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- Renal artery stenosis facts
- What are the renal arteries?
- What is renal artery stenosis?
- What are the causes of renal artery stenosis?
- How common is renal artery stenosis?
- What are the symptoms of renal artery stenosis?
- What problems does renal artery stenosis cause?
- Who should be screened for renal artery stenosis?
- How is renal artery stenosis diagnosed?
- What are the common imaging tests to evaluate renal artery stenosis?
- What functional tests are used for the diagnosis of renal artery stenosis?
- What are medical treatments for renal artery stenosis?
- What surgical procedures are available for renal artery stenosis?
- Which patients can benefit from surgical procedures for renal artery stenosis?
What functional tests are used for the diagnosis of renal artery stenosis?
The main functional tests for renal artery stenosis include the plasma renin activity test and captopril renogram. These tests have been largely replaced by the imaging tests described above because they are less accurate, but they may be still performed to help establish the diagnosis of renal artery stenosis.
The plasma renin activity measures the activity of the hormone renin (described above). Activity of renin is generally higher in the kidney with renal artery stenosis compared to the other kidney. This response may be exaggerated by administration of captopril (Capoten), an ACE inhibitor medication used to treat high blood pressure.
The renogram measures the activity of the kidneys after injection of a radioactive material that is taken up by the kidney. By administering captopril prior to the test, the activity may become more enhanced on the normal kidney compared to the one with renal artery stenosis. This may indicate a significant renal artery narrowing on the side with less activity.
What are medical treatments for renal artery stenosis?
In bilateral (both-sided) and unilateral (one-sided) renal artery stenosis associated with high blood pressure, controlling the blood pressure with usual blood pressure medications is the first and the safest treatment. ACE inhibitors or ARB medications with or without a diuretic (water pill) may be tried first. This approach may lead in some patients to worsening of their kidney function. Therefore, kidney function needs to be followed closely and if worsening of kidney function is evident, these medications may need to be stopped.
It is worth noting that if renal artery stenosis is found incidentally when performing a test for another disease and there is no evidence of kidney dysfunction or high blood pressure, then no treatment may be necessary. Sometimes even significant stenosis may not be associated with high blood pressure or kidney dysfunction. In these situations, periodic monitoring of blood pressure and kidney function may be advised.