Renal/Kidney Artery Disease
The renal arteries supply blood to the kidneys, which are responsible for filtering toxins from the body and maintaining blood pressure and volume. Renal artery disease refers to a narrowing (stenosis) in the arteries to the kidneys due to cholesterol plaque (atherosclerosis) or other diseases, including fibromuscular dysplasia and inflammatory vasculitis. Atherosclerosis in the most common cause of renal artery disease.
Renal/Kidney Artery Disease Symptoms
Stenosis of the renal arteries most often causes high blood pressure (hypertension) requiring medications. With advancing renal artery stenosis, blood pressure may become difficult to control despite good medical therapy. In cases of uncontrolled blood pressure, chest pain, confusion or sleepiness, and sudden difficulty breathing due to rapid accumulation of water in the lungs (flash pulmonary edema) may occur.
Over time, renal artery stenosis can lead to kidney failure with accumulation of toxins and fluid. Advanced kidney failure may lead to a need for renal replacement therapy, known as dialysis. Symptoms of kidney failure include swelling, shortness of breath, confusion, and acid-base disturbances in the body.
Difficulty breathing, confusion, chest pain or uncontrolled blood pressure should prompt an urgent medical evaluation by a physician.
Diagnosing Renal/Kidney Artery Disease
Renal artery disease is diagnosed with imaging that identifies an area of stenosis due to atherosclerosis or other etiologies. The Vascular Diagnostic Laboratory at Mount Sinai was instrumental in developing non-invasive techniques to diagnosis renal artery stenosis.
The diagnostic technologies used at The Mount Sinai Hospital to detect renal artery disease include:
- Catheter-based angiography allows for the direct application of contrast to the arteries supplying the kidney via placement of a catheter in the groin that is fed up to the artery of interest. In addition to high accuracy in diagnosing renal artery disease, catheter-based angiography also allows for endovascular treatment, if warranted.
- Computed tomographic angiography (CTA) is a detailed exam that generates three-dimensional (3D) pictures of the arteries of the kidney with the use of contrast material that is injected through an IV. The exam is fast; however, the patient is exposed to contrast radiation. Patients with kidney disease or failure may not be eligible for this exam, due to kidney-stress related to contrast agent.
- Duplex ultrasonography is a sonogram of the abdomen with the ability to measure blood flow in the arteries. This is an effective, first-line diagnostic test and is preferred as a non-invasive technique that can accurately identify renal artery stenosis without the use of iodinated-contrast agents or radiation. Fasting is required the day of the procedure to optimize imaging and reduce interference with bowel gas.
- Magnetic resonance angiography (MRA) combines intravenous contrast to enhance blood vessels with magnetic waves to produce three-dimensional (3D) pictures with good resolution; there is no radiation involved in this test. If the kidneys function at less than 30 percent compared to normal function, this test should not be used because the gadolinium contrast agent can be dangerous.
Renal/Kidney Artery Disease Treatments
The treatment of renal artery disease depends in part on the underlying etiology, as well as the severity or degree of stenosis and patient's other medical conditions. The specialists at Mount Sinai are well-versed in all treatment therapies and experts in common and uncommon causes of renal artery disease.
Medical therapy is focused on blood pressure control and managing risk factors related to renal artery disease (e.g., atherosclerosis). The physician will need to consider if one or both kidneys are involved, as well as the patient's other medical conditions in creating the medical therapy plan. Common agents to control blood pressure include:
- Diuretics (such as hydrochlorothiazide, chlorthalidone and furosemide) to manage blood pressure and, in some cases, volume control
- Angiotensin converting enzyme inhibitor (ACE inhibitor) or angiotensin receptor blocker (ARB), as these agents have additional benefits in patients with coronary heart disease, congestive heart failure, peripheral artery disease and diabetes
- Calcium channel blockers (CCBs), including amplodipine, felodipine and nifedipine.
- Beta blockers (such as metoprolol, labetalol, atenolol, carvedilol), which have additional benefits in patients with coronary artery disease and congestive heart failure
- Nitrates, including isosorbide mononitrate or dinitrate
- Hydralazine or clonidine in refractory cases of hypertension
In patients with atherosclerosis of the renal arteries, cholesterol medications and antiplatelet therapies (e.g., aspirin) are recommended for total body cardiovascular health. In patients with renal artery disease secondary to other processes (fibromuscular dysplasia or vasculitis), treatment involves directed therapy for the underlying process.
In some cases, medical therapy may not be sufficient and endovascular or, rarely, surgical therapies may be required. Endovascular therapies include balloon angioplasty (inserting and inflating a balloon in the stenosed artery) to open the area, followed by placement of a metal mesh tube (stent) to keep the artery open. For some, balloon angioplasty alone is the procedure of choice. Bypass surgery may be considered in cases of concomitant aortic disease, complicated renal artery stenosis, or if there are aneurysms present. However, the large majority (more than 95 percent) can be managed with medications alone or with balloon angioplasty and stenting. Patients that undergo angioplasty or stenting will require regular surveillance with ultrasound to monitor renal artery patency.
Long-Term Effects of Renal/Kidney Artery Disease
The long-term outcome of renal artery disease depends on the underlying process (atherosclerosis or another cause), severity of stenosis at diagnosis, and involvement of one or both renal arteries. In many cases, patients do well without progression of disease on medical therapy and never require endovascular or surgical therapies. In addition, patients with kidney disease are at increased risk of heart attack, stroke, and death; thus, it is important to follow cardiovascular disease risk reduction recommendations.
Patients with more advanced renal failure, including involvement of both renal arteries, have worse prognosis than patients with single kidney involvement and no clinical manifestations of disease (in the case that the condition is incidentally discovered on imaging). For these patients, it is crucial to discuss the role of endovascular and surgical revascularization to minimize poor outcomes. At Mount Sinai, we recognize that each patient is unique and will tailor a treatment plan with our colleagues across the hospital to your meet your specific needs. The goals of revascularization are to minimize kidney damage, prevent progression to kidney failure, and minimize complications including heart failure and uncontrolled hypertension.
Division of Vascular and Endovascular Surgery
Vascular Interventions – Cardiac Cath Lab
1190 Fifth Avenue, 1st Floor
New York, NY 10029