Exam 1 Review:  Chapter 18:  Coronary Artery Disease

coronary artery disease - A condition in which the coronary arteries narrow from an accumulation of plaque (atherosclerosis) which causes a decrease in blood flow to the myocardium.

atherosclerosis = arteriosclerosis - The blockage of arteries from a build-up of fatty plaques containing cholesterol and other lipids on the innermost layers of the walls of large and medium-sized arteries; common risk factors are a high fat diet, high blood cholesterol, smoking, obesity, diabetes, high blood pressure, physical inactivity and/or family history; these arterial build-ups limit blood circulation and often cause thrombus (blood clots); symptoms and signs include angina pectoris, heart attacks (cardiac arrest), and strokes; treatments range from prevention, to drug therapy, and coronary bypass surgery.  nickname:  hardening of the arteries

atherosclerotic plaque - A characteristic lesion of arteriosclerosis caused by the deposition of cholesterol and other lipids on the innermost layer of the walls of large and medium-sized arteries; changes in the character of arterial wall smooth muscle cells are also observed in the plaque.

 

Describe:

 

8. the possible cause and progression of atherosclerosis. 

Atherosclerosis is a common disorder of the arteries. Lipids including cholesterol, and other substances accumulate in the walls of arteries and form "atheromas" or plaques.  Eventually, this fatty tissue can erode the wall of the artery, diminish its elasticity (stretchiness) and interfere with blood flow. Plaques can also rupture, causing debris to migrate downstream within an artery. This is a common cause of heart attack and stroke.  Clots can also form around the plaque deposits, further interfering with blood flow and posing added danger if they break off and travel to the heart, lungs, or brain.

Many physicians now suspect that there is an immune system component to the problem (inflammation may help cause atherosclerosis).  When blood flow in the arteries to heart muscle becomes severely restricted, it leads to symptoms like chest pain.

Risk factors include smoking, diabetes, obesity, high blood cholesterol, a diet high in fats, and having a personal or family history of heart disease. Cerebrovascular disease, peripheral vascular disease, high blood pressure, and kidney disease involving dialysis are also disorders that may be associated with atherosclerosis.

Follow this atherosclerosis link for diagrams and micrographs of the progression of the disease.

9. the techniques used in the diagnosis and treatment of coronary artery disease.
 

Diagnosis of Coronary Artery Disease
The clinician may suspect atherosclerosis due to the symptoms and gentle external palpation of the arteries by hand.

More definite tests may then be suggested, including an electrocardiogram (ECG), echocardiogram radionuclide scan, and angiography.

An electrocardiogram (ECG) is an electrical recording of the heart and is used in the investigation of heart disease. Electrodes covered with conducting jelly are placed on the person’s chest. An exercise electrocardiography ("stress test") may be conducted while the person exercises on a treadmill.

The echocardiogram (ultrasound) uses sound waves to create an image of the heart's chambers and valves. It is usually performed by placing a probe with a conducting jelly on the person’s chest to transmit sound waves into the body and the images are displayed on a monitor. Severe coronary artery disease may cause abnormal heart motion that is detected by echocardiography. Ultrasound can also used to assess the characteristics of arteries in the neck or thighs.

Radionuclide angiogram and thallium scanning enable the doctors to view the blood flow through the coronary arteries and the heart chambers. A small amount of radioactive material (thallium) is injected into the bloodstream and pictures of the heart can be recorded. Scanning is usually performed in a hospital's nuclear medicine department. Each scan takes 30-60 minutes.

An angiogram by cardiac catheterization is the most accurate diagnostic method. The person is injected into the coronary arteries with a contrast dye that makes the heart visible to x-rays. A specialist then inserts a viewing instrument into a blood vessel in the leg or arm and guides it into the heart. Pictures are taken of the contrast dye flowing though the arteries and any plaque or blockages can be clearly seen. This procedure is done under sedation.

Treatment of Coronary Artery Disease
Lifestyle changes will help prevent the formation and growth of plaques including: a low-fat, low-cholesterol diet, losing weight (if overweight), regular exercise, controlling blood pressure, and not smoking.

Lipid-lowering medication including statins can be used to lower cholesterol levels by an average of 25-30% when combined with a low-fat, low-cholesterol diet. Aspirin is also known to helps prevent thrombosis.

Coronary angioplasty also called balloon angioplasty, balloon dilatation or PTCA (percutaneous transluminal coronary angioplasty) is a procedure in which a catheter with a balloon on the end is passed from a blood vessel in the thigh into the blocked artery. The balloon is inflated which applies pressure to the plaque to enlarge the blood vessel, and open the blocked artery. Coronary angioplasty is performed by a specialist in hospital. In approximately 30% of people the artery narrows again within six months. The procedure can however be repeated and a stent may be placed in the artery to help keep it open.

Coronary artery bypass surgery is a diversion around the blockage using a healthy vein or artery. This is carried out in a hospital under general anaesthesia and uses a heart-lung machine.

In an atherectomy, a specialist shaves off and removes strips of plaque from the blocked artery or a catheter with a laser tip is inserted to burn or break down the plaque. Coronary angioplasty or the insertion of a stent may be used after an atherectomy.