Blocked arteries can also cause the blood to clot inside the artery. These blood clots can get knocked loose and block small arteries, which can also trigger a heart attack. If one of the arteries that carries blood to the heart itself become blocked, the muscles of the heart can die and make the heart much weaker. When an artery within the brain becomes blocked, it prevents the flow of oxygen to the brain and neurons begin to die, causing a stroke. Strokes can lead to memory loss, speech impairment, and even death.