Impact of complete recanalization on clinical recovery in cardioembolic stroke patients with M2 occlusion

Background and purpose: We investigated the impact of complete recanalization beyond partial recanalization in distal (M2) middle cerebral artery (MCA) occlusion. Methods: Data regarding M2 occlusion patients treated with endovascular thrombectomy (EVT) and/or intravenous thrombolysis (tPA) were reviewed from our prospective EVT registry and multicenter tPA (YAMATO study) data bank. Complete recanalization was modified thrombolysis with cerebral infarction score (TICI) of 3 at the end of EVT or similar appearances of both MCAs on magnetic resonance angiography (MRA) within 1.5 h after tPA. Partial recanalization was defined as TICI >= 2b or > 50% recanalization on MRA. At 3 months, favorable outcome was defined as a modified Rankin Scale score <= 2. Result: Data on 121 patients were analyzed. EVT-alone was in 38 patients; combined EVT and tPA in 28; and tPA-alone in 55. Complete recanalization was achieved in 27 (22%), partial recanalization in 48 (40%), and no-to-limited recanalization in 46 (38%). At 3 months, 51% of patients had favorable outcomes, and this rate was significantly higher in the complete recanalization group than in the partial and no-to-limited recanalization groups (75% vs. 41% vs. 49%, p=.043). Multivariate regression analysis showed that complete recanalization was an independent parameter related to favorable outcomes (odds ratio 4.78, 95% CI: 1.16-19.73, p=.030). However, combined complete and partial recanalization was not associated with favorable outcomes (odds ratio 1.49, 95% CI 0.53-4.22, p=.449). Conclusion: Complete recanalization, but not partial recanalization, at the end of EVT and tPA therapy is associated with favorable outcomes in patients with M2 occlusion.