Renal artery stenosis

The renal artery stenosis describes a one - but also occurring on both sides narrowing of the renal artery supplying ( A.renalis ). Consequence of this narrowing can be a by the gold leaf effect ( activation of the renin -angiotensin -aldosterone system ) induced high blood pressure ( hypertension ).

Causes and frequency

The cause of arterial hypertension, the renal artery is relatively rare with approximately 1%. Causes of renal artery stenosis are:

  • Atherosclerosis ( common cause with 60-90 %, especially at the transition aorta - renal artery localized)
  • Fibromuscular dysplasia ( 10-30 % is this change of the connective tissue, the cause, especially in young patients, most likely localized in the middle third of the renal artery )
  • Arteritis, for example, Takayasu 's arteritis
  • Other rare causes are: thrombosis, injury or an aneurysm of the A.renalis

Pathophysiology ( Goldblatt effect)

The pathophysiology of renal artery stenosis is based to a large extent in the so-called gold leaf effect. With a reduction of the renal artery diameter to less than 40% leads to a decrease in renal blood flow. The kidney responds with an increased release of renin, which leads via the renin -angiotensin -aldosterone system to vasoconstriction ( narrowing of blood vessels ) and an increased reabsorption of sodium and water. Sequence of both processes is the typical of the disease increases in systemic blood pressure. So the diseased kidney is trying to improve their own limited circulation, but it increases the pressure in the systemic circulation pathological values ​​. Named this mechanism according to the U.S. American Pathologists Harry Goldblatt.

Clinic

  • High blood pressure ( particularly diastolic blood pressure value )
  • Reversed day -night rhythm in long-term blood pressure measurement
  • Stenosegeräusch in the area of the belly button and / or flanks (audible in 30% by means of stethoscope ) Herold, Internal Medicine - 2009 edition, page 294
  • Often fast during development of high blood pressure
  • Blood pressure can not be or is difficult to set ( > 2 drugs)

Diagnostics

  • History ( atypical age, rapid progression, hypertensive emergencies in the history )
  • Physical examination: blood pressure measurement ( often diastolic hypertension), Stenosegeräusch in the area of the belly button and / or the edges ( in 30% by means of stethoscope audible)
  • Classical testing in connection with high blood pressure
  • Ultrasonography ( duplex and color Doppler )
  • Magnetic resonance imaging ( MRI)
  • Renogram
  • Digital subtraction angiography

Therapy

  • Drug therapy: ACE inhibitors combined with beta-blockers (but under close control). Achieves one so no improvement, interventional and surgical procedures come into question. (For bilateral renal artery stenosis or a solitary kidney, therapy may, however, lead to an ACE inhibitor for acute renal failure and is therefore not recommended. )
  • Interventional therapy: Percutaneous transluminal angioplasty (PTA ): 80 % success rate, often with subsequent stent implantation.
  • Surgical therapy: Aortorenale ( anatomical ) or extra- anatomic bypass surgery.
Renin–angiotensin system Takayasu's arteritis Acute kidney injury Medical guideline
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