Brain Aneurysms: Diagnosis, Risk & Treatment
Being told you have a brain aneurysm can be frightening. Many people discover an aneurysm unexpectedly — on an MRI or CT scan ordered for a headache, a head injury, or another reason entirely. The first thing to know is that most unruptured aneurysms do not rupture, and many are safely managed without immediate surgery. The most important step you can take is getting an evaluation by a team with deep experience in cerebrovascular disease.
At UNMH, our neurovascular team — comprising neurosurgeons, neurointerventional specialists, and vascular neurologists — evaluates every aneurysm individually and recommends the approach that is safest and most appropriate for you. We offer the full spectrum of treatment options, including the most advanced minimally invasive techniques available in New Mexico.
What Is a Brain Aneurysm?
A brain aneurysm is a weak or thin spot in the wall of an artery in or around the brain that balloons outward under the pressure of blood flow. Over time, the bulging wall can stretch and weaken further. Most aneurysms are small and stable; some grow over time; and a small percentage can rupture, causing a life-threatening bleed around the brain called a subarachnoid hemorrhage (SAH).
The most common type — called a saccular or 'berry' aneurysm — looks like a small round pouch attached to an artery. These typically form at the points where arteries branch, where the vessel walls experience the most mechanical stress. Less commonly, an aneurysm can affect a longer stretch of the artery wall, creating a more elongated bulge called a fusiform aneurysm.
How Common Are They? Brain aneurysms are more common than most people realize. Studies estimate that approximately 3 to 5 percent of the population has an unruptured brain aneurysm — the vast majority of whom will never know it and never have a problem. The challenge for your medical team is determining which aneurysms carry enough risk to warrant treatment, and which can be safely monitored.
Risk factors for developing a brain aneurysm include:
- Hypertension: High blood pressure (hypertension)
- Smoking: Current or past cigarette smoking — one of the strongest modifiable risk factors
- Family history: A family history of brain aneurysms or subarachnoid hemorrhage (especially in a first-degree relative)
- Genetic conditions: Certain genetic conditions, including polycystic kidney disease and connective tissue disorders such as Ehlers-Danlos syndrome
- Prior aneurysm: Prior history of a brain aneurysm (patients with one aneurysm have a higher chance of having additional aneurysms)
Understanding the Risk of Rupture
Not all aneurysms behave the same way. One of the most important things your neurovascular team will do is carefully assess your aneurysm's specific characteristics to estimate its rupture risk — and weigh that risk against the risks of treatment. This is not a one-size-fits-all decision.
Factors That Influence Rupture Risk
| Factor | Higher Risk | What This Means |
|---|---|---|
| Size |
Larger aneurysms (especially >7 mm) |
Smaller aneurysms (<5 mm) generally carry lower annual rupture risk. Risk rises significantly with size. Very large or 'giant' aneurysms (>25 mm) carry the highest risk. |
| Location | Anterior or posterior communicating artery, basilar tip, posterior circulation | Aneurysms in certain locations — particularly the back of the brain (posterior circulation) — tend to rupture more readily than those in other locations. |
| Shape & Apperance | Irregular shape, lobulated contour, 'daughter sac' (a small bud on the aneurysm dome) | A smooth, round aneurysm is generally lower risk. Irregular shapes or small outpouchings on the dome suggest wall instability and higher rupture risk. |
| Growth on Imaging | Any increase in size on follow-up imaging | An aneurysm that is growing — even if still small — is a warning sign that warrants reassessment of treatment options. |
| Symptoms | An aneurysm causing symptoms (e.g., headache, eye drooping, double vision) without rupture | A symptomatic aneurysm — particularly one pressing on a nearby nerve — may be at higher risk of rupture and typically warrants prompt treatment. |
| Personal History | Smoking, poorly controlled high blood pressure | Both significantly increase rupture risk and are important targets for medical management regardless of treatment decision. |
| Family History | First-degree relative with SAH | A family history of rupture suggests a possible heritable tendency toward aneurysm formation and rupture. |
Your UNMH neurovascular team uses validated clinical tools — including the PHASES score, which incorporates population, hypertension, age, aneurysm size, earlier subarachnoid hemorrhage, and aneurysm site — to estimate your individual five-year rupture risk. This score helps guide a transparent, shared discussion about whether and when to treat.
Why Rupture Is So Serious: The Consequences of SAH
When a brain aneurysm ruptures, it causes a subarachnoid hemorrhage (SAH) — bleeding into the space surrounding the brain. SAH is a life-threatening emergency and one of the most devastating forms of stroke. Understanding the consequences of rupture is an important part of the conversation about whether to treat an unruptured aneurysm.
