Endovascular Embolization or Coiling
Endovascular (meaning within the blood vessel) embolization, or coiling, uses the natural access to the brain through the bloodstream via arteries to diagnosis and treat brain aneurysms. The goal of the treatment is to safely seal off the aneurysm and stop further blood from entering into the aneurysm and increasing the risk of rupture or possibly rebleeding.
Endovascular treatment of aneurysms is a treatment that became available in the 1980’s. With the advent of this treatment, some patients who previously may have been told they had inoperable aneurysms are now given an alternative and a chance for treatment. Currently many aneurysms that are amenable to surgery for clipping can also be considered for coiling and the risk and benefits of each treatment must be discussed with the treating physicians. In some patients, because of advanced age, serious medical problems or other factors that increase the risk of brain surgery for clipping, coiling is the preferred treatment.
A small incision is made over the artery and a needle is used to puncture the blood vessel. A sheath (hollow thin tube) is then placed in the artery, which provides constant access to the artery. This catheter sheath can remain in the artery for 24 to 48 hours after the procedure, so that further interventions can be performed, if necessary. Using a catheter (hollow plastic tube) over a guiding wire, the artery leading to the aneurysm is selected. The wire is removed and the catheter is used to inject a contrast dye into the blood stream in order to visualize the normal blood vessels as well as delineate the aneurysm.
The entire process is done using continual x-ray visualization and high-speed radiographic filming techniques. The doctor takes measurements and views of the aneurysm. Once the angiogram has detected the presence, size, and location of the aneurysm, a smaller “micro catheter” is then placed inside the initial catheter. Once the micro catheter is successfully navigated into the aneurysm opening, the coil system is introduced.
Platinum coils are deposited into the aneurysm, reducing or blocking the flow of blood into the aneurysm. Once placed inside the aneurysm, a small electrical current is passed through the wire. As a result of this electrolysis, the coil detaches from the wire and remains inside the aneurysm. The wire is removed. It may take several coils to obliterate the aneurysm. In some cases the opening into the aneurysm may be wide, and a balloon or a small stent can be placed inside the blood vessel along the neck of the aneurysm to assist in the coiling procedure. If a balloon is used, it is deflated and removed at the end of the procedure. If a stent is used, it is implanted permanently into the artery, sometimes in a separate procedure, prior to coiling. The stent acts as a scaffold inside the artery to help keep the coils in place inside the aneurysm. After aneurysm packing with coils, the catheter systems are removed and the patient is transferred to the Intensive Care Unit for monitoring and further care.