Understanding vulnerable plaque opens new strategies for finding people who are at risk of heart attacks so treatments can be targeted to prevent them. Already this quiet breakthrough is helping to answer several conundrums of heart disease. One reason the significance of small but vulnerable plaque has been slow to dawn is that cardiologists have not worried much about the things they cannot see. And what they see is limited largely to the power of the angiogram. For this test, done 1.1 million times a year in the United States, doctors inject opaque dye into the heart arteries, then aim an X-ray camera.
Doctors look for spots where thick rims of plaque slow blood flow to a trickle.
In these places, the heart gets too little oxygen, and even modest exertion can cause chest pain. However, tending to these blockages does nothing much to prevent heart attacks. Trying to understand plaque by looking at an angiogram is like trying to understand a doughnut by looking at the hole,'' says Dr. Peter Libby of Brigham and Women's Hospital in Boston. And they are discovering that plaque, like most things in the body, is a very complicated structure. The rusty pipe analogy hardly begins to describe it.