Coronary Artery Disease is the narrowing of the specific blood vessels – the coronary arteries – that supply oxygen and other nutrients to the heart muscle. You’ll find that some people refer to this as ‘coronary heart disease’. But this term actually – and a bit confusingly – refers to more than just blockage of the coronary arteries. It also includes blockages to the arteries in the neck which increase the risk of stroke.
Either way, the same problem causes both which means someone with coronary artery disease also has an increased risk of stroke. The underlying problem is atherosclerosis - stiffening and thickening of the artery lining over many years with the build-up of what’s called plaque.
The build up of plaque is a complex process that can all start in childhood where LDL or ‘bad’ cholesterol is ‘dumped’ into the artery lining, the body’s defences – the immune system – reacts to this and the lining becomes inflamed and swollen (see ‘How atherosclerosis develops’) .
Post mortems of adolescents who’ve died of other causes often show quite marked atherosclerosis and unless our lifestyles are changed, coronary artery disease steadily and often silently progresses through our life, which is why heart disease is such a major killer.
Heart attacks occur when plaques rupture and blood clots form and break off, blocking the coronary artery. Angina is when the plaque builds up more steadily causing a narrowing which starves the heart muscle of oxygen when you exert yourself. Strokes are caused when plaque in the neck (carotid) arteries rupture and clots break off and land in and blocked brain arteries.
Arteries are blood vessels which carry blood, which has picked up oxygen in the lungs, away from the heart. Blood in arteries moves faster than veins (which return blood to the heart and lungs) and is under more pressure and therefore more prone to damage. Understanding how atherosclerosis occurs helps you understand why changing your lifestyle helps to prevent heart disease.
The bad guy is LDL (low density lipoprotein) cholesterol which is raised when you eat saturated fats (the fat in meat and unmodified dairy products like butter and milk). LDL is balanced by the good guy, HDL (high density lipoprotein) cholesterol, which can remove free cholesterol from the arteries. HDL is lowered by smoking and raised (a good thing) by exercise, weight loss and modest amounts of alcohol.
While a bad diet raises LDL, it also does something else that’s not good for your arteries. It increases a highly toxic form of oxygen called free radicals. These free radicals react with LDL oxidising it – like rusting in fact. When this oxidised LDL in the blood comes in contact with the artery lining, it damages it, causing an immune response in which white blood cells attack the offending LDL molecules which are now inside the artery wall.
If there’s too little HDL around to mop things up, all this becomes ‘trapped’ in the artery walls, which in turn captures more oxidised cholesterol. This heightens the original immune response, which is then repeated. The build-up is called plaque. Eventually the immune reaction causes scarring - “fibrotic” changes - which harden the artery wall.
The swelling first bulges outward – that is, away from the central tube of the artery, or ‘lumen’. But eventually it squeezes inward, narrowing the lumen and restricting the flow of oxygenated blood through the artery.
Atherosclerosis can affect any artery in the body, causing different diseases depending on where those arteries are.
Specifically, its ill effects include:
In its early and middle stages, coronary artery disease has few symptoms, if any at all. In its later stages, the most common symptom of coronary artery disease is angina. Angina is often referred to as chest pain but it is actually a group of symptoms. it’s also described by patients as chest discomfort, heaviness, tightness pressure, aching, burning, numbness, fullness or squeezing. Although these symptoms are most often felt in the chest, they can also be felt in the back, shoulders and arms, sometimes radiating into the neck or jaw.
In summary, the most common symptom of coronary artery disease is angina, described as:
Less common symptoms can include:
Last published: 31 October 2011
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