Impact of Antiplatelet Therapy During Endovascular Therapy for Tandem Occlusions: A Collaborative Pooled Analysis.

Background and Purpose- Antiplatelet agents could be used in the setting of endovascular therapy for tandem occlusions to reduce the risk of de novo intracranial embolic migration, reocclusion of the extracranial internal carotid artery lesion, or in-stent thrombosis in case of carotid stent placement but have to be balanced with the intracerebral hemorrhagic transformation risk. In this study, we aim to investigate the impact of acute antiplatelet therapy administration on outcomes during endovascular therapy for anterior circulation tandem occlusions. Methods- This is a retrospective analysis of a collaborative pooled analysis of 11 prospective databases from the multicenter observational TITAN registry (Thrombectomy in Tandem Lesions). Patients were divided into groups based on the number of antiplatelet administered during endovascular therapy. The primary outcome was favorable outcome, defined as a modified Rankin Scale score of 0 to 2 at 90 days. Results- This study included a total of 369 patients; 145 (39.3%) did not receive any antiplatelet agent and 224 (60.7%) received at least 1 antiplatelet agent during the procedure. Rate of favorable outcome was nonsignificantly higher in patients treated with antiplatelet therapy (58.3%) compared with those treated without antiplatelet (46.0%; adjusted odds ratio, 1.38 [95% CI, 0.78-2.43]; P=0.26). Rate of 90-day mortality was significantly lower in patients treated with antiplatelet therapy (11.2% versus 18.7%; adjusted odds ratio, 0.47 [95% CI, 0.22-0.98]; P=0.042), without increasing the risk of any intracerebral hemorrhage. Successful reperfusion (modified Thrombolysis in Cerebral Ischemia score 2b-3) rate was significantly better in the antiplatelet therapy group (83.9% versus 71.0%; adjusted odds ratio, 1.89 [95% CI, 1.01-3.64]; P=0.045). Conclusions- Administration of antiplatelet therapy during endovascular therapy for anterior circulation tandem occlusions was safe and was associated with a lower 90-day mortality. Optimal antiplatelet therapy remains to be assessed, especially when emergent carotid artery stenting is performed. Further randomized controlled trials are needed.

Using a mouse-adapted A/HK/01/68 influenza virus to analyse the impact of NS1 evolution in codons 196 and 231 on viral replication and virulence.

Seasonal influenza viruses circulating between 1918 and 2009 harboured two prevalent genetic variations in the NS1 coding region. A glutamic acid (E)-to-lysine (K) exchange at position 196 was reported to diminish the capacity of NS1 to control interferon induction. Furthermore, alterations at position 231 determine a carboxy-terminal extension of seven amino acids from 230 to 237 residues. Sequence analyses of NS1 of the last 90 years suggest that variations at these two positions are functionally linked. To determine the impact of the two positions on viral replication in vivo, we used a mouse-adapted variant of A/Hong Kong/01/68 (maHK68) (H3N2). maHK68 encodes an NS1 of 237 amino acids with lysine at position 196. A panel of recombinant maHK68 viruses was generated encoding NS1 variants that differed at positions 196 and 231. Our analyses showed a clear effect of the K-196-to-E exchange on interferon induction and virus virulence. These effects were further modulated by the loss of the seven-amino-acid extension. We propose that the combination of NS1 E-196 with the short C-terminal variant conferred a fitness advantage that is reflected by increased virulence in vivo. Notably, this particular NS1 constellation was observed for the pandemic 1918 H1N1 virus.

Flow-Controlled Ventilation Attenuates Lung Injury in a Porcine Model of Acute Respiratory Distress Syndrome: A Preclinical Randomized Controlled Study.

