Low Density Lipoprotein (LDL) is a macromolecule composed of lipids and proteins. Its main function is lipids transport. Lipids are insolubles in water, for this, their need help to be carried through bloodstream. LDL transports lipids from adipose tissue to outhers tissue, where lipids will be used. Some distubes responsables about acumulation of lipids, as in hypercholesterolemia, cause buildup of this macromolecules. The accumulation of LDL in the blood cause the formation of atheroma plaques, are responsables about partial or total obstruction of the bloodstream. The atheroma plaques are formed from infiltration of LDL into the artery wall, which results in an inflammatory process. The total obstruction cause the tissue die, wich we called infarction. When the infartion happend in the heart, we called heart attack.