Procedural time, quality of reperfusion and number of passes are known prognosis factors for patients with acute ischemic stroke due to large vessel occlusion strokes treated by mechanical thrombectomy (MT) [1Alawieh A., Vargas J., Fargen K.M., Langley E.F., Starke R.M., De Leacy R., e al. Impact of procedure time on outcomes of thrombectomy for stroke J Am Coll Cardiol 2019 ;  73 (8) : 879-890 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 2Zaidat O.O., Castonguay A.C., Linfante I., Gupta R., Martin C.O., Holloway W.E., e al. First pass effect: a new measure for stroke thrombectomy devices Stroke 2018 ;  49 (3) : 660-666 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 3Zaidat O.O., Yoo A.J., Khatri P., Tomsick T.A., von Kummer R., Saver J.L., e al. Recommendations on angiographic revascularisation grading standards for acute ischemic stroke: a consensus statement Stroke 2013 ;  44 (9) : 2650-2663 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti]. These procedural efficiency metrics are known to vary with various factors, amongst which operator's previous endo-vascular experience as well as center annual procedural volume [4Hess C.N., Peterson E.D., Neely M.L., Dai D., Hillegass W.B., Krucoff M.W., e al. The learning curve for transradial percutaneous coronary intervention among operators in the United States: a study from the National Cardiovascular Data Registry® Circulation 2014 ;  129 (22) : 2277-2286 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti]. We aimed to evaluate amongst trained interventional neuroradiologist (INR), whether increasing experience was associated with an improvement in MT procedural performance metrics.

This retrospective cohort study pooled MT procedural data across 3 high volume academic comprehensive stroke centers. Main study endpoints were duration of procedure, final angiographic recanalisation according to mTICI classification, number of passes, rate of first-pass complete recanalisation and rate of arterial perforation. Operator experience was defined for each operator as a continuous variable, cumulating the number of mechanical thrombectomy procedures performed since January 2015 or, if ulterior, since the operator started performing mechanical thrombectomies. Experience>2 years as a senior INR before 2015 was rated as a nominal variable.

A total of 1872 patients were included, treated by 14 operators (Mean 133 MT/operator, min 57 max 218). After adjustment for age, IV thrombolysis, on vs. off hours and occlusion location, increasing operator experience was significantly associated with shortened procedure duration. (Beta −3,50; 95% CI [−5.03 to −1.98]; P<0.001, See Fig. 1). Previous experience>2 years in INR was also associated with shorter procedural duration. No significant association was found between increasing operator experience and successful reperfusion (mTICI 2b-3), number of passes or first pass recanalisation rates.

In trained interventional neuroradiologists, increasing experience in mechanical thrombectomy is associated with significantly shorter procedural duration. Whether these delays reductions translate to better clinical outcomes should be investigated in larger scale registries. These results may inform future training guidelines to set minimal experience standards before seniorisation.