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. Half of the plaques had ruptured, half hadn’t. The scientists measured the fat content, the calcification, and the fibrous cap that holds a plaque together.

Scientists have sought to uncover what causes stress on this cap. In their study, Lee’s group relied on a computer program normally used to design cars and buildings to analyze the structural integrity of the plaques. This technique revealed that fatty plaques were roughly 25 percent less stable than calcified plaques and were therefore, more prone to rupture, Lee says. The findings reinforce other evidence indicating that cutting cholesterol is a good idea, Lee says.