Atherosclerosis

One of the foremost leaders of mortality in the US is coronary artery disease (CAD). Atherosclerosis is an abnormal thickening and hardening of the arterial walls caused by fat and fibrin deposits. It is a form of arteriosclerosis, which is the actual thickening, hardening, and loss of elasticity of arterial walls. It affects primarily the coronary arteries (arteries that carry blood to the heart, arranged in a crown-like shape around the heart), the aorta, the arteries of the lower extremities, and the arteries that provide blood to the brain. It is a disease that can affect a person at any age, although it usually does not pose a threat until people reach their forties or fifties. This disease strikes many older men and women, as a result from the infamous factors of high cholesterol, high blood pressure, and diabetes mellitus, not to mention others. Thanks to research over the last decade, there is more understanding of the role endothelium plays in the coronary system. Instead of having non-active, diffusion barrier-like qualities, as was once thought, the endothelium serves many critically important functions. At the blood vessel walls, the endothelium synthesizes and releases active substances such as nitric oxide and bradykinin, two potent regulators of vessel function. It is found that the physiologic changes in the endothelium affect the mechanisms responsible for atherosclerosis, and progressively in coronary artery disease.

There are a few risk factors for developing Atherosclerosis. They include; having high cholesterol, aging, having a family history, high blood pressure, diabetes, smoking,

stress, obesity, sedentary life style, and gender. The risk factors are divided into two categories, those that can be modified, and those that cannot. Risk factors that cannot be modified include age, history, and gender. Males are more at risk for developing atherosclerosis than women, and women usually develop it after menopause. Usually, the patient with atherosclerosis is directed to reduce the risk factors that can be modified.

Coronary artery disease is usually asymptomatic until the tissues blood supply is reduced by at least 60%. In CAD the left anterior descending artery is most often affected. Pain is the most frequent symptom, it originates in the chest, and this is called angina pectoris. When too little blood flows to the heart, angina results. It occurs more frequently during exercise and activity. It is caused by spasms of the coronary arteries, thrombus, or occlusion of the lumen. The pain may radiate to the arm, the shoulder, the jaw, the neck or even the epigastrium. Two less common types of angina are unstable angina and Prinzmetal’s angina. Unstable angina indicates acute coronary in sufficiency. It may occur at rest or with minimal exertion and is often relieved by nitroglycerin. Patients with unstable angina are at increased risk for AMI and sudden cardiac death. Prinzmetal’s angina occurs at rest and may occur without evidence or atherosclerosis. Some other symptoms that may come along with it are diaphoresis, dyspnea, nausea and vomiting. Heart attack and thrombosis are also signs of CAD. LDL deposits occur early when cholesterol accumulates within the arterial wall. Lesions usually develop in the tunica intima and have three different types. The three different types of the lesions are fatty streaks, fibrous plaque, and advanced lesions. The fatty streak is the earliest lesion to develop. Lipids, yellow in color, fill smooth muscle cells, which produces streaks of fat that cause no obstruction to the affected vessel. Fibrous plaque is the common lesion of advanced atherosclerosis. The lipid-laden smooth muscle cells become in closed by c collagen, elastic fibers, and a mucoprotein matrix. The raised lesions, go into the lumen, and fixes itself into the inner walls of the tunica intima. If it enlarges it may occlude the lumen. Advanced lesions develop due to hemorrhage, calcification, cellular necrosis, and thrombi of the intima. The fibrous plaques are altered and help with losing the elasticity of the vessels. Some effects of arteriosclerosis are hypertension, impaired tissue perfusion, and aneurysms.

There are a number of tests that doctors use in diagnosing cardiovascular diseases, including blood tests, electrocardiograms (ECG), stress testing, coronary angiography, ultrasound, and computed tomography (CT). An electrocardiogram is when electrodes are placed on the skin to detect electrical activity of the heart. It detects abnormalities in conduction of impulses. Stress testing is a noninvasive method of assessing the presence and severity of CAD by recording a person’s cardiovascular response to exercise. A negative result doesn’t ban out that the patient does not have CAD, but is the best noninvasive screening procedure used. A coronary angiography, or better known as a cardiac catheterization, is a procedure