Study Rationale

· Endovascular therapy (EVT) in addition to standard care is superior to standard care alone in patients with acute anterior circulation stroke.

· Patients with tandem occlusion or tandem lesion (TL), that is, stroke with an acute intracranial anterior circulation occlusion and an ipsilateral cervical ICA (c-ICA) high-grade stenosis or occlusion, constitute about 15-20% of patients undergoing EVT.

· The majority of c-ICA lesions in TL patients are due to atherosclerosis, fewer due to dissection and still fewer due to a proximal embolus (ex. cardiac) or carotid web.

· Patients with TL have worse outcomes than patients with isolated intracranial occlusions and in these patients intravenous (IV) thrombolysis is less effective.

· For patients with tandem lesions undergoing EVT, two main approaches to address the c-ICA lesion exist:

a. Acute stenting during the EVT procedure

b. No acute stenting with possible deferred revascularization beyond the hyperacute phase

· Three of the major EVT trials excluded patients with TL. Among 122 patients with TL in the remaining trials, EVT was beneficial over standard therapy.

· However, no EVT trial routinely mandated how to treat the c-ICA lesion (treatment left to physician discretion) and little has been published on patients with TL from these trials.

· Most data on optimal management of the ICA lesion in patients with TL undergoing EVT are derived from retrospective, non-randomized case-series, in which the majority of patients underwent acute stenting of the ICA.

· These data, including meta-analyses of case-series, are not consistent in their results, showing either equivalence between ICA stenting and not stenting or superiority of stenting with regards to functional outcomes on the modified Rankin Scale (mRS) (7 point scale from 0 to 6 with a score of 0 indicating no disability, higher scores indicating more severe disability and 6 indicating death).

· There are theoretical benefits and potential disadvantages of acute ICA stenting which in general oppose the competing risks of ischemic stroke progression or recurrence and of intracranial hemorrhage:

a. Benefits: may more effectively treat the cause of stroke; favor intracranial clot lysis; decrease the risk of recurrence; improve overall cerebral perfusion

b. Disadvantages: need for early administration of antiplatelet agents which may increase the risk of intracranial hemorrhage (particularly in patients having received IV thrombolysis or having a large core of infarction); inherent risk of in-stent thrombosis; risk reperfusion-hyperperfusion injury

· Community equipoise exists regarding optimal management of the ICA lesion in these patients.

· Proof of superiority and safety of acute ICA stenting in patients with TL undergoing EVT would elevate the level of evidence for this procedure and thus change clinical practice.