Up to 30–40%
of patients who suffer a ruptured aneurysm do not survive to hospital discharge
~50%
of SAH survivors are left with lasting neurological disability affecting daily life
10–15%
of patients with SAH die before reaching the hospital
Those who do survive SAH often face a prolonged and difficult recovery, including risk of rebleeding in the first hours to days, arterial spasm (vasospasm) that can cause a secondary stroke days after the initial rupture, hydrocephalus (fluid buildup in the brain requiring drainage), and significant cognitive and physical rehabilitation needs.
The best time to treat an aneurysm is before it ruptures. For the right patient, elective treatment of an unruptured aneurysm — performed by an experienced team in a controlled setting — carries far lower risk than treating the same aneurysm after it has bled.
How Brain Aneurysms Are Managed
There is no single right answer for every aneurysm. Treatment decisions are made collaboratively by a multidisciplinary team — including a neurosurgeon, a neurointerventional specialist, and a vascular neurologist — and are tailored to your aneurysm's specific characteristics, your overall health, and your preferences. At UNMH, all complex aneurysm cases are discussed at our neurovascular conference, where the team recommends the safest and most durable treatment strategy.
There are three broad categories of aneurysm management:
Option 1: Endovascular Treatment (Minimally Invasive)
What Endovascular Means: Endovascular procedures are performed through a small puncture in the wrist or groin — no open brain surgery required. A thin, flexible tube (catheter) is guided through the blood vessels to reach the aneurysm in the brain. Most patients spend one to two days in the hospital after an elective endovascular procedure and return to normal activities within one to two weeks.
Endovascular Coil Embolization (Coiling)
Coiling is one of the most common treatments for brain aneurysms. Tiny platinum coils are threaded through the catheter into the aneurysm sac, where they pack tightly together. This fills the aneurysm, prevents blood from flowing into it, and triggers the body's natural clotting process to seal it off. Coiling is particularly well-suited for aneurysms with a narrow neck. For aneurysms with a wide neck or difficult configuration, stent-assisted coiling can be performed. A stent is a small tube that helps hold the coils in place.
Intrasaccular Flow Disruptors (i.e. Woven EndoBridge (WEB) Device ) — First in New Mexico at UNMH
The WEB device is an innovative, single-session treatment for wide-necked aneurysms at arterial branch points — aneurysms that were historically more challenging to treat with conventional coiling. A small, mesh-like implant is deployed directly inside the aneurysm, disrupting blood flow into the sac and allowing it to heal. The WEB device requires no stent, which in many cases means patients do not need prolonged dual antiplatelet therapy after the procedure.
UNMH First in New Mexico: UNMH was the first hospital in New Mexico to offer the WEB device. Our team has performed this procedure in patients who previously had limited endovascular options.
Flow Diversion — Pipeline Embolization Device (PED) or Surpass Evolve
A flow diverter is a small, densely woven mesh tube placed inside the parent artery that feeds the aneurysm. Rather than filling the aneurysm directly, the device redirects blood flow away from the aneurysm and across its opening, causing the aneurysm to gradually clot off and shrink over months. It is particularly effective for large, giant, or fusiform aneurysms that are difficult to treat with other methods.
UNMH First in New Mexico: UNMH was the first center in New Mexico to offer the Pipeline Embolization Device. This technology has expanded treatment options for patients with complex aneurysms that were previously considered very difficult or impossible to treat safely.
Option 2: Microsurgical Clipping (Open Surgery)
Surgical clipping is a time-tested, highly effective treatment for brain aneurysms. A neurosurgeon makes a small opening in the skull (craniotomy) and navigates carefully to the aneurysm using a surgical microscope. A tiny titanium clip is then placed across the neck of the aneurysm, cutting off blood flow into it permanently. The clip remains in place for life and does not require blood-thinning medication after the procedure.
Surgical clipping remains the preferred treatment for certain aneurysm types — particularly those with a very wide neck, those that have previously been coiled and require retreatment, or those in locations that are more accessible through surgery. It is also associated with very high rates of complete and durable aneurysm closure, often confirmed immediately on angiography performed in the operating room.
Recovery from microsurgical clipping is typically two to four days in the hospital, followed by several weeks of recovery at home. The majority of patients return to full activity within four to six weeks.
Option 3: Medical Management & Observation
Not every aneurysm needs to be treated right away — or at all. For small aneurysms in lower-risk locations, particularly in older patients or those with significant other health conditions, the risks of intervention may outweigh the risks of rupture. In these cases, the recommended approach is active surveillance: regular imaging to monitor the aneurysm for growth, combined with aggressive risk factor management.
