The ischemic (ischaemic) cascade is a series of biochemical reactions that are initiated in the brain and other aerobic tissues after seconds to minutes of ischemia (inadequate blood supply). This is typically secondary to stroke, injury, or cardiac arrest due to heart attack. Most ischemic neurons that die do so due to the activation of chemicals produced during and after ischemia. The ischemic cascade usually goes on for two to three hours but can last for days, even after normal blood flow returns.

Mechanism

A cascade is a series of events in which one event triggers the next, in a linear fashion. Thus "ischemic cascade" is actually a misnomer, since the events are not always linear: in some cases they are circular, and sometimes one event can cause or be caused by multiple events. In addition, cells receiving different amounts of blood may go through different chemical processes. Despite these facts, the ischemic cascade can be generally characterized as follows:

Mitigation of effects

The fact that the ischemic cascade involves a number of steps has led doctors to suspect that cerebroprotectants could be produced to interrupt the cascade at a single one of the steps, blocking the downstream effects. Over 150 cerebroprotectants have been tested in clinical trials, leading to the approval of tissue plasminogen activator (also known as tPA, t-PA, rtPA, Activase, or Alteplase or Actilyse) in the US and other countries, and edaravone (Radicut) in Japan.