What Kind of Stroke Is It?

Abstract

The search for protein biomarkers in peripheral blood to aid in the diagnosis of stroke and the prediction of prognosis after stroke and risk of future stroke is an active area of investigation. Although some markers, such as S100b and neuron-specific enolase, have been shown to have prognostic value in ischemic stroke (1)(2), no biochemical markers have proven to be really useful in routine clinical practice. In this issue of Clinical Chemistry , Nybo and associates present similarly discouraging data for osteoprotegerin as a potential stroke biomarker (3). Why are we continuing to see lack of demonstrated clinical utility in studies for stroke biomarkers? Should the search for biomarkers for stroke be abandoned? Some answers may lie in the deceptively simple question, what is a stroke? Stroke is currently defined as a disruption of brain function due to a vascular insult, with symptoms lasting 24 h or more. This definition, now old, is in flux and in truth, our understanding of stroke has evolved tremendously with the evolution of new diagnostic technology. MRI has allowed us to show that ischemic stroke damage can occur with complete resolution of symptoms well before a 24-h time limit. Transient ischemic attack may be caused by …