New stent for old hearts

Heart attacks kill 500,000 people in the US each year, caused by fatty cholesterol lesions that narrow coronary arteries (stenosis), depriving the heart muscle of oxygen.

For years, the only available treatment was by-pass surgery, an open-chest procedure. In the 1990s, cardiologists replaced surgery with a minimally invasive intervention: with just a small hole in the leg, they managed to place a stent (a small metal tube) inside the heart’s arteries to keep them open.

The recent addition of a drug coating on stents to prevent re-narrowing (restenosis) of blood vessels boosted the market value of stents to $5.4bn in 2006.

But some coronary artery disease patients are still not cured completely. Even with the most advanced drug-eluting stents, treatment of bifurcations (where one vessel branches from another) is ineffective in 23-26 per cent of cases.

Bifurcated areas are a common location for buildup of plaque and are particularly difficult to treat with currently available stents because of the risk of blocking blood flow to the side vessel.