Coiling is a MINIMALLY INVASIVE ENDOVASCULARPROCEDURE performed to treat an aneurysm - a balloon-like bulge or weakening of an artery wall. As an aneurysm grows, it thins and weakens. It can become so thin that it leaks or ruptures, releasing blood into the space around the brain. This bleeding is called a subarachnoid hemorrhage (SAH) and is life threatening.
The goal of endovascular coiling is to isolate an aneurysm from the normal circulation without blocking off any small arteries nearby or narrowing the main vessel. A flexible catheter is advanced from the femoral artery to one of four arteries in the neck that lead to the brain. Once the catheter reaches the aneurysm, a very thin platinum wire is inserted. The wire coils up as it enters the aneurysm and is then detached. Multiple coils are then packed inside the dome to block normal blood flow from entering. Over time, a clot forms inside the aneurysm, effectively removing the risk of aneurysm rupture. Coils remain inside the aneurysm permanently. Coils are made of platinum and other materials, and come in a variety of shapes, sizes, and coatings that promote clotting.
No procedure is without risk. General complications related to an invasive procedure include infection, allergic reactions to anesthesia, stroke, seizure, and bleeding. Complications specifically related to aneurysm coiling include:
- Blood clots (thromboembolism): clots can form inside the guiding catheter, on the coils, or in the parent vessels. Clots can break loose and travel downstream to block a smaller artery, potentially causing a stroke. Blood clots occur in 8% of cases, but stroke only occurs in 3% [5]. Giving heparin during the procedure reduces clot formation.
- Aneurysm rupture: caused by puncture of the aneurysm with the catheter, guidewire, or the coils.
- Vasospasm: an abnormal narrowing or constriction of an artery resulting from irritation by blood in the subarachnoid space or from catheter manipulation during an endovascular procedure. Vasospasm can be treated with drugs and angioplasty.
- Coil position: after placement, some coils may protrude out of the aneurysm neck and narrow the parent artery. A stent or temporary balloon may be inflated to push the coils back into the aneurysm. In rare cases, coils can travel downstream during the procedure. These coils are retrieved to prevent them from blocking a smaller artery, potentially causing a stroke. It is rare for a coil to move out of the aneurysm after the procedure is complete. However, coils can compact into the aneurysm allowing blood to re-enter.
- Incomplete occlusion: occurs when coils do not completely fill the aneurysm, leaving a residual neck. Blood can enter the residual neck and cause the aneurysm to regrow (recur).
