Ask a Doc: The facts on coronary artery disease Coronary artery disease is a build-up of plaque in the arteries Check out this story on azcentral.com: http://azc.cc/2hyStbu Answer: Coronary artery disease is a build-up of plaque in the arteries, which restricts the flow of oxygen-rich blood and nutrients to the heart. The build-up of plaque could rupture, resulting in a heart attack or sudden cardiac death.