Background The incidence of intracranial atherosclerotic disease (ICAD) in acute ischemic stroke treated with mechanical thrombectomy (MT) is not well defined, and its description may lead to improved stroke devices and rates of first pass success.

Methods A retrospective study was performed on MT patients from 2012 to 2019 at a comprehensive stroke center using chart review and angiogram analysis. Angiograms at the time of MT were reviewed for ICAD, and location and severity were recorded. Patients with ICAD were divided according to ICAD location relative to the large vessel occlusion (LVO) site. Statistical analyses were performed on baseline demographics, comorbidities, MT procedure variables, outcome variables, and their association with ICAD.

Results Of the 533 patients (mean age 70.4 (SD 13.20) years, 43.5% women), 131 (24.6%) had ICAD. There was no significant difference in favorable discharge outcomes (modified Rankin Scale score of 0–2; 23.8% ICAD vs 27.0% non-ICAD; p=0.82) or groin puncture to recanalization times (average 43.5 (range 8–181) min for ICAD vs 40.2 (4–204) min for non-ICAD; p=0.42). Patients with ICAD experienced a significantly higher number of passes (average 1.8 (range 1–7) passes for ICAD vs 1.6 (1–5) passes for non-ICAD; p=0.0059). Adjusting for age, ≥3 device passes, baseline National Institutes of Health Stroke Scale, rates of angioplasty only, rates of concurrent angioplasty and stenting, coronary artery disease and atrial fibrillation incidences, and time from emergency department arrival to recanalization, yielded no significant difference in rates of favorable outcomes between the two groups.

Conclusion Patients who underwent MT with underlying ICAD had similar rates of favorable outcomes as those without, but required a higher number of device passes.