SOLITAIRE™ with the intention for thrombectomy (SWIFT) trial: design of a randomized, controlled, multicenter study comparing the SOLITAIRE™ Flow Restoration device and the MERCI Retriever in acute ischaemic stroke

Rationale: Self-expanding stent retrievers are a promising new device class designed for rapid flow restoration in acute cerebral ischaemia. The SOLITAIRE™ Flow Restoration device (SOLITAIRE) has shown high rates of recanalization in preclinical models and in uncontrolled clinical series.

Aims: (1) To demonstrate non-inferiority of SOLITAIRE compared with a legally marketed device, the MERCI Retrieval System®; (2) To demonstrate safety, feasibility, and efficacy of SOLITAIRE in subjects requiring mechanical thrombectomy diagnosed with acute ischaemic stroke. DESIGN : Multicenter, randomized, prospective, controlled trial with blinded primary end-point ascertainment.

Study procedures: Key entry criteria include: age 22-85; National Institute of Health Stroke Scale (NIHSS) ≥8 and <30; clinical and imaging findings consistent with acute ischaemic stroke; patient ineligible or failed intravenous tissue plasminogen activator; accessible occlusion in M1 or M2 middle cerebral artery, internal carotid artery, basilar artery, or vertebral artery; and patient able to be treated within 8 h of onset. Sites first participate in a roll-in phase, treating two patients with the SOLITAIRE device, before proceeding to the randomized phase. In patients unresponsive to the initially assigned therapy, after the angiographic component of the primary end-point is ascertained (reperfusion with the initial assigned device), rescue therapy with other reperfusion techniques is permitted.

Outcomes: The primary efficacy end-point is successful recanalization with the assigned study device (no use of rescue therapy) and with no symptomatic intracranial haemorrhage. Successful recanalization is defined as achieving Thrombolysis In Myocardial Ischemia 2 or 3 flow in all treatable vessels. The primary safety end-point is the incidence of device-related and procedure-related serious adverse events. A major secondary efficacy end-point is time to achieve initial recanalization. Additional secondary end-points include clinical outcomes at 90 days and radiologic haemorrhagic transformation.