The kidney is a high-performance center in the body. It constantly filters toxins out of the blood, supports the metabolism, regulates the water balance and thus regulates the blood pressure in the long term. It also controls the electrolyte balance and produces important hormones.
Disorders of kidney function therefore affect a large number of processes in the body. A gradual narrowing of one or both renal arteries causes high blood pressure or makes existing hypertension worse. Doctors refer to such constrictions as renal artery stenosis.
“As a rule, the risk of renal artery stenosis increases with age,” emphasizes Prof. Dr. Martin Hausberg, Director of Medical Clinic I at the Municipal Clinic in Karlsruhe and specialist in kidney diseases. “However, the disease can also occur at a younger age.”
The symptoms of renal artery stenosis are often non-specific, which means that the patient does not feel anything about the narrowed blood vessel. Rather, in many cases, high blood pressure is the first clue to renal artery stenosis. Sudden phases of high blood pressure are also signals. High blood pressure is indicated by dizziness, morning headaches, nervousness, nausea or even blurred vision.
Arterial stenosis can be detected with modern imaging in the Karlsruhe Clinic. Until the late 1990s, angiography of the renal vessels was the method of choice for diagnostic clarification. “We have favored duplex sonography for 15 years,” explains Prof. Dr. Peter Reimer, Director at the Institute for Diagnostic and Interventional Radiology at the hospital. “If this does not bring satisfactory results, we visualize and check the function and appearance of the kidney vessels using computed tomography or magnetic resonance imaging.”
The high blood pressure resulting from renal artery stenosis can primarily be treated well with drug therapy. “We use beta blockers, diuretics, blood thinners and ACE inhibitors to control hypertension,” summarizes Hausberg.
If the kidney tissue is impaired by the reduced blood flow, if there is cardiac insufficiency or if the high blood pressure cannot be controlled with medication, interventional therapy for renal artery stenosis makes sense.
The Medical Clinic I and the Institute for Diagnostic and Interventional Radiology also cooperate. “In percutaneous transluminal angioplasty, which we also use for narrowed heart vessels, we insert a narrow, flexible tube into the blood vessel,” says Reimer, describing the method. “We use this catheter to insert a small balloon or a small metal mesh tube (stent) into the narrowed area, which widens the artery and keeps it open.”
The chances of success are good with both drug and interventional treatment. “The catheter procedure has the advantage that the patients can do without at least one medication afterwards,” emphasizes Reimer.
Nevertheless, people with renal artery stenosis should come for regular check-ups in order to identify any deterioration in good time. Medical Clinic I offers special follow-up examinations for this purpose. “Smoking, obesity and diabetes mellitus are the greatest risk factors,” concludes Hausberg. “At these points, patients can positively influence their risk of disease themselves.”
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The image rights belong to: Markus Kümmerle; Municipal Clinic Karlsruhe, Markus Kümmerle; Municipal Clinic Karlsruhe, Markus Kümmerle; City Clinic Karlsruhe
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