Cerebral Aneurysm Coiling

A brain aneurysm forms where an artery wall is weak, most often at a branching point of the arteries at the base of the brain. Blood pressure pushes the weak area outwards into a pouch that can slowly enlarge and, in some cases, burst. Coiling, also called endovascular coil embolisation, treats the aneurysm from inside the blood vessel. Under X-ray guidance, a catheter is passed through an artery to the neck, and an even finer microcatheter is steered into the aneurysm itself. Soft platinum coils, thinner than a hair and shaped to curl inside the pouch, are released one after another until the aneurysm is packed. Blood flowing into it slows and clots around the coils, sealing it from the circulation. Related techniques use a small stent or a temporary balloon to hold coils in a wide-necked aneurysm, or a flow diverter, a fine mesh tube placed in the parent artery that redirects blood past the aneurysm so it gradually closes.

When an aneurysm ruptures, it causes bleeding around the brain, called subarachnoid haemorrhage. The typical sign is a sudden, extremely severe headache that peaks within about a minute, called a thunderclap headache, sometimes with vomiting, a stiff neck or collapse. This is a medical emergency, and the aneurysm is usually secured within the first day or two to prevent a second, often more dangerous bleed. Unruptured aneurysms are a different situation. Many are found by chance on a scan done for another reason, and the decision to treat balances the risk of a future rupture against the risk of treatment. Size, location, shape, growth on repeat scans, previous bleeding, family history, age, smoking and blood pressure all influence the advice. Many small aneurysms are monitored with periodic imaging and careful blood pressure control rather than treated. When treatment is advised, a team of neurosurgeons and interventional neuroradiologists decides whether coiling, a related endovascular device or open surgical clipping suits the aneurysm.

Planned coiling is usually done under general anaesthesia in an angiography suite, a room fitted with X-ray equipment that produces detailed images of the blood vessels. A small sheath is placed in the artery at the top of the leg or at the wrist, and a catheter is guided up to the arteries of the neck. Contrast dye is injected to map the aneurysm in three dimensions, and its size and the width of its neck are measured. A microcatheter is then steered into the aneurysm and coils of graded sizes are released until it is densely packed. For wide-necked aneurysms, a temporary balloon or a permanent stent may be placed in the parent artery to hold the coils in place, or a flow diverter may be used on its own. Blood thinners are given during the procedure to prevent clots. A final angiogram confirms how well the aneurysm is sealed, the sheath is removed and the puncture site closed. The procedure usually takes about 1.5 to 3 hours.

Whether an unruptured aneurysm should be treated, and how, depends on a careful review of high-quality imaging, usually CT angiography or MR angiography, often followed by catheter angiography for detailed planning. Aneurysms with a narrow neck are generally well suited to coiling, while some wide-necked or unusually shaped aneurysms need a stent, a flow diverter or open surgery. Your kidney function, allergies, especially to contrast dye, and other medical conditions are checked. If a stent or flow diverter is planned, you usually start two antiplatelet tablets several days beforehand, with blood tests to confirm they are working, and must be able to continue them for months afterwards. Stopping smoking and controlling blood pressure are important whatever the decision. For international patients, scan images and reports can usually be reviewed remotely before travel, which makes a second opinion on whether to treat possible before any trip is booked.

After planned coiling, you are usually observed closely overnight, often in a high-dependency or intensive care area, with checks of your neurological function and the puncture site. Most people go home after one to three nights and return to normal daily activities within one to two weeks, avoiding heavy lifting and strenuous exercise for the first days. A mild headache for some days is common. If a stent or flow diverter was used, the antiplatelet tablets must be taken exactly as prescribed. For travel, it is sensible to stay about 7 to 10 days so your team can confirm you are well before flying. After a rupture, the picture is very different: intensive care, often for two weeks or more, careful monitoring for artery spasm and fluid build-up, and frequently rehabilitation. Families of patients treated after a rupture abroad should plan repatriation only when the team confirms it is safe. Follow-up imaging, often at about 6 months and later, can be arranged near home or abroad.

Coiling avoids opening the skull and is a well-established treatment, but it acts directly on the arteries of the brain, so it carries a small but real risk of serious complications. These include a stroke from a clot or a damaged vessel, rupture of the aneurysm during the procedure, bleeding or bruising at the puncture site, an allergic reaction to contrast dye and, with stents or flow diverters, bleeding linked to the antiplatelet medicines. Your team will discuss your personal risk based on the aneurysm and your health. Most coiled aneurysms remain sealed, but over time the coils can compact and blood can flow back into part of the aneurysm, which is why follow-up imaging matters. A minority of patients need a second treatment. Flow diverters close the aneurysm gradually, over months, rather than at once. For people treated after a rupture, the long-term outcome depends mainly on the severity of the original bleed rather than on the coiling itself.