Renal artery stenosis

Synonyms in the broadest sense

Renal artery narrowing, renovascular hypertension, narrowing of the renal artery, atherosclerotic renal artery stenosis, fibromuscular renal artery stenosis

definition

The vessels of the kidneys or just one kidney are in patients with a Renal artery stenosis (Renal artery narrowing) are affected by a pathological process. More precisely, there is a narrowing of the Renal artery before that in 80% of the cases by arteriosclerosis of the Main artery (aorta) and the renal artery branching out of it. This mostly affects older people who smoke. The other 20% of patients with constriction of the kidney arteries, preferably women, have congenital narrowness of the kidney artery, which is caused by particularly pronounced vessel wall muscles and connective tissue structure of the vessel.

Often it is Renal artery stenosis of a high blood pressure accompanied.

Forms of renal artery stenosis

In the case of renal artery stenosis caused by arteriosclerosis, one speaks of arteriosclerotic renal artery stenosis. A characteristic of this form is that above all People get sick in old age.

The second form is fibromuscular renal artery stenosis, in which the vessel wall of the renal artery is thickened and thus narrows the vascular opening. This form mainly affects younger patients.

Blood supply to the kidney

1. Abdominal artery (aorta abdominalis)
2. Superior intestinal artery (arteria mesenterica superior)
3. kidney
4. Renal artery (ateria renalis)
5. Ovarian vein / testicular vein (vena ovarica / testicularis)
6. Ovarian / testicular artery (arteria ovarica / testicularis)
7. Renal vein (vena renalis)
8. Lower vena cava (vena cava)

Occurrence in the population

This vasoconstriction of the kidneys is to be named as the cause of high blood pressure in 1-5% of all cases.

Info: causes of high blood pressure

Other causes are: primary high blood pressure, pheochromocytoma, sleep apnea syndrome, pregnancy high blood pressure, coarctation of the aorta, Cushing's syndrome.

Symptoms

The disease can proceed without symptoms. In many cases, however, the so-called occur renovascular hypertension, a high blood pressure caused by kidney disease. “Renovascular” means that the vessels of the kidneys are affected by a pathological process.

Since the blood supply to the kidneys may be reduced by the narrowed vessels, kidney dysfunction is possible.

Furthermore, an isolated increase in the second, diastolic blood pressure value can occur (see also: Increase in the second blood pressure value).

diagnosis

Renal artery stenosis can be heard with the stethoscope, especially in slim people:
During the physical examination by the doctor, a flow noise is noticed over the abdomen and flanks, which suggests changes in the kidney vessels.

This vascular change is initially determined with a Ultrasound examination the kidneys and their vessels. The flow rate of the blood through the vessels and the vessel width can be measured. Therapy is necessary if a significant constriction with a low flow velocity is found. This procedure does not use X-rays and is particularly gentle on the patient.

A very precise representation of the kidney vessels can be obtained with a magnetic resonance tomographic examination, a so-called MRI-Angiography. The patient receives a contrast medium through the vein, with the help of which the kidney vessels can be made clearly visible.

Read more about the topic here Angiography

therapy

For the treatment of renal artery stenosis, catheter procedures (therapeutic tubes) and surgical procedures as well as drug treatment options are available:
Catheters can be used in a similar way to Cardiac catheter If the coronary arteries are constricted or blocked, a balloon can be advanced to the renal artery. This balloon is expanded to widen the blood vessel: the artery becomes open again. If necessary, a stent, a vascular support, can be used. The stent is intended to ensure that the vessel is kept open. This procedure is carried out when the drug treatment of the high blood pressure does not lead to a sufficient reduction in pressure or the artery is more than 70% blocked and thus an improvement in the blood pressure situation is not expected.

If the catheter treatment is unsuccessful, therapy with several antihypertensive drugs is necessary to normalize the patient's high blood pressure.

Less often an operation is necessary in which the narrowed vascular section has to be removed and, if necessary, bridged with a vascular prosthesis.

forecast

The balloon expansion of the narrowed renal vessel is of particular use in the fibromuscular form of renal artery stenosis. Namely, normalization of blood pressure can be achieved in the majority of cases.

Normal blood pressure is achieved in only 20% of cases of arteriosclerotic renal artery stenosis. The longer the stenosis was untreated and the blood pressure was high, the lower the chance that the blood pressure will drop again. Persistent high blood pressure is referred to as fixed high blood pressure.

If no treatment is given in patients with renal artery stenosis, there is a risk of gradual loss of function and shrinkage of the kidney. The unaffected kidney can then enlarge, which is called hypertrophy of the kidney.