Sunday, November 4, 2007

AHA - 2007: MASS Stent

Study looks at differences in drug-eluting vs. bare metal stents

American Heart Association Scientific Sessions Late-Breaking News:

ORLANDO, Nov. 4 – Drug-eluting stents to open blocked coronary arteries caused no more risks for death or heart attack than bare metal stents, according to a late-breaking outcomes trial presented at the American Heart Association’s Scientific Sessions 2007.

The Massachusetts stent (MASS Stent) trial compared death rates between patients who received drug-eluting stents (stents coated with a drug to reduce restenosis or re-narrowing of the artery) and those who received bare metal stents (stents not coated with a drug). They reviewed records of all adults undergoing percutaneous coronary intervention (PCI) with stenting between April 1, 2003 and December 31, 2004 at all acute care non-U.S. governmental hospitals in Massachusetts. Using this criterion, they identified 20,654 patients from a state database with mandatory follow-up after PCI.

“This is the largest study of patients comparing drug-eluting stents and bare metal stents for long-term outcomes in the U.S.,” said Laura Mauri, M.D., principal investigator of the trial and assistant professor of medicine at Harvard Medical School and Brigham and Women’s Hospital in Boston, Mass.

PCI, also called angioplasty, is done in patients who have blocked or narrowed heart arteries. During the procedure, a thin tube called a catheter is inserted into a blood vessel in the groin or leg, and then threaded through to the blocked coronary artery. A small balloon at the tip of the wire is then inflated to push back the blockage and allow more blood flow to the heart. Often, a tiny wire mesh tube called a stent is put in place to hold the vessel open and prevent restenosis (reclosing of the artery). However, stent thrombosis (blood clots forming inside the stent) is possible. Patients are prescribed anti-clotting drugs after the procedure to lessen the chance of stent thrombosis.

“It was previously established that drug-eluting stents make it less likely that patients will need repeat procedures within the first year after a stent procedure,” Mauri said. “What we were less certain about before this study was the long-term safety of drug-eluting stents compared to bare metal.”

Mauri adds that this trial has several benefits for addressing this issue. “It is a very large study with long-term follow up, it reflects contemporary U.S. practice – where most patients receive drug-eluting stents – and it includes all patients who were undergoing PCI – not just those who would have qualified for a randomized trial.”

Patients were followed up for at least two years after receiving a stent. Researchers compared the number of deaths, heart attacks, and revascularization procedures (either bypass surgery or another PCI) between the two groups. The adjusted incidence of mortality at two years was 9.4 percent for those with drug-eluting stents and 11.9 percent for those with bare metal stents.

Statements and conclusions of study authors that are presented at American Heart Association scientific meetings are solely those of the study authors and do not necessarily reflect association policy or position. The American Heart Association makes no representation or warranty as to their accuracy or reliability.

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