The procedure of endovascular coiling is used to stop blood flow into an aneurysm (a weakened area in the wall of an artery). Endovascular coiling is a newer treatment for aneurysms that has been performed in patients since 1991. Endovascular coiling is a minimally invasive method that eliminates the need for a skull incision to treat a brain aneurysm. To reach the aneurysm in the brain, a catheter is used instead.
A catheter is inserted via the groin into the artery containing the aneurysm during endovascular coiling. After that, platinum coils are released. The coils cause clotting (embolization) of the aneurysm, preventing blood from flowing into it.
The purpose of endovascular coiling is to isolate an aneurysm from the rest of the body’s circulation without obstruction or narrowing the main vessel.
Endovascular Coiling is the minimally invasive technique of reaching the aneurysm from within the bloodstream, specifically during angiography. The femoral artery in the upper leg is the location. The bloodstream is entered through it. From the femoral artery, a flexible catheter is advanced to one of four arteries in the neck that lead to the brain. The doctor guides the catheter through the blood vessels while injecting a specific dye that allows the doctor to see the vessels on the monitor. As a result, a kind of artery map develops.
A very thin platinum wire is placed after the catheter reaches the aneurysm. As the wire enters the aneurysm, it coils up and is then disconnected. Inside the dome, several coils are packed to prevent normal blood flow from entering. A clot grows inside the aneurysm over time, effectively eliminating the risk of rupture. The coils remain permanently inside the aneurysm. Coils, which are made of platinum and other materials, come in a range of forms, diameters, and clotting-promoting coatings. Coils do the same thing on the inside as a surgical clip on the outside: they stop blood from flowing into the aneurysm while allowing blood to flow freely through the normal arteries.
Aneurysms occur in a variety of sizes and shapes. Saccular aneurysms have a neck and a dome that can expand like a balloon at their origin on the main artery. Other types of aneurysms, known as wide-necked or fusiform, lack a distinct neck. Coil placement in these aneurysms might be difficult, requiring additional support from stents or balloons. Coiling is not an option for some aneurysms; thus, they must be surgically clipped.
The danger of rupture and the patient’s overall health must be considered before deciding on aneurysm treatment (observation, surgical clipping or bypass, or endovascular coiling).
The following conditions may benefit from coiling:
Ruptured Aneurysm: A subarachnoid hemorrhage (SAH) occurs when aneurysms rupture and spill blood into the space between the brain and the skull. Within the first 14 days after the initial bleed, there is a 22% chance of bleeding again. As a result, treatment must be started within 72 hours following the first bleed. A typical consequence of SAH is vasospasm (narrowing of an artery).
Unruptured Aneurysm: Unruptured Aneurysms are commonly detected through routine testing for another condition and do not cause symptoms. Aneurysm rupture occurs about 1% a year, however the risk varies based on the size and location of the aneurysm. When a rupture occurs, however, the risk of death is 40%, and the chance of disability is 80%.
Through the initial catheter, a microcatheter is introduced. The microcatheter is attached to the coil. An electrical current is used to detach the coil from the catheter once the microcatheter has reached the aneurysm and been inserted into the aneurysm. The coil seals off the aneurysm’s opening. The coil is left in the aneurysm permanently. Depending on the aneurysm’s size, more than one coil may be required to completely seal it off.
The coils used in this treatment are formed like a spring and are made of soft platinum metal. These coils are extremely small and thin, ranging in size from twice the width of a human hair (biggest) to less than one hair’s width (smallest).
This treatment is aided with fluoroscopy (a specific type of x-ray). The catheter, which is put into a groin into the Femoral artery, is directed along the length of the blood vessel by a thin wire inside the catheter to reach the aneurysm. The catheter is guided to the aneurysm’s site in the brain using fluoroscopy.
A stent is used to help keep the coils in place in aneurysms with a wide neck or odd shape. The stent is inserted into the healthy artery next to the aneurysm through the catheter. A stent is a metal tube that looks like chicken wire and adheres to the contour of the artery. To send coils into the aneurysm, the guide wire is passed through the stent. The stent is permanently implanted in the artery, keeping the coils in place.
Flow Diverter Stent. Across the aneurysm, a densely woven mesh tube is put inside the parent artery. Blood flows inside the flow-diverter and continues down the artery without entering the aneurysm because blood cannot readily pass through the gaps of the tight mesh stent. The aneurysm will clot and diminish in 6 weeks to 6 months if there is no pulsating blood flow.
Intrasaccular flow Disruptor. Inside the sac of the aneurysm, a densely woven mesh basket is implanted. It forms a bridge across the aneurysm’s large neck, preventing blood from passing through the tight mesh’s spaces. Blood continues to flow down the artery without entering the aneurysm.
Endovascular coiling for aneurysms has a long-term success rate of 80 to 85 percent. Recurrence of aneurysms following coiling occurs in 20% of patients. If the coils do not entirely block off the aneurysm or if the coils become compacted within the aneurysm, recurrence occurs. A recurrence may not be severe enough to necessitate further treatment. Additional coils or a surgical clip can be used to limit aneurysm expansion if a significant amount of the aneurysm remains empty. In general, 5-10% of patients will require a second procedure to insert more coils, which usually occurs within the first year.
Complete closure of aneurysms treated with a flow diversion stent occurs between 6 weeks to 6 months after the operation. To avoid clots from sticking to the stent, you’ll need to take two antiplatelet (blood thinner) medications for several weeks.
Because endovascular coiling has a higher risk of aneurysm recurrence than surgical clipping, all patients with coiled aneurysms should have a diagnostic angiogram at 6, 12, and 24 months to check for a residual or returning aneurysm. Three months after an aneurysm rupture, the patient should be evaluated again. Although angiography is an intrusive treatment, the risk of complications associated with angiographic monitoring of coiled aneurysms is minimal.
A patient with a recurrent coiled aneurysm should be examined by MRA once a year for the next three years (years 3, 4, and 5).
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