Introduction
Stroke may be defined as a syndrome of thrombohemorrhagic disorders affecting the
central nervous system. In this setting, considerable efforts have been directed to
improve clinical outcome with antithrombotic agents, including platelet inhibitors,
anticoagulants, and plasminogen activators. The search for a role for antithrombotic
agents in ischemic stroke rests on the observation that, overall, 75% to 80% of strokes
involve thrombotic events. Recent experience with plasminogen activators (PAs) in
acute ischemic stroke indicates that, in select patients, clinical improvement is
associated with shorter interval from symptom onset to treatment, while clinically
significant hemorrhagic transformation increases with delays in treatment. The time-dependence
and the subpopulation characteristics of outcomes following PA exposure is entirely
compatible with an evolution of brain injury and varies individually, but where microvascular
integrity in the ischemic bed decreases with time. These relationships have not been
developed or explored with other antithrombotic agents, including antiplatelet agents
or anticoagulants. Thus, among antithrombotic agents, only certain PAs have been used
in a strictly “acute” setting, that is within 6 to 8 hours of symptom onset. This
presentation summarizes current experience with antithrombotic interventions in focal
cerebral ischemia in the acute and early (>8) hours following symptom onset.