Doctors Excited by 'Breakthrough' Heart Stent

From the WebMD Archives

Sept. 4, 2001 -- Doctors say a new, tiny metal scaffold used to reopen blocked heart arteries could be more successful in keeping them open, now that it can release drugs to prevent the cardiac curse of restenosis, or vessel reclogging.

A study of 238 patients in Europe and Latin America, presented Tuesday at a meeting of the European Society of Cardiology in Stockholm, found that the arteries closed up again in 26% of patients who got a regular stent. But there was no narrowing at all in any of the patients who got the drug-coated device.

"The study is a major breakthrough," said David Faxon, MD, president of the American Heart Association, in a prepared statement. He adds the findings could dramatically change the way doctors try to open clogged heart arteries short of full-blown bypass surgery. "Unlike the stents that were introduced in early '90s that resulted in only a modest decrease in reblockage, these drug-eluting stents have the potential to offer significant reductions in the restenosis rate."

Nearly all of the patients who got the new stent, called Cypher, had no further heart trouble in the following six months, compared with about three-quarters of the others.

"We are probably witnessing a new era in the treatment of coronary [heart] disease," said the study's lead investigator, Dr. Marie-Claude Morice, head of interventional cardiology at the Jacques Cartier Hospital Institute in Massy, France.

Among heart doctors, enthusiasm ran high.

Dr. Wim van der Giessen, professor of cardiology at Erasmus University in Rotterdam, Netherlands, who was not involved in the study, predicted the new type of stent could eventually be used in other blood vessels and for bigger blockages. Those patients are now treated with drugs or surgery.

"It's very convincing. It's a definite breakthrough," added Dr. Philip Urban, director of interventional cardiology at Latour Hospital in Geneva, who was not connected with the research either.

In his prepared statement, Faxon also noted more study will be needed to determine how helpful the new stent could be for patients who need a procedure to open narrowed heart arteries. Other experts are being more cautious.

"I'm impressed," said Dr. Karl Karsch, head of cardiology at Bristol University in England, "but I'm always suspicious when the complication rate is zero. We have seen devices before that were very promising at this stage. Everybody was excited and it turned out that after two or three years there was a certain [relapse]."

Van der Giessen added that the rarely reported problem of contaminated (or infected) stents may get worse because the drug coating hampers the immune response.

More than one third of heart disease patients get angioplasty -- about 1 million people every year worldwide. Some patients have it done several times because their arteries keep renarrowing. An additional 700,000 people worldwide have heart surgery every year.

"At the moment, many patients are still treated with medicines, unless they have a [significant artery] blockage. Now, if you have a safe device that really works -- the effectiveness of angioplasty is now over 90% -- [fewer] patients will go to surgery," Morice said.

With simple angioplasty, a balloon at the end of a long tube is threaded through an artery in the groin. The doctor shimmies the probe up through the patient's leg and right into the arteries of the heart, inflating the tiny balloon at the spot where the vessel has narrowed. The balloon cracks open the plaque and stretches the walls of the vessel. Then the balloon is deflated and removed. In about 25% or 30% of patients, the arteries close up again.

To keep the vessel open, doctors often add a stent to the end of the balloon catheter. Stents bring the rate of renarrowing down to about 15% to 25% of cases.

It happens because the blood vessel wall is injured when the stent is implanted. The area then becomes inflamed and new cells start to grow to form scar tissue. The attempt to heal the wound becomes exaggerated and the artery walls become so thick that it sometimes protrudes into the inside of the mesh scaffold. This tends to happen within six months of the stent being implanted.

Doctors then have to stretch the blood vessel again, put a new stent inside the existing one, or perform bypass surgery.

The new stent is coated with Rapamune, usually used to prevent organ rejection in kidney transplants. It stops new cells forming without impairing the proper healing of the vessel, dampens inflammation, and also has antibiotic properties.

The stent releases the drug, generically known as sirolimus or rapamycin, over 45 days.

Johnson & Johnson, which developed the stent, said it expects the device to be on the market in Europe next year and in the U.S. in 2003. The study was sponsored by the company.

This past spring, doctors have shown they can use radiation to treat restenosis around stents. In fact, doctors had been so optimistic about the procedure that they told WebMD that most cardiologists will be using radiation to treat restenosis and prevent a recurrence.

The advantage of using this new stent, if it proves successful, is that the initial renarrowing could be prevented and not even require the radiation treatment.