Pulverizing plaque

"Hold still, sweetie!" Dr. Daniel Dulas cheerfully commanded.

Flat on her back and sedated in the cardiac catheter lab at Mercy Hospital in Coon Rapids, Jerene Olson, 60, mumbled and stared blankly at the ceiling. Her left leg jerked involuntarily.

Cloaked head-to-toe in surgical blues, Dulas held a spaghetti-thin wire between his fingers and delicately snaked it into Olson's femoral artery near her groin. He peered at a computer screen image overhead to gauge its progress.

The guide wire was inched ever so deliberately through the artery in Olson's left leg until it met its expected foe: a pocket of calcified plaque the consistency of uncooked pasta. Dulas pumped a foot pedal, causing the wire to rotate erratically like a jump rope in furious motion.

The device is part of a clinical trial financed by New Brighton-based Cardiovascular Systems Inc. (CSI). The wire's diamond-encrusted crown sanded and pulverized the plaque, clearing the artery and restoring blood flow to Olson's leg and foot.

Bzzzzzzz.

Twenty seconds. Twenty-three. Twenty-nine. Thirty.

"Almost home, honey!" Dulas called.

Unbearable pain

Olson, of St. Francis, was found to have peripheral arterial disease last year after her lunchtime walks became unbearably painful. "My legs would cramp up so bad I could hardly walk," she said. "Sometimes I could get a block, sometimes two blocks, and then it was like, 'How am I going to get back?' "

The disease, caused by blockages in the arteries that supply the legs with blood, affects eight to 12 million people in the United States, according to the American Heart Association. Smokers, diabetics and those with high blood pressure and cholesterol are most at risk.

Their most common symptom: A crampy kind of leg pain called claudication.

"In the main artery in her thigh, which feeds all the arteries below her knee, she has at least three severe blockages," explained Brian Wise, an imaging technologist who assisted Dulas in last November's procedure. "So it's the same thing as a heart attack in the leg."

While the concept of a heart attack is easy for most patients to understand, peripheral arterial disease is not exactly a well-thumbed page in most Merck Manuals. As a result, the disease often goes undiagnosed. Or misdiagnosed as "muscle pain" or "arthritis."

Most patients suffering from the disease see their worlds gradually grow smaller and smaller as their capacity to exercise declines and perhaps disappears.

"Maybe they can't golf the back nine anymore, maybe they can't make it out to the mailbox anymore, but they really don't think to tell their doctor about the pain," said Paul Tyska, CSI's vice president of business development.

And even if a patient is vocal about the pain, there's no guarantee peripheral arterial disease will be diagnosed.

John Borrell, CSI's vice president of sales and marketing, said he recently visited his family doctor for a lingering cold. The two chatted and Borrell asked the doctor how many claudication cases he'd seen in his career.

None, the doctor replied.

Scooping plaque

For now, CSI is betting much of its future on treatment of peripheral arterial disease below the knee. The device used to treat Olson is the main product for the five-year-old company, which received $25 million in private funding last summer to help in part finance its clinical trail.

CSI officials hope their device will gain Food and Drug Administration (FDA) approval by the end of the year, but there are no guarantees the agency will adhere to the company's timeline, or even approve the device.

Besides regulators, one of the company's main challenges is educating physicians, particularly family doctors, about the disease.

Because Olson had heart surgery five years ago, her leg pain was diagnosed relatively easily during a routine stress test. "The technicians had to help me off the treadmill when I was done, I had such horrible cramps in my legs," she said.

Her right leg was 95 percent blocked, the left leg less so.

As a single mother of three and a grandmother, Olson wants to stay active. And her job in shipping and receiving at St. Francis-based manufacturer Temperature Specialists Inc. requires a fair amount of bending, lifting, squatting and walking about the factory floor.

Ironically, many doctors prescribe exercise once determining a patient has the disease -- plus drugs to thin the blood, lower cholesterol and mitigate pain. Beyond that, some will have leg bypass surgery -- not unlike heart bypass surgery where a surgeon creates a new pathway for blood flow using a natural or man-made graft.

But many doctors prefer to use minimally invasive methods to treat the disease, and typically use a variety of procedures and devices from different companies to treat leg blockages.

Often this involves entering the leg arteries through the femoral artery with a guidewire armed with either a balloon or a stent. Stents are tiny mesh struts used to prop open clogged arteries, and typically they are used to treat patients with blocked heart arteries. But a type of stent used to prop open the bile duct in patients with blockages related to pancreatic cancer recently attracted the FDA's attention because a large number of them are used "off-label" in the legs. This type of stenting is not approved by the FDA, but is relatively common.

In addition, doctors snake angioplasty-like balloons into leg arteries where they are inflated (and ultimately removed) to expand the artery.

There also are several devices that shave or clean plaque and calcium from leg arteries. In Olson's procedure, the clogged arteries in her upper thigh were treated with devices approved by the FDA made by Fox Hollow Technologies Inc., of Redwood City, Calif., and Plymouth-based EV3 Inc.

The plaque that broke loose from Olson's upper leg using those devices was scooped out by a small, cheesecloth-like filter, which Wise dumped onto surgical cloth for examination. The plaque's consistency varied between hard pieces that looked like clipped toenails, while other material that was flushed out had the gooey sway of a popped pimple.

Safe and effective?

Because smaller arteries in Olson's calf also were blocked, Dulas asked her to participate in a 124-patient nationwide clinical trial using the CSI Orbital Atherectomy device, which pulverizes the plaque and which he thinks will work better.

Powered by air pressure, the Roto-Rooter-like device moves back and forth to shave the plaque from the artery wall, like a razor shaves a whiskery chin, presumably leaving smooth skin intact. Because the plaque is destroyed and later absorbed by the body, there's no need to scoop it out.

The trial will determine whether the device, which consists of a flexible guidewire and a console that serves as a power source, is safe and effective. CSI's Borrell says preliminary results look promising.

Olson professed that she was a little nervous about being part of a clinical trial using an experimental device. "But Dr. Dulas said they've been having really good success," she said.

Following the three-hour procedure, Dulas, an interventional cardiologist with Metropolitan Cardiology Consultants, held up an X-ray image of Olson's new and improved arteries. "Beautiful," he said. "Very smooth. Very wide open."

Walks during lunch

On a recent warm day four months after surgery, Olson slipped on her tennis shoes and took to the side streets of St. Francis on her lunch break -- a trek she hopes to take every day once the weather finally warms. After huffing it for 15 minutes, she stopped and declared that her ankle and calf ached. "Hopefully it's because things are so weak and the restrengthening has to still come," she said.

"It's not horrible," she added. "Before, I couldn't have made it out here."

Janet Moore • 612-673-7752 • jmmoore@startribune.com