OBJECTIVES: Lung-protective ventilation for acute respiratory distress syndrome aims for providing sufficient oxygenation and carbon dioxide clearance, while limiting the harmful effects of mechanical ventilation. "Flow-controlled ventilation", providing a constant expiratory flow, has been suggested as a new lung-protective ventilation strategy. The aim of this study was to test whether flow-controlled ventilation attenuates lung injury in an animal model of acute respiratory distress syndrome. DESIGN: Preclinical, randomized controlled animal study. SETTING: Animal research facility. SUBJECTS: Nineteen German landrace hybrid pigs. INTERVENTION: Flow-controlled ventilation (intervention group) or volume-controlled ventilation (control group) with identical tidal volume (7 mL/kg) and positive end-expiratory pressure (9 cm H2O) after inducing acute respiratory distress syndrome with oleic acid. MEASUREMENTS AND MAIN RESULTS: PaO2 and PaCO2, minute volume, tracheal pressure, lung aeration measured via CT, alveolar wall thickness, cell infiltration, and surfactant protein A concentration in bronchoalveolar lavage fluid. Five pigs were excluded leaving n equals to 7 for each group. Compared with control, flow-controlled ventilation elevated PaO2 (154 ± 21 vs 105 ± 9 torr; 20.5 ± 2.8 vs 14.0 ± 1.2 kPa; p = 0.035) and achieved comparable PaCO2 (57 ± 3 vs 54 ± 1 torr; 7.6 ± 0.4 vs 7.1 ± 0.1 kPa; p = 0.37) with a lower minute volume (6.4 ± 0.5 vs 8.7 ± 0.4 L/min; p < 0.001). Inspiratory plateau pressure was comparable in both groups (31 ± 2 vs 34 ± 2 cm H2O; p = 0.16). Flow-controlled ventilation increased normally aerated (24% ± 4% vs 10% ± 2%; p = 0.004) and decreased nonaerated lung volume (23% ± 6% vs 38% ± 5%; p = 0.033) in the dependent lung region. Alveolar walls were thinner (5.5 ± 0.1 vs 7.8 ± 0.2 µm; p < 0.0001), cell infiltration was lower (20 ± 2 vs 32 ± 2 n/field; p < 0.0001), and normalized surfactant protein A concentration was higher with flow-controlled ventilation (1.1 ± 0.04 vs 1.0 ± 0.03; p = 0.039). CONCLUSIONS: Flow-controlled ventilation enhances lung aeration in the dependent lung region and consequently improves gas exchange and attenuates lung injury. Control of the expiratory flow may provide a novel option for lung-protective ventilation.

Improved lung recruitment and oxygenation during mandatory ventilation with a new expiratory ventilation assistance device: A controlled interventional trial in healthy pigs.

BACKGROUND: In contrast to conventional mandatory ventilation, a new ventilation mode, expiratory ventilation assistance (EVA), linearises the expiratory tracheal pressure decline. OBJECTIVE: We hypothesised that due to a recruiting effect, linearised expiration oxygenates better than volume controlled ventilation (VCV). We compared the EVA with VCV mode with regard to gas exchange, ventilation volumes and pressures and lung aeration in a model of peri-operative mandatory ventilation in healthy pigs. DESIGN: Controlled interventional trial. SETTING: Animal operating facility at a university medical centre. ANIMALS: A total of 16 German Landrace hybrid pigs. INTERVENTION: The lungs of anaesthetised pigs were ventilated with the EVA mode (n=9) or VCV (control, n=7) for 5 h with positive end-expiratory pressure of 5 cmH2O and tidal volume of 8 ml kg. The respiratory rate was adjusted for a target end-tidal CO2 of 4.7 to 6 kPa. MAIN OUTCOME MEASURES: Tracheal pressure, minute volume and arterial blood gases were recorded repeatedly. Computed thoracic tomography was performed to quantify the percentages of normally and poorly aerated lung tissue. RESULTS: Two animals in the EVA group were excluded due to unstable ventilation (n=1) or unstable FiO2 delivery (n=1). Mean tracheal pressure and PaO2 were higher in the EVA group compared with control (mean tracheal pressure: 11.6 ±â€Š0.4 versus 9.0 ±â€Š0.3 cmH2O, P < 0.001 and PaO2: 19.2 ±â€Š0.7 versus 17.5 ±â€Š0.4 kPa, P = 0.002) with comparable peak inspiratory tracheal pressure (18.3 ±â€Š0.9 versus 18.0 ±â€Š1.2 cmH2O, P > 0.99). Minute volume was lower in the EVA group compared with control (5.5 ±â€Š0.2 versus 7.0 ±â€Š1.0 l min, P = 0.02) with normoventilation in both groups (PaCO2 5.4 ±â€Š0.3 versus 5.5 ±â€Š0.3 kPa, P > 0.99). In the EVA group, the percentage of normally aerated lung tissue was higher (81.0 ±â€Š3.6 versus 75.8 ±â€Š3.0%, P = 0.017) and of poorly aerated lung tissue lower (9.5 ±â€Š3.3 versus 15.7 ±â€Š3.5%, P = 0.002) compared with control. CONCLUSION: EVA ventilation improves lung aeration via elevated mean tracheal pressure and consequently improves arterial oxygenation at unaltered positive end-expiratory pressure (PEEP) and peak inspiratory pressure (PIP). These findings suggest the EVA mode is a new approach for protective lung ventilation.

