Renal Hypertension/Renal Vascular Disease
Approximately five percent of people with hypertension or high blood pressure suffer from renal or renovascular hypertension, caused by narrowing or blockage in the arteries to the kidneys. With this blockage, the kidneys see a reduction of blood pressure and compensate for it by causing a rise in overall blood pressure, resulting in systemic hypertension. Early in its course, this hypertension can be treated with medication. However, as the blockage worsens, hypertension may become severe and difficult to control, even with multiple medications. Furthermore, it may result in sudden spikes in blood pressure, which can be extremely dangerous. In these cases, treatment of the underlying blockage may help eliminate or significantly reduce the hypertension to allow better control with fewer medications.
Hypertension itself can have a devastating effect on the kidneys (as well as many other organs). Exposure to abnormally high blood pressure over time will lead to kidney damage and a reduction in its ability to function normally. Because damage to the kidneys may not show up on routine blood tests until it is severe and possibly irreversible, early diagnosis and treatment are critical to protecting renal function.
In addition to intrinsic kidney damage from high blood pressure exposure, the kidney may also lose function due to decreased blood flow. Over time the kidney may atrophy or whither and lose its ability to function. If the blockage becomes severe, blood to the kidney may stop flowing altogether, resulting in kidney failure. Should that occur, preserving the other kidney is crucial to maintaining overall kidney function and avoiding dialysis and the need for transplant.
Causes of Renal Hypertension/Renal Vascular Disease
Plaque buildup in the arteries, also known as atherosclerosis, increases with age and causes most renovascular hypertension. Other risk factors for atherosclerosis development include tobacco use, poor diet, diabetes, and genetics.
The buildup of plaque is a slow, progressive disease, frequently beginning in young and middle-aged adults. However, as the buildup is generally slow, a severe blockage often does not become apparent until a person reaches their 60s or 70s. Early recognition and modification of risk factors are crucial in slowing and possibly reversing the process at a young age.
Another less common cause of renovascular hypertension, often present in younger patients – particularly young women – is fibromuscular dysplasia or FMD. FMD is an abnormal buildup of tissue in the arterial wall, resulting in a narrowing of the arterial wall. The cause of FMD is not known, although there is likely a genetic predisposition.
Treatment for Renal Hypertension
The mainstay of treatment for hypertension is medication to lower blood pressure. However, because of the consequences of renal hypertension, early diagnosis and additional treatment may provide the key to long-term control of hypertension and preservation of renal function. Several imaging studies are now available to evaluate the renal arteries and kidneys including duplex ultrasound, CT angiography and MR angiography. Each has its advantages and limitations, but all can be quite accurate in the detection of renal artery disease. When onset of hypertension is before age 30 or after age 50, or when stable hypertension becomes difficult to control with medication, renovascular hypertension should be suspected. These imaging tests should then be utilized to evaluate for possible renal artery disease.
Balloon valvuloplasty and stent placement are usually the recommended treatment for renal artery disease. These are generally low-risk procedures, often performed on an outpatient or single night hospital stay basis. The goal of treatment is to normalize blood pressure and blood flow to the kidney, ultimately reducing hypertension and preserving kidney function. Fibromuscular disease is frequently cured by balloon angioplasty alone. Atherosclerotic disease often requires the placement of small stents for optimum results. Following treatment, it is imperative to follow the results both clinically with frequent blood pressure checks, as well as with follow-up imaging.
How can high blood pressure affect the health of my kidneys?
Known as renal hypertension, this type of high blood pressure needs to be diagnosed and treated as soon as it is identified to prevent decreased blood flow and potential loss of function to a kidney. If the blockage becomes severe, blood flow to the kidney may stop completely, resulting in kidney failure.
Excellent imaging tests are now available to diagnose renal hypertension, as are low-risk treatments to improve blood flow to the kidney and preserve kidney function.
High blood pressure is a serious health condition that needs to be controlled, most often with medication, to prevent negative effects on organs throughout the body. However, about 1 out of 20 people have high blood pressure caused by narrowed or blocked arteries leading to the kidneys