Relationship between Flow Restoration/Re-occlusion and Recanalization during Deployment of Stent Retriever

Abstract

Objective: There has been no detailed study reporting the relationship between flow restoration (FR)/re-occlusion status and recanalization results during the acute thrombectomy using stent retrievers. In this study, we examined the influence of FR/re-occlusion during stent deployment on recanalization in our experiences. Subjects and Methods:In all, 24 patients with cardiogenic cerebral embolism underwent thrombectomy with a TREVO stent retriever (10 males, 14 females, mean age: 77.2 years). Intravenous tissue plasminogen activator (tPA) infusion was preceded in 17 of 24 patients, occlusion sites were as follows: internal carotid artery, 9 patients; M1 of middle cerebral artery, 13 patients; and basilar artery, 2 patients. We investigated the relationship between the presence or absence of FR/re-occlusion and grade of recanalization thrombolysis in cerebral infarction (TICI). We also examined the interval from FR until re-occlusion and frequency of stent deployment. Results:In the first session of stent deployment, FR and subsequent re-occlusion were observed in 11 patients (11/24, 46%). Of these, TICI 2b or higher grade recanalization was achieved in nine patients (9/11, 81%). Of 10 patients who had FR but no re-occlusion in the first session of stent deployment (10/24, 42%), TICI 2b or higher scale recanalization was achieved in 4 (4/10, 40%). In three patients without FR (3/24, 13%), TICI 2b or higher scale recanalization was not achieved. Of the above 11 patients who showed FR and subsequent re-occlusion in the first session of stent deployment, the waiting time until re-occlusion was 5 minutes in seven patients and 10 minutes in four patients.Of the 10 patients who had FR but no re-occlusion, the waiting time was 5 minutes in four patients, 10 minutes in four patients, and 20 minutes in two patients. In 9 of the 24 patients, several sessions of stent deployment were required, and the total frequency of stent deployment was 37 times. In 37 sessions of stent deployment showed the achievement of FR and re-occlusion in 17 sessions (17/37, 46%). Of these, TICI 2b or higher scale recanalization was achieved in 14 (14/17, 82%). Of 12 sessions with FR but no re-occlusion (12/37, 32%), TICI 2b or higher scale recanalization was achieved in 5 (5/12, 41%). TICI 2b or higher scale recanalization was not achieved in eight sessions without FR (8/37, 22%). Conclusion:Flow restoration immediately after stent deployment was a necessary condition for recanalization. If re-occlusion is confirmed after FR, satisfactory recanalization may be achieved at a high percentage. The results demonstrated that satisfactory recanalization was not achieved without FR, and less likely without re-occlusion following FR.