Thrombectomy in Acute Stroke With Tandem Occlusions From Dissection Versus Atherosclerotic Cause.

BACKGROUND AND PURPOSE: Tandem steno-occlusive lesions were poorly represented in randomized trials and represent a major challenge for endovascular thrombectomy in acute anterior circulation strokes. The impact of the cervical carotid lesion cause (ie, atherosclerotic versus dissection) on outcome of tandem patients endovascularly treated remains to be assessed. METHODS: We retrospectively analyzed individual data of prospectively collected consecutive tandem patients treated with endovascular thrombectomy. The primary outcome was favorable outcome at 90 days (modified Rankin Scale score of 0-2). Secondary efficacy outcomes included successful reperfusion (modified Thrombolysis in Cerebrovascular Infarction scores of 2b-3), time to reperfusion, and safety outcomes encompassed procedural complications, symptomatic intracerebral hemorrhage, and 90-day mortality. RESULTS: Among the 295 included patients, 65 had cervical carotid dissection and 230 had cervical carotid atherosclerotic cause. The rate of favorable outcome was 56.3% in the dissection group versus 47.6% in the atherosclerotic arm (center-, age-, and admission National Institutes of Health Stroke Scale-adjusted odds ratio, 1.08; 95% confidence interval, 0.50-2.30; P=0.85). No significant differences were observed in secondary outcomes. The rates of successful reperfusion, symptomatic intracerebral hemorrhage, and 90-day mortality were 78.5% versus 74.5% (P=0.13), 4.6% versus 5.2% (P=1.0), and 7.8% versus 15.3% (P=0.94) in the dissection versus atherosclerotic groups, respectively. The median procedural time was 76 minutes (interquartile range, 52-95 minutes) in the dissection group and 67 minutes (interquartile range, 45-98 minutes) in the atherosclerotic group (P=0.24). CONCLUSIONS: We found no differences in the outcomes of patients with anterior circulation tandem atherosclerotic and dissection lesions treated with endovascular thrombectomy. Further studies are warranted.

Selective intra-carotid blood cooling in acute ischemic stroke: A safety and feasibility study in an ovine stroke model.

Selective therapeutic hypothermia (TH) showed promising preclinical results as a neuroprotective strategy in acute ischemic stroke. We aimed to assess safety and feasibility of an intracarotid cooling catheter conceived for fast and selective brain cooling during endovascular thrombectomy in an ovine stroke model.Transient middle cerebral artery occlusion (MCAO, 3 h) was performed in 20 sheep. In the hypothermia group (n = 10), selective TH was initiated 20 minutes before recanalization, and was maintained for another 3 h. In the normothermia control group (n = 10), a standard 8 French catheter was used instead. Primary endpoints were intranasal cooling performance (feasibility) plus vessel patency assessed by digital subtraction angiography and carotid artery wall integrity (histopathology, both safety). Secondary endpoints were neurological outcome and infarct volumes.Computed tomography perfusion demonstrated MCA territory hypoperfusion during MCAO in both groups. Intranasal temperature decreased by 1.1 °C/3.1 °C after 10/60 minutes in the TH group and 0.3 °C/0.4 °C in the normothermia group (p < 0.001). Carotid artery and branching vessel patency as well as carotid wall integrity was indifferent between groups. Infarct volumes (p = 0.74) and neurological outcome (p = 0.82) were similar in both groups.Selective TH was feasible and safe. However, a larger number of subjects might be required to demonstrate efficacy.

