What Is Minimally Invasive Endovascular Treatment?
Endovascular describes the Minimally Invasive Technique of accessing the aneurysm from within the bloodstream, specifically during angiography. The bloodstream is entered through the large femoral artery in the upper leg (groin area) where a flexible catheter is advanced from the femoral artery to one of four arteries in the neck that lead to the brain.
Endovascular procedures are usually performed in a special procedures room or angiography suite in the radiology department. The procedure takes between 2 to 4 hours.
Preparation
You will lie on your back on the x-ray table and be given anesthesia. The type of anesthesia used varies: conscious sedation for those in good condition or general anesthesia for others. Anti-clotting medication (heparin) is injected throughout the procedure to prevent blood clots from forming. Your head is positioned so that it will not move during the procedure.
THE PROCEDURE
After the inner thigh and groin area are shaved and cleansed, a local numbing agent is given to minimize discomfort as the skin incision is made. The femoral artery is located and a hollow needle is inserted into the artery. a long tube made of flexible plastic called a catheter, is then passed through the needle to enter the bloodstream. A special dye, called a contrast agent, is injected into the bloodstream through the catheter. The dye makes the blood vessels visible on the x-ray monitor (fluoroscope). Watching the monitor while injecting dye, the doctor carefully guides the catheter from the femoral artery in the leg, up the aorta, past the heart, and to one of four arteries in the neck that lead to the brain (Fig. 2). You may feel brief pain when the catheter is inserted, but most catheter manipulation is painless.
When the catheter is placed correctly, the doctor injects the contrast agent while x-ray pictures are taken. You may feel a hot, flush that lasts 5 to 20 seconds. This procedure may be repeated several times until the doctor can view all necessary arteries and take measurements of the aneurysm, especially its neck.
A second smaller catheter, about the size of a string of spaghetti, is advanced through the first catheter. This microcatheter travels through the arteries and into the aneurysm itself. Next, small platinum coils are advanced through the catheter until they emerge inside the aneurysm Once again, contrast agent is injected to allow the doctor to see the coils on the fluoroscope monitor. If the position is good, the doctor releases the coil from a guide wire. Coils are inserted in this manner, one after another, until the aneurysm is packed. Sometimes an inflatable balloon is used to guide coils into the aneurysm.
Some aneurysms with a wide neck or unusual shape require a stent to help hold the coils in place. The stent is advanced through the catheter and positioned in the normal artery next to the aneurysm. A stent is a small, metal, mesh tube that conforms to the shape of the artery. The guide wire is passed through the mesh to deliver coils into the aneurysm. The stent remains in the artery permanently holding the coils in place.
By injecting contrast agent, the doctor inspects the coils to ensure that blood is no longer flowing into the aneurysm. This technique also verifies that the coils are inside the aneurysm and not narrowing the main artery.
The catheter is then removed. Pressure is applied to the groin area for about 10 to 15 minutes so that the artery won't bleed. A bandage is tightly applied to the incision.
In some patients, an Angio-Seal may be used to close the puncture site in the artery. It seals the opening by sandwiching an anchor inside the artery with a collagen sponge outside the artery. A suture holds the sandwich together. In about 60 to 90 days, the body absorbs the anchor and sponge naturally.