Trevo versus Merci retrievers for thrombectomy revascularisation of large vessel occlusions in acute ischaemic stroke (TREVO 2): a randomised trial.

BACKGROUND: Present mechanical devices are unable to achieve recanalisation in up to 20-40% of large vessel occlusion strokes. We compared efficacy and safety of the Trevo Retriever, a new stent-like device, with its US Food and Drug Administration-cleared predecessor, the Merci Retriever. METHODS: In this open-label randomised controlled trial, we recruited patients at 26 sites in the USA and one in Spain. We included adults aged 18-85 years with angiographically confirmed large vessel occlusion strokes and US National Institutes of Health Stroke Scale (NIHSS) scores of 8-29 within 8 h of symptom onset. We randomly assigned patients (1:1) with sequentially numbered sealed envelopes to thrombectomy with Trevo or Merci devices. Randomisation was stratified by age (≤68 years vs 69-85 years) and NIHSS scores (≤18 vs 19-29) with alternating blocks of various sizes. The primary efficacy endpoint, assessed by an unmasked core laboratory, was thrombolysis in cerebral infarction (TICI) scores of 2 or greater reperfusion with the assigned device alone. The primary safety endpoint was a composite of procedure-related adverse events. Analyses were done by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01270867. FINDINGS: Between Feb 3, 2011, and Dec 1, 2011, we randomly assigned 88 patients to the Trevo Retriever group and 90 patients to Merci Retriever group. 76 (86%) patients in the Trevo group and 54 (60%) in the Merci group met the primary endpoint after the assigned device was used (odds ratio 4·22, 95% CI 1·92-9·69; p(superiority)<0·0001). Incidence of the primary safety endpoint did not differ between groups (13 [15%] patients in the Trevo group vs 21 [23%] in the Merci group; p=0·1826). INTERPRETATION: Patients who have had large vessel occlusion strokes but are ineligible for (or refractory to) intravenous tissue plasminogen activator should be treated with the Trevo Retriever in preference to the Merci Retriever. FUNDING: Stryker Neurovascular.

Safety of periprocedural heparin in acute ischemic stroke endovascular therapy: the multi MERCI trial.

BACKGROUND: There are limited data on the safety of periprocedural heparin in acute ischemic stroke endovascular therapy. METHODS: A post hoc analysis was performed on patients enrolled in the Multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial to compare baseline characteristics and clinical outcomes between patients who received periprocedural heparin (HEP(+)) with patients who did not receive periprocedural heparin (HEP(-)). Data on periprocedural heparin use or nonuse was collected on patients enrolled between February 1, 2006 and July 31, 2006. RESULTS: Of 51 patients included in the analysis cohort, 24 (47%) received periprocedural heparin with a median dose of 3000 U. Baseline and procedural characteristics were similar between the 2 groups, although HEP(+) patients were more likely to have vertebral or basilar occlusion than HEP(-) patients (16.7% v 0%; P = .04). There was no significant difference in rates of hemorrhage, procedural complications, or 90-day mortality between the 2 groups. In multivariable analysis, a 90-day good outcome (modified Rankin scale score of 0-2) was associated with age (odds ratio [OR] 0.92; 95% confidence interval [CI] 0.86-0.98; P = .0104), final revascularization success (OR 6.86; 95% CI 1.39-33.81; P = .0179), and periprocedural heparin use (OR 5.89; 95% CI 1.34-25.92; P = .0189). CONCLUSIONS: In this small subgroup of the Multi MERCI trial, periprocedural heparin use in acute ischemic stroke endovascular therapy was not associated with increased rates of intracerebral hemorrhage or 90-day mortality. The improved 90-day good outcome among patients undergoing mechanical thrombectomy combined with periprocedural heparin warrants further study in a larger cohort.

Disinhibition outside receptive fields in the visual cortex.

By definition, the region outside the classical receptive field (CRF) of a neuron in the visual cortex does not directly activate the cell. However, the response of a neuron can be influenced by stimulation of the surrounding area. In previous work, we showed that this influence is mainly suppressive and that it is generally limited to a local region outside the CRF. In the experiments reported here, we investigate the mechanisms of the suppressive effect. Our approach is to find the position of a grating patch that is most effective in suppressing the response of a cell. We then use a masking stimulus at different contrasts over the grating patch in an attempt to disinhibit the response. We find that suppressive effects may be partially or completely reversed by use of the masking stimulus. This disinhibition suggests that effects from outside the CRF may be local. Although they do not necessarily underlie the perceptual analysis of a figure-ground visual scene, they may provide a substrate for this process.