Medical management focuses on the two most powerful modifiable risk factors:
- Blood Pressure Control: Uncontrolled hypertension is one of the leading contributors to aneurysm growth and rupture. Maintaining blood pressure at goal — typically below 130/80 mmHg — is one of the most important things you can do to reduce your risk. Your primary care provider and stroke team will work together on blood pressure management.
- Smoking Cessation: Smoking dramatically increases the risk of aneurysm rupture and is also associated with worse outcomes after treatment. Quitting smoking — at any age — reduces rupture risk over time. Our team can connect you with evidence-based cessation support.
- Avoid Triggers: Heavy alcohol consumption and recreational drug use (particularly cocaine and methamphetamine, which cause sudden spikes in blood pressure) should be avoided.
Surveillance imaging — typically an MRI angiogram (MRA) or CT angiogram (CTA) — is recommended at regular intervals, usually six to twelve months after diagnosis and then annually or every few years depending on the findings. Any growth in the aneurysm, change in appearance, or new symptoms should prompt reassessment.
Observation Is Active Care: Choosing observation over treatment is not 'doing nothing.' It is an active, ongoing commitment to monitoring and risk factor control. Your UNMH team will provide a clear surveillance plan and will remain available to reassess your aneurysm at any time.
Comparing Treatment Approaches
The table below summarizes the key differences between the three management strategies. The best choice depends on your specific aneurysm, health, and individual circumstances.
| Endovascular (Coiling / WEB / PED) | Microsurgical Clipping | Medical Management & Observation | |
|---|---|---|---|
| Approach | Catheter through wrist or groin — no open surgery | Small opening in the skull; titanium clip placed on aneurysm neck | Regular imaging + aggressive risk factor management |
| Hospital Stay | 1–2 days (elective cases) | 2–4 days | No hospitalization required |
| Recovery Time | 1–2 weeks | 4–6 weeks | N/A — return to normal immediately |
| Best Suited For | Wide range of aneurysm types; large/complex aneurysms (PED); wide-neck bifurcation aneurysms (WEB) | Wide-neck aneurysms; previously coiled aneurysms; aneurysms accessible through surgery | Small, low-risk aneurysms; patients where intervention risk exceeds rupture risk |
| Durability | High; some aneurysms may require follow-up imaging or retreatment over years | Very high; complete closure often confirmed in the OR; rarely requires retreatment | Ongoing commitment to imaging surveillance and risk factor control |
| Blood thinners after procedure? | Sometimes required (coiling/PED); usually not required for WEB | Not required | Antiplatelet therapy may be recommended depending on other factors |
| Available at UNMH? | Yes — including WEB and PED, first in New Mexico | Yes | Yes — with structured surveillance program |
Aneurysm Care at UNMH: Our Experience
Choosing where to have your aneurysm evaluated and treated is one of the most important decisions you will make. Volume and experience matter: outcomes for complex cerebrovascular procedures are consistently better at high-volume centers with dedicated neurovascular teams. UNMH is that center for New Mexico.
Our Volume & Experience
- Approximately 50 ruptured aneurysm (subarachnoid hemorrhage) cases per year — the highest-volume SAH center in New Mexico
- New Mexico's only Comprehensive Stroke Center — the highest level of stroke care certification from The Joint Commission
- 24/7 neurovascular coverage: emergencies and elective cases handled by the same experienced team
Our Technology & Firsts
- First in New Mexico to offer the Woven EndoBridge (WEB) device
- First in New Mexico to offer the Pipeline Embolization Device (PED)
- Full spectrum of endovascular and microsurgical treatment options — no need to travel out of state
- Advanced intraoperative imaging to confirm complete aneurysm closure during surgery
- All complex cases reviewed at multidisciplinary neurovascular conference
For patients coming from outside Albuquerque or New Mexico, our team is experienced in coordinating evaluations and second opinions efficiently. Many patients receive a full assessment — imaging review, neurovascular consultation, and a treatment recommendation — within a short visit.
Learn More & Meet Our Team
Our neurovascular team includes specialists in neurosurgery, neurointerventional radiology, and vascular neurology, each with dedicated expertise in aneurysm management. We encourage you to review their backgrounds and experience before your consultation.
Getting an Evaluation at UNMH
If you have been diagnosed with an unruptured brain aneurysm and would like an evaluation or second opinion at UNMH, please contact our neurovascular program through your referring physician or primary care provider.