Placing a stent (angioplasty) in artery takes about 30 minutes.
Genetic factor MEF2A codes for a protein that makes up part of the cell’s membrane. When mutated the risk factor for coronary is over 95%.
Other genes are being found, such as apoE4, which is involved in arterial inflammation. There is a mechanism whereby to deal with arterial inflammation plaque forms in affected
areas. This mechanism is mediated by white blood cells. Vioxx and all the COX-2 inhibitors except aspirin block the part of this mechanism which switches off the
plaque formation.
Sudden death from heart attack, without significant prior symptoms, occurs in 59% of
men and 64% of women.
Coronary artery walls are about a millimeter thick and flex about 70 times a minute as
the heart pumps. It is thus tough to get a clear image of how occluded. An angiography (where a die is injected into the blood vessel, can only show how much
blood is flowing through the artery, and not the plaque embedded in the wall. Computed
tomography (CT) scanner (a 3-dimensional x-ray machine) can produce striking images, however, it is too risky, and costly
for standard screening.
Risk Factors
Factor |
Results |
|
Poor ratio of LDL to HDL |
4x |
|
Diabetes |
4x women |
2x men |
Hypertension |
2x women |
3x men |
Stress & depression* |
3x |
3x |
Healthy diet |
- 30% |
|
Abdominal obesity |
2x |
|
Lack of exercise |
+ 20% |
|
Smoking long term |
2x (1 pack) |
|
|
|
|
- Psychological factors do not directly affect the heart, but rather
have an impact on lifestyle or for some are associated with increased blood pressure.
THE CHOLESTEROL PROCESS:
1. Cholesterol in the bloodstream infiltrates the arterial wall
2. Immune system dispatches macrophages to consume the cholesterol.
The bloated macrophages become foam cells.
3. Foam cells accumulate to become a major component of the plaque.
4. To keep the arterial walls slick and smooth muscle cells form a cap.
5. Foam cells in the plaque secrete chemicals that weaken the cap.
6. When the cap cracks, plaque seeps into the bloodstream, and can form a clot which can block the flow
of blood.
7. Inflammation process is believed to soften the plaque.
Ischemic heart disease, also called myocardial ischemia, a diseased characterized by
reduced blood supply to the heart muscles through narrowing or blockage in the coronary arteries. The main cause is atherosclerosis. Plaque in the artery wall
leaks out and blocks further down stream coronary artery, which results in permanent damage to the heart muscle through reduction
in the muscle’s oxygen supply. It is the most common cause of death in
developed countries.
Treatment of a mytocardio infraction
1. cardiopulmonary resuscitation (use of a ventilator)
2. Defibrillator to stop cardiac arrhythmias
3. Pacemaker to assure regular beat
4. Stimulants such as adrenaline which both speed up and strengthen contractions.
5. Thrombolytic agents clear away blood clots
6. anticoagulants reduce risk of additional blood clots.
7. Inotropic drugs to raise blood pressure.
8. angioplasty, stents, and bypass surgery to open blocked coronary arteries.