Corrigendum: Development of a Routinely Applicable Imaging Protocol for Fast and Precise Middle Cerebral Artery Occlusion Assessment and Perfusion Deficit Measure in an Ovine Stroke Model: A Case Study.

[This corrects the article DOI: 10.3389/fneur.2019.01113.].

Head or Neck First? Speed and Rates of Reperfusion in Thrombectomy for Tandem Large Vessel Occlusion Strokes.

BACKGROUND: We aim to evaluate the speed and rates of reperfusion in tandem large vessel occlusion acute stroke patients undergoing upfront cervical lesion treatment (Neck-First: angioplasty and/or stent before thrombectomy) as compared to direct intracranial occlusion therapy (Head-First) in a large international multicenter cohort. METHODS: The Thrombectomy In TANdem Lesions (TITAN) collaboration pooled individual data of prospectively collected thrombectomy international databases for all consecutive anterior circulation tandem patients who underwent emergent thrombectomy. The co-primary outcome measures were rates of successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/3) and time from groin puncture to successful reperfusion. RESULTS: In total, 289 patients with tandem atherosclerotic etiology were included in the analysis (182 Neck-First and 107 Head-First patients). Except for differences in the Alberta Stroke Program Early CT Score (ASPECTS; median 8 [range 7-10] Neck-First vs. 7 [range 6-8] Head-First; p < 0.001) and cervical internal carotid artery (ICA) lesion severity (complete occlusion in 35% of the Neck-First vs. 57% of the Head-First patients; p < 0.001), patient characteristics were well balanced. After adjustments, there was no difference in successful reperfusion rates between the study groups (odds ratio associated with Neck-First: 1.18 [95% confidence interval, 0.60-2.17]). The time to successful reperfusion from groin puncture was significantly shorter in the Head-First group after adjustments (median 56 min [range 39-90] vs. 70 [range 50-102]; p = 0.001). No significant differences in the rates of full reperfusion, symptomatic hemorrhage, 90-day independence, or mortality were observed. Sensitivity analysis excluding patients with complete cervical ICA occlusion yielded similar results. CONCLUSIONS: The upfront approach of the intracranial lesion in patients with tandem large vessel occlusion strokes leads to similar reperfusion rates but faster reperfusion as compared to initial cervical revascularization followed by mechanical thrombectomy. Controlled studies are warranted.

High-resolution contrast-enhanced vessel wall imaging in patients with suspected cerebral vasculitis: Prospective comparison of whole-brain 3D T1 SPACE versus 2D T1 black blood MRI at 3 Tesla.

PURPOSE: Vessel wall imaging (VWI) using T1 dark blood MRI can depict inflammation of intracranial arteries in patients with cerebral vasculitis. Recently, 3D VWI sequences were introduced at 3 Tesla. We aimed to compare 2D and 3D VWI for detection of intracranial vessel wall enhancement (VWE) in patients suspected of cerebral vasculitis. METHODS: 44 MRI scans of 39 patients were assessed that included bi-planar 2D T1 and whole-brain 3D T1 SPACE dark blood VWI pre and post contrast. Visibility and VWE were analyzed in 31 pre-specified intracranial artery segments. Additionally, leptomeningeal and parenchymal contrast enhancement was assessed. RESULTS: Overall, more arterial segments were visualized with 3D VWI (p<0.0001). Detection of VWE showed fair agreement between 2D and 3D VWI (κ = 0.583). On segmental level, more VWE was detected in intradural ICA by 2D VWI (p<0.001) and in VA V4 segment by 3D VWI (p<0.05). 3D VWI showed more leptomeningeal (p<0.05) and parenchymal (p<0.01) contrast enhancement. In patients with positive diagnosis of cerebral vasculitis, sensitivity was of 67% (2D and 3D VWI) and specificity was 44% (2D VWI) and 48% (3D VWI); more VWE was seen in arteries distal to VA and ICA compared to non-vasculitic patients. CONCLUSION: 2D and 3D VWI differed in the ability to detect VWE. Whole brain coverage with better evaluability of VAs and distal intracranial artery segments, and depiction of more parenchymal and leptomeningeal enhancement make 3D VWI more favorable. As VWE in arteries distal to VA and ICA may be used for discrimination of vasculitic and non-vasculitic patients, future increase in spatial resolution of 3D VWI sequences may be beneficial.

