Health
New catheter technique helps stroke treatment

By Beverly Creamer
Advertiser Staff Writer

On a double row of computer monitors suspended above the patient, Dr. Felix Song watches the progress as he manipulates a catheter thin as a paper clip into a small cut in the patient's leg and up through the arterial pathways of his body to a clot deep inside the man's brain.

Drs. Wesley Hakkei and Felix Song, at the Queen's Medical Center, look over an angiographic unit used to view a patient's arteries after a stroke. Eugene Tanner • The Honolulu Advertiser

With deliberate and delicate moves, Song guides the catheter up through the patient's body until it stops just short of the clot. Then, with a syringe connected to the catheter at its entry point, he is ready to send the clot-busting drug TPA (tissue plasminogen activator) deep inside the brain and dribble it with pinpoint accuracy onto the blockage.

"It's like putting something directly into a clogged drain," said Song, O'ahu's only interventional neuro-radiologist and a member of the stroke team at the Queen's Neuroscience Institute.

TPA — which breaks up clots — was heralded as a breakthrough in stroke therapy when it was introduced here in 1996. Now this new delivery technique is another leap forward. It gives the added precision of attacking only the damaging clot, with fewer side effects, such as unexpected bleeding in other areas of the brain.

Not everyone is a candidate for TPA therapy. Reasons not to administer the drug include: if the patient is on blood thinners or has suffered head trauma or a recent bleeding incident. "We know patients can benefit, but we have to be very careful who we use it on," said Dr. Cherylee Chang, director of the Neuroscience Institute at Queen's.

The new technique also opens the window for TPA treatment wider than was previously considered effective. In the past, TPA was only considered to be useful if it could be administered by IV within three hours of the stroke's onset. With the new intra-arterial TPA technique, treatment can be given with equally good results up to six hours after the stroke.

"You give just enough drug to open everything and then you stop," said Song. "That way you use less TPA, minimize side effects, and, within a few minutes, can confirm if it's open."

"Intra-arterial" TPA (also called intra-cranial) administered by an interventional neuro-radiologist is the latest dramatic improvement in stroke treatment since TPA was introduced five years ago.

"In a lot of ways this is better," said Song, who in the year and a half he's been in Hawai'i has treated eight patients with this delicate drip.

"And if you do intra-arterial you can do other fancy things. For instance, if there's a narrowing of the artery, you can open it up or physically remove the clot with balloon angioplasty (making the artery wider through the use of some device, usually a balloon)."

"It opens a whole new world for people," said Song. "People who are too sick for surgery or have other factors that make it too risky for surgery."

A second physician trained in this specialty will join the staff of Kuakini Medical Center later in the summer while at Maui Memorial Hospital in Wailuku, Dr. Chris Neal has performed 30 of the same delicate procedures.

Said the Maui Medical Center's medical director Jonathan Wiesul: "It makes sense to deliver the drug to the point where it will have its greatest impact." The surgery has been available at the Valley Island's largest medical facility intermittently over the last two years.

"It is a better therapy. The difficulty we have on Maui is maintaining state-of-the-art personnel and equipment. A true stroke team on 24-hour notice requires tremendous (financial) commitment on the part of the medical staff and the institution."

The catheter used by Dr. Felix Song, shown beside a coin to illustrate its small size, is a narrow tube, threaded up into the brain through arteries. Eugene Tanner • The Honolulu Advertiser

In the five years since TPA began changing the outlook for some stroke victims, Hawai'i has seen several hundred stroke patients spared crippling damage or even death. If patients reach medical care quickly, strokes caused by blood clots are no longer the inevitable and debilitating sentence they once were. "The heroes are the loved ones who notice the stroke and bring the person in," said Song.

But, too often, strokes go unnoticed or are dismissed as something else, or hidden by stroke sufferers reluctant to admit what's happening to them with the result that too few people are getting to the hospital in time to receive TPA treatment.

"We're still missing the education component," said Dr. Melvin Wong, a stroke neurologist who practices at Pali Momi Medical Center, St. Francis Medical Center and Queen's. "We need to maximize that so we get patients coming in."

Wong said that a program called Operation Stroke is spending big money for TV ads in other states to make the public aware of how quickly they need to reach a hospital. That's not happening to the same extent here.

