Endovascular coiling, or endovascular emobilization, is a surgical treatment for cerebral aneurysm

Cerebral aneurysm

A cerebral or brain aneurysm is a cerebrovascular disorder in which weakness in the wall of a cerebral artery or vein causes a localized dilation or ballooning of the blood vessel.- Signs and symptoms :...

s. It was developed in 1991 by Guido Guglielmi at UCLA

Ronald Reagan UCLA Medical Center

The Ronald Reagan UCLA Medical Center is a hospital located on the campus of the University of California, Los Angeles in Los Angeles, California....

. It is one of two surgical treatments for aneurysms, the other being surgical clipping.

Procedure

The treatment uses detachable coils made of platinum that are inserted into the aneurysm using a microcatheter. A variety of coils are available. In the case of wide-necked aneurysms, a stent

Stent

In the technical vocabulary of medicine, a stent is an artificial 'tube' inserted into a natural passage/conduit in the body to prevent, or counteract, a disease-induced, localized flow constriction. The term may also refer to a tube used to temporarily hold such a natural conduit open to allow...

may be used as well. The treatment works by promoting blood clotting around the coils, eventually sealing the aneurysm and reducing pressure on its outer wall.

There are a number of coil types used in the procedure. These include Guglielmi Detachable Coils (GDC) which are platinum, Matrix coils which are coated with a biopolymer, and hydrogel coated coils.

Studies

A number of studies have questioned the efficacy of endovascular coiling over the more traditional surgical clipping. Most concerns involve the chance of later bleeds or other recanalization. Due to its less invasive nature, endovascular coiling usually presents faster recovery times than surgical clipping.

A 2007 study by Jacques Moret and colleagues indicates that 28.6% of aneurysms recurred within one year of coiling, and that the recurrence rate increased with time. These results are similar to those previously reported by other endovascular groups. Other studies have questioned whether new matrix coils work better than bare platinum coils.

International Subarachnoid Aneurysm Trial

The International Subarachnoid Aneurysm Trial, or ISAT, was a large clinical trial that tested the efficacy of endovascular coiling against the traditional micro-surgical clipping. The study initially found very favorable results for coiling, however its results and methodology were criticized. Since the study's release in 2002, and again in 2005, some studies have found higher recurrence rates with coiling, while others have concluded that there is no clear consensus between which procedure is preferred.