Secondary Hypertension
Fibromuscular Dysplasia

Hypertension (High Blood Pressure) is known as the silent killer because many people who have Hypertension are unaware that they have it. Untreated hypertension can cause a wide variety of problems. Hypertension is among the leading risk factors responsible for cardiovascular disease including heart attacks and is the leading cause for stroke.

In most patients with hypertension, there is no identifiable cause for the elevated blood pressure. Such high blood pressure is often referred to as 'Essential Hypertension' because it used to be thought that it was 'essential' for the blood pressure to increase as one grew older in order to perfuse the brain and other vital organs. This was due, in part, to the impression that people developed 'hardening of the arteries' (atherosclerosis) as they got older and that higher blood pressure was needed to overcome this problem. We now appreciate that hypertension is a risk factor for the development of vascular disease and stroke.

In a small percentage of patients, however, a secondary cause for hypertension can be identified. Once diagnosed, it can often be treated such that a patient requires fewer medicines to control their blood pressure. The most commonly identified causes of secondary hypertension are related to vascular disease that affects the kidney (renal) arteries. Reno-Vascular hypertension generally occurs because of two different pathologies. The more common variety is simple atherosclerosis that affects the renal arteries. This is very similar to atherosclerosis that affects the coronary arteries and other blood vessels. The atherosclerotic plaque is often composed of fat, cholesterol, degenerated cells, and calcium. Atherosclerotic renal artery disease often responds quite well to angioplasty and/or stenting.

Another, albeit uncommon, form of secondary hypertension is illustrated above. Fibromuscular dysplasia is different than atherosclerotic vascular disease. It often has the appearance of 'beads on a string' as shown above. This is due to abnormalities in the fibromuscular lining of the artery that often results in 'webs' that restrict blood flow through the artery. These webs often respond to simple balloon dilatation. Fibromuscular dysplasia can affect other vascular territories as well and is sometimes seen as a cause for carotid artery stenosis which may affect the risk of stroke.

In addition to controlling high blood pressure (particularly in patients on multiple blood pressure medications and for those with difficult to treat high blood pressure), other reasons to treat renal artery disease include preservation of kidney function, flash pulmonary edema, and to allow certain types of medical therapy in patients with heart failure.