Medical records identified 17 patients who underwent emergent CAS for treatment of acute stroke related to an athero-thrombotic cervical ICA occlusion between 2009 and 2013. All patients underwent examination by computed tomographic (CT) perfusion imaging, followed by magnetic resonance (MR) imaging before conventional angiography. The indication for emergent CAS was determined by mismatch between the diffusion-weighted MR imaging finding of localized high intensity areas and the CT perfusion finding of decreased CBF related to the occluded ICA. Patients who present within 4.5 hours of symptom onset and without contraindication to systemic thrombolysis are treated immediately with intravenous tPA (0.9 mg/kg) and, unless immediate neurological improvement is observed, are then transferred rapidly to the angiography suite. In contrast, patients who present between 4.5 and 6 hours after symptom onset do not undergo systemic thrombolysis, but are transferred immediately to the neurointerventional suite.

Patients matching the following criteria were included in our analysis : 1) onset of acute stroke symptom and arrival at the hospital within 6 hours, 2) National Institutes of Health Stroke Scale (NIHSS) score on admission ≥5, 3) athero-thrombotic occlusion of the cervical ICA confirmed by catheter-based angiography : as the balloon configuration during inflation and features of residual stenosis after predilatation or the stent configuration before balloon angioplasty, and 4) negative findings on brain CT or limited hypodensities involving less than one-third of the middle cerebral artery (MCA) territory. We excluded patients in whom a dissection of the ICA was diagnosed due to the different nature of the disease. Patients with radiologic signs of chronic ICA occlusions were also excluded. Patients presenting with transient ischemic attack (TIA) were excluded from the analysis. TIA was defined as an acute transient focal neurological deficit caused by vascular disease, which showed a complete reversal within 24 hours, and caused no acute lesion, as confirmed by diffusion-weighted MR imaging.

Interventional procedures were performed in the neuroangiography room equipped with a digital subtraction angiography system (Axiom Artis, Siemens, Germany). All angiographic procedures were performed using a transfemoral approach under local anesthesia using an electrocardiogram, arterial oxygen saturation, and blood pressure monitoring. Four-vessel angiography was performed for estimation of collateral flow from the anterior and posterior communicating arteries, and to determine the presence of concomitant intracranial artery occlusion. The interventional treatment consists of two steps : first, emergent CAS for athero-thrombotic occlusion of the cervical ICA, and second, intracranial recanalization. A loading dose of 300 mg clopidogrel plus 300 mg aspirin was administered before endovascular treatment. Prior to the therapeutic procedure, patients were administered a systemic heparinization and a bolus injection of heparin 3000 IU. An additional 1000 IU bolus of heparin was administered every hour in order to maintain an ACT of >200 seconds throughout the procedure. Coaxial catheter-flushing fluid was mixed with heparin at a concentration of 1000 IU of heparin per 1000 mL of saline.

An 8 Fr guiding catheter (Envoy; Cordis, Miami Lakes, FL, USA) or 6 Fr Shuttle sheath was advanced to the common carotid artery, and it was connected to a continuous saline flush. A 0.014-in microwire (Transend; Boston Scientific, Natick, MA, USA) was placed into the petrous ICA passing the occluded segment. Then, a self-expandable stent was advanced over the microwire and positioned across the occlusion. A stent deployment and balloon angioplasty were performed with or without distal protection device (Spider device, ev3, Plymouth, MN, USA) to prevent distal embolic event.

The entire length of the ICA and the intracranial area was then imaged for determination of whether there was any further stenosis or occlusion of the ICA or MCA. If there was no distal patency of the ICA, we attempted restoration of distal flow using forced arterial suction thrombectomy using a 50-mL syringe. If an additional occlusion was present in the terminal segment of the ICA or MCA, a 6 Fr guiding catheter was advanced as far as possible into the recanalized ICA. The devices used for mechanical thrombectomy were the Penumbra system (Penumbra Inc., Alameda, CA, USA) or the Solitaire AB/FR (ev3 Europe SAS, Paris, France) with or without additional intra-arterial thrombolysis with urokinase. We initially attempted forced arterial suction thrombectomy using a Penumbra reperfusion catheter, but switched to Solitaire in difficult cases, which means failed thrombectomy despite several attempts at recanalization.

Immediately after the therapeutic procedure, we obtained the detailed neurologic history and performed a complete examination of all patients. The patients underwent non-enhanced brain CT imaging for evaluation of possible hemorrhagic complications. Following endovascular stent placement, patients were transferred to a stroke intensive care unit for strict control of blood pressure for prevention of hyperperfusion syndrome.

After the procedure, patients were administered aspirin 100 mg and clopidogrel 75 mg daily. Low-molecular-weight nadroparin calcium (Fraxiparine; GlaxoSmithKline, Marly-le-Roi Cedex, France) 2850 IU was also administered subcutaneously three times per day for at least three days.

