This study explores the use of CRP level reduction in patients after suffering from acute ischemic stroke. Using selective CRP-apheresis, the investigators aim to reduce the secondary inflammatory tissue damage in the course of infarction maturation using infarction growth in MRI as the primary outcome as a surrogate.

C-reactive protein (CRP) is an acute-phase protein binding to phosphocholine, thereby marking damaged tissue. This in turn activates the complement system and the cellular immune system engaging the unspecific immune system in an inflammatory tissue-degrading reaction. Such a pattern is observed in ischemic stroke, and elevated CRP levels can be measured in stroke survivors' sera. Several observational studies reproduced higher CRP levels with negative outcome in stroke. In another vascular model disease, myocardial infarction, selective CRP apheresis reduced infarct size in humans. The investigators therefore designed this pilot study to explore the effects of selective CRP reduction in ischemic stroke patients.

Inclusion Criteria:

• Age 18 - 85 years
• Informed consent signed by patient
• Patients with acute ischemic stroke in the Arteria cerebri media (MCA) territory within 36 hours of event
• Acute MRI with evidence of infarction
• NIHSS ≥ 4
• CRP > 5 mg/l

Exclusion Criteria:

• Withdrawal of consent
• Systolic blood pressure <100 mmHg before the apheresis
• Blood pressure relevant extra- and intracranial stenoses (NASCET 70)
• Apheresis contraindication
• Participation in other interventional studies