Long-Term Outcome of Rescue Stenting for Acute Intracranial Atherosclerotic Stenosis–Related Large Vessel Occlusion in the Anterior Circulation

Ethical Approval

This study was a retrospective analysis of individual-level data of patients with RS for ICAS-related LVO, which were identified from a prospectively maintained multicenter database of RS after MT failure for AIS. Patients or their next of kin provided written informed consent for AIS treatment and inclusion in the registry at each center. This study received ethics approval from the institutional review boards of all participating centers, and the requirement for obtaining informed consent from each patient for study inclusion was waived because of the retrospective nature of this study. Data sharing is not applicable for this article because we could not obtain written consent for their data to be shared publicly. This study follows the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines (www.strobe-statement.org), and the STROBE checklists are included in the Supplemental Data.

Patient Inclusion

This study included patients with RS for ICAS-related LVO in the anterior circulation who were identified from the prospectively maintained database of RS after MT failure in 7 comprehensive stroke centers in South Korea between June 2010 and March 2021 (Fig 1). To be eligible for inclusion in this study, patients needed to undergo intracranial RS as a rescue treatment following the failure of first-line MT, and they were required to meet the following criteria: 1) older than 18 years of age; 2) baseline NIHSS score of ≥4; 3) ICAS-related LVO of the anterior circulation (ICA; M1 or proximal M2 segment of the MCA); 4) time from stroke onset to puncture ≤24 hours; 5) preprocedural CT-ASPECTS ≥6 or MR-ASPECTS ≥5; and 6) premorbid mRS score ≤1. Patients eligible for treatment with IV tPA were treated with a dose of 0.9 mg/kg. Truncal-type occlusion with either a fixed focal stenosis of >50% using the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial method or any reocclusion tendency was regarded as ICAS-related LVO.^14⇓-16 The identification of ICAS-related LVO was also supported if the patient had atherosclerosis without atrial fibrillation, a tapered occluded stump, and the absence of the hyperdense sign on CT imaging or the susceptibility sign on T2-weighted gradient-echo or SWI.^5,17 In addition, possible ICAS-mimics such as Moyamoya disease, dissection, or vasculitis were excluded as much as possible on the basis of the absence of their typical angiographic findings and laboratory data.

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FIG 1.

Flow chart of outcomes analyzed at each step.

Endovascular Procedure and Periprocedural Medication

Local anesthesia was used for all endovascular procedures, with conscious sedation administered as needed. The decision to use a balloon-guide catheter was left to the discretion of the operators. The first-line endovascular treatment was MT (stent retriever, contact aspiration, or both) for all patients. The specific MT procedure and the total number of MT attempts were also determined on the basis of the neurointerventionists’ judgment. Failure of first-line MT was declared if the target occlusion site failed to recanalize (modified TICI grade 0–2a) or demonstrated a tendency to reocclude despite multiple attempts.

Rescue endovascular treatment, comprising intraprocedural infusion of thrombolytic drugs (e.g., the glycoprotein IIb/IIIa inhibitor), percutaneous balloon angioplasty, RS, or their combination was performed after first-line MT failure. Among them, only the patients who underwent RS, regardless of whether they also received other rescue endovascular treatment including thrombolytic drug or balloon angioplasty, were enrolled in this study. Because the type of stent was not specified, patients with any type of intracranial stent (such as Solitaire FR, Medtronic; Wingspan, Stryker; or Enterprise, Johnson and Johnson) were eligible for enrollment. The choice of stent was left to the neurointerventionalist’s discretion. The infusion of glycoprotein IIb/IIIa inhibitor was determined on the basis of the protocols followed by each participating center. All centers administered 0.2–2.0 mg of tirofiban (0.05-mg/mL concentration at 0.1 mg/min) as the glycoprotein IIb/IIIa inhibitor for intra-arterial (IA) infusion. For IV tirofiban administration, the total dose and infusion rate were determined in accordance with pharmacologic guidance (usually 0.1 μg/kg/min). IV infusion was initiated on the basis of the administration of IA tirofiban, and the decision to maintain IV tirofiban was made by the neurointerventionalists or stroke neurologists of each center (Fig 2).

