Reperfusion Injury After Endovascular Stroke Treatment

Immediately after mechanical thrombectomy, patients will be investigated with bedside neurosonography (including TCD) at the stroke unit or neurointensive care unit. Apart from routine assessment of brain-supplying vessels, experienced sonographers will especially focus on intracranial blood flow velocities and determine the MCA mean blood flow velocity index (recanalized divided by contralateral artery). To assess potential dynamic blood flow changes, these investigations will be repeated at 24-48 hours after thrombectomy and at day 7 when we expect a (more) stable stroke phase. During these neurosonographic assessments, other important and potentially influential (hemodynamic) parameters such as blood pressure, heart rate and use of vasoactive medications will be documented. Assessment of intracranial blood flow will be standardized to dedicated measuring points.

The investigators will use magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) routinely performed on day 1 after thrombectomy to assess (1) the size and location of acute ischemic damage including (vasogenic) cerebral edema formation, (2) hemorrhagic transformation, (3) concomitant chronic ischemic and hemorrhagic brain changes, and (4) patency of intracranial vessels. Contrast-enhanced or arterial spin labeling perfusion MRI will be used to (5) measure cerebral perfusion status. Findings from perfusion MRI will be correlated with blood flow information from TCD. MRI including MRA and perfusion sequences will be interpreted centrally in Graz as successfully demonstrated in previous large multicenter stroke studies.

"Apart from the assessment of outcome-relevant routine blood parameters of inflammation, coagulation, glucose metabolism, renal and liver function, the investigators will also investigate novel biomarkers of interest that could be indicative of endothelial damage / blood brain barrier disruption. Candidate markers for this purpose are interleukins (i.e., interleukin-6) and matrix metalloproteinases (i.e., MMP-9). Furthermore, the investigators will also measure neurofilament light chain protein as a marker for neuro-axonal damage that has been shown to indicate cerebral tissue destruction including vascular brain lesions with a very high sensitivity.~For analysis, peripheral blood will be taken by venipuncture on day one and at follow- up three months after MT. Serum will be immediately stored at -80°C according to international consensus guidelines. Markers will be centrally analyzed in the neurological laboratory of the Department of Neurology, Medical University of Graz."