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Coronary Artery Disease- Definition, incidence, Coronary Atherosclerosis, risk factors, sign and symptoms

Coronary Artery Disease

Normal functioning of the heart is based on balance between oxygen supply and oxygen demand. To function as an effective pump, the heart muscle must be adequately supplied with blood from the coronary arteries. However narrowing or obstruction of coronary arteries can lead to coronary artery disease.

Coronary artery disease (CAD) is the most prevalent type of cardiovascular disease. For this reason, it is important to become familiar with the various types of coronary artery conditions and the methods for assessing, preventing and treating these disorders medically and surgically.

DEFINITION 

Coronary heart disease (or coronary artery disease) is a narrowing of the small blood vessels that supply blood and oxygen to the heart (coronary arteries).

Coronary artery disease leads to the interruption of blood flow to cardiac muscle when the arteries are obstructed by plaque.

INCIDENCE

  • Coronary artery disease is the most common type of cardiovascular disease and accounts for majority of deaths.
  • There has been an alarming nine fold increase in the urban and over two fold increase in CAD among rural population over the last four decades.
  • Indians have more risk of developing CAD than Japanese by 20 times than Chinese by 6 times than white Americans by four times.
  • At present 25% death among Indians are attributable to CAD. With the present trend mortality from CAD will increase by 103% in male and 90% in females from 1985 to 2015
  • By 2015 CAD will account for 34 percent all male death and 32 percent all female death in India.

CORONARY ATHEROSCLEROSIS

The most common heart disease is atherosclerosis which is an abnormal accumulation of lipid, or fatty, substances and fibrous tissue in the vessel wall. These substances create blockages or narrow the vessel in a way that reduces blood flow to the myocardium.

ETIOLOGY

Non modifiable Risk Factors

  • Family history of coronary heart disease
  • Increasing age
  • Gender (three times more in men than in premenopausal women)
  • Race (higher incidence in African Americans than in Caucasians)

Modifiable Risk Factors

  • High blood cholesterol level
  • Cigarette smoking, tobacco use
  • Hypertension
  • Diabetes mellitus
  • Lack of estrogen in women
  • Physical inactivity
  • Obesity

PATHOPHYIOLOGY

Deposition of fatty streaks & lipids in the intima of the arterial wall cause Inflammatory response. T lymphocytes and monocytes infiltrate to ingest the lipids & die. Then smooth muscle cells within the vessel proliferate and form a fibrous cap over the dead fatty core resulting in deposits called atheromasor plaques that protrude in lumen of vessel. It narrows lumen and obstruct blood flow.

If thick, resist the stress from blood flow and vessel movement. If thin, the lipid grows, rupture and hemorrhage into the plaque resulting in thrombus formation impeding blood flow.

It can result in sudden cardiac death or an acute myocardial infarction (MI)

CLINICAL MANIFESTATIONS( Sign and symptoms)

Coronary atherosclerosis produces symptoms and complications according to the location and degree of narrowing of the arterial lumen, thrombus formation, and obstruction of blood flow to the myocardium.

  • Acute onset of chest pain
  • Shortness of breath
  • Nausea
  • Unusual fatigue
  • Changes on electrocardiogram (ECG),
  • High levels of cardiac enzymes
  • Dysrhythmias
  • Sudden death

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