Abstract Number ‐ 90: Bailout Technique for Entangled Stentriever and Carotid Stent during Tandem Large Vessel Occlusion Endovascular Therapy
Authors: Malik Kunal , Nogueira Raul , Nidamanuri Priya , Mohammaden Mahmoud , Rajani Ravi , Haussen Diogo C , Al‐Bayati Alhamza 
Published: April 2023

Introduction
Tandem occlusions represent 10–20% of all acute ischemic stroke patients.1 Endovascular Thrombectomy (EVT) for this subset of patients is more challenging given the proximal underlying steno occlusive disease. Emergent carotid artery stenting could achieve a considerably high chance of reperfusion and functional independence.2

Methods
This is a case report of a 73‐year‐old woman who presented with left MCA syndrome‐NIHSS 13 found to have left ICA/MCA tandem occlusions. EVT was pursued, initial angiographic run of the left common carotid artery demonstrated severe stenosis at the origin of left cervical ICA which harbors a mid‐cervical ICA loop and proximal left MCA occlusion. Following our retrograde revascularization approach, an intracranial pass using an embotrap 5mm x 37 mm stent retriever (SR) was attempted however given proximal cervical ICA tortuosity and underlying proximal stenosis, the stability of triaxial system prevented optimal placement of the SR and achieving intracranial reperfusion. An antegrade revascularization approach was then pursued with uneventful cervical ICA angioplasty followed by extracranial carotid closed cell Xact stent placement. A stable triaxial system was navigated through the stented cervical ICA. An ideal SR pass was performed. Upon retrieving the clot‐incorporated SR with the intention to fully retrieve the SR into the locally placed aspiration catheter (AC) in the supraclinoid ICA under continuous aspiration, the triaxial system collapsed into the distal CCA, likely due to the mid cervical ICA loop, leading to entanglement of the proximal end of SR and distal ICA stent (Figure1‐A). Large thrombus was recovered from the AC aspirate.

Results
Numerous attempts to disentangle the SR from the ICA stent including attempts to re‐sheath the SR with different size microcatheters and guide catheters were unsuccessful. The cervical ICA lumen remained patent without evidence of dissection or residual thrombus however, the presence of SR pusher‐wire would preclude safe termination of the procedure. Surgical bailout with emergent carotid endarterectomy and removal of the stent/SR metal mesh was considered.3,4 However, given the high surgical risk with recent intravenous load of antithrombotics for emergent stent placement, this option was deemed as a last resort. We decided to attempt safe separation of the SR from its pusher wire and leave behind the patent ICA stent/SR in place. A gradual pulling pressure was applied to the SR wire while maintaining adjacent microwire access and fully inflated Viatrac 5mm x 30 mm extracranial balloon over the entangled portion to ensure continuous vascular access (Figure1‐B). The SR wire was then separated from the SR and fully retracted outside the body (Figure1‐C). Delayed angiographic runs continued to demonstrate full patency of the ICA lumen (Figure1‐D). No residual dissection, spasm or thrombus noted. Patient was discharged home with NIHSS of 3.

Conclusions
Exposure to EVT technical complications and bailout techniques are of utmost importance.