Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
What are the common imaging tests to evaluate renal artery stenosis?
An angiogram of the renal arteries is the best test
available to detect the degree of narrowing. This is similar to an
angiogram of the heart and involves insertion of a catheter through the groin into the main
artery (the aorta), that is advanced to the level of the renal arteries. A dye is
injected, and x-ray images are taken to see the caliber of the blood vessel and
extent of the narrowing.
An angiogram is considered an invasive test (insertion of the catheter inside
the body) and therefore is not widely used because of the risk of complications.
This test also may not determine if narrowing is truly significant to cause the
problem or not, and so it may be necessary to combine this with a functional
test. Generally, a narrowing of greater than 75% by angiogram is considered
significant enough to cause high blood pressure or kidney dysfunction. An
additional advantage of an angiogram is that if a treatable narrowing is seen,
it may be fixed at the same time via angioplasty or by placing a stent
(described in more detail below).
Other less invasive imaging tests are available to detect renal artery
stenosis, but they are not generally as accurate as the angiogram and could
potentially miss some cases of correctable disease. The most commonly used
additional imaging tests are:
Magnetic resonance angiography
Computed tomographic angiography
Duplex Doppler ultrasonography
Magnetic resonance angiography (MRA) is similar to a
magnetic resonance imaging (MRI). Contrast dye is injected into the blood via a vein in the arm,
and pictures of the specific area of the body (in this case the renal arteries)
are taken and analyzed. The accuracy (specificity and sensitivity) of this test
is reasonable. This test cannot be done in patients with metal implants,
pacemakers, or claustrophobia (fear of
closed spaces). It may be used in people
with mild to moderate, but not severe, kidney problems.
Computed tomographic angiography is similar to a
computed tomography (CT scan) and has reasonable accuracy. This is also done by injecting a contrast dye
into the blood and taking pictures of the renal arteries. This is not
recommended in people with moderate to severe kidney problems as it may make the
problem worse.
Doppler ultrasound is the least invasive imaging test for renal artery
stenosis. It is performed similarly to a regular ultrasound by placing a probe
on the abdomen to visualize the flow across the renal arteries and also to
measure any narrowing. Its accuracy is similar to the other tests above, but its
advantage is that it can measure the size of the narrowing as well as the flow
across it. The disadvantage of this test is that it is time-consuming and may
take up to a couple of hours to complete. It is also very operator-dependent,
meaning that the accuracy of the result is dependent upon the expertise and
experience of the ultrasound technician.
Kidney failure can occur from an acute event or a chronic condition or disease. Prerenal kidney failure is caused by blood loss, dehydration, medication. Some of the renal causes of kidney failure are from sepsis, medications, rhabdomyolysis, multiple myeloma, and acute glomerulonephritis. Post renal causes of kidney failure include bladder obstruction, prostate problems, tumors, or kidney stones. Treatment options included diet, medications, or dialysis.
Low blood pressure, also referred to as hypotension, is blood pressure that is so low that it causes symptoms or signs due to the low flow of blood through the arteries and veins. Some of the symptoms of low blood pressure include light-headedness, dizziness, or even fainting if not enough blood is getting to the brain. Diseases and medications can also cause low blood pressure. When the flow of blood is too low to deliver enough oxygen and nutrients to vital organs such as the brain, heart, and kidneys; the organs do not function normally and may be permanently damaged.
High blood pressure, also known as hypertension, is a repeatedly
elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above
140 with a diastolic pressure above 90. There are two causes of high blood pressure, primary and secondary. Primary high blood pressure is much more common that secondary and its basic causes or underlying defects are not always known. It is known that a diet high in salt increases the risk for high blood pressure, as well as high cholesterol. Genetic factors are also a primary cause. Secondary high blood pressure is generally caused by another condition such as renal hypertension, tumors, and other conditions. Treatment for high blood pressure is generally lifestyle changes and if necessary, diet.
Diabetes mellitus is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are referred to as type 1 (insulin dependent) and type 2 (non-insulin dependent). Symptoms of diabetes include increased urine output, thirst, hunger, and fatigue. Treatment of diabetes depends on the type.
A stroke results from impaired oxygen delivery to brain cells via the bloodstream. A stroke is also referred to as a CVA, or cerebrovascular incident. Symptoms of stroke include: sudden numbness or weakness of the face, arm or leg. Sudden confusion, trouble speaking or understanding. Sudden trouble seeing in one or both eyes, sudden trouble walking, dizziness, or loss of balance, and/or sudden severe headache with no known cause. A TIA, or transient ischemic attack is a short-lived temporary impairment of the brain caused by loss of blood supply. Stroke is a medical emergency.
Cholesterol is naturally produced by the body, and is a building block for cell membranes and hormones. Low-density lipoprotein (LDL) cholesterol is the "bad" cholesterol, conversely, high-density lipoprotein (HDL) cholesterol is the "good" cholesterol. High cholesterol treatment includes lifestyle changes (diet and exercise), and medications such as statins, bile acid resins, and fibric acid derivatives.
Heart attack happens when a blood clot completely obstructs a coronary
artery supplying blood to the heart muscle. A heart attack can cause chest pain, heart failure, and electrical
instability of the heart.
Vasculitis is a general term for a group of uncommon diseases which feature inflammation of the blood vessels. Each form of vasculitis has its own characteristic pattern of symptoms. The diagnosis of vasculitis is definitively established after a biopsy of involved tissue demonstrates the pattern of blood vessel inflammation. Treatment is directed toward decreasing the inflammation of the arteries and improving the function of affected organs.
The major goal in treating diabetes is controlling elevated blood sugar without causing abnormally low levels of blood sugar. Treatment for type 1 diabetes is with insulin, exercise, and a diabetic diet. Treatment for type 2 diabetes is first treated with weight reduction, a diabetic diet, and exercise. When these measures fail to control the elevated blood sugar, oral medications are used. If oral medications are still insufficient, insulin medications are considered.
High blood pressure (hypertension) means high pressure (tension) in the arteries. Treatment for high blood pressure include lifestyle modifications (alcohol, smoking, coffee, salt, diet, exercise), drugs and medications such as ACE inhibitors, angiotensin receptor blockers, beta blockers, diuretics, calcium channel blockers (CCBs), alpha blockers, clonidine, minoxidil, and Exforge.
Smoking is an addiction. More than 430,000 deaths occur each year in the U.S. from smoking related illnesses. Secondhand smoke or "passive smoke" also harm family members, coworkers, and others around smokers. There are a number of techniques available to assist people who want to quit smoking.
High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease). Kidney damage, like hypertension, can be unnoticeable and detected only through medical tests. If you have kidney disease, you should control your blood pressure. Other treatment options include prescription medications.
Smoker's lung photo essay is a collection of pictures and microscopic slides of lung disease caused by cigarette smoking. Smoker's lung refers to the diseases and structural abnormalities in the lung caused by cigarette smoking.
The risks for developing type 2 diabetes include family history, ethnicity, birth weight, metabolic syndrome, and obesity. Warning signs pointing to an increased risk for developing type 2 diabetes include irregular menstruation, impaired fasting glucose, inflammatory markers, and other risks. Gestational diabetes is also a risk factor for developing type 2 diabetes later in life. Prevention of type 2 diabetes can be achieved through a healthy diet (Mediterranean diet), exercise, weight control, not smoking, and medication.
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