As they float through the bloodstream, the LDL particles occasionally become stuck in the arterial wall. In response the immune system sends white blood cells to remove the lipoprotein from the wall. Once the particle has been removed, this natural inflammatory response ends and everything returns to normal.
The inflammatory response is usually successful and leaves no long-term issues. However if there are too many particles stuck in the wall, it may be insufficient to remove them all. The brain knows that there are particles still stuck in the wall, so it keeps sending white blood cells to remove them. The area then becomes permanently inflamed.
Over time the white blood cells mix with the cholesterol, and the triglycerides inside the lipoprotein, and the arterial wall. The resulting mush eventually hardens to create the arterial plaque that we’ve all been warned about. This is heart disease, also known as atherosclerosis.
The plaque narrows the artery making blockages more likely. It also makes the wall more likely to break. It is not just the narrowing of the artery that leads to heart problems. Ruptured arteries are a major cause of heart attacks and strokes.