Each year, approximately 15 million people suffer a stroke worldwide of which 80% are due to ischemic cerebral infarction. Based on the results of randomized controlled trials, treatment options and patient outcomes in acute ischemic stroke have dramatically improved in recent years. However, these advances in thrombolysis and endovascular therapy need to be established outside controlled trials to optimize stroke management, treatment procedures, patient selection and inter-hospital transfer in clinical practice. This multicenter longitudinal cohort study is based on a large stroke care network in Northern Bavaria, Germany (region of more than 3.5 million inhabitants) to evaluate and improve treatment in ischemic stroke.

Methods: This multicenter longitudinal cohort study will include ischemic stroke patients treated within a telemedical stroke care network and patients transferred to tertiary stroke centers for treatment procedures from hospitals outside the telemedical network. Individual patient data are available from two tertiary stroke centers and 24 primary and secondary stroke facilities in Northern Bavaria, Germany. Patients with ischemic stroke transferred to the tertiary stroke centers for treatment procedures - i.e. endovascular therapy or thrombolysis in stroke with an unknown time of onset - and all stroke patients with either large vessel occlusion (LVO) and/or thrombolysis therapy admitted to the University Hospital Erlangen will be integrated from institutional prospective stroke registries. Consecutive patients admitted between January 2006 and December 2019 will be included, an estimated total number of more than 3000 ischemic stroke patients - approximately 1000 patients with LVO receiving endovascular therapy, 1000 patients with LVO not receiving endovascular therapy and 1000 patients without LVO receiving thrombolysis therapy.

Demographic and clinical data including medical history, medication and laboratory results will be obtained by review of medical charts, institutional databases or prospective registries, supplemented by structured interviews on follow-up information or by review of all available medical records. In detail the following parameters will be evaluated: prior medical history (e.g. comorbidities, premorbid functional status, medication), admission status (e.g. NIHSS, GCS, body temperature, arterial blood pressure), cerebral imaging parameters (e.g. Alberta Stroke Program Early CT score [ASPECTS], perfusion volumes, mismatch and collateral status on admission imaging, final infarct volume on follow-up imaging), treatment procedures (e.g. intravenous thrombolysis, endovascular therapy, decompressive surgery), time intervals (e.g. symptom onset or last seen normal until admission, imaging, thrombolysis, groin puncture, recanalization), complications (e.g. hemorrhagic transformation, arterial dissection, distant ischemic stroke), laboratory parameters, clinical and diagnostic follow-up (e.g. neurological status, blood pressure, vascular ultrasound), stroke etiology, secondary prevention (e.g. lipid lowering medication, antiplatelet therapy, anticoagulation) and clinical outcomes (e.g. mortality, modified Rankin Scale).

Ethics Approval: The study was approved by the Institutional Review Board of the Friedrich-Alexander-Universität Erlangen-Nürnberg.

Inclusion Criteria:

• Clinical signs and symptoms consistent with the diagnosis of an acute ischemic stroke
• Presence of large vessel occlusion (as evidenced by CTA, MRA or DSA) and/or intravenous thrombolysis therapy applied

Exclusion Criteria:

• Age < 18 years

Ischemic stroke patients treated within a stroke care network in Northern Bavaria, Germany.

Because of local ethics committees restrictions the final decision upon release of the raw data has not been made.