Development of a Routinely Applicable Imaging Protocol for Fast and Precise Middle Cerebral Artery Occlusion Assessment and Perfusion Deficit Measure in an Ovine Stroke Model: A Case Study.

Temporary middle cerebral artery occlusion (MCAO) in sheep allows modeling of acute large vessel occlusion stroke and subsequent vessel recanalization. However, rapid and precise imaging-based assessment of vessel occlusion and the resulting perfusion deficit during MCAO still represents an experimental challenge. Here, we tested feasibility and suitability of a strategy for MCAO verification and perfusion deficit assessment. We also compared the extent of the initial perfusion deficit and subsequent lesion size for different MCAO durations. The rete mirabile prevents reliable vascular imaging investigation of middle cerebral artery filling status. Hence, computed tomography perfusion imaging was chosen for indirect confirmation of MCAO. Follow-up infarct size evaluation by diffusion-weighted magnetic resonance imaging revealed fluctuating results, with no apparent relationship of lesion size with MCAO at occlusion times below 4 h, potentially related to the variable collateralization of the MCA territory. This underlines the need for intra-ischemic perfusion assessment and future studies focusing on the correlation between perfusion deficit, MCAO duration, and final infarct volume. Temporary MCAO and intra-ischemic perfusion imaging nevertheless has the potential to be applied for the simulation of novel recanalization therapies, particularly those that aim for a fast reperfusion effect in combination with mechanical thrombectomy in a clinically realistic scenario.

Effect of extracranial lesion severity on outcome of endovascular thrombectomy in patients with anterior circulation tandem occlusion: analysis of the TITAN registry.

INTRODUCTION: Endovascular treatment (EVT) for tandem occlusion (TO) of the anterior circulation is complex but effective. The effect of extracranial internal carotid artery (EICA) lesion severity on the outcomes of EVT is unknown. In this study we investigated the effect of EICA lesion severity on the outcomes of tandem occlusion EVT. METHODS: A multicenter retrospective TITAN (Thrombectomy In TANdem lesions) study that included 18 international endovascular capable centers was performed. Patients who received EVT for atherosclerotic TO with or without EICA lesion intervention were included. Patients were divided into two groups based on the EICA lesion severity (high-grade stenosis (≥90% North American Symptomatic Carotid Endarterectomy Trial) vs complete occlusion). Outcome measures included the 90-day clinical outcome (modified Rankin Scale score (mRS)), angiographic reperfusion (modified Thrombolysis In Cerebral Ischemia (mTICI) at the end of the procedure), procedural complications, and intracranial hemorrhage at 24 hours follow-up. RESULTS: A total of 305 patients were included in the study, of whom 135 had complete EICA occlusion and 170 had severe EICA stenosis. The EICA occlusion group had shorter mean onset-to-groin time (259±120 min vs 305±202 min; p=0.037), more patients with diabetes, and fewer with hyperlipidemia. With respect to the outcome, mTICI 2b-3 reperfusion was lower in the EICA occlusion group (70% vs 81%; p=0.03). The favorable outcome (90-day mRS 0-2), intracerebral hemorrhage and procedural complications were similar in both groups. CONCLUSION: Atherosclerotic occlusion of the EICA in acute tandem strokes was associated with a lower rate of mTICI 2b-3 reperfusion but similar functional and safety outcomes when compared with high-grade EICA stenosis.

