Cardiovascular pathology
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Cardiovascular pathology, a branch in pathology, is the study of diseases of the heart and blood vessels.
Please see Cardiology and Cardiovascular diseases.
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There are a large number of different diseases that affect blood vessels. [[Atherosclerosis]] One of the commonest is atherosclerosis. This name come from the Greek athere = porridge and scleros = hardness. Atherosclerosis is a disease of medium to large arteries and has a predilection for certain sites mainly branches and bends. Atherosclerosis is the main cause of (1) coronary heart disease, also known as ischaemic heart disease, which can cause 'heart attacks'; (2) occlusion of the carotid artery or thromboembolism into smaller branches mainly the cerebral arteries. This is a major cause of the form of stroke, called cerebral infarct. (3) abdominal aortic atherosclerotic aneurysm, where the main artery in the abdomen becomes abnormally wide with a thin wall and can burst. (4) peripheral vascular disease (PVD), which causes pain in the legs when walking, relieved by rest. Severe PVD can result in death of the affected part (usually toes first) and amputation. In the well known images of smokers in wheelchairs, the disease is atherosclerosis. There have been several theories of atherogenesis over the years. Amazingly, the famous German pioneer Virchow (1852) foresaw much recent development, forecasting that atherosclerosis was due to fats in the blood leaking into the vessel wall and accumulating. More recently, the main fats concerned have been shown to comprise low density lipoproteins, which contain cholesterol, and accumulate in the vessel wall in oxidised and related modified forms (oxLDL). These abnormal forms are highly inflammatory, activating white blood cells caled macrophages. It is thought that OxLDL 'fools' macrophages into behaving as if pathogens were present and causing (broadly put) further vessel wall damage.
Heart attacks - or coronary thrombosis - are typically due to plaque rupture. in this process, the atherosclerotic lesion (abnormal area of artery) has a thin fibrous lining that is more mechanically weak, has increased macrophage cells, and has reduced vascular smooth muscle cells (which normally make collagen). In plaque rupture the plaque inflammation erodes the fibrous lining (fibrous cap) to the point where it breaks apart (possibly under added haemodynamic stresses), releasing clot-promoting material in the middle of the lesion into contact with blood. this stimulates clotting that blocks off the artery. Unless reopened (see reperfusion) by drugs or percutaneous coronary intervention (a surgical procedure carried out by cardiologist heart doctors) the blocked artery causes teh heart muscle to die of lack of nutrients and oxygen. This is termed a myocardial infarction.
