Assessment of Mendelian and risk-factor genes in Alzheimer disease: A prospective nationwide clinical utility study and recommendations for genetic screening.

PURPOSE: To assess the likely pathogenic/pathogenic (LP/P) variants rates in Mendelian dementia genes and the moderate-to-strong risk factors rates in patients with Alzheimer disease (AD). METHODS: We included 700 patients in a prospective study and performed exome sequencing. A panel of 28 Mendelian and 6 risk-factor genes was interpreted and returned to patients. We built a framework for risk variant interpretation and risk gradation and assessed the detection rates among early-onset AD (EOAD, age of onset (AOO) ≤65 years, n = 608) depending on AOO and pedigree structure and late-onset AD (66 < AOO < 75, n = 92). RESULTS: Twenty-one patients carried a LP/P variant in a Mendelian gene (all with EOAD, 3.4%), 20 of 21 affected APP, PSEN1, or PSEN2. LP/P variant detection rates in EOAD ranged from 1.7% to 11.6% based on AOO and pedigree structure. Risk factors were found in 69.5% of the remaining 679 patients, including 83 (12.2%) being heterozygotes for rare risk variants, in decreasing order of frequency, in TREM2, ABCA7, ATP8B4, SORL1, and ABCA1, including 5 heterozygotes for multiple rare risk variants, suggesting non-monogenic inheritance, even in some autosomal-dominant-like pedigrees. CONCLUSION: We suggest that genetic screening should be proposed to all EOAD patients and should no longer be prioritized based on pedigree structure.

Glial Fibrillary Acidic Protein Autoimmunity: A French Cohort Study.

BACKGROUND AND OBJECTIVES: To report the clinical, biological, and imaging features and clinical course of a French cohort of patients with glial fibrillary acidic protein (GFAP) autoantibodies. METHODS: We retrospectively included all patients who tested positive for GFAP antibodies in the CSF by immunohistochemistry and confirmed by cell-based assay using cells expressing human GFAPα since 2017 from 2 French referral centers. RESULTS: We identified 46 patients with GFAP antibodies. Median age at onset was 43 years, and 65% were men. Infectious prodromal symptoms were found in 82%. Other autoimmune diseases were found in 22% of patients, and coexisting neural autoantibodies in 11%. Tumors were present in 24%, and T-cell dysfunction in 23%. The most frequent presentation was subacute meningoencephalitis (85%), with cerebellar dysfunction in 57% of cases. Other clinical presentations included myelitis (30%) and visual (35%) and peripheral nervous system involvement (24%). MRI showed perivascular radial enhancement in 32%, periventricular T2 hyperintensity in 41%, brainstem involvement in 31%, leptomeningeal enhancement in 26%, and reversible splenial lesions in 4 cases. A total of 33 of 40 patients had a monophasic course, associated with a good outcome at last follow-up (Rankin Score ≤2: 89%), despite a severe clinical presentation. Adult and pediatric features are similar. Thirty-two patients were treated with immunotherapy. A total of 11/22 patients showed negative conversion of GFAP antibodies. DISCUSSION: GFAP autoimmunity is mainly associated with acute/subacute meningoencephalomyelitis with prodromal symptoms, for which tumors and T-cell dysfunction are frequent triggers. The majority of patients followed a monophasic course with a good outcome.

Usefulness of a single-parameter tool for the prediction of large vessel occlusion in acute stroke.

BACKGROUND: In acute stroke, large vessel occlusion (LVO) should be promptly identified to guide patient's transportation directly to comprehensive stroke centers (CSC) for mechanical thrombectomy (MT). In many cases, prehospital multi-parameter scores are used by trained emergency teams to identify patients with high probability of LVO. However, in several countries, the first aid organization without intervention of skilled staff precludes the on-site use of such scores. Here, we assessed the accuracy of LVO prediction using a single parameter (i.e. complete hemiplegia) obtained by bystander's telephone-based witnessing. PATIENTS AND METHODS: This observational, single-center study included consecutive patients who underwent intravenous thrombolysis at the primary stroke center and/or were directly transferred to a CSC for MT, from January 1, 2015 to March 1, 2020. We defined two groups: patients with initial hemiplegia (no movement in one arm and leg and facial palsy) and patients without initial hemiplegia, on the basis of a bystander's witnessing. RESULTS: During the study time, 874 patients were included [mean age 73 years (SD 13.8), 56.7% men], 320 with initial hemiplegia and 554 without. The specificity of the hemiplegia criterion to predict LVO was 0.88, but its sensitivity was only 0.53. CONCLUSION: Our results suggest that the presence of hemiplegia as witnessed by a bystander can predict LVO with high specificity. This single criterion could be used for decision-making about direct transfer to CSC for MT when the absence of emergency skilled staff precludes the patient's on-site assessment, especially in regions distant from a CSC.

