Figure 2. Brain MRA (axial cuts) showing an enlarged 15mm x 6.5mm posterior communicating artery aneurysm (dashed circle).
The aneurysm remained asymptomatic. The patient’s past medical history was remarkable for arterial hypertension, depression, chronic constipation, non-insulin dependent diabetes mellitus, memory problems, arthritis, and minor ischemic stroke. Hypertension and diabetes were adequately managed with oral medication.
Due to the rapid change in size the patient was at increased risk for complications arising from continuous growth and worsening instability of the arterial wall (with potential rupture) of the aneurysm. Eradication of the aneurysm was recommended, and treatment was performed with endovascular coiling (Figure 3).
The embolization was successful, and the patient was discharged home.
Figure 3. Pre-operative cerebral angiogram, left internal carotid artery injection (A/B: lateral/AP view; C: 3D reconstruction) showing an enlarged 15mm x 6.5mm posterior communicating artery aneurysm (A-C: dashed circle). Cerebral angiogram post endovascular coiling, internal carotid artery injection (D: AP view; E: lateral view). Visualization of arterial branches of the anterior cerebral circulation. Coil mass inside the previous aneurysm, now without contrast filling (D/E: dashed circle)
The prevalence of brain aneurysms is estimated to be 3%1. Age and women are associated with increasing prevalence, as are autosomal dominant polycystic kidney disease and positive family history (one or more)1. Brain aneurysms commonly occur at bifurcations of cerebral arteries, most often at the base of the brain, and usually remain asymptomatic unless they grow to a significant size and mass effect starts to disrupt adjacent cranial nerves or vascular structures.
The major health risk is associated with the rupture of a brain aneurysm which causes subarachnoid hemorrhage (SAH), a condition that leads to death or disability in more than 80%2,3,4. The incidence of aneurysmal SAH in the US is approximately 30,000 per year5. Thus, most aneurysms will remain intact and likely asymptomatic over a person’s lifetime.
Due to increased utilization of brain imaging more aneurysms are found that are asymptomatic (incidental)6. Furthermore, longer life-expectancy and aging of the population elevate chances for detecting brain aneurysms later in life. In addition, longer life-expectancy also means that a middle-aged person with a brain aneurysm will be living with a potential risk of rupture for many decades. It is therefore important to have an adequate management plan for patients with unruptured brain aneurysms7.
The goal of treatment is eradication of the brain aneurysm and consists of endovascular embolization (coiling and stent-assisted procedures) or surgical clipping8,9. For most brain aneurysms, endovascular coiling is the primary mode of treatment8.
The risk of rupture must be weighed against the risk of adverse effects of any inpatient and invasive treatment. Tools are available to estimate the future chance of rupture which have been derived from meta-analyses of several large population-based observational and treatment studies10. Although not perfect, they offer a practical approach to risk assessment.
In our practice, the Center for Unruptured Brain Aneurysms of NSPC (CUBA), we have developed a sophisticated surveillance and treatment plan that currently manages several hundred patients with unruptured brain aneurysms. Surveillance involves medical treatment and behavioral modifications to improve known modifiable risk factors for aneurysm occurrence and growth.
The present case is an example that highlights the importance of this surveillance and treatment program. Risk assessment and the choice of follow-up intervals are individualized to the patient. This program is led by an inter-disciplinary team of highly experienced professionals.
Clearly, it would be most desirable to stabilize the aneurysm or even shrink the aneurysm with non-invasive means. However, our current understanding of brain aneurysms is still limited. NSPC’s Center for Unruptured Brain Aneurysms is an attempt to add to the knowledge to improve the care that we can give to the many patients living with this condition. Until we manage to unravel the unknown surrounding this arterial wall-remodeling disease, careful observation, treatment of known modifiable risk factors, and early intervention when indicated, are practices that are meant to disrupt the patient the least and benefit the patient the most.
A woman in her 70s with an asymptomatic and incidental left posterior communicating artery aneurysm (9mm x 6mm, Figure 1) was enrolled in NSPC’s specialized brain aneurysm surveillance program (the Center for Unruptured Brain Aneurysms, CUBA).
The brain aneurysm remained stable over three years as monitored with the annual imaging follow-up. However, in her fourth year of aneurysm surveillance the aneurysm had grown significantly to approximately 15mm x 6.5mm (Figure 2).