|Renovascular hypertension is a rise in blood pressure that results from narrowing (stenosis) of the main artery (renal artery) or its branches supplying a kidney. The arterial stenosis may affect one or both kidneys (unilateral or bilateral disease). Stenosis reduces blood flow to the kidney, which in turn decreases the amount of oxygen within kidney tissue (renal ischemia).|
The decreased blood supply and decreased oxygen levels stimulate the kidney to release the hormone renin. Renin is one of several hormones that can cause peripheral blood vessels to constrict (vasoconstriction). This vasoconstriction leads to high blood pressure (hypertension).
In approximately 70% of cases, the stenosis and subsequent decreased blood flow are caused by the build-up of fatty deposits or plaque along vessel walls (atherosclerotic disease). The remaining 30% of cases are caused by fibromuscular disease of the renal artery wall.
Individuals at high-risk for renovascular hypertension include those with high amounts of cholesterol in the blood (hyperlipidemia), severe high blood pressure, atherosclerotic disease of other blood vessels, particularly of the vessels in the legs, a family history of the disease, and diabetes. Other findings that suggest renovascular hypertension include hypertension with sudden onset and shorter length of time the blood pressure is elevated, difficult to control hypertension, more episodes of extremely elevated blood pressure (malignant hypertension), and hypertension associated with fluid in the lungs (pulmonary edema) or decreased renal function over time.
Risk: Male sex, smoking, and increasing age increase the risk of renovascular hypertension attributed to atherosclerotic disease.
Incidence and Prevalence: Renovascular hypertension occurs in 0.2% to 5% of individuals with high blood pressure. In selected groups, the incidence may be as high as 30% and is less common in blacks than whites.
Source: Medical Disability Advisor