The coronary arteries supply blood to the heart muscle itself. Damage to or blockage of a coronary artery can result in injury to the heart. Normally, blood flows through a coronary artery unimpeded. However, a process called atherosclerosis can cause a buildup of cholesterol and cells and other substances in the wall of the artery forming a plaque. If this process restricts blood flow enough it may result in a lack of oxygen to the heart muscle and cause angina. If the inner wall of a coronary artery becomes damaged, the inner contents of plaque can be exposed to the bloodstream and the body can bring substances such as platelets to the injured site and cause a further narrowing or complete blockage.
If blood flow is reduced severely or completely, death of part of the heart muscle that the artery supplies can occur. This is called a heart attack.
Update Date 1/9/2015
Updated by: Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.