Treatment of Strokes

When a clot blocks the flow of blood to the brain it is just as much of an emergency as when a clot blocks the flow of blood to the heart. The key goal is to remove or dissolve the clot so that blood flow to the brain can be restored. The Neurovascular Surgery Center offers state-of-the-art stroke treatments, including the Penumbra System clot-retrieval device, and the Merci clot retrieval system.

Pioneering New Approaches to Blood Clot Removal in the Brain

The Cedars-Sinai Department of Neurosurgery's Neurovascular Center was the first medical center in California to use the Penumbra clot retrieval device for patients who have had acute strokes.

The Penumbra clot retrieval system is an effective treatment option for people who have suffered a moderate to severe stroke due to the blockage of a blood vessel by a clot. The system can be used up to eight hours after stroke symptoms first appear, depending on the size and severity of the stroke and how accessible the clot is.

How the Penumbra Stroke System Works

The first step in treating a stroke with the Penumbra system is to find where the clot is. To do this, cerebral angiography (brain catheterization) is used. A tube (called a catheter) is passed into a large artery in the groin. Using X-ray guidance and monitors, the catheter is threaded up through the carotid artery to the brain.

A dye (called a contrast agent) is injected into the carotid arteries. Using X-rays, the neurovascular surgeon can capture images of the dye flowing through the blood vessels.

When the clot is found, the Penumbra system is sent through the catheter to the blood clot. One device, a separator, is used to dislodge the clot. A suction device then grasps the clot to remove it from the blood vessel.

Unlike other mechanical devices to remove clots from blood vessels, the Penumbra stroke system is less likely to cause damage to the walls of the vessel.

According to Michael J. Alexander, MD, Director of the Neurovascular Center and of Endovascular Neurosurgery at Cedars-Sinai, "Initial data from use of the Penumbra device indicates it may be effective in retrieving clot from blocked arteries in the brain in approximately 80% of patients within eight hours of the onset of their symptoms, giving patients a better chance at recovering from a stroke."

Dr. Alexander sat on the data safety and monitoring board for Penumbra device safety study. The device was approved by the FDA for use in December 2007.
Because the Penumbra stroke system offers an eight-hour window for treatment, it offers a greater opportunity to get effective treatment to stroke patients.

"A patient may be given a dose of IV tPA at another hospital before transfer to our stroke center for definitive care. That does not preclude the use of the Penumbra device," Dr. Alexander said. "On the other hand, if a patient comes here directly and we find in the angiography suite that there is a large clot and the patient is outside the 3 hour window for IV tPA, we would just go immediately with the clot-retrieval device."

An Alternative Approach to Stroke Treatment: Tissue Plasminogen Activator (tPA)

Not all strokes can be treated using the Penumbra system.

In these cases, dissolving the blood clot with drugs may be effective. The drug that is used most commonly is tissue plasminogen activator (tPA). The FDA has approved the use of intravenous tPA for use in acute strokes within the first three hours after symptoms appear. However, intra-arterial TPA has been shown to be useful six to eight hours after the appearance of symptoms if the stroke affects the circulation of the carotid artery.

The Merci Clot Retrieval device can also be used to treat patients with acute stroke by traveling up inside the artery under x-ray guidance. The Merci device is a thin, soft, coiled wire that acts like a corkscrew to pull out the clots lodged in the blocked brain artery. Often, unblocking the clogged artery in the brain in the first few hours after the beginning of stroke symptoms can totally reverse the effects of the stroke or significantly reduce the symptoms.