UPmémoires

English

Clinical outcome and technical success in mechanical thrombectomy of large vessel occlusion of anterior circulation according to the operator's experience : a retrospective single center study

Background and purpose: Consensus is lacking on mechanical thrombectomy (MT) volume threshold to maximize good results in acute ischemic stroke due to anterior large vessel occlusion (AIS-LVO). We aimed to evaluate technical success and good clinical outcome after MT according to operator's experience.

Material and methods: The study took place in our TCSC of Poitiers (179 MT fulfilled in 2019, reference year before the coronavirus pandemic). We retrospectively analyzed our institutional stroke database including patient characteristics, procedural variables, and outcomes from January 2015 to December 2020. Operator's experience was defined by annual procedural volume (APV) as a continuous and ordinal variable divided into three sequential groups: 1-14, 15-29, and more than 30 MT per year. Successful reperfusion (modified Thrombolysis In Cerebral Infarction (mTICI) score ≥ 2b) and good clinical outcome (modified Rankin Scale (modified Rankin (mRS) score 0-2) were the response variables. Univariate and multivariate models were conducted to assess the impact of operator's experience on these variables.

Results: 589 MT performed from January 2019 to December 2020 were included in the analysis. We did not find any significant difference between selection criteria according to the APV. The rates of successful reperfusion were respectively 89.4% (244/273), 84.2% (165/196), and 85% (102/120) and the rates of good clinical outcome were respectively 40.5% (106/273), 44.5% (85/196) and 42.7% (50/120) in groups A, B, and C. P-values for technical success and clinical outcome were respectively 0.214 and 0.686 in univariate analysis. There was a linear relationship between APV and positive clinical outcome in multivariate analysis: for every 5 more annual cases, patients had an increase of 0.164 adjusted odds of good outcome. Confidence intervals contained 1.

Conclusion: Mechanical thrombectomy clinical outcome and technical success did not significantly associate with annual procedural volume. This retrospective single center study finding suggests either a lack of strength or a fast learning curve after years under mentorship in a polyvalent team.

Keywords : mechanical thrombectomy, operator experience, procedural volume, clinical outcome, successful reperfusion.