Analytic Reviews : Potential New Therapies for Acute Ischemic Stroke

Abstract

Evidence from animal models of acute stroke suggests ischemia may be reversible if blood flow is restored in the first few hours. Studies of human stroke using posi tron emission tomography demonstrate areas with re duced blood flow and relatively preserved metabolism, indicating potentially reversible ischemic brain. Resto ration of blood flow during this reversible phase should improve outcome after stroke.

Many therapeutic strategies for treatment of acute ischemic stroke have been proposed, including increas ing collateral flow, removing vascular obstructions, and interfering with the intracellular cascade of events that lead to neuronal cell death. Hypervolemic hemodilution reduces viscosity and increases cerebral blood flow, and this may hopefully raise blood flow above the critical threshold of irreversible ischemia. Naloxone, calcium channel blockers, and glutamate antagonists alter blood flow and influence intracellular events during and after acute ischemia. Thrombolytic therapy restores blood flow by lysis of obstructing clot. These therapies show promise in preliminary studies, but additional ran domized controlled studies are needed.