Don Weisman, a spokesman for the American Heart Association, which heads Operation Stroke, said there's little money available for advertising and the organization must depend on public service announcements, which are donated by radio and TV stations on a limited basis, along with spreading the word at community health fairs where people are also screened free for stroke risk. Another approach is to find sponsors in the private sector willing to pay the air time for such announcements, Weisman said.

Strokes are a major killer nationally, with an estimated 600,000-750,000 people suffering a potentially crippling or life-threatening attack each year. Many more are hit by silent strokes that may never be diagnosed but leave subtle memory problems, and place the person at high risk for further brain attack.

Only some can benefit

There are essentially two types of stroke: ischemic, caused by a blood clot, and accounting for from 70-83 percent of the total; and hemorrhagic, caused by a rupture of a vessel, which then spills blood into brain tissue. Only the first can be treated with TPA.

"TPA is not meant to be a drug that's going to help everyone," said Wong. "It's only supposed to help a small portion of the patients who come in."

One patient who had the good fortune to receive TPA within an hour of her stroke is Sally Antonio, a Kaiser Permanente Medical Center nurse who suffered weakness in her right arm and on the right side of her face one March afternoon while she was at work.

"The first person in the hallway, I grabbed her and started talking, but my speech was already slurred," remembers Antonio, 53. "I knew what was happening but I couldn't say any words anymore."

By a lucky coincidence, Antonio works with Kaiser chief of neurology Dr. Stuart Pang, who had her rushed immediately to the emergency room. A CT scan found no bleeding in the brain and she was hooked up in the first hour to a TPA IV drip in her arm. Within another hour, the weakness in her arm and face began easing and she was speaking again.

"I am very lucky," said Antonio. "Everything was done right away."

Doctors are convinced TPA works. "We kept statistics initially (on TPA use) to see if it was helping patients," said Pang. "When we found it did, we didn't follow up with it. The majority who do take it have some improvement."

Drug carries risks

But the drug is not without risks. National statistics put the death rate among those treated with TPA at between 17 and 21 percent. The Queen's rate is about 19 percent.

The primary concern is that the clot-busting drug can promote internal bleeding in other areas of the brain. That can be of special concern for older stroke patients who may have suffered other small bleeds that have gone unrecognized.

Pang said while there have been bleeds with TPA at Kaiser, so far none has been the cause of death.

According to two national studies published recently in the Journal of the American Medical Association, half of the patients receiving TPA nationally suffered complications because of deviations from treatment guidelines. The drug was either given later than the three-hour window of opportunity after a stroke, or to patients who should never have had it because of other factors.

Even though TPA therapy is becoming more precise, researchers continue to look for what Chang calls a "magic pill" to protect brain tissue from damage with either kind of stroke. Queen's has participated in several clinical trials testing hopeful drugs, but nothing yet has proven effective.

"There have been at least 100 medications that have looked great in animals," said Chang, "and we still haven't found any that are effective and safe in humans. We've tried four (that were unsuccessful) and now we're trying a fifth."

This one involves a chemical agent called an AMPA antagonist meant to minimize the damage to brain tissue when oxygen is cut off.

"When we know there's a lack of oxygen in the brain, there's a domino effect in the brain tissue where little chemicals in the cells start an injury pattern which spreads inside the tissue," said Chang. "The AMPA antagonist tries to block those injury signals so it keeps the stroke smaller in size."

Another trial involves cooling patients by inserting a catheter in the bloodstream that contains tiny balloons filled with a cool saline solution. As blood flows over this stationary item, it becomes cooler, too.

"Potentially, cooling patients may help protect the brain as well. It works great in animals," said Chang, "but we'll see."

Most common warning signs of a stroke

• Sudden numbness or weakness of the face, arm or leg, especially on one side of the body.
• Sudden confusion, trouble speaking or understanding.
• Sudden trouble seeing in one or both eyes.
• Sudden trouble walking, dizziness, loss of balance or coordination.
• Sudden severe headache with no known cause.
• Any of these symptoms may be temporary, lasting anywhere from a few minutes up to 24 hours. This may be due to a mini-stroke. Either way, call 911 and get medical help immediately. Clot-busting drugs must be administered with a few hours of a stroke.
• For more information: call Operation Stroke at the American Heart Association, 538-7021, exts. 14 or 34.