Technical success of emergent CAS was defined as restoration of ICA flow with more than 50% recanalization of the cervical ICA. Intracranial arterial recanalization was assessed using the Thrombolysis in Cerebral Infarction (TICI) scores and was recorded prospectively at the end of each case by the treating interventionalist¹¹⁾. Angiographic success of intracranial arterial recanalization was defined as restoration of ICA flow with normal or near-normal perfusion in the ipsilateral ICA territory (TICI ≥2b flow).

For clinical outcome evaluation, the NIHSS was checked on admission and at seven days after the procedure. Improvement of neurological function was defined as reduction of ≥4 points on the NIHSS at seven days after the procedure compared with baseline. In addition, clinical functional outcome was assessed upon discharge from hospital or at the last clinical visit using the modified Rankin Scale (mRS). A score of ≤2 was considered a favorable outcome.

The 17 patients with acute stroke related to athero-thrombotic cervical ICA occlusion were treated by emergent CAS between 2009 and 2013. The mean age of the patients (15 men and 2 women) was 70.5±7.7 years (range, 54-82 years). The patients' mean NIHSS score on admission was 15.1±5.4 (range, 6-23). All patients had an NIHSS score of at least 6 on admission. Six patients had contraindications to intravenous administration of tPA, however, the others received a standard 10% bolus of the maximum dose (0.9 mg/kg body weight). The mean time from stroke onset to recanalization was 277±110 minutes (range, 120-460 minutes).

Angiography showed complete occlusion in 13 patients and near complete occlusion in four. Stents were deployed uneventfully and the cervical ICA was recanalized successfully in all cases. Some difficulties were encountered during passage of the guidewire through the occluded segment; it was possible in all cases. In six patients, no further vessel occlusion was detected after successful recanalization of the cervical ICA (Fig. 1). A distal protection filter was used selectively. The stent used was Protégé (ev3, Plymouth, MN, USA) in 15 patients and Wallstent (Boston Scientific, Natick, MA, USA) in two. Of 17 patients, 11 (11/17, 64.7%) showed an additional intracranial occlusion after flow restoration in the cervical ICA (Fig. 2) : at the level of the terminal segment of the ICA (n=3) and at the level of the MCA in eight patients. Intracranial arterial recanalization to a TICI ≥2b flow was achieved in four of 11 patients (36.4%). The overall recanalization rate (cervical ICA and intracranial artery) was 10 of 17 patients (58.8%).

Procedure-related complications developed in two patients (2/17, 11.8%). In Patient 3, although a distal protection filter was used, distal embolism occurred after CAS. Immediate thrombolysis using a combination of mechanical thrombectomy and intraarterial urokinase led to recanalization to a TICI 2b flow. However, afterward, relevant infarction was observed and his neurological status worsened. In one patient who suffered acute in-stent thrombosis, abciximab was administered intraarterially with a maintenance drip, yielding stent recanalization; however, the patient subsequently developed massive intracranial hemorrhage (ICH) and died (Patient 12). Thus, procedure-related mortality was 5.9% (1/17, Patient 12) and morbidity was 5.9% (1/17, Patient 3), respectively.

Ten of 17 patients (58.8%) showed improvement (decrease in NIHSS score of ≥4 points compared with admission score) during the hospital course at seven days after recanalization. Follow-up CT scan obtained immediately after each intervention showed occasional enhancement around the area of ischemia, which had resolved by the time the scan was repeated later. Three patients (3/17, 17.6%) had an ICH after CAS. These hemorrhages occurred within 48 hours after treatment. In two of them, the ICH was symptomatic with neurologic deterioration, resulting in death (Patients 9 and 12). The other patient suffered an asymptomatic hemorrhage in the basal ganglia (Patient 2). One patient (Patient 13) died secondary to pneumonia and sepsis 21 days after the procedure. Thus, there were three in-hospital deaths (3/17, 17.6%), respectively. At the end of the observational period, nine patients showed a good clinical outcome, with an mRS score of ≤2 (9/17, 52.9%), while the other eight (8/17, 47.1%) were dependent or dead (mRS score, 3-6). All surviving patients were followed up for 6-21 months (mean, 12.5 months). No neurologic deterioration or ischemic event occurred during the follow-up period in all surviving patients. A summary of characteristics and clinical outcomes according to existence of intracranial tandem lesion is shown in Table 3. Near-complete occlusion of the cervical ICA was identified in half of patients without an intracranial tandem lesion, while in only one patient with an intracranial tandem lesion. A favorable outcome (mRS ≤2) was obtained in four of the six patients with isolated cervical ICA occlusion (66.7%) and five of 11 patients with intracranial tandem occlusion (45.5%) at the last follow up. No patient with isolated cervical ICA occlusion suffered from a symptomtic ICH or in-hospital mortality, However, there were two cases of symptomtic ICH (18.2%) and three cases of in-hospital mortality (27.3%) in the patients with intracranial tandem occlusion. More favorable outcomes were achieved in patients without intracranial tandem lesion, compared to a patient population with intracranial tandem lesion. Representative cases are shown in Fig. 1, 2.