimulation.

CONCLUSIONS

The positive clinical outcomes were revealed in most patients with critical limb ischemia one year after spinal cord stimulation. The low values of peripheral tissue metabolism with the disturbed functional status of the microvasculature are associated with the negative clinical outcome. The patients with baseline TcPO₂ <10 mm Hg can recover if they still have a sufficient microcirculatory reserve capacity. Duration of critical ischemic symptoms and high comorbidity burden with allowance for age are negative factors affecting the clinical outcome.

A2, M2, P2 aneurysms and beyond: results of treatment with pipeline embolization device in 65 patients

BACKGROUND

Intracranial aneurysms located in the distal vessels are rare and remain a challenge to treat through surgical or endovascular interventions.

OBJECTIVE

To describe a multicenter approach with flow diversion using the pipeline embolization device (PED) for treatment of distal intracranial aneurysms.

METHODS

Cases of distal intracranial aneurysms defined as starting on or beyond the A2 anterior cerebral artery, M2 middle cerebral artery, and P2 posterior cerebral artery segments were included in the final analysis.

RESULTS

65 patients with distal aneurysms treated with the PED were analyzed. Median aneurysm size at the largest diameter was 7.0 mm, 60% were of a saccular morphology, and 9/65 (13.8%) patients presented in the setting of acute rupture. Angiographic follow-up data were available for 53 patients, with a median follow-up time of 6 months: 44/53 (83%) aneurysms showed complete obliteration, 7/53 (13.2%) showed reduced filling, and 2/53 (3%) showed persistent filling. There was no association between patient characteristics, including aneurysm size (P=0.36), parent vessel diameter (P=0.27), location (P=0.81), morphology (P=0.63), ruptured status on admission (P=0.57), or evidence of angiographic occlusion at the end of the embolization procedure (P=0.49). Clinical outcome data were available for 60/65 patients: 95% (57/60) had good clinical outcome (modified Rankin Scale score of 0-2) at 3 months.

CONCLUSIONS

This large multicenter study of patients with A2, M2, and P2 distal aneurysms treated with the PED showed that flow diversion may be an effective treatment approach for this rare type of vascular pathology. The procedural compilation rate of 7.7% indicates the need for further studies as the flow diversion technology constantly evolves.

Transvenous Treatment of Carotid Aneurysms Through Transseptal Access

BACKGROUND

Transseptal puncture has been widely used by cardiologists to reach the left side of the heart through a transvenous access. Rarely, it also can be used to pass into the supra-aortic arteries from the venous side when conventional transarterial access pathways (transfemoral, transradial/brachial routes, or direct carotid puncture) are likely to fail.

CASE DESCRIPTION

We report 2 cases of transvenous femoral access followed by transseptal access to aorta to treat dissecting carotid artery aneurysms at the level of the skull base with flow diverters. In one case, multiple cervical arterial bypass operations and in the other a rare anomaly of the aortic arch precluded endovascular treatment through conventional routes.

CONCLUSIONS

Transvenous-transseptal access enabled treatment of both cases easily and without complications. On follow-up computed tomography angiograms, both flow diverters were patent, there were no residual aneurysms, and no neurologic or cardiac adverse events in either patient.

Initial experience with precipitating hydrophobic injectable liquid in cerebral arteriovenous malformations

BACKGROUND

Precipitating hydrophobic injectable liquid is a newly introduced liquid embolic agent for endovascular embolization with some technical advantages over other liquid embolic agents. We present our initial experience with precipitating hydrophobic injectable liquid in the endovascular treatment of cerebral arteriovenous malformations.

METHODS

From October 2015 to January 2018, 27 patients harboring cerebral arteriovenous malformations underwent endovascular embolization with precipitating hydrophobic injectable liquid 25. Clinical features, angiographic results, procedural details, complications, and follow-up details were retrospectively analyzed.

RESULTS

Twenty-seven patients with cerebral arteriovenous malformations were included. Total obliteration in one endovascular session was confirmed for 14/27 (52%) patients. Partial embolization was attained in 13 patients (48%) in whom staged treatment with following radiosurgery or surgery was planned. No mortality was recorded in this series. Complications during or after the embolization occurred in six of 27 (22.2%) patients.

CONCLUSION

In our initial experience, precipitating hydrophobic injectable liquid has acceptable clinical outcome comparable to other liquid embolic agents. Although this is the largest reported study in arteriovenous malformation treatment with precipitating hydrophobic injectable liquid, further studies are needed to validate its safety and efficacy.

Assessment of periprocedural hemodynamic changes in arteriovenous malformation vessels by endovascular dual-sensor guidewire

Endovascular embolization is an important modality in the treatment of brain AVMs. Nowadays staged embolization is the method of choice for the prevention of perioperative hemorrhagic complications. Current theory suggests that simultaneous occlusion of more than 60% of AVM volume induces significant redistribution local blood flow. That, in turn, may lead to hemorrhage due to AVM rupture. Aside from angiographic findings, there is still no method that predicts the degree of safe partial embolization. Intraluminal measurement of flow velocity and pressure in the vicinity of the AVM nidus might allow detecting the changes in local hemodynamics. That can provide a valuable data and shed the light on the origin of vascular catastrophes. Ten patients underwent 12 embolization sessions with intraluminal flow velocity and pressure monitoring. The measurements were performed by dual-sensor guidewire. The "Combomap" (Volcano) system with Combowire microguidewires was chosen for measurements, as there is a documented experience of safe use of said guidewires in the cerebral vasculature. The findings observed during the study matched empirical data as well as the current physiological hypothesis of AVM hemorrhage. In conjunction with DSA runs, intraluminal flow velocity and pressure monitoring has the potential to become a valuable tool in AVM treatment.

Experience using pipeline embolization device with Shield Technology in a patient lacking a full postoperative dual antiplatelet therapy regimen

Utilization of flow diverting devices is accompanied with dual antiplatelet therapy to reduce the risk of thromboembolic events, even though this increases the risk of hemorrhagic complications. The updated Pipeline Flex embolization device with Shield Technology has been created using a phosphorylcholine coating that reduces thrombogenicity and possibly reduces the need for dual antiplatelet therapy. However, because of the potential risk to patients of utilizing a pipeline embolization device without dual antiplatelet therapy, the pipeline embolization device with Shield Technology has not been tested in human subjects without dual antiplatelet therapy, and its contribution to preventing thromboembolic events is therefore unknown. We report a case in which a patient, following complications that limited his absorption of dual antiplatelet therapy, had low levels of dual antiplatelet therapy medications in his bloodstream following treatment for an intracranial aneurysm with a pipeline embolization device with Shield Technology. The patient recovered without signs of luminal stenosis or thromboembolic event.