Renal artery stenosis

Classification according to ICD-10
I70.1	Atherosclerosis of the renal artery
Q27.1	Congenital renal artery stenosis
ICD-10 online (WHO version 2019)

The renal artery is a single, but also on both sides occurring narrowing of the renal supplying artery (renal artery). The consequence of this narrowing can be high blood pressure ( arterial hypertension ) triggered by the gold leaf effect (activation of the renin-angiotensin-aldosterone system ) . Depending on the cause of the stenosis and the age and course of the patient, drug treatment of the sequelae or an intervention to remove the constriction can be considered.

distribution

Renal artery stenoses are found in up to 40% of people older than 75 years in autopsies . Depending on the examination and patient group, renal artery stenosis is present in around 1–5% of patients with elevated blood pressure. Thus, renal artery stenosis as a cause of hypertension is rare, but it is the most common cause in patients who do not suffer from primary hypertension, that is, an increase in blood pressure without a tangible organic cause.

causes

Around 70 to 90% of renal artery stenoses are based on arteriosclerotic plaques, which mostly occur at the transition from the aorta to the renal artery. It mainly affects male patients over the age of 50. Around 10–20% of renal artery stenoses are due to a change in the connective tissue, which is referred to as fibromuscular dysplasia . This occurs in younger patients and is more common in women. Rarer causes of a narrowing of the lumen of the renal artery are vascular inflammation , including giant cell arteritis and Takayasu arteritis . Likewise, a renal artery aneurysm or a dissecting aortic aneurysm can lead to stenosis. Similarly, emboli lead to stenosis of the renal artery. In rare cases, tumors or cysts can narrow the renal artery due to external pressure.

Pathophysiology (gold leaf effect)

The pathophysiology of renal artery stenosis is largely based on the so-called Goldblatt effect . If the diameter of the renal artery is reduced to less than 40%, the blood flow to the kidney falls. The kidneys react with an increased release of renin , which via the renin-angiotensin-aldosterone system leads to vasoconstriction (constriction of the vessels) and increased reabsorption of sodium and water. The consequence of both processes is the rise in systemic blood pressure that is typical for the disease. The diseased kidney tries to compensate for its own restricted blood flow , but increases the pressure in the body's circulation to pathological values. This mechanism is named after the American pathologist Harry Goldblatt .

clinic

The renal artery stenosis itself does not cause any symptoms. However, it leads to severe, often therapy-refractory arterial hypertension. It can lead to secondary aldosteronism . If hypertension occurs before the age of 30, clarification should be carried out. In elderly patients with severe hypertension onset suddenly, a diagnosis should be considered. Hypertension with repeated pulmonary edema as part of a blood pressure crisis can also be an indication of the presence of renal artery stenosis. Likewise, a deterioration in renal function under antihypertensive medication, which is aimed at the RAAS, is an indication of renal artery stenosis. A newly developed hypotrophy of a kidney should also lead to clarification regarding a vascular stenosis of the kidney.

Diagnosis

In around 40% of patients, a flow noise can be heard next to the navel or over the flanks with the stethoscope . However, this also occurs in a few patients with hypertonic blood pressure values without stenosis. A Doppler ultrasound examination of the renal arteries can detect this in 88% of the present cases and rule it out in 89% of the non-present cases. An MRI examination of the renal artery examination or a computed tomography achieve this with a sensitivity and specificity of more than 94%. The gold standard of diagnostics is digital subtraction angiography , in which a catheter is inserted into the renal artery by puncturing the inguinal artery in order to make it directly visible through the flow of contrast medium. In the imaging process, an arteriosclerotic constriction can be distinguished from a fibromuscular dysplasia.

Therapy and prospect of healing

With regard to treatment, a distinction is made between conservative treatment and invasive elimination of the bottleneck. Conservative treatment tries to normalize blood pressure through medication and lifestyle changes and to eliminate risk factors for the progression of atherosclerosis. In the conservative-reconstructive procedure, the constriction in the renal artery is removed using a PTA . In patients with fibromuscular dysplasia, PTA succeeds in 95% of cases and leads to a significant improvement in blood pressure in 75%. The long-term results in five to ten-year follow-ups are rated as favorable.

Randomized controlled studies are now available on the interventional treatment of arteriosclerotic stenoses. These could not prove that the intervention was superior to drug therapy. There were isolated cases of intervention-related deaths or serious complications such as loss of a limb or loss of kidney function. The indication for intervention in arteriosclerotic lesions is therefore now viewed critically and should be reserved for patients in whom drug therapy fails or in whom a rapid loss of kidney function due to the stenoses is assumed.

In the case of bilateral renal artery stenosis or a stenosis of a single kidney, the use of antihypertensive drugs that act by inhibiting the RAAS is contraindicated, as this can lead to kidney failure.

Medical history

The expansion of renal arteries was established by Andreas Roland Grüntzig from 1974, who transferred his expertise in this area to coronary arteries and is therefore considered the founder of interventional cardiology.

Angiography of renal artery stenosis due to fibromuscular dysplasia

The post-expansion stenosis (PTA) shown above

literature

Heinrich Wieneke u. a .: The renal artery stenosis. In: Medical Clinic , 104 (5), May 2009, pp. 349-355.
S2 guideline : Diseases of the renal arteries. AWMF register number 004/008, status 08/2008 (currently being revised)

Web links

Renal artery stenosis www.urologielehrbuch.de
nierenratgeber.de

Individual evidence

↑ ^a ^b ^c ^d ^e ^f Ulrich Kuhlmann, Joachim Böhler, Friedrich C. Luft, Mark Dominik Alscher, Ulrich Kunzendorf: Nephrology - Pathophysiology - Clinic - Renal Replacement Procedure . Stuttgart 2015, pp. 623-638.
↑ ^a ^b Michal Tendera, Victor Aboyans, Marie-Louise Bartelink, Iris Baumgartner, Denis Clement a. a .: ESC Guidelines on the diagnosis and treatment of peripheral artery diseases. In: European Heart Journal. 32, 2011, pp. 2851-2906. doi: 10.1093 / eurheartj / ehr211
↑ S. Jenks, SE Yeoh, BR Conway: Balloon angioplasty, with and without stenting, versus medical therapy for hypertensive patients with renal artery stenosis. In: The Cochrane database of systematic reviews . tape 12 , December 5, 2014, p. CD002944 , doi : 10.1002 / 14651858.CD002944.pub2 , PMID 25478936 .

[Kuhlmann2015623628-1] ↑ ^a ^b ^c ^d ^e ^f Ulrich Kuhlmann, Joachim Böhler, Friedrich C. Luft, Mark Dominik Alscher, Ulrich Kunzendorf: Nephrology - Pathophysiology - Clinic - Renal Replacement Procedure . Stuttgart 2015, pp. 623-638.

[esc2011-2] Michal Tendera, Victor Aboyans, Marie-Louise Bartelink, Iris Baumgartner, Denis Clement a. a .: ESC Guidelines on the diagnosis and treatment of peripheral artery diseases. In: European Heart Journal. 32, 2011, pp. 2851-2906. doi: 10.1093 / eurheartj / ehr211

[Cochrane2014-3] S. Jenks, SE Yeoh, BR Conway: Balloon angioplasty, with and without stenting, versus medical therapy for hypertensive patients with renal artery stenosis. In: The Cochrane database of systematic reviews . tape 12 , December 5, 2014, p. CD002944 , doi : 10.1002 / 14651858.CD002944.pub2 , PMID 25478936 .