Coronary Disease

Coronary disease (CD) is defined as a reduction in blood flow to the heart muscle, usually caused by a narrowing or hardening of its supplying arteries, the coronary arteries. CD has also been called coronary artery disease, coronary heart disease, atherosclerotic coronary artery disease, and ischemic heart disease. It imposes an extensive global health burden, with implications for public health and patient care.

CD is the primary cause of heart attack, which is the leading cause of death in Western society. In the Western world, lower incidence has been reported in Mediterranean countries, such as Spain. CD is also [Page 451]prevalent in the developing world, as over 60 percent of the world's share of CD is found in those countries.

In the United States, approximately 13 million live with CD. In 2003, the Centers for Disease Control and Prevention (CDC) reported that CD was present in 6.6 percent of nondiabetic Americans, and 24.5 percent of diabetics. CD is also the leading cause of premature, permanent disability in the U.S. labor force, accounting for 19 percent of disability allowances by the Social Security Administration.

Every year, up to 1.5 million Americans have new or recurrent myocardial infarction, with approximately one-third mortality. Lifetime risk for developing CD in the general U.S. population is also noteworthy: 48.6 percent for men and 31.7 percent for women at age 40; 34.9 percent for men and 24.2 percent for women at age 70. Those with CD are exposed to a significantly greater risk of heart attack, stroke, and other serious complications.

In one recent study of 14,062 Americans aged 45–64, the incidence of CD over 7-to-10-year fol-low-up was 5.1/1,000 person-years in black women, 4.0/1,000 in white women, 10.6/1,000 in black men, and 12.5/1,000 in white men.

The normal function of the coronary arteries is to supply the heart muscle with oxygen-rich blood. In CD, the coronary arteries are thickened and occluded by cholesterol plaques, a process known as atherosclerosis. This process is attributed to dietary fat and cholesterol intake, genetic factors, the internal chemical milieu and various patient risk factors, such as smoking status.

In myocardial infarction, or heart attack, a cholesterol plaque becomes unstable and ruptures. A blood clot forms and expands, cutting off blood supply to surrounding heart tissues, causing ultimate heart muscle death. As the clot grows, blood supply may be compromised and the area of heart muscle death may spread. This can lead to life-threatening arrhythmias, sudden cardiac death, and congestive heart failure, a reduced pumping function of the heart.