Heart disease and stroke often result from a narrowing of the blood vessels. This narrowing can severely reduce or even stop blood flow to important organs like the heart or brain.
Blood carries oxygen and important nutrients to cells in the body. Without oxygen, heart muscle cells or brain cells begin to die. The patient can suffer permanent disability, and even death.
![Leading causes of death in U.S.](https://learn-genetics.b-cdn.net/history/heart/images/leading-death.png)
Heart disease is the #1 cause of death in America, accounting for almost a third of all deaths in the country. Stroke is the fourth leading cause of death.