Learning Curve Effect of Combined Technique Thrombectomy as First-Line Attempt for Acute Ischemic Stroke: A Single-Center Retrospective Study

Abstract

We retrospectively examined the initial experience and learning curve after the introduction of thrombectomy with the combined technique using an aspiration catheter and a stent retriever as first-line attempt for acute ischemic stroke. Consecutive patients undergoing thrombectomy for acute ischemic stroke at our institution between January 2020 and December 2022 were divided into three groups according to the year of thrombectomy. Patient characteristics and procedural, safety, and clinical outcomes were compared between the three year periods to determine predictors of favorable clinical outcome. In 2020, 2021, and 2022, the numbers of patients were 74, 70, and 90, respectively, with similar patient characteristics across the three years; successful recanalization rates were 79.7%, 97.1%, and 93.3%, respectively (p<0.01 for the first 2 years); median procedure times were 67, 43, and 32 minutes, respectively (p<0.01 for the first 2 years and p=0.018 for the last 2 years); first pass effect rates were 20.3%, 41.4%, and 44.4%, respectively (p<0.01 for the first 2 years); symptomatic intracranial hemorrhage rates were 14.9%, 2.9%, and 1.1%, respectively (p=0.018 for the first 2 years); and percentages of modified Rankin Scale score 0 to 2 at 90 days were 24.3%, 42.9%, and 41.1%, respectively (p=0.022 for the first 2 years). Procedure time (p=0.038) and successful recanalization (p=0.041) were independent predictors of favorable clinical outcome. The learning curve effect of the combined technique may be associated with better clinical outcome due to increased successful recanalization rates, shortened procedure time, and reduced symptomatic intracranial hemorrhage.