Background: Occlusion of the internal carotid artery (ICA) may extend into the middle or anterior cerebral artery (ICA-T) or be confined to the intracranial (ICA-I) or extracranial segment (ICA-E). While there is excellent evidence for endovascular therapy (EVT) in ICA-T occlusions, studies on EVT in non-tandem ICA-I or ICA-E occlusions are scarce.
Objective: To characterize EVT-treated patients with ICA-I- and ICA-E occlusion by comparing them with ICA-T occlusions.
Methods: The German Stroke Registry (GSR), a national, multicenter, prospective registry was searched for EVT-treated patients with isolated ICA occlusion between June 2015 and December 2021. We stratified patients by ICA occlusion site: (a) ICA-T, (b) ICA-I, (c) ICA-E. Baseline factors, procedural variables, technical (modified Thrombolysis in Cerebral Infarction (mTICI)), and functional outcomes (modified Rankin scale score at 3 months) were analyzed.
Results: Of 13 082 GSR patients, 2588 (19.8%) presented with an isolated ICA occlusion, thereof 1946 (75.2%) ICA-T, 366 (14.1%) ICA-I, and 276 (10.7%) ICA-E patients. The groups differed in age (77 vs 76 vs 74 years, Ptrend=0.02), sex (53.4 vs 48.9 vs 43.1% female, Ptrend<0.01), and stroke severity (median National Institutes of Health Stroke Scale score at admission 17 vs 14 vs 13 points, Ptrend<0.001). In comparison with ICA-T occlusions, both ICA-I and ICA-E occlusions had lower rates of successful recanalization (mTICI 2b/3: 85.4% vs 80.4% vs 76.3%; aOR (95% CI for ICA-I vs ICA-T 0.71 (0.53 to 0.95); aOR (95% CI) for ICA-E vs ICA-T 0.57 (0.42 to 0.78)). In adjusted analyses, ICA-E occlusion was associated with worse outcome when compared with ICA-T occlusion (mRS ordinal shift, cOR (95% CI) 0.70 (0.52 to 0.93)).
Conclusion: Patient characteristics and outcomes differ substantially between ICA-T, ICA-I, and ICA-E occlusions. These results warrant further studies on EVT in ICA-I and ICA-E patients.
Keywords: Angiography; Atherosclerosis; Cervical; Stroke; Thrombectomy.
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