One of the main jobs of the kidneys is to filter the waste from the blood. They also balance the volume of fluids and minerals in the body. Another function of the kidneys is the production of hormones:
Renin keeps blood pressure normal. People with kidney disease can also develop high blood pressure, which in turn can be linked to other problems such as heart attacks and strokes.
Erythropeitin prompts the body to make red blood cells. A lack of these hormones can lead to anemia. They also help convert vitamin D so that the body can use it to absorb calcium.
In order for the kidneys to work properly, they need a good blood supply. When the blood supply is limited, the kidneys cannot filter the waste from the blood, urine is not produced, and the waste is not properly removed from the body. If kidney function worsens, you may need dialysis to filter your blood for you.
The blood is transported from the renal arteries to the kidneys. When these arteries become narrowed due to the build-up of plaque (arteriosclerosis or hardening of the arteries), the blood supply to the kidneys becomes increasingly restricted (stenosis). This is known as atherosclerotic renovascular disease, or ARVD. The symptoms of ARVD can be:
High blood pressure that does not respond to usual drug treatments
Loss of kidney function or acute kidney failure
Chronic kidney disease
Most people with ARVD have other vascular diseases and atherosclerosis elsewhere in their body.
An angiogram is used to take a closer look at the blood supply to your kidneys. It is an x-ray of the arteries and is done by puncturing the artery under local anesthesia and injecting a contrast medium (dye) to outline the blood vessels. If the renal arteries are narrowed and blood flow is restricted, a balloon (angioplasty) can be used to stretch them to improve blood flow, lower blood pressure, and maintain better kidney function. Before your procedure You will be given an appointment for the clinic before admission, where you will be examined by a specialist nurse a few weeks before the procedure to check that you are fit enough and to draw blood for routine tests and an EKG (electrical heart test). This also gives you the opportunity to ask further questions.
The procedure is usually carried out on an inpatient basis. You will be asked to come directly to the ward the day before or the morning of the procedure and you will have to stay overnight.
Come to the hospital
Please bring any medication you are currently taking with you. When you arrive at the ward, one of the nurses will show you to your bed, who will also fill out your medical record. You will be visited by one of the junior doctors who will ensure that all formalities are completed prior to the x-ray. You must fast for 4 hours before the X-ray. The staff will tell you when this starts.
The procedure is performed under local anesthesia, sometimes supplemented with sedation. Local anesthetic is used to numb the skin and a small tube is inserted into the artery in the groin – this is the only uncomfortable part of the procedure. The local anesthetic stings a little for about 45 seconds, and then you shouldn’t feel anything. If sedation is required, it can be administered either orally or intravenously. it helps you relax. If you are nervous please ask your nurse about it.
A small incision is made in the anesthetized skin at the level of the groin, usually about 8 mm long. The femoral artery is pierced with a needle and a fine wire is passed through the needle up the artery into the artery in the abdomen. A flexible narrow tube (cannula) is run along the wire and artery from the groin area to the diaphragmatic level (just below your ribs). You don’t feel that at all. Once the tip of the cannula is in place, the wire is temporarily removed and contrast (dye) is injected. We can get an overview of the arteries from your diaphragm to your feet.
When the contrast is injected you may get a warm feeling in your legs. This is a temporary and usually not an uncomfortable sensation. The contrast will outline the arteries to the kidneys. Usually there is only one artery per kidney, but sometimes there can be up to four. If the artery narrows, it will be clearly visible.
Next, the radiologist guides a balloon catheter along the wire from the level of the groin to the narrowed renal artery. Again, you can’t feel that at all. Once in position, the balloon will inflate and the constriction will gradually widen. This procedure is known as angioplasty.
In some cases the artery will open successfully, but sometimes the narrowing will retract a little when the balloon is deflated. If the dilation is not entirely satisfactory, the radiologist can place a stent at the site of a persistent narrowing. Again you don’t feel it at all.
A stent is a tube made from a special metal alloy that looks like chicken wire. It is inserted squeezed small and can be opened to its maximum width with an angioplasty balloon. The stent is also inserted over the wire from the level of the groin. Once the stent is positioned at the site of the constriction, it is opened to a predetermined width and keeps the renal artery open.
When the process is complete, the cannula and wire are withdrawn. The puncture in the artery must be sealed to prevent bleeding. Sometimes the puncture is sealed with a device called an angioseal, a small plug of collagen. It is inserted when the cannula is removed. It immediately closes the opening in the artery.
If an angioseal is not being used, the radiologist will apply pressure to the puncture site with their hand for up to 20 minutes to ensure that the puncture seal seals.
The entire process usually takes between 30 and 90 minutes. Usually, you can see what’s going on on a TV screen (if you want).
After the procedure
You will return to the ward from the x-ray as soon as the x-ray staff are happy that the inguinal puncture is not bleeding. You will stay in bed for 12 hours on the ward. After that, you can get up and walk around. You will be given something to eat later in the day. You will usually return home the day after the x-ray. A blood test will usually be done before you leave the hospital.
When you get home it will be uncomfortable in the groin for up to a week. Sometimes this is associated with a visible bridging. Once you get home, you can do as much exercise as you want after this process. The kidney specialists will examine you on an outpatient basis within a few weeks of your discharge from the hospital.
Wound infection: wounds sometimes become infected and may need antibiotic treatment. Serious infections are rare.
False aneurysm: Sometimes, when the arterial puncture does not seal completely, blood will leak out and form a cavity under the skin called a false aneurysm. A false aneurysm is associated with discomfort in the groin and a pulsating lump. False aneurysms are rare (around one in 100).
Main Complications: As with any procedure, there is a low risk of medical complications such as heart attack, stroke, kidney failure, chest problems, or loss of circulation in the legs or intestines. Each of these are rare, but overall it means that some patients can have fatal complications from their surgery. For most patients, this risk is around 1% – in other words, 99 out of 100 patients will fully recover from the operation. The doctors and nurses will try to prevent these complications and treat them quickly if they arise.
If your risk of a serious complication is higher, usually because you already have a serious medical problem, your surgeon will discuss this with you.