CLINICAL NEED

A Stroke is often referred to as a "brain attack" and occurs when a blood vessel in the brain becomes blocked or ruptures. An ischemic stroke occurs when a blood vessel in the brain becomes blocked. Ischemic strokes comprise about 87% of all strokes. A hemorrhagic stroke, which account for the remaining 13% of strokes, occurs when a blood vessel in the brain ruptures.

• Stroke is the third leading cause of death in the United States, behind heart disease and cancer and is the leading cause of severe, long-term disability. Each year roughly 700,000 Americans experience a new or recurrent stroke. Stroke is the number one cause of inpatient Medicare reimbursement for long-term adult care. Total stroke costs now exceed $63 billion per year in US healthcare dollars.

• Penumbra Inc.'s device platform is designed to revascularize or open up a blood vessel that is blocked by a blood clot. The pathological course of a blood vessel that is blocked is a gradual progression from reversible ischemia to irreversible infarction (cell death).

• The "penumbra," a rim of ischemic but still viable tissue that surrounds a central core of infarction, has consistently been demonstrated in animal models to be salvageable if blood flow can be restored within a time window of several hours. Data from human studies with surrogate measurements of cell viability tended to support this hypothesis.

• Thus, current treatment strategy for ischemic stroke is based on an urgent restoration of blood flow to the ischemic penumbra within the tolerance time window to prevent the permanent loss of brain cells, leading to improved outcome for the patient.

• Currently there is only one FDA-approved treatment for an acute ischemic stroke: intravenous (IV) delivery of Tissue Plasminogen Activator (t-PA) (Activase), which is a thrombolytic agent. The agent is designed to dissolve the blood clot that is blocking blood flow to the brain. IV t-PA is currently limited in use since it must be used within a 3 hour window from the onset of the stroke and it appears to carry an increased risk of bleeding.

• An option beyond the 3 hour window is a thromboembolectomy device. Penumbra's device has been designed taking into account many of the variables and complications that have prevented other devices from working well in this area.
  
  
• The Penumbra System has recently completed a Pivotal clinical trial evaluating the device in the revascularization of patients with acute ischemic stroke and is available for sale in the United States and Europe.