Publication Date: Friday, May 13, 2005
New device combats stroke
New device combats stroke
(May 13, 2005) MV firm provides new tool that can save patients
By Diana Reynolds Roome
Sixteen-year-old Melissa Welch had a severe stroke five months ago, but last Saturday at Shoreline Park she walked five kilometers.
"To me, Melissa is like a miracle," said her mother Alberta Birge, as she joined scores of others who walked, ran or rode in wheelchairs in support of the Peninsula Stroke Association's drive to prevent stroke.
Melissa's life was saved with less than an hour to spare by a revolutionary device called the Merci, designed by Concentric Medical in Mountain View and approved by the FDA last year.
Working at her after-school job in a store near her home, the teenager -- who loves electronic music and studying French -- felt dizzy and couldn't focus. She went to the stock room to sit down, and was discovered by a coworker 20 minutes later, unable to speak or stand up.
A stroke in someone this young is so unusual that at Kaiser Santa Teresa Medical Center in San Jose she was given a second MRI to double-check the diagnosis.
"They were very, very surprised," said Birge. "The nurses couldn't believe it."
A blood clot was blocking a major artery to the part of the brain that controls critical functions such as breathing. Melissa was flown by helicopter to UCSF Children's Hospital in San Francisco, but by this time it was 3 a.m., more than seven hours since the stroke began. Oxygen starvation due to a blood clot can cause a range of problems, from paralysis, loss of speech and memory, double vision, learning difficulties, to death, depending on which area of the brain is affected. To avoid irreversible damage to the brain, the Merci retriever must be used within eight hours of a stroke's onset.
The Merci (short for Mechanical Embolus Retrieval in Cerebral Ischemia) looks like a miniature corkscrew, and works to hook and remove blood clots lodging in blood vessels, which cause the majority (85 percent) of strokes. Doctors who perform the surgery thread the device attached to a catheter into an artery through a small incision in the groin and guide it up to the affected area in the brain. Moments after the procedure is finished, blood starts to flow again, nourishing brain cells that can die off quickly when starved of oxygen.
Soon after Melissa came round from the operation, her movements and speech returned to normal. The first thing she asked her mother was whether she still had her hair. Knowing she'd had an operation on her brain, she thought they might have shaved her head. The next day, she asked for an Internet connection so she could e-mail her friends and tell them about her experience.
"She walked to the computer room dragging her IV," said her mother. "I had to ask her to wait for me. She was working fast on the keys."
The Merci "could be the start of a whole new era in terms of treatment for stroke," said David Tong, MD, associate director of the Stanford Stroke Center. "It's very exciting because it gives us another tool in our armamentarium."
However, he added that only a very select group of doctors, mostly neurosurgeons and neuroradiologosts, are qualified to use the device.
For this reason, the Merci will be available only at major medical centers, not in community hospitals, at least for the time being. Though it is safe, and has a 53 percent success rate, the Merci's effectiveness has not yet been proven in a large-scale trial.
Until recently, the only other effective treatment for stroke was tPA, a drug that dissolves clots and must also be administered by specialist physicians. Its other major drawbacks are that it is not suitable for everyone and can only be effective within a three-hour window from the onset of stroke.
Aside from technology and drugs, another vital ingredient is needed to combat stroke, said Tong, and that is education. Everyone needs to know the symptoms of stroke, and then act quickly if they feel they might be experiencing one, or see someone else suddenly becoming dizzy and disoriented, with unusual tingling or loss of strength on one side of the body.
"I'd heard of stroke but didn't think it could happen to someone like me," said Melissa. "I thought it only happened to older people."
In Melissa's case, the cause was a small, undetected flaw in her heart that caused the blood clot that traveled to her brain. But causes, which can be wide-ranging, are sometimes never identified and stroke can happen to anybody, regardless of age. Some major risk factors are high blood pressure, smoking, diabetes and heart problems such as atrial fibrillation. Mini-strokes, or TIAs (transient ischemic attacks) which cause stroke symptoms that resolve after a short time, should also be taken seriously as they can herald a much bigger event.
"Stroke can be devastating," said Tong. "It's the number-one cause of disability in the United States and the third leading cause of death. But in many cases it is preventable with good health care, a careful diet and exercise."
Stroke symptoms are notoriously hard to recognize, ranging from unexplained weakness or dizziness to changes in vision, speech and sensation, and sometimes a severe headache. Many people in the early stages think they are exhausted, stressed or just feeling odd, so they soldier on or retire to bed hoping they'll feel better in the morning.
"If that ever happens to you," Birge advises, "do not hesitate to go to emergency and have an MRI done - that's how they detected Melissa's stroke. Take it seriously. Time is important."
For more than five years, the Peninsula Stroke Association has been getting this message out to the community, teaching about warning signs and the vital importance of getting to a hospital without delay - if possible one that is accredited to treat stroke. For those who have suffered stroke's after-effects, the PSA provides education, support and encouragement.
"Fortunately, there is hope," said Tong. "New treatments and innovations are happening right here in the Bay Area."
For more information, call (650) 565-8485 or go to www.psastroke.com. On Wednesday, May 25, a panel of stroke experts will speak at the event Victory over Stroke 2005, at Garden Court Hotel, Palo Alto, from 11 a.m. to 2 p.m. Call PSA for details. Or see the Web site, www.concentric-medical.com.
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