Thrombectomy alone versus intravenous alteplase plus thrombectomy in patients with stroke: an open-label, blinded-outcome, randomised non-inferiority trial.

BACKGROUND: Whether thrombectomy alone is equally as effective as intravenous alteplase plus thrombectomy remains controversial. We aimed to determine whether thrombectomy alone would be non-inferior to intravenous alteplase plus thrombectomy in patients presenting with acute ischaemic stroke. METHODS: In this multicentre, randomised, open-label, blinded-outcome trial in Europe and Canada, we recruited patients with stroke due to large vessel occlusion confirmed with CT or magnetic resonance angiography admitted to endovascular centres. Patients were randomly assigned (1:1) via a centralised web server using a deterministic minimisation method to receive stent-retriever thrombectomy alone or intravenous alteplase plus stent-retriever thrombectomy. In both groups, thrombectomy was initiated as fast as possible with any commercially available Solitaire stent-retriever revascularisation device (Medtronic, Irvine, CA, USA). In the combined treatment group, intravenous alteplase (0·9 mg/kg bodyweight, maximum dose 90 mg per patient) was administered as early as possible after randomisation for 60 min with 10% of the calculated dose given as an initial bolus. Personnel assessing the primary outcome were masked to group allocation; patients and treating physicians were not. The primary binary outcome was a score of 2 or less on the modified Rankin scale at 90 days. We assessed the non-inferiority of thrombectomy alone versus intravenous alteplase plus thrombectomy in all randomly assigned and consenting patients using the one-sided lower 95% confidence limit of the Mantel-Haenszel risk difference, with a prespecified non-inferiority margin of 12%. The main safety endpoint was symptomatic intracranial haemorrhage assessed in all randomly assigned and consenting participants. This trial is registered with ClinicalTrials.gov, NCT03192332, and is closed to new participants. FINDINGS: Between Nov 29, 2017, and May 7, 2021, 5215 patients were screened and 423 were randomly assigned, of whom 408 (201 thrombectomy alone, 207 intravenous alteplase plus thrombectomy) were included in the primary efficacy analysis. A modified Rankin scale score of 0-2 at 90 days was reached by 114 (57%) of 201 patients assigned to thrombectomy alone and 135 (65%) of 207 patients assigned to intravenous alteplase plus thrombectomy (adjusted risk difference -7·3%, 95% CI -16·6 to 2·1, lower limit of one-sided 95% CI -15·1%, crossing the non-inferiority margin of -12%). Symptomatic intracranial haemorrhage occurred in five (2%) of 201 patients undergoing thrombectomy alone and seven (3%) of 202 patients receiving intravenous alteplase plus thrombectomy (risk difference -1·0%, 95% CI -4·8 to 2·7). Successful reperfusion was less common in patients assigned to thrombectomy alone (182 [91%] of 201 vs 199 [96%] of 207, risk difference -5·1%, 95% CI -10·2 to 0·0, p=0·047). INTERPRETATION: Thrombectomy alone was not shown to be non-inferior to intravenous alteplase plus thrombectomy and resulted in decreased reperfusion rates. These results do not support omitting intravenous alteplase before thrombectomy in eligible patients. FUNDING: Medtronic and University Hospital Bern.

Mechanical thrombectomy with a novel device: initial clinical experience with the ANA thrombectomy device.

INTRODUCTION: The ANA™ (Anaconda Biomed) thrombectomy system is a novel stroke thrombectomy device comprising a self-expanding funnel designed to reduce clot fragmentation by locally restricting flow while becoming as wide as the lodging artery. Once deployed, ANA allows distal aspiration in combination with a stentretriever (SR) to mobilize the clot into the funnel where it remains copped during extraction. We investigate safety and efficacy of ANA™ in a first-in-man study. METHODS: Prospective data was collected on 35 consecutive patients treated as first line with ANA™ at a single centre. Outcome measures included per-pass reperfusion scores, symptomatic intracerebral hemorrhage (sICH), NIHSS at day 5, and mRS at 90 days. RESULTS: Median NIHSS was 12(9-18). Sites of primary occlusion were: 5 ICA, 15 M1-MCA, 15 M2-MCA. Primary performance endpoint, mTICI 2b-3 within 3 passes without rescue therapy was achieved in 91.4% (n = 32) of patients; rate of complete recanalization (mTICI 2c-3) was 65.7%. First pass complete recanalization rate was 42.9%, and median number of ANA passes 1(IQR: 1-2). In 17.1% (n = 6) rescue treatment was used; median number of rescue passes was 2(1-7), leading to a final mTICI2b-3rate of 94.3% (n = 33). There were no device related serious adverse events, and rate of sICH was 5.7% (n = 2). At 5 days median NIHSS was 1 (IQR 1-6) and 90 days mRS 0-2 was achieved in 60% of patients. CONCLUSIONS: In this initial clinical experience, the ANA™ device achieved a high rate of complete recanalization with a good safety profile and favourable 90 days clinical outcomes.

SWIFT DIRECT: Solitaire™ With the Intention For Thrombectomy Plus Intravenous t-PA Versus DIRECT Solitaire™ Stent-retriever Thrombectomy in Acute Anterior Circulation Stroke: Methodology of a randomized, controlled, multicentre study.

RATIONALE: Whether treatment with intravenous alteplase prior to mechanical thrombectomy (MT) in acute ischemic stroke patients with large vessel occlusion is beneficial remains unclear. AIM: To determine whether patients experiencing acute ischemic stroke due to occlusion of the intracranial internal carotid artery or the M1 segment of the middle cerebral artery who are referred to an endovascular stroke center and who are candidates for intravenous alteplase will have non-inferior functional outcome at 90 days when treated with MT alone (direct MT) with stent retrievers compared to patients treated with combined intravenous thrombolysis (IVT) with alteplase plus MT (IVT + MT) with stent retrievers. SAMPLE SIZE: To randomize 404 patients 1:1 to direct MT or combined IVT+MT. METHODS AND DESIGN: A multicenter, prospective, randomized, open-label, blinded-endpoint (PROBE) trial utilizing an adaptive statistical design. OUTCOMES: The primary efficacy endpoint is functional independence (modified Rankin Scale 0-2) at 90 days. Secondary clinical efficacy outcomes include change in National Institutes of Health Stroke Scale score from baseline to day 1 and health-related quality of life at 90 days. Secondary technical efficacy outcomes include successful reperfusion prior to start of MT and time from randomization to successful reperfusion. Safety outcomes include all serious adverse events, symptomatic intracranial hemorrhage, and mortality up to 90 days. DISCUSSION: SWIFT DIRECT will inform physicians whether direct MT in acute ischemic stroke patients with large vessel occlusion is equally or more efficacious than combined treatment with intravenous alteplase and MT. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03192332.