Former President Bill Clinton received two stents in one of his coronary arteries Thursday at a New York City hospital, according to a prepared statement by his adviser Douglas Band. Clinton, who underwent a quadruple bypass in 2004, left New York–Presbyterian Hospital on Friday.

Coronary stents are mesh scaffolds that are threaded into arteries and then expanded, usually by inflating a balloon inside the stent, to hold a previously plaque-clogged vessel open. Stents are often employed following angioplasty, in which an unstented balloon is first inflated to widen a clogged or narrowed artery; the stent is then inserted and expanded by another balloon to keep the vessel from renarrowing. Direct stenting [above] opens the artery and implants the stent in one step.

A 2007 study in The New England Journal of Medicine cast doubt on the benefits of stents in typical heart-disease patients, but stenting remains a common medical procedure. According to The Wall Street Journal, about one million stents are implanted in the U.S. each year.

For more on stents, see "Expanding Use," from the July 2006 issue of Scientific American.

Illustration: Ken Eward/BioGrafx