Washington ? In a major advance for heart patients, the government has approved an eagerly awaited type of stent that emits a drug to help keep newly unblocked arteries from reclogging. But it has a big price tag.

Cardiologists are expected to quickly begin using the new Johnson & Johnson Cypher stent in many of the 800,000 Americans who undergo artery-clearing angioplasties every year.

The Food and Drug Administration approved sales of the drug-coated stent Thursday after studies suggested it could cut by almost 60 percent the chance of a heart attack or need for additional treatment compared with today’s stents.

“This is a significant breakthrough,” said FDA Commissioner Mark McClellan, using a term rarely uttered at the cautious agency. “This could have a substantial impact on the course of care” for many heart patients.

But with a list price of $3,195 — three times the cost of a regular stent — hospitals are worried about how to afford the device. Most stent recipients are older patients covered by the federal Medicare program. Medicare is raising its stent reimbursement, but not enough to cover all of the extra cost, especially if patients need more than one stent, as many do.

“This is a very significant advance,” said American Heart Assn. President Dr. Robert Bonow, a cardiologist at Northwestern Memorial Hospital in Chicago.

Like many cardiologists, Bonow delayed several patients’ angioplasties in recent weeks so they could get the new stent, which began shipping Thursday just hours after FDA’s approval.

Not every angioplasty candidate needs the new, more expensive stent, Bonow stressed — because the cheaper, regular kind works very well in the majority of patients.

How to determine just which patient is at high enough risk of an artery reclogging to justify the more expensive stent is tricky, Bonow said, and cardiology organizations are working on guidelines.

“The patient’s going to want the best,” he said. But “there are going to be economic issues that have to be considered.”

In one study, 1,058 angioplasty patients were given either the Cypher stent or a plain stent. Over the next year, doctors tracked how many suffered a heart attack or needed additional treatment to clear a reclog: 25 percent of the plain-stent recipients compared with just 9.9 percent of those given the drug-coated stent.