Establishing Final Infarct Volume

Abstract

See related article, pages 2765–2768. Surrogate end points in acute stroke trials are manifold, albeit neither the optimum variable nor the optimum time point for assessment at present is known. They serve either as secondary end points or may serve as primary end points in phase 2a and 2b trials or proof of concept studies. Examples of frequently used surrogate end points are early neurological improvement at 24 hours (eg, in NINDS and ECASS 1), recanalization and/or reperfusion at 4 to 8 hours (eg, DEFUSE, DIAS and DEDAS) or >24 hours (eg, secondary end point in EPITHET). Trends toward benefit using clinical scales at phase II have been notoriously poor predictors of clinical outcomes in phase III trials on much larger samples.1,2 The optimum time point of reperfusion/recanalization assessment is still a matter of debate; however, imaging within 6 hours after a therapeutic intervention is considered as appropriate but also of limited practicality. Modern imaging may be useful for sample size reductions …