Hypertension, renovascular

Renovascular Hypertension is a condition characterized by high blood pressure caused by the narrowing (stenosis) or blockage of the arteries that supply blood to the kidneys (renal arteries). This condition is a form of secondary hypertension, meaning it is the result of an identifiable cause, in this case, compromised renal artery blood flow. Renovascular hypertension is significant because the kidneys play a crucial role in regulating blood pressure through the management of blood volume and the secretion of renin, an enzyme that affects blood pressure.

Causes

Renovascular hypertension occurs when the renal arteries are narrowed or blocked, a condition often caused by atherosclerosis or fibromuscular dysplasia. Atherosclerosis leads to the buildup of plaques in the arteries, while fibromuscular dysplasia is a condition that causes abnormal growth within the walls of the arteries. In both cases, the flow of oxygen-rich blood to the kidneys is reduced, prompting the kidneys to release renin, which in turn activates the renin-angiotensin-aldosterone system (RAAS), leading to increased blood pressure.

Symptoms

Many individuals with renovascular hypertension may not exhibit symptoms until the condition has progressed. When symptoms do occur, they may include:

• Severe or resistant hypertension
• Sudden onset of high blood pressure
• Deterioration of kidney function
• Edema (swelling) due to fluid retention
• Headaches

Diagnosis

Diagnosis of renovascular hypertension involves a combination of patient history, physical examination, and diagnostic tests. Tests may include:

• Doppler ultrasound: To assess blood flow in the renal arteries.
• CT angiography or MR angiography: To provide detailed images of the renal arteries.
• Renal scintigraphy: To evaluate kidney function and blood flow.
• Renal vein renin measurements: To compare the levels of renin in the blood from each kidney.

Treatment

Treatment for renovascular hypertension aims to restore blood flow to the kidneys and manage high blood pressure. Options include:

• Medical management with antihypertensive medications.
• Percutaneous transluminal renal angioplasty (PTRA) with or without stenting, to open narrowed arteries.
• Surgical revascularization for severe cases, involving bypass of the blocked artery or arteries.

Prognosis

The prognosis for individuals with renovascular hypertension varies depending on the underlying cause, the severity of the condition, and the effectiveness of treatment. Early diagnosis and appropriate treatment can improve outcomes and reduce the risk of complications such as chronic kidney disease and cardiovascular events.

See Also

• Hypertension
• Kidney
• Atherosclerosis
• Fibromuscular dysplasia
• Renin-angiotensin-aldosterone system