Ischemia

Ischemia is an insufficient supply of blood to an organ, usually due to a blocked artery.

Myocardial ischemia is an intermediate condition in coronary artery disease during which the heart tissue is slowly or suddenly starved of oxygen and other nutrients. Eventually, the affected heart tissue will die. When blood flow is completely blocked to the heart, ischemia can lead to a heart attack. Ischemia can be silent or symptomatic. According to the American Heart Association, up to four million Americans may have silent ischemia and be at high risk of having a heart attack with no warning.

Risk factors

The risk factors for myocardial ischemia are the same as those for coronary artery disease, TIA, and stroke:

• Heredity. People whose parents have coronary artery disease are more likely to develop it. African-Americans also are at higher risk.
• Sex. Men are more likely to have heart attacks than women, and to have them at a younger age. Angina is more likely to occur in women.
• Age. Men who are 45 years of age and older and women who are 55 years of age and older are considered to be at risk. Risk also increases with age.
• Smoking. Smoking increases both the chance of developing coronary artery disease and the chance of dying from it. Secondhand smoke also may increase risk.
• High cholesterol levels. Risk of developing coronary artery disease increases as blood cholesterol levels increase. When combined with other factors, the risk is even greater.
• High blood pressure. High blood pressure makes the heart work harder, and with time, weakens it. When combined with obesity, smoking, high cholesterol levels, or diabetes, the risk of heart attack or stroke increases several times.
• High fibrinogen levels. Fibrinogens are the proteins involved in blood clotting and plaque formation.
• High homeocysteine levels. Homeocysteine also is involved in plaque formation.
• Oxidant damage, as indicated by high lipid peroxide levels. High lipid peroxide levels represent a high level of free radical damage and antioxidant deficiency.
• Lack of physical activity. Lack of exercise increases the risk of coronary artery disease.
• Diabetes mellitus. The risk of developing coronary artery disease is seriously increased for diabetics.
• Obesity. Excess weight increases the strain on the heart and increases the risk of developing coronary artery disease, even if no other risk factors are present. Obesity increases blood pressure and blood cholesterol, and can lead to diabetes.
• Stress and anger. Some scientists believe that stress and anger can contribute to the development of coronary artery disease. Stress increases the heart rate and blood pressure and can injure the lining of the arteries. Angina attacks often occur after outbursts of anger, as do many heart attacks and strokes.