Excerpt from Healthy Women, Healthy Lives

by Susan E. Hankinson, R.N., Sc.D., Graham A. Colditz, M.D., JoAnn E. Manson, M.D., and Frank E. Speizer, M.D.

Chapter 4: Lowering the Risk of Coronary Heart Disease

BACKGROUND

Coronary heart disease is a leading killer of women in the United States-a fact often overshadowed by the media attention given to other diseases, such as breast cancer. While approximately 180,000 women will develop breast cancer during the course of a year, nearly a million women will develop coronary heart disease. Often perceived as a man's disease, it is clearly not. Nearly equal numbers of men and women die of coronary heart disease each year, and though men tend to develop the disease earlier than women-the average woman has the same risk as the average man ten years her junior-women tend to live longer, giving them a longer period of time in which to develop the disease.

Fig. 4-1. In a group of 100 women who are fifty years old, 20 will develop coronary heart disease before they reach the age of eighty.
(Source: Lloyd-Jones et al.)

Even though it is such a large health burden, the good news is that the risk of heart disease is largely modifiable. Only a few of the risk factors for the disease are completely out of your control, and the rest-such as smoking, high blood pressure (also called hypertension), high blood cholesterol, and diet- you can control. Taking steps to control these factors and reduce the risk of the disease may be particularly important for women. The Framingham Heart Study found that nearly two-thirds of the women in their study who had died suddenly from coronary heart disease had no previous symptoms-highlighting the need to keep the disease from developing initially.

The Heart and Coronary Heart Disease

The heart is a muscle that pumps blood throughout the body. Like all muscles, it needs a constant supply of oxygen and nutrients to work properly, which it receives through the coronary arteries. When these arteries become narrowed by a disease called atherosclerosis, the condition is called coronary heart disease (CHD).

In atherosclerosis, cholesterol and fat build up inside the artery walls. The process most likely begins when the artery wall is injured-by factors such as hypertension, high blood cholesterol, smoking, and diabetes-and the body overreacts in repairing the damage. White blood cells (cells that respond to injury in the body) enter the artery wall and bring with them, through a complex process, fat and cholesterol, which get deposited. Over time, enough fat and cholesterol can accumulate that the wall bulges inward, and the artery begins to narrow. In advanced stages, the site of the buildup (plaque) develops a hard, fibrous cap.

When the artery is significantly narrowed by the buildup, a person can experience chest pain (angina), caused by the heart muscle's not getting all the blood it needs to work properly. The condition becomes dangerous when an artery becomes completely blocked. This occurs most often when the hard cap over a buildup suddenly ruptures, and a blood clot forms that cuts off all blood flow. A portion of the heart then starves for oxygen and nutrients. If this continues for even a relatively short period of time (about 5 to 10 minutes), part of the heart muscle dies, an episode called a heart attack (myocardial infarction) (see Figure 4-2).

Fig. 4-2. The coronary arteries supply oxygen and nutrients to the heart. When they become narrowed and obstruct the blood supply, the condition is called coronary heart disease. A heart attack occurs when an artery becomes completely blocked, most often due to a blood clot forming at the narrowing, and part of the heart muscle fed by the artery dies.

In some instances, blood flow to the heart may be blocked by a spasm in a coronary artery that constricts the vessel. Spasms can occur in arteries with or without atherosclerosis and often result in chest pain. If a spasm occurs at the site of atherosclerosis, it can rupture the hard cap, which can lead to blood clots and then a heart attack.

A potentially dangerous, immediate result of coronary heart disease, particularly a heart attack, is an irregular heartbeat (arrhythmia) called ventricular fibrillation, in which the main pumping chambers of the heart (ventricles) start quivering (fibrillating) and lose their ability to pump blood throughout the body. Ventricular fibrillation is the main cause of sudden death in women with coronary heart disease.

Although heart disease most often develops in women over sixty, many studies have shown that atherosclerosis may actually begin very early in life. Children as young as ten to fourteen years of age have been found to have the earliest form of the buildup, called a fatty streak. Not all fatty streaks develop into atherosclerosis, but over time, some do.