Fatty plaques are unstable in vessels

Plaques that clog arteries do the most damage when they break free. Blood clots form at the rupture site–essentially a wound–creating a potentially dangerous blockage. In the Feb. 27 Circulation, researchers report that soft, fatty plaques carry a greater risk of rupture than do hard, calcified ones.

Richard T. Lee of Harvard Medical School in Boston and his colleagues analyzed the composition of coronary artery plaques in 20 deceased people during autopsies.