Early Loss of Immediate Reperfusion While Stent Retriever in Place Predicts Successful Final Reperfusion in Acute Ischemic Stroke Patients

BACKGROUND AND PURPOSE: Degree of stent retriever engagement with target thrombi may be reflected by (1) immediate reperfusion (IR) on first deployment, indicating displacement of clot toward the vessel wall, and (2) by early loss of IR (ELOIR), indicating penetration of retriever struts through the thrombus. The relation of these early findings to final reperfusion and clinical outcomes has not been well delineated. METHODS: We investigated IR and ELOIR in patients undergoing stent retriever mechanical thrombectomy at an academic medical center between March 2012 and June 2014. RESULTS: Among 56 patients, IR itself was not associated with final successful reperfusion, which occurred in 66.7% of IR patients and 71.4% of non-IR patients (P=0.999). However, ELOIR was associated with a higher rate of final successful reperfusion (92% versus 44%; P=0.046). Patients with ELOIR had a higher nominal rate of final favorable outcome (42% versus 22%; P=0.64). CONCLUSIONS: ELOIR during the embedding period after deployment of stent retrievers is associated with successful final reperfusion, likely because of greater thrombus engagement with the stent retriever. ELOIR may be a useful finding to guide duration of embedding time in clinical practice and design of novel stent retrievers.