Periprocedural Heparin During Endovascular Treatment of Tandem Lesions in Patients with Acute Ischemic Stroke: A Propensity Score Analysis from TITAN Registry.

BACKGROUND AND PURPOSE: Data on safety and efficacy of periprocedural use of heparin are limited during treatment of acute ischemic stroke patients with anterior circulation tandem occlusion. This study aimed to investigate the impact of heparin use during endovascular therapy of anterior circulation tandem occlusions on the functional and safety outcomes. METHODS: A retrospective analysis of the multicenter observational TITAN registry was performed. Patients with anterior circulation tandem occlusion and treated with endovascular therapy (EVT) were included, with or without extracranial carotid intervention. We divided patients into two groups based on periprocedural heparin use (heparin vs. non-heparin). The dose of intravenous unfractionated heparin ranged from 1500 to 2500 I.U. Primary study endpoint was 90-day Modified Rankin Scale (mRS). Secondary study endpoint included angiographic and safety endpoints such as hemorrhagic complications. A propensity-score-matched analysis was performed. RESULTS: Among 369 patients, heparin was used in 68 patients (18.4%). In the propensity-score-matched cohort, favorable outcome (mRS 0-2) occurred in 51.3% in heparin group and 58.0% in non-heparin group (matched OR, 0.76; 95% CI, 0.32-1.78; P = 0.52). Similar result was found in propensity-score-adjusted cohort (adjusted OR, 0.72; 95%CI, 0.39-1.32; P = 0.28). Likewise, there was no difference in the rate of successful reperfusion (mTICI 2b-3) (propensity-score-adjusted OR, 1.03; 95%CI, 0.50-2.09; P = 0.93) neither in safety endpoints between the two groups. CONCLUSIONS: Periprocedural heparin use during EVT of anterior circulation tandem occlusions was not associated with better functional, angiographic or safety outcomes. These findings are applicable for low doses of heparin, and further studies are warranted.

Carotid Stenting With Antithrombotic Agents and Intracranial Thrombectomy Leads to the Highest Recanalization Rate in Patients With Acute Stroke With Tandem Lesions.

OBJECTIVES: The aim of this study was to identify the optimal endovascular approach in patients with acute stroke with tandem lesions. BACKGROUND: At present, there is no consensus about the ideal technical strategy for the endovascular treatment of patients with acute ischemic stroke with tandem lesions of the extracranial internal carotid artery (ICA) and intracranial cerebral arteries. METHODS: This was an international, multicenter registry with a total of 482 patients with acute ischemic stroke and tandem lesions. Patients were treated by intracranial thrombectomy as well as 1 of the following 4 strategies: 1) acute carotid artery stenting of the extracranial ICA with antithrombotic agents; 2) acute carotid artery stenting of the extracranial ICA without antithrombotic agents; 3) balloon angioplasty of the extracranial ICA; and 4) intracranial thrombectomy alone. The main outcome endpoints of the study were the degree of recanalization and the 90-day clinical outcome. The safety endpoints were symptomatic intracerebral hemorrhage and all causes of mortality at 90 days. RESULTS: Using univariate analysis, the rates of successful reperfusion (modified Thrombolysis in Cerebral Infarction grades 2B and 3) and favorable clinical outcome after 90 days were significantly higher after acute carotid stenting with antithrombotic therapy and thrombectomy compared with the group with thrombectomy alone. After adjusting for confounding variables, acute stenting with antithrombotic therapy was independently associated with successful recanalization (odds ratio: 2.4; 95% confidence interval: 1.25 to 4.59; p = 0.008). The rates of symptomatic intracerebral hemorrhage and 90-day mortality were comparable among all 4 treatment groups. CONCLUSIONS: Acute stenting of the extracranial ICA with antithrombotic therapy in combination with intracranial thrombectomy is associated with higher recanalization rates in treatment of patients with acute stroke with tandem lesions.