Gary Walker

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.

Endovascular Thrombectomy for Acute Ischemic Stroke in Failed Intravenous Tissue Plasminogen Activator Versus Non–Intravenous Tissue Plasminogen Activator Patients: Revascularization and Outcomes Stratified by the Site of Arterial Occlusions

Background and Purpose— Intracranial mechanical thrombectomy is a therapeutic option for acute ischemic stroke patients failing intravenous tissue plasminogen activator (IV tPA). We compared patients treated by mechanical embolus removal in cerebral ischemia (MERCI) thrombectomy after failed IV tPA with those treated with thrombectomy alone. Methods— We pooled MERCI and Multi MERCI study patients, grouped them either as failed IV tPA or non–IV tPA, and assessed revascularization rates, procedural complications, symptomatic hemorrhage rates, clinical outcomes, and mortality. We also evaluated outcomes stratified by the occlusion site and final revascularization. Results— Among 305 patients, 48 failed, and 257 were ineligible for IV tPA. Nonresponders to IV tPA trended toward a higher revascularization rate (73% versus 63%) and less mortality (27.7% versus 40.1%) and had similar rates of symptomatic hemorrhage and procedural complications. Favorable 90-day outcomes were similar in failed and non–IV tPA patients (38% versus 31%), with no difference according to occlusion site. Among patients failing IV tPA, good outcomes tended to occur more frequently in revascularized patients (47.1% versus 15.4%), although this relationship was attributable solely to middle cerebral artery and not internal carotid artery occlusions, with no difference in mortality. Among IV tPA–ineligible patients, revascularization correlated with good outcome (47.4% versus 4.4%) and less mortality (28.5% versus 59.6%). Conclusions— The risks of hemorrhage and procedure-related complications after mechanical thrombectomy do not differ with respect to previous IV tPA administration. Thrombectomy after IV tPA achieves similar rates of good outcomes, a tendency toward lower mortality, and similar revascularization rates when stratified by clot location. Good outcomes correlate with successful revascularization except with internal carotid artery occlusions in tPA-nonresponders.

Clinical Outcomes in Middle Cerebral Artery Trunk Occlusions Versus Secondary Division Occlusions After Mechanical Thrombectomy Pooled Analysis of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI Trials

Background and Purpose— The benefit of endovascular revascularization of patients with acute ischemic stroke with middle cerebral artery (MCA) secondary division (M2) occlusions as compared with MCA trunk (M1) occlusions is not known. In this analysis, we compared revascularization status and clinical outcomes in patients with angiographically confirmed MCA M1 versus isolated M2 occlusions treated with mechanical thrombectomy using the Merci Retriever devices. Methods— We retrospectively analyzed the pooled data of patients with MCA strokes from the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials. Patient data were dichotomized into 2 groups: MCA M1 occlusions and isolated M2 occlusions. Baseline characteristics, revascularization rates, hemorrhage rates, complications, outcomes, and mortality were evaluated for both groups. Results— Of 178 patients with MCA occlusion treated in the MERCI and Multi MERCI trials, 84.3% had M1 lesions and 15.7% had isolated M2 lesions. Patients with isolated M2 occlusions were revascularized at a higher rate, required a lower mean number of passes, and were associated with a trend toward shorter mean procedure time than patients with M1 occlusions. No statistically significant differences were found between M2 and M1 groups for symptomatic hemorrhage, clinically significant procedural adverse events, favorable 90-day outcome, or 90-day mortality, although in all instances, the M2 outcomes were numerically better than those in M1 subjects. In multivariate analysis, final revascularization was the strongest independent predictor of good outcome at 90 days. Conclusions— Patients with both MCA M1 occlusions and isolated M2 occlusions can achieve a relatively high rate of revascularization and favorable clinical outcomes after mechanical thrombectomy. In fact, patients with isolated M2 occlusions had a higher rate of revascularization, required fewer passes, and had no increased complications compared with patients with M1 occlusions.

Effect of Time to Reperfusion on Clinical Outcome of Anterior Circulation Strokes Treated With Thrombectomy: Pooled Analysis of the MERCI and Multi MERCI Trials

Background and Purpose— Previous studies have demonstrated a strong correlation between treatment time and outcomes after intravenous recombinant tissue-type plasminogen activator. However, the temporal profile of ischemia may vary according to the level of occlusion, and it is likely that more proximal occlusions have a more variable temporal course than their distal counterparts. We sought to establish how time influences outcomes in anterior circulation proximal arterial occlusions. Methods— All patients from the MERCI/Multi MERCI trials with intracranial internal carotid artery and/or middle cerebral artery (M1-M2 segments) occlusions who were successfully revascularized were included in univariate/multivariate analyses to define the predictors of independent functional outcomes (modified Rankin Scale score ⩽2) and mortality at 90 days. The effect of time to reperfusion on outcomes was calculated after adjustment for age, baseline National Institutes of Health Stroke Scale, and glucose levels. Results— A total of 175 patients presenting with internal carotid artery/M1/M2 occlusions were revascularized. There was no definite association between time (to treatment or reperfusion) and outcomes in the unadjusted analysis. Baseline National Institutes of Health Stroke Scale score and age were independent predictors of independent outcome and mortality. High glucose demonstrated a strong trend toward worse outcomes. After adjustment for age, baseline National Institutes of Health Stroke Scale score, and glucose, there was a strong trend toward fewer independent outcomes with later reperfusion times. Notably, 40% of the patients reperfused at ≥6.9 hours achieved independent functional outcomes. Conclusions— Time (to treatment or reperfusion) is only one of the many variables that may impact outcome in proximal arterial occlusions strokes. Reperfusion therapies should be started promptly, but our findings also suggest that stroke patients presenting at later time points may still benefit.

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.

Analysis of a Coordinated Stroke Center and Regional Stroke Network on Access to Acute Therapy and Clinical Outcomes

Background and Purpose— Compare access and outcomes in a tertiary care community hospital (Saint Luke’s Neuroscience Institute) and its stroke network to hospitals in 3 national databases. Methods— Retrospective analysis of ischemic stroke patients (2005, 2007, 2010) in Saint Luke’s (n=1576), Get With The Guidelines-Stroke (n=423 809), Premier (n=91 598), and Merci Registry (n=966). Study measures were use of computed tomography scans and tissue plasminogen activator (tPA), symptomatic intracranial hemorrhage, discharge disposition, discharge National Institutes of Health Stroke Scale scores, and 90-day modified Rankin Scores. Results— Saint Luke’s increased access to care with higher tPA use than other hospitals (17.2% received intravenous tPA therapy compared with 5.8% at Get With The Guidelines–Stroke hospitals, P<0.001; 22.1% of Saint Luke’s patients received tPA by any route compared with 3.5% of Premier patients, P<0.001). Use of intravenous tPA within 4.5 hours of onset was associated with more discharges to home (odds ratio, 2.123; 95% confidence interval, 1.394–3.246) and improved National Institutes of Health Stroke Scale scores (P=0.001). Saint Luke’s patients also were more likely than those in other hospitals to receive computed tomography scans (99.4% vs 58.6% at Premier hospitals). Embolectomy at Saint Luke’s was associated with better outcomes than peer hospitals, and treatment at Saint Luke’s was independently associated with more discharges to home (odds ratio, 3.92; 95% confidence interval, 1.84–8.32). In 2010, symptomatic intracranial hemorrhages after tPA therapy was similar for Saint Luke’s patients and Premier patients (2.2% vs 1.5%; P=0.590). Conclusions— Regionally coordinated stroke programs can substantially improve access and patient outcomes.