Complications During Inter-Hospital Transfer of Patients with Acute Ischemic Stroke for Endovascular Therapy.

Purpose: Few data are available on complications occurring during inter-hospital transfer from a primary stroke center (PSC) to a comprehensive stroke center (CSC) for endovascular treatment (EVT) after large vessel occlusion (LVO). Therefore, we prospectively studied data from consecutive patients transferred from our PSC to the next CSC during 4 years to determine the incidence and risk factors of complications during transfer. Methods: This observational, single-center study included consecutive patients transferred from January 1, 2015 to December 31, 2018. During inter-hospital transfer, all medical incidents were systematically recorded. A new complete clinical examination was performed on arrival at the CSC. Results: Among the 253 patients transferred to the CSC during the study period, 68 (26.9%) had one or more complications. In 11 patients (4.3%) these were life-threatening and required emergency intervention by a physician. Baseline characteristics were not different between patients with and without complications, except for the LVO location. Specifically, basilar artery (BA) occlusion was strongly associated with complications during the transport (p < 0.0005). Conclusion: Complications occurred in 26.9% of patients during transfer. Only BA occlusion could predict complication during transfer. Future studies should identify variables to help stratifying patients at high and low risk of complications during transportation.

Which Patients Require Physician-Led Inter-Hospital Transport in View of Endovascular Therapy?

INTRODUCTION: The current guidelines advocate the implementation of stroke networks to organize endovascular treatment (ET) for patients with acute ischemic stroke due to large vessel occlusion (LVO) after transfer from a Primary Stroke Centre (PSC) to a Comprehensive Stroke Centre (CSC). In France and in many other countries around the world, these transfers are carried out by a physician-led mobile medical team. However, with the recent broadening of ET indications, their availability is becoming more and more critical. Here, we retrospectively analysed data of patients transferred from a PSC to a CSC for potential ET to identify predictive factors of major complications (MC) at departure and during transport that absolutely require the presence of a physician during interhospital transfer. METHODS: This observational, single-centre study included patients with evidence of intracranial LVO transferred for ET from Perpignan to a 156 km-distant CSC between January 1, 2015 and -December 31, 2018. We compared 2 groups: MC group (patients who required emergency intervention by the medical team due to life-threatening complications, including need of mechanical ventilation at departure) and non-MC group (all other patients who experienced no or only minor complications that could be managed by the emergency paramedics alone). RESULTS: Among the 253 patients who were transferred to the CSC, 185 (73.1%) had no complication, 57 (22.6%) minor complications, and 11 (4.3%) had MC. In multivariate analysis, MC was associated with basilar artery (BA) occlusion (p < 0.0001), initial National Institute of Health Stroke Scale (NIHSS) score >22 (p < 0.005), and history of atrial fibrillation (p < 0.04). Among the 168 patients treated with intravenous thrombolysis (IVT), only 1 patient (0.6%) had MC due to an IVT-related adverse event during transfer. CONCLUSIONS: Physician-led inter-hospital transports are warranted for patients with BA occlusion, initial NIHSS score >22, or history of atrial fibrillation. For the other patients, transfer without a physician may be considered, even if treated with IVT.

Mechanical Recanalization after Transfer from a Distant Primary Stroke Center: Effectiveness and Future Directions.

