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The kidneys play a very important role in maintaining a healthy internal environment. Adequate blood supply is essential for the kidneys to perform their function. Each kidney receives its blood supply usually via one large artery directly from the aorta.
Narrowing or occlusion of these arteries leads to a multitude of disorders collectively known as renovascular disease. These disorders include resistant hypertension with its adverse effects on the heart and other organs and impaired kidney function which may eventually lead to complete renal failure
Hypertension due to renovascular disease is notoriously difficult to control. Often, patients require several blood pressure lowering drugs. Even with this combined therapy, blood pressure control may still be inadequate. The reason for this is that a kidney will interpret the reduced blood flow through its diseased artery as a drop in the main blood pressure. The kidney will then produce certain chemicals to raise the main blood pressure in order to get some more blood. This, however, will have little effect as the diseased renal artery will not allow more blood through. The kidney will then continue to produce these chemicals leading to a severe form of hypertension. This state of severe hypertension can have very serious effects not only on the kidneys themselves but on other organs and in particular the heart.
The lack of blood supply to a kidney can also lead to direct damage to the kidney tissues. The affected kidney gradually looses the tissues that allows it to extract and produce urine. It gradually becomes smaller and eventually becomes badly scarred and looses all of its functions. Since the body can survive with only one half of a normal kidney, a loss of one kidney may be well tolerated provided the other one is relatively healthy. However, renovascular disease tends to affect both renal arteries
Treatment of renovascular disease can be quite difficult. The options for such treatment include medical only, medical in addition to balloon angioplasty with or without stenting and surgery.
The indications for radiological or surgical intervention remain unclear. The long term results of such interventions remain uncertain. Some clinicians will advocate pre-emptive balloon angioplasty of incidentally found renal artery disease. Others will only reserve treatment for certain types of occlusion and for when medical treatment has failed.
Surgery is only contemplated when angioplasty is deemed unsuitable or when there is another indication for surgery such as the presence of an aortic aneurysm. |
