Diabetes 18, Macrovascular complications of diabetes
Macrovascular disease affects the large arteries. It has been suggested that atheroma formation in diabetes is triggered by glucose levels in the blood being raised over a period of time. This allows glucose to migrate into the inner lining of arterial walls. Harmful low density lipoproteins seem to adhere to tissues which contain higher than normal levels of glucose, resulting in fatty accumulations in the vessel lumens. This process is then developed by higher levels of fatty material in the blood caused by the insulin lack mechanism already discussed.
The presence of fatty deposits in turn leads to the deposition of fibrous collagen and the development of atheromatous plaques.
Whatever the precise reasons, diabetics often develop more advanced atheroma than other people of the same age and sex. The development of atherosclerosis is accelerated in diabetes. Atherosclerosis affects the coronary arteries leading to angina and myocardial infarction. Coronary heart disease is the leading cause of morbidity in people with DM, accounting for up to 70% of deaths. Atheroma in the vessels supplying the brain leads to cerebral ischaemia and possible cerebrovascular accident. In the peripheral vessels atheroma will result in peripheral vascular disease. This leads to ischaemia and possible gangrene (areas of necrosis) in more advanced cases, explaining why lower limb amputations are significantly more common in diabetics compared to non- diabetics. Renal arterial involvement contributes to chronic nephron ischaemia.
Smoking will potentiate the development of macrovascular atheroma so it is particularly important that diabetics do not smoke. Serum cholesterol should be kept at low levels using statins as required. Blood pressure should also be closely monitored and lowered as necessary.