Abstract 144: Strategy for Managing Tandem Extracranial and Intracranial Occlusions: A Technical Note
Authors: Khachatryan T. , Xu J. , Granstein J. , Yuki I. , Golshani K. , Suzuki S. 
Published: January 2025

Introduction
Acute ischemic stroke (AIS) due to tandem extracranial and intracranial occlusions (TOs) occurs in 15‐30% of cases and poses significant challenges during acute stroke therapy, leading to worse outcomes compared to thrombectomies without tandem occlusions. Traditional approaches, including antegrade (intracranial revascularization first) and retrograde (extracranial revascularization first) strategies, have shown variable success. The retrograde approach, while potentially offering faster recanalization, often encounters difficulties in advancing the aspiration catheter through the extracranial occlusion site. This abstract outlines our technical algorithm for managing TOs in acute stroke therapy.

Methods
We conducted a retrospective review of patient records for those who underwent endovascular thrombectomy (EVT) for AIS from July 2021 to June 2024. Our recanalization algorithm for TOs involved: • Prioritizing stent‐retriever deployment across the occlusion site by crossing the extracranial occlusion with a microcatheter. This step aims to achieve early reperfusion via intracranial collaterals from the circle of Willis. Simultaneously, the stent retriever serves as an anchor which facilitates the passage of the aspiration catheter past the cervical occlusion, which is especially useful in case of tortuous vascular anatomy. • If the aspiration catheter successfully advanced through the extracranial occlusion, a retrograde approach was implemented using a combination of aspiration and stent retrieval. After successful intracranial thrombectomy, extracranial balloon angioplasty was performed if necessary. When performing balloon angioplasty, we redeployed the stent retriever in the supraclinoid internal carotid artery to serve as an anchor and distal protection device while using its wire for balloon advancement. • If passage through the cervical occlusion was unsuccessful, the microcatheter was removed while retaining the stent retriever. A 0.18 wire‐compatible PTA balloon was then advanced into the cervical internal carotid artery (ICA) for balloon angioplasty using the stent retriever's wire, thus implementing a modified antegrade approach while providing perfusion to the affected vascular territory. After angioplasty, the aspiration catheter was advanced into the intracranial occlusion site, and stent retrieval with contact aspiration was performed. We avoided extracranial stent angioplasty whenever feasible.

Results
Among 192 patients, 17 were identified with tandem extracranial and intracranial occlusions. The mean age was 72 years (range: 60‐83). Successful reperfusion on the final angiogram (TICI 2b/3) was achieved in all but one patient (TICI 1). Based on our proposed algorithm, 12 patients were treated with the retrograde approach, and 5 patients were treated with the modified antegrade approach. Six patients underwent thrombectomy only, without the need for angioplasty, while 10 patients required cervical ICA angioplasty. One patient required emergent carotid artery stent angioplasty due to recoiling and reocclusion of the cervical ICA. At three months, 9 patients (53%) had favorable clinical outcomes (mRS ≤3), 5 patients (29%) had unfavorable outcomes (mRS ≥4), and 3 patients were lost to follow‐up (18%).

CONCLUSIONS
Tandem occlusions represent a highly complex form of AIS. This retrospective review highlights our stepwise decision‐making approach to achieving satisfactory reperfusion. Further prospective studies with larger patient cohorts are needed to evaluate whether this strategy enhances the likelihood of successful reperfusion and improves clinical outcomes.