Coronary vascular disease is the most common type of heart disease, resulting in almost 500,000 deaths annually in the United States. According to the American Heart Association's "Heart Disease and Stroke Statistics 2010 Update," an estimated 785,000 Americans had a first-time heart attack in 2009, and another 470,000 who already had one or more heart attacks had another one. The association estimates that approximately every 25 seconds, an American experiences a coronary event, and that someone dies from one every minute.
Cholesterol and Lipoproteins
To carry out the job of pumping blood through the body, the heart muscle needs a continuous supply of oxygen-rich blood, which is supplied through a network of coronary arteries that wrap around the surface of the heart. If the flow of blood through the coronary arteries is interrupted, a heart attack can occur. Coronary vascular disease, also known as atherosclerosis, starts when the inner lining of a coronary artery is damaged by an accumulation of cholesterol and low-density lipoprotein (LDL). LDL can form plaque, a thick, hard, irregular accumulation in the inner lining of the artery wall. Plaques can gradually build up inside the artery, causing a narrowing that reduces the flow of oxygen-rich blood.
Role of Oxidation
Oxidation is a chemical process resulting from the production of unstable particles known as oxygen-free radicals. In excess amounts, these radicals can cause dangerous inflammation. In coronary vascular disease, free radicals accumulate in the linings of arteries, where they combine with and oxidize LDLs. According to Mohamad Navab, writing in the Journal of Lipid Research, at reasonable concentrations in the blood, LDLs can pass in and out of the inner lining of blood vessels, but in excess, they become stuck in the lining. As they accumulate, their lipid content and other proteins undergo oxidation, which is the basis for the collection of cholesterol on the inner walls of the arteries.
Inflammatory Response
Inflammation is a primary player in the development of coronary vascular disease. It occurs when white blood cells that normally defend against infection invade and become active in a tissue. Dr. Peter Libby, writing in the journal Circulation, explains that excess LDL particles accumulate in the artery wall and undergo a series of chemical changes. These modified LDLs combine with many other immune cells in the blood--including macrophages, which ingest the oxidized LDLs--producing many inflammatory factors. These fat-laden macrophages accumulate and attach themselves to the inner lining of the artery, initiating the earliest form of the atherosclerotic plaque that will eventually obstruct the flow of blood through the artery.
Symptoms and Prevention
Coronary vascular disease usually doesn't cause symptoms until it critically constricts or completely blocks the affected artery. Symptoms include chest pain; pain in the left shoulder, neck, arms or back; difficulty breathing; dizziness; rapid pulse; or extreme tiredness. Sometimes, unfortunately, the first symptom is a heart attack. Several lifestyle strategies, such as reducing the intake of cholesterol by eating healthier foods and exercising more, are very effective in slowing or reversing the development of coronary vascular disease.
Treatment
The treatment of coronary vascular disease usually starts with lifestyle changes, including a healthy diet, regular exercise, no smoking and weight loss. Medications such as ACE inhibitors, beta-blockers, anticoagulants or drugs to reduce cholesterol may be prescribed. In advanced cases of atherosclerosis, the individual may require special surgical procedures such as angioplasty or coronary bypass surgery.
References
- Circulation (journal); "Heart Disease and Stroke Statistics---2010 Update"; Donald Lloyd-Jones et al.; 2010
- Journal of Lipid Research; "The Oxidation Hypothesis of Atherogenesis: The Role of Oxidized Phospholipids and HDL; Mohamad Navab"; 2004
- Circulation (journal); "Inflammation and Atherosclerosis"; Dr. Peter Libby; 2002
