Which targets are relevant for therapy of acute ischemic stroke?

Background-The efficiency of various strategies of neuroprotection is well documented in animal experiments but is thus far disappointing in ischemic stroke, for which only early reperfusion induced by thrombolysis has improv ed clinical outcome. This discrepancy between expectation from experimental research and clinical reality may be related to differences in the pathoge netic factors contributing to infarction. Summary of Comment-Positron emission tomography cerebral blood now studies within 3 hours of onset were used to identify the various compartments of t he infarct outlined on MRI 2 to 3 weeks after a hemispheric stroke in 10 pa tients. Critical hypoperfusion below the viability threshold accounted for the largest proportion (mean, 70%) of the final infarct, whereas penumbral tissue (18%) and initially sufficiently perfused tissue (12%) were responsi ble for considerably smaller portions of the final infarct. Conclusions-These results indicate that early critical now disturbance lead ing to rapid cell damage is the predominant cause of infarction, while seco ndary and delayed pathobiochemical processes in borderline or initially suf ficiently perfused regions contribute only little to the final infarct. The refore, emerging therapeutic strategies should be targeted to the initially critically perfused tissue subcompartments. Clinical drug trials might ben efit from stratification of patients for target tissue compartments applyin g functional imaging.