Patient Selection
All patients with acute symptomatic extracranial ICA occlusion or high-grade stenosis with or without intracranial vessel occlusion (tandem occlusion), who were treated with the CGuard stent at the University Hospital of Bern, Switzerland, were collected prospectively between December 2018 and November 2021. The study was approved by the local ethics committee (amendment access number: 231/2014).
Patients underwent endovascular intervention immediately after computer tomography (CT) or magnetic resonance imaging (MRI) if (1) diagnosis of ischemic stroke was established on imaging by a neuroradiologist, (2) intracranial hemorrhage was excluded on CT or MRI, (3) symptom duration was not longer than 24 h, (4) no further clinical conditions contraindicated the procedure [
14] and (5) occlusion or severe stenosis of the cervical ICA (with or without an intracranial occlusion) was demonstrated by initial or peri-interventional imaging. When indicated, intravenous thrombolysis (IVT) was administered prior to endovascular therapy.
Endovascular Procedure
The general approach to treating tandem occlusions at our institution has been described previously [
16,
17]. Briefly, all patients underwent the endovascular procedures under general anesthesia. After puncture of the common femoral artery, an 8 or 9 French sheath was introduced. Selective digital subtraction angiography (DSA) of the three non-occluded cervical vessels was routinely performed on a biplane high-resolution angiographic system (Artis Icono and Artis Q; Siemens, Erlangen, Germany) to assess cross flow and collaterals, followed by angiography of the occluded vessel. Based on clinical data and angiographic morphology, atheromatous occlusions were distinguished from ICA dissections.
A retrograde approach was chosen for all patients with tandem occlusions (treatment of the extracranial ICA occlusion or stenosis after intracranial recanalization) [
3,
18]. After placement of a guiding catheter (8 French Guider Softtip, Boston Scientific, Marlborough, MA, USA; 9 French Merci balloon-guide catheter, Concentric Medical, Mountain View, CA, USA) a 0.021″ microcatheter (Prowler Select Plus, Codman & Shurtleff Inc., Raynham, MA, USA; Phenom 21, Medtronic, Dublin, Ireland) was navigated through the stenosis over a 0.014″ microwire (Traxess, Microvention, Aliso Viejo, CA, USA) under proximal balloon occlusion and flow arrest. Only when intracranial access was not possible due to difficult vessel anatomy or high-grade stenosis, was balloon angioplasty of the ICA stenosis performed first. Once the microcatheter position distally to the occlusion or stenosis had been confirmed by a contrast injection, an intermediate 5 or 6 French catheter (5max ACE, Penumbra, Alameda, CA, USA; Vasco +35Aspi, Balt Extrusion, Montmorency, France; Sophia 5/6 French, Microvention, React 68/71, Medtronic) was advanced over the microcatheter into the distal ICA. The intracranial thrombus was passed with a microcatheter over the microwire and mechanical thrombectomy (MT) was performed using a stent retriever device with distal aspiration. Successful recanalization was defined as a modified thrombectomy in cerebral infarction (mTICI) of 2b or 3.
Before performing cervical stenting or PTA, a filter protection device (FilterWire EZ, Boston Scientific) was placed distal to the ICA occlusion to protect against distal embolization before deflation of the balloon-guided catheter and implantation of the CGuard stent at the stenotic site of the ICA. The final decision on whether to stent was at the discretion of the treating physicians. Predilatation and postdilatation was performed using balloon angioplasty (Aviator Plus PTA Dilatation Catheter, Cardinal Health, Dublin, OH, USA). DSA was performed at the end of the stent implantation process to check for acute in-stent thrombosis, distal embolism or other complications. Standard antiplatelet therapy consisted of intravenous administration of 250–500 mg aspirin after intracranial recanalization, prior to stenting. Control imaging was performed within 24 h to exclude intracranial hemorrhage and assess infarct evolution. If no intracranial hemorrhage was detected, dual antiplatelet therapy (DAPT) with additional clopidogrel 75 mg was initiated and continued for 3–6 months. All imaging data were analyzed by an interventional neuroradiologist.
Outcome Evaluation
The National Institutes of Health Stroke Scale (NIHSS) was assessed by a neurologist on admission and at discharge. Following internal guidelines, CT or MRI within 24 h after the intervention was used to assess intracranial bleeding and infarct evolution. Symptomatic intracranial hemorrhage (sICH) was defined as hemorrhage associated with a decline of ≥ 4 points in the NIHSS [
19]. Stent patency was assessed using ultrasound or CT or MR angiography. Routine clinical follow-up was performed at 3 months by an independent neurologist to evaluate patients’ recovery. The modified Rankin Scale (mRS) at 3 months was used as the indicator of clinical outcome.