How do plaque hemorrhage and thrombus reduce blood flow to the heart?

When a coronary artery goes into spasm, it can injure the lining of the artery, leading to cholesterol deposition and plaque buildup. Also, another mechanism known as plaque hemorrhage can result: the spasm can injure the lining of the coronary artery so badly that bleeding occurs into the wall of the vessel, causing the wall of the artery to bulge into the artery, thus obstructing blood flow through the artery.

Another important mechanism that can reduce blood flow to the heart is a thrombus, or blood clot. Small blood clots can form and lodge inside a coronary artery, thereby obstructing blood flow to the heart.