Abstract WP28: Eligibility for Mechanical Thrombectomy in Acute Ischemic Stroke: a Phase IV Multi-center Screening Log Registry

Background & Purpose: No eligibility screening logs were kept to support recent mechanical thrombectomy (MT) RCTs establishing safety and efficacy for acute ischemic stroke (AIS). We sought to evaluate the potential eligibility for MT among consecutive AIS patients in a prospective multicenter study. Methods: We prospectively evaluated consecutive patients admitted with the diagnosis of AIS in three tertiary care stroke centers during a twelve-month period. Admission stroke severity was documented using NIHSS-score, while all patients underwent baseline neurovascular imaging using MRA/CTA. Potential eligibility for MT was evaluated using inclusion criteria from MR CLEAN & REVASCAT as these protocols utilized imaging and selection methods that most closely mirrored everyday clinical practice. Results: Our study population consisted of 1161 AIS patients (mean age 66±14 years, 55% men, median admission NIHSS-score: 5 points, IQR 2-8). A total of 86 (7%, 95%CI: 6%-9%) and 66 (6%, 95%CI: 4%-7%) patients fulfilled the inclusion criteria for MR CLEAN & REVASCAT respectively, while 57 cases were eligible for inclusion in both trials (5%, 95%CI: 4%-6%). There was no evidence of heterogeneity (p>0.150) regarding the eligibility of AIS for MT across the three participating centers. Absence of proximal intracranial occlusion (70%), followed by hospital arrival outside the eligible time window (31% for MR CLEAN 6-hour window & 29% for REVASCAT 8-hour window), low baseline NIHSS-score (16% below the 2 point cut-off of MR Clean & 46% below the 6 point cut-off of REVASCAT) and posterior circulation cerebral ischemia (16%) were the four most common reasons for ineligibility for MT. Conclusion: Our everyday clinical practice experience suggests that approximately one out of fourteen to seventeen consecutive AIS may be eligible for MT if inclusion criteria for MR CLEAN and REVASCAT are strictly adhered to. Delayed presentation from symptom onset represents the only modifiable MT exclusion factor.