CORONARY ARTERY DISEASE

Coronary artery disease (CAD) is a disease of the blood vessels that supply blood to the muscles of the heart.  Atherosclerosis, i.e., the deposition of plaque on the inner wall of the vessels, is the primary cause of the CAD.  The plaques are characteristically fat and other cellular and protein deposits.  Rupture of the plaques could lead to blood clots leading to narrowing of the diameter of the vessels and reduced blood supply to the heart muscle leading to oxygen deficiency of the tissues.

Epidemiology:
The disability and fatality associated with CAD have a significant impact and is estimated to be more than about 4.5 million in the developing world.  In the western world, it is estimated that 11.5%, i.e., 24.7 million are living with CAD.  It contributes to about 1/3^rd of all deaths in individuals over age 35.  Recent research by the WHO points to a fall of 4% in the death rates due to CAD in over 21 countries.

Atherosclerosis initiates as the fatty streak or plaques which appear initially in the aorta and coronary vessels.  This appears on the inner vessel wall with deposits of fat.  The plaque may also have protein and fibrous deposits.  The plaques develop their own microscopic blood vessels known as vasa vasorum.  Several theories have been put forward to describe the reasons for development of the plaques including injury of the arterial wall and the damage caused by accumulation of free radicals due to oxidative stress.  Atherosclerosis is a chronic condition that develops over a period of time.  The plaque might rupture with formation of clots and further narrow the flow of blood in the coronary vessels.  The obstruction of the vessels due to the plaques leads to conditions of insufficiency in the heart muscles and resultant ischemic conditions and coronary artery syndromes. 

Atherosclerosis increases with age.  Men are more at risk of developing heart disease than pre-menopausal women.  Menopausal women with a history of oral contraceptives who are over the age of 35 and are smokers are at greater risk.  Studies have proven a higher risk of heart disease among those with a familial history of premature heart attacks.  

Chronic conditions such as hypertension and type II diabetes can progressively worsen CAD with changes in the heart muscles and coronary blood vessels.  Obesity is also one of the leading causes of CAD which can in turn affect hypertension and diabetes.  This may promote atherosclerosis.   Smoking emerges as an independent risk factor as seen from several studies.  Chronic kidney conditions can also affect the development of CAD.  A high level of apoprotein B also predicts development of CAD.

Narrowing of the blood vessels may lead to angina or chest pain.  This occurs when any part of the heart muscle does not get enough blood supply.  There may also be sharp neck or back pain or a feeling of pressure which is located in the centre of the chest or the breastbone.  Exertion or stress can precipitate the attack.  This may be associated with nausea, a rapid heartbeat or abnormal rhythms.  The patient may feel fatigued and weak with shortness of breath and anxiety.

Differential Diagnosis:

General Treatment:
Lifestyle changes including diet and exercise with health education to adhere to medical treatment including for chronic underlying diseases such as hypertension, type II diabetes, etc., regular exercise, weight control, and most importantly smoking cessation.

Medical Treatment:

Surgical Treatment:

Quitting smoking, maintaining a healthy lifestyle with nutritious diet and regular medication and follow-up may ensure better prognosis although some individuals may progressively worsen the condition and need surgical interventions.

Primary prevention and creating awareness in the community on the modifiable risk factors goes a long way in preventing the disease.  Early detection and treatment can improve quality of life in the long term.  Lifestyle modifications with regular exercise can control cholesterol, increase HDL and lower LDL.  Regular exercise and activities can help reduce stress.  Monitoring and treatment of underlying chronic conditions such as hypertension can help prevent development of CAD.  A weight control program with diet modifications, can go a long way in reducing the risk for CAD.