It's flexible as rope, coated with a cell growth-retarding drug, and bears a sports car-like name.

Called the Zilver PTX, the new high-tech stent to treat artery blockages comes from the labs of Cook Medical -- and it could be a game-changer for the Bloomington medical device maker.

The Bloomington medical device maker is known for filling niches in its industry (more than 90 percent of its products have sales under $1 million).

But the Zilver PTX holds the potential to be a medical-category dominator and one of Cook's best-selling products ever. And that's saying a lot for a company that turned founder Bill Cook into a billionaire and made his widow, Gayle, the richest woman in Indiana, with a net worth of $3.7 billion.

In tests, the stent has out-performed rivals in a difficult medical task: treating blockages that occur in many people in the long and twisting femoral arteries that run through the thigh.

Given that sort of medical promise, hundreds of U.S. patients and their doctors were anxious for the Food and Drug Administration to approve the Zilver PTX. The agency finally gave the go-ahead last month, after more than a year of deliberation. Cook will start shipping the stent soon, and it should be widely available in a month or two.

"It really is a big deal . It changes the treatment paradigm for vascular disease. I've got at least 80 patients waiting for this," said Dr. Gary Ansel, director of the Center for Critical Limb Care at Riverside Methodist Hospital in Columbus, Ohio.

Stents are nothing new, of course. They've been around for years, used mostly in the arteries of the heart. There, the tiny, spring-like devices are used to prop open clogged arteries, restoring critical blood flow.

Cook's Zilver PTX stands out because it's the first drug-coated stent approved for the femoral arteries. The drug coating is key. It addresses the common problem of growth of scar tissue in the artery after it's been cleared of the problem blockage.

With a bare-metal stent, tissue buildup happens within a year at least 40 percent of the time. With the Zilver PTX, the failure rate falls to 15 percent.

That's the changing treatment paradigm that Ansel refers to. It means far fewer revisits to the doctor to clear out the unwanted growth of tissue, and big savings for patients and their health plans.

Patients "don't come back any more" for retreatment after getting the coated stent implanted, said Rob Lyles, vice president and global leader of Cook's peripheral intervention division.

The arrival of the Zilver PTX "represents a new strategy" for surgeons who treat peripheral arterial disease, said Dr. Michael Dake, professor in the Department of Cardiothoracic Surgery at Stanford University School of Medicine in California.

"Most people do believe this will completely replace . . . bare stents," said Dake, who like Ansel worked on studies of the stent for Cook. "With drug-eluting stents clearly . . . we can do better than bare stents alone."

Dake said he has "a couple of dozen" patients with leg blockages who could use the new stent. "People . . . have been sort of waiting for this. The first wave (of patients) will be a particularly needy population."

For Cook, the Zilver PTX represents a reward that's been a long time coming.

The company under founder Bill Cook was a pioneer in stent development but ceded heart stents to the bigger players in its industry. Instead, Cook focused on stents for organs and peripheral arteries. And it signed a fortuitous deal in 1997 with Canadian company Angiotech Pharmaceuticals to get proprietary rights to its technology to use a chemo drug called paclitaxel as a stent coating.

Two bigger Cook rivals -- Cordis and Boston Scientific -- tried and failed in the early 2000s to get peripheral-artery stents with a polymer-based coating to market, said Lyles. That didn't discourage Cook's scientists, who had a hunch that paclitaxel was the way to go.

"People really thought we were crazy" for forging ahead with coated peripheral stents, Lyles said. "They thought it was something that wouldn't work. What we knew . . . was, if you take the polymer out of the equation, you get a much better result."

Dake, of Stanford, praised Cook for sticking with it. "Cook's been committed to this for the long haul. When others have fallen off . . . Cook has been able to power through."

Which may explain why Cook now faces no competition for coated peripheral stents, giving it free rein to mop up business in a $600 million global market (about 60 percent of that in the U.S.).

"We kind of have the playing field to ourselves right now," said Lyles. "We probably have a four- to five-year window" before a competitor pops up.

The one disappointment for Cook is the slow FDA approval. The United States becomes the last major developed nation besides Canada to approve the Zilver PTX. The first approval came in Singapore and Hong Kong five years ago, followed by European approval in mid-2009. Even Japan, known for being a laggard in approving medical devices, gave its OK before the U.S. did.

In recent years, some American patients became so impatient with the lack of U.S. approval that they flew to Europe to get access to the stent, said Ansel, the Columbus physician.

"It was absolutely frustrating for everybody involved," Lyles said of the lengthy U.S. approval process.

Cook won unanimous support in October 2011 from the expert panel of doctors that the FDA assigned to review the Zilver PTX. But it still took another 13 months for final FDA approval.

Cook Chairman Steve Ferguson, who's been outspokenly critical of a new 2.3 percent federal tax on medical device company sales that was part of the federal health-care law pushed by President Barack Obama, said he won't blame the slow approval process on any political retribution by federal politicians.

"I don't have any (evidence of that), and I haven't looked for it. I always assume our government is fair and does not prejudice because of opinion," Ferguson said.

Cook's chief regulatory science officer, Ted Heise, said he thinks FDA action on the Zilver PTX took longer than most medical device approvals because the new stent combined a drug and a medical device and was a first-of-its-kind product.

FDA spokeswoman Michelle Bolek said approval ran longer because of "nonclinical concerns" the FDA had. Cook officials said those concerns included questions about the manufacturing process for the stent.

"Because of these issues, a portion of the time between the panel meeting and approval of the device was spent waiting for (Cook) to provide the required information," the FDA spokeswoman said.

Final manufacturing of the stent is at Cook's Limerick, Ireland, plant. The 650-employee plant has grown into a center of the company's stent development efforts, and now stands as the main production site for a product that could do much to shape Cook's future.