INTRODUCTION: Little is known about the effectiveness of endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) admitted to a primary stroke center (PSC). The aim of this study was to assess EVT effectiveness after transfer from a PSC to a distant (156 km apart; 1.5 hour by car) comprehensive stroke center (CSC), and to discuss perspectives to improve access to EVT, if indicated. PATIENTS AND METHOD: Analysis of the data collected in a 6-year prospective registry of patients admitted to a PSC for AIS due to LVO and selected for transfer to a distant CSC for EVT. The rate of transfer, futile transfer, EVT, reperfusion (thrombolysis in cerebral infarction score ≥2b-3), and relevant time measures were determined. RESULTS: Among the 529 patients eligible, 278 (52.6%) were transferred and 153 received EVT (55% of transferred patients) followed by reperfusion in 115 (overall reperfusion rate: 21.7%). Median times (interquartile range) were: 90 minutes (76-110) for PSC-door-in to PSC-door-out, 88 minutes (65-104) for PSC-door-out to CSC-door-in, 262 minutes (239-316) for PSC-imaging to reperfusion, and 393 minutes (332-454) for symptom onset to reperfusion. At 3 months, rates of favorable outcome (modified Rankin Scale 0-2) were not significantly different between patients eligible for EVT (42.4%), transferred patients (49.1%) and patients who underwent EVT (34.1%). DISCUSSION AND CONCLUSIONS: Our study suggests that transfer to a distant CSC is associated with reduced access to early EVT. These results argue in favor of on-site EVT at high volume PSCs that are distant from the CSC.

Futile inter-hospital transfer for mechanical thrombectomy in a semi-rural context: analysis of a 6-year prospective registry.

BACKGROUND AND PURPOSE: Inter-hospital transfer for mechanical thrombectomy (MT) might result in the transfer of patients who finally will not undergo MT (ie, futile transfers [FT]). This study evaluated FT frequency in a primary stroke center (PSC) in a semi-rural area and at 156 km from the comprehensive stroke center (CSC). METHODOLOGY: Retrospective analysis of data collected in a 6-year prospective registry concerning patients admitted to our PSC within 4.5 hours of acute ischemic stroke (AIS) symptom onset, with MR angiography indicating the presence of large vessel occlusion (LVO) without large cerebral infarction (DWI-ASPECT ≥5), and selected for transfer to the CSC to undergo MT. Futile transfer rate and reasons were determined, and the relevant time measures recorded. RESULTS: Among the 529 patients screened for MT, 278 (52.6%) were transferred to the CSC. Futile transfer rate was 45% (n=125/278) and the three main reasons for FT were: clinical improvement and reperfusion on MRI on arrival at the CSC (58.4% of FT); clinical worsening and/or infarct growth (16.8%); and longer than expected inter-hospital transfer time (11.2%). Predictive factors of FT due to clinical improvement/reperfusion on MRI could not be identified. Baseline higher NIHSS (21 vs 17; P=0.01) and lower DWI-ASPECT score (5 vs 7; P=0.001) were associated with FT due to clinical worsening/infarct growth on MRI. CONCLUSIONS: In our setting, 45% of transfers for MT were futile. None of the baseline factors could predict FT, but the initial symptom severity was associated with FT caused byclinical worsening/infarct growth.

Target Door-to-Needle Time for Tissue Plasminogen Activator Treatment with Magnetic Resonance Imaging Screening Can Be Reduced to 45 min.

OBJECTIVE: The purpose of this study was to demonstrate that the median door-to-needle (DTN) time for intravenous tissue plasminogen activator (tPA) treatment can be reduced to 45 min in a primary stroke centre with MRI-based screening for acute ischaemic stroke (AIS). METHODS: From February 2015 to February 2017, the stroke unit of Perpignan general hospital, France, implemented a quality-improvement (QI) process. During this period, patients who received tPA within 4.5 h after AIS onset were included in the QI cohort. Their clinical characteristics and timing metrics were compared each semester and also with those of 135 consecutive patients with AIS treated by tPA during the 1-year pre-QI period (pre-QI cohort). RESULTS: In the QI cohort, 274 patients (92.5%) underwent MRI screening. While the demographic and baseline characteristics were not significantly different between cohorts, the median DTN time was significantly lower in the QI than in the pre-QI cohort (52 vs. 84 min; p < 0.00001). Within the QI cohort, the median DTN time for each semester decreased from 65 to 44 min (p < 0.00001) and the proportion of treated patients with a DTN time ≤45 min increased from 25 to 58.9% (p < 0.0001). Overall, DTN time improvement was associated with a better outcome at 3 months (patients with a modified Rankin Scale score between 0 and 2: 61.8% in the QI vs. 39.3% in the pre-QI cohort; p < 0.0001). CONCLUSIONS: A QI process can reduce the DTN within 45 min with MRI as a screening tool.

Subacute combined degeneration of the spinal cord caused by nitrous oxide anaesthesia.

Vitamin B12 deficiency causes haematological, gastrointestinal and neurological diseases. Subacute combined degeneration (SCD) of the spinal cord is characterised by degeneration of the posterior and lateral columns. We report a case of SCD associated with nitrous oxide anaesthesia.