Giving critical organs a second chance
The kidneys are a pair of truly incredible organs – powerful, vital, and essential to the regulation of the human body. Located directly below the chest, with vascular connections to the aorta (the main artery of the body that supplies oxygenated blood through the circulatory system), this pair of bean-shaped organs carry many responsibilities on their back, despite only being the size of a clenched fist.
The primary function of the kidneys is to filter the blood. Through a process which removes metabolism’s waste products, all of the blood found in the body passes through the kidneys several times a day, which helps to regulate the balance of electrolytes and controlling the body’s fluid balance. Found in each kidney are nephrons – over one million infinitesimal units that filter the blood in a healthy human being.
The kidneys also serve several other crucial regulatory roles in the urinary system. Whenever blood passes through the kidneys, they excrete urea and ammonium, which are dispensed from the body when urination occurs. Additionally, the kidneys are responsible for the reabsorption of compounds like amino acids, glucose and water, as well as the hormones erythropoietin and calcitriol and the enzyme, renin, which acts in negative feedback to cause an increase in blood pressure, as a result of the perfusion pressure in the kidneys.
However, these connections wouldn’t be able to be made if it weren’t for the renal arteries and veins. From the aorta, the renal arteries deliver oxygen-rich blood to the kidneys, while the renal veins carry oxygen-poor blood away from the organs. If it weren’t for the renals, nearly all of the kidney’s main functions wouldn’t be able to take place.
Renal Artery Stenosis
Keeping this in mind, it’s important to understand how renal artery stenosis can affect not only the arteries, but the processes that they aid the kidneys in as well. This condition occurs when the renal arteries are blocked or narrowed, preventing the amount of blood flow that occurs through the kidneys. If proper blood flow isn’t achieved, high blood pressure and injury to the tissues can occur, and blood can’t be efficiently filtered. Through this disease, plaque builds up on the walls of the arteries, causing more severe medical problems, such as aortic dissections, cardiac problems, stroke and aneurysms.
Women have a higher chance of developing renal artery stenosis, but its effects are synonymous between both genders. Many contributing factors increase a person’s risk for developing renal artery stenosis, including, but not limited to:
· Fibromuscular dysplasia
· Inflammatory diseases
· Tumors or aneurysms
· High cholesterol
· Obesity or physical inactivity
· Smoking, or a history of using tobacco products
· Heart disease
Renal artery stenosis can be diagnosed through a multitude of processes. Duplex ultrasound checks the structure of renal arteries and veins and the blood flow received through them. Diagnostic angiogram involves the insertion of a thin, flexible tube into the artery, as well as the injection of dye under x-ray imaging to note areas of blockage, narrowing or aneurysms. Additionally, venography helps to test the function and structure of the kidneys by the use of a small amount of a radioactive substance. Finally, MRA or CTA imaging uses the formation of contrast dye to visualize areas of narrowing or blockage in the kidney arteries.
Though the effects of renal artery stenosis may seem daunting, all hope is not lost: There are many options for treating this condition in affected patients. Some treatment options are as simple as adopting new or altered lifestyle changes, such as quitting smoking, implementing a 30-minute exercise regimen three days a week, or maintaining a healthy diet to, in turn, maintain a healthy body weight.
Many of these changes are used in part with medications to help control the risk factors discussed earlier. Some of these medications aid in establishing a more relaxed heartbeat or blood vessels, such as beta blockers, ACE inhibitors and Calcium channel blockers, while others help to control cholesterol levels or eliminate excess water from the body, such as statin drugs or diuretics. All of these medications are to be prescribed by a vascular surgeon, however, and should not be taken until proper diagnosis has taken place.
Surgery / Procedures
Finally, in severe cases of renal artery stenosis, where the previously described lifestyle changes and medications are not enough to take care of the condition, minimally invasive surgery can be done, depending on the overall health of a patient, as well as the extent and location of their blockages.
Angioplasty and stenting are procedures done by placing a catheter into a small puncture over an artery in the arm or groin, and directed towards the blockage under x-ray guidance. A small balloon is inflated and deflated several times, pushing and compressing the plaque to the walls of the artery, which helps allow blood to flow freely.
Bypass surgery can also be utilized. A graft, or a synthetic, round tube, is inserted into a vein, where the blood flow is rerouted to a different artery, restoring the correct amount of blood to the affected tissues. Additionally, renal artery endarterectomy can help to remove the build-up of fats, cholesterol, and the total summation of plaque from the renal arteries.
Though renal artery stenosis can affect many of the overall processes that kidneys are responsible for, the condition is treatable, and, through varying treatment options, will help to give patients and their afflicted organs another shot at a healthy life.