New treatment buys time for stroke patients

The MERCI Retriever – Mechanical Embolus Removal in Cerebral Ischemia – is a device with a coiled tip that can be fed through the femoral artery in the groin to the carotid artery and into the brain to remove stroke-causing clots.

Dr. Michael Workman, a board-certified radiologist and fellowship trained interventional neuroradiologist at CoxHealth affiliate Springfield Neurological and Spine Institute, is trained to use the MERCI Retriever. He said the device has been used at Springfield Neurological only once since last November, and the procedure was successful.

MERCI treatment also includes administration of the drug tissue plasminogen activator, or t-PA. It is the only drug approved by the U.S. Food & Drug Administration for stroke patients and is used to dissolve blood clots. Used on its own, t-PA must be administered within three hours of the onset of a stroke.

While MERCI’s window of opportunity is considerably longer – six to eight hours, only an estimated 10 percent of patients might be candidates for inter-arterial therapy, Workman said.

“For various reasons – timing, the type of stroke they have … or whether it’s a small vessel stroke or a large vessel stroke,” he said.

Types of stroke

There are two primary types of stroke. The most common is ischemic, which occurs when a clot blocks the flow of blood to the brain. The other type, a hemorrhagic stroke, is caused by a broken blood vessel that spills blood into the brain.

A third type, a transient ischemic attack, or TIA, disrupts the blood flow to the brain for a short period of time and is seen as a warning sign for a full-scale stroke.

“It is still a medical emergency,” said Carol Beal, stroke coordinator at St. John’s Stroke Center.

In the 2005 update of the American Heart Association’s Heart Disease and Stroke Statistics, a study of 1,707 TIA patients showed that 10 percent developed a stroke within the next 90 days – 5 percent of those patients did so within the first two days after their TIA.

Precious time

A pre-treatment workup, including a CT scan to confirm the stroke, can take as long as 60 minutes, another reason why

it’s important for people to seek help immediately if they think they’ve had a stroke.

“We need a very clear picture before we can administer the drug,” said Judie Songer, stroke coordinator at CoxHealth. “People don’t come in soon enough … . You’re losing brain cells every second you wait.”

And, although MERCI can buy some time for stroke patients, it’s still very much of the essence.

“As far as treatment for patients that come in less than – usually six hours, the MERCI Retriever was tested at eight – between three and eight hours, they have an option for inter-arterial therapy. Whereas, if you come in under three hours, the standard is to receive (intravenous) t-PA,” Workman said.

Not every patient who suffers a stroke is able to take t-PA, either.

Conditions that may rule out the administration of t-PA include seizures, the appearance of bleeding on a CT scan and uncertainty about the time stroke symptoms began, Beal said. “Sometimes, patients wake up with symptoms,” she added.

Stroke symptoms

Stroke symptoms include numbness and tingling on one side of the body;

dimness or loss of vision; sudden, severe headaches; difficulty talking or understanding speech; difficulty in walking, dizziness or weakness.

“Something just doesn’t feel or work right. Think function: Your brain won’t let you walk across the room right,” Songer said.

There are a variety of ways patients rationalize away stroke symptoms, including “I slept on it wrong,” Beal said.

“Patients go into denial. They may think, ‘If I just take a nap, it’ll go away,’” she added.

Workman said stroke treatment becomes an art in making a judgment to treat or not to treat and in deciding which method to use.

“Every decision you make has risk. You have to play the numbers, you have to have experience in treating stroke, and you have to work as a team,” he added.

Expanded programs

The stroke teams at both St. John’s and Springfield Neurological and Spine Institute are expanding in July. St. John’s Stroke Center has hired Dr. Matthew V. Burry, an endovascular neurosurgeon from the University of Florida.

Workman said that with the addition of endovascular neurosurgeon Dr. Edwin Cunningham, from the Cleveland Clinic, Cox will be able to provide around-the-clock coverage of acute and hemorrhagic