Time Trends in Mechanical Thrombectomy (2017 -2021): Do real-world data reflect advances in evidence?

Christoph Riegler ^1,2* Viktoria Rücker ³ Regina Von Rennenberg ^1,2 Kerstin Bollweg ^1,2 Bastian Cheng ⁴ Anna Alegiani ⁴ Fabian Flottmann ⁵ Marlena Schnieder ⁶ Marielle Ernst ⁷ Waltraud Pfeilschifter ^8,9 Christoffer Kraemer ⁸ Ruben Mühl-Benninghaus ¹⁰ Steffen Tiedt ^11,12 Lars Kellert ¹² Hanna Zimmermann ¹³ Felix Jürgen Bode ¹⁴ Gabor Petzold ¹⁴ Franziska Dorn ¹⁵ Jörg Berrouschot ¹⁶ Albrecht Bormann ¹⁷ Kathleen Bernkopf ¹⁸ Silke Wunderlich ¹⁸ Tobias Boeckh-Behrens ¹⁹ Martina Petersen ²⁰ Lars Udo Krause ²⁰ Stephan Lowens ²¹ Heinrich Audebert ^1,2 Eberhard Siebert ²² Peter U Heuschmann ^23,24,3 Christian H Nolte ^1,2,25,26

• ¹ Center for Stroke Research Berlin, Charité University Medicine Berlin, Berlin, Berlin, Germany
• ² Department of Neurology, Charité – Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
• ³ Institute of Clinical Epidemiology and Biometry, Julius-Maximilians-Universität (JMU) Würzburg, Würzburg, Germany
• ⁴ Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Hamburg, Germany
• ⁵ Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
• ⁶ Department of Neurology, University Medical Center Göttingen, Goettingen, Lower Saxony, Germany
• ⁷ Institute for Diagnostic and Interventional Radiology, University Medical Center Goettingen, Goettingen, Lower Saxony, Germany
• ⁸ Department of Neurology and Clinical Neurophysiology, Städtisches Klinikum Lüneburg, Lüneburg, Germany
• ⁹ Department of Neurology, Centre for Neurology and Neurosurgery, Goethe University, Frankfurt am Main, University Hospital Frankfurt, Frankfurt, Germany
• ¹⁰ Department of Radiology, Städtisches Klinikum Lüneburg, Lüneburg, Germany
• ¹¹ Institute for Stroke and Dementia Research, LMU Munich University Hospital, Munich, Bavaria, Germany
• ¹² Department of Neurology, University Hospital, LMU Munich, Munich, Germany
• ¹³ Institute for Neuroradiology, Ludwig-Maximilians-University (LMU) Munich, Munich, Germany
• ¹⁴ Department of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
• ¹⁵ Department of Neuroradiology, University Hospital Bonn, Bonn, North Rhine-Westphalia, Germany
• ¹⁶ Klinik für Neurologie, Klinikum Altenburger Land, Altenburg, Germany
• ¹⁷ Klinik für Radiologie, Interventionsradiologie und Neuroradiologie, Klinikum Altenburger Land, Altenburg, Germany
• ¹⁸ Department of Neurology, School of Medicine Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
• ¹⁹ Department of Diagnostic and Interventional Neuroradiology, University Hospital rechts der Isar, Technical University of Munich, Munich, Bavaria, Germany
• ²⁰ Department of Neurology, Klinikum Osnabrück, Osnabrück, Germany
• ²¹ Department of Radiology, Klinikum Osnabrück, Osnabrück, Germany
• ²² Department of Neuroradiology, University Hospital Berlin (Charité), Berlin, Baden-Württemberg, Germany
• ²³ Institute of Medical Data Science, University Hospital of Würzburg, Würzburg, Bavaria, Germany
• ²⁴ Clinical Trial Center, University Hospital Würzburg, Würzburg, Bavaria, Germany
• ²⁵ Berlin Institute of Health (BIH) at Charité - Universitätsmedizin Berlin, Berlin, Germany
• ²⁶ Deutsches Zentrum für Herz-Kreislaufforschung DZHK, Berlin, Germany

Recent years have witnessed a continuous, evidence-driven broadening of indications for endovascular therapy (EVT) in the treatment of ischemic stroke. With advances in extended time windows and target vessel occlusion, our study aimed to assess whether patients' characteristics, treatment, and outcomes changed over time in clinical practice. We used data from the German Stroke Registry, a large national multicentre prospective registry of patients receiving EVT for ischemic stroke. Baseline factors, treatment details and clinical outcomes (modified Rankin scale [mRS] at three months) were analysed over a fiveyear period (2017-2021). We included 6,251 patients from eight centres. Characteristics of patients receiving EVT changed over time (2017 vs. 2021) with patients getting older (median: 76 [IQR: 65-82) vs. 77 [65-84 years]; ptrend=0.02]), less severely affected (NIHSS (15 [11-19] vs. 13 [8-18]; ptrend <0.001), treated later (last-seen-well to hospital admission > 6h: 22.0% vs. 28.3%; ptrend<0.001), more often for medium vessel occlusion (16.1% vs. 28.1%; ptrend<0.001), and received intravenous thrombolysis less often (52.4% vs. 40.4%; ptrend<0.01). Good functional outcome decreased (mRS ≤ 2: 36.0% vs. 34.9%, aOR 0.94 [0.89 -0.99] per year), and mortality at three months increased from 25.3% (2017) to 34.7% (2021); aOR 1.13 [1.07 -1.19] per year). Between 2017 and 2021, patients' characteristics changed substantially and EVT indication was expanded. Despite lower degree of stroke severity, functional outcomes did not improve and mortality increased notably. This may reflect willingness to treat patients with more severe general health conditions.