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FIG 2.

Example of a follow-up assessment in RS for ICAS-related LVO after a failed first-line MT. The patient presented to the hospital with left-sided weakness and aphasia. The baseline NIHSS score was 17, and the onset-to-puncture time was 360 minutes. A, The initial DSA shows occlusion of the M1 segment of the MCA (black arrow). B, Angiography performed 30 minutes after RS because of reocclusion of the M1 segment of the MCA shows successful recanalization (black arrow). Three days after RS, the NIHSS score improved to 1 and the mRS score was zero. C, A follow-up MRA performed at 3 days after RS demonstrates intact distal flow beyond the RS (white arrow). After 84 days following RS, the mRS score was zero, and there were no instances of stroke recurrence. D, A follow-up CTA reveals the patent stented artery (white arrow).

The types of postprocedural antiplatelet medications were determined on the basis of consensus among neurointerventionalists and stroke neurologists at each center. Postprocedural antiplatelet medications included the following: 1) IV tirofiban infusion lasting 12–24 hours after endovascular treatment, followed by oral dual antiplatelet therapy (DAPT) consisting of aspirin, 100 mg, with clopidogrel, 75 mg; and 2) immediate administration of DAPT (aspirin, 100 mg, with clopidogrel, 75 mg, or their loading dose if necessary) after finishing the endovascular procedure. DAPT was continued for at least 12 months following RS, unless intracranial hemorrhage or systemic bleeding events developed. If any form of intracranial hemorrhage developed, the decision to either continue or change the antiplatelet medication regimen was determined in accordance with the protocol of each center. Furthermore, high-intensity statin therapy was consistently maintained. Hypertension and diabetes were also strictly managed according to the current stroke guidelines.¹⁸

Data Collection and Assessment

Routine clinical and imaging follow-up were conducted according to the protocol of each center and documented in the registry of each center. Successful recanalization was defined as a score of 2b or 3 on modified TICI on the final angiogram. A good functional outcome was defined as an mRS score of 0–2. If a patient was unable to attend a follow-up appointment, stroke neurologists or trained nurses conducted a telephone interview with the patient or the family to assess the mRS score using a standardized questionnaire.

Intracranial hemorrhage was assessed through CT or MR imaging and was considered symptomatic if the patient’s NIHSS score increased by ≥4 without any identifiable causes associated with neurologic deterioration. Stroke recurrence was characterized by the development of new neurologic symptoms with an NIHSS score of ≥2, accompanied by the presence of positive lesions in the corresponding brain region on DWI.

Follow-up vascular imaging such as CT, MR, and conventional angiography was performed according to the protocol of each center to evaluate the patency of the stented vessel. Follow-up vascular images were sent to the central laboratory for analysis. The vessel was not regarded as patent if it was either occluded or had insufficient distal blood flow beyond the stented vessel. Patency was evaluated by 2 independent neuroradiologists in the central laboratory who were blinded to clinical and endovascular treatment information. The κ value for the interrater agreement was 0.95. All discrepancies were resolved by consensus.

Follow-Up and Outcome Measurement

Successful recanalization was evaluated after the completion of endovascular treatment. Regarding clinical outcomes, a good functional outcome, mortality at 3 months, stroke recurrence in the relevant brain region, and symptomatic intracranial hemorrhage (SICH) within 3 months, were evaluated. Additionally, good functional outcomes and mortality at the last follow-up (≥12 months) as well as stroke recurrence and SICH after 3 months from the final follow-up (≥12 months) were evaluated in patients who were eligible for clinical follow-up at ≥12 months. Finally, the assessment of stent patency was performed in the patients who underwent follow-up vascular imaging within the initial 3 months and was repeated at least once, extending beyond the 12 months after RS (Fig 1).

Statistical Analysis

The characteristics of the study population including demographics, comorbidities, endovascular treatment details, etiologies for RS, and associated antiplatelet medications were evaluated. Clinical outcomes and the patency of the stented artery were measured during the follow-up period. Data are presented as the mean (SD), median (interquartile range [IQR]), or as number (percentage), as appropriate.