See Tables XVII and XLV in online Data Supplement 1. 3.7.2. 0 to 6 Hours From Onset COR LOE New, Revised, or Unchanged Patients should receive mechanical thrombectomy with a stent retriever if they meet all the following criteria: (1) prestroke mRS score of 0 to 1; (2) causative occlusion of the internal carotid artery or MCA segment 1 (M1); (3) age 18 years; (4) NIHSS score of 6; (5) ASPECTS of 6; and (6) treatment can be initiated (groin puncture) within 6 hours of symptom onset. I A Recommendation revised from 2015 Endovascular. Results from 6 recent randomized trials of mechanical thrombectomy using predominantly stent retriever devices (MR CLEAN, SWIFT PRIME, EXTEND-IA, ESCAPE, REVASCAT, THRACE) support COR I, LOE A recommendations for a defined group of patients as described in the 2015 Guidelines.105 110 A pooled, patient-level analysis from 5 of these studies reported by the HERMES Collaboration showed treatment effect in the subgroup of 188 patients not treated with IV alteplase (cOR, 2.43 [95% CI, 1.30 4.55]); therefore, pretreatment with IV alteplase has been removed from the prior recommendation. 