As the degree of atherosclerosis increases two potentially life-threatening conditions are developing. First, the plaque buildup causes a narrowing of the arteries, reducing blood flow to the heart muscle tissue. As a result, some heart muscle cells are deprived of sufficient oxygen and nutrients, which may lead to permanent injury or may lead to a heart attack. At the same time, the narrowing of the arteries causes the blood pressure to rise, increasing the risk of hemorrhages (bleedings) in small arteries. If the hemorrhages occur in the brain it may lead to a stroke.