The coronary arteries are also called the epicardial arteries because they run along the outer surface of the heart on the epicardium; the main ones are the left coronary artery and the right coronary artery. The left coronary artery divides into the left anterior descending and the left circumflex arteries. The right coronary artery gives rise to the posterior descending artery along the back surface of the heart.
(A) Location of the heart in the body; (B) front surface of the heart, including the coronary arteries and major blood vessels. Source: NHLBI, 2016b.
Normally, there is little overlap between the areas to which the coronary arteries and their branches provide blood. A secondary circulation does exist, but it is made of small arteries. With enough time, these collateral arteries can widen and offer some circulation to the heart muscle with a partly blocked coronary artery. However, a sudden blockage in a coronary artery will cut off most of the oxygen and nutrients to the corresponding region of heart muscle with no time for secondary circulation to compensate.
Mr. Hansen received an emergency angiogram in the hospital to which he was transferred. It showed a 99% blockage in the LAD (left anterior descending coronary artery), also known as the “widow maker.” His wife was very grateful they were able to identify the blockage before she became a young widow! Mr. Hansen received two coronary stents to open the blockage.
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The two main coronary arteries:
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