Not yet taking people in FranceNo phase

Surveillance Versus Treatment of Unruptured Intracranial Aneurysms of Fortuitous Discovery

Key facts

Who runs it: Assistance Publique - Hôpitaux de Paris
Where: Paris, FranceSee the site
Trial code: NCT07817511
Status: Not yet recruiting
People taking part: 600 people, planned
Started: Nov 2026
Expected to end: May 2033
Type of study: Interventional, 2 groupsOne group gets an existing treatment, for comparison.
Treatments tested: Clinical and imaging surveillance
Endovascular or neurosurgical aneurysm treatment
Record updated: 14 September 2026

Who can take part

Age: 35 years to 75 years
Sex: Women and men
Healthy volunteers: Cannot take part

The registry criteria, word for word

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Who can take part

UIA (Unruptured Intracranial Aneurysms) located in an intradural position, with confirmed presence on CT (Computed Tomography) angiography or conventional cerebral angiography
Largest diameter between 2 mm and 7.9 mm inclusive in height or width (excluding oblique measurements)
Patients with one or more UIAs, provided that at least one aneurysm (index aneurysm) fulfills all inclusion criteria and is selected for study evaluation
Patients aged ≥ 35 years to 75 years
Patients must have signed informed consent
Patients must be affiliated with the French healthcare system

Who cannot take part

Aneurysms deemed inoperable by endovascular or surgical techniques, and patients with absolute contraindications to anaesthesia
Patients with a history of prior treatment for a cerebral aneurysm (ruptured or unruptured)
Patients with a disease reducing life expectancy to less than 3 years
History of unexplained SAH (Subarachnoid Haemorrhage)
Patients with autosomal dominant polycystic kidney disease (ADPKD), hereditary connective tissue disorders (HCTDs), or sickle cell disease (SCD)
Allergy to iodinated contrast material
Severe renal impairment (Glomerular Filtration Rate (GFR) < 30 mL/min/1.73m2)
Patients with a mRS score of ≥2
UIA discovered in the context of a recent thunderclap or exertional headache
Fusiform, mycotic, or intracavernous UIAs
Infundibulum of the posterior communicating artery (PcomA) and choroidal artery
Very distal saccular UIAs: A3/A4, M3/M4, P3/P4
UIA associated with brain AVM (Arteriovenous Malformation)
Patients presenting with multiple UIAs in whom at least one aneurysm measures ≥ 8 mm, in order to avoid inclusion of patients at higher overall rupture risk not compatible with the study population
Pregnancy or a desire for pregnancy during the study period
Current participation in another interventional research study
Patients likely to fail to attend follow-up visits or adhere to the protocol

Check if you might fit

Answer for yourself. This is not a decision: only the study team can say whether you can take part.

Are you between 35 and 75 years old?

Where in France

Service de Neuroradiologie - Hôpital Lariboisière - APHP NordParis, FranceContact: Alexis GUEDON, MD,PhDNo longer taking part

About the trial

What the trial wants to find out

The goal of this clinical trial is to determine whether a watchful waiting strategy with imaging surveillance is superior to immediate aneurysm treatment in adults with incidentally discovered unruptured intracranial aneurysms (UIAs).

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The main questions it aims to answer are:

* Does watchful waiting reduce the risk of clinically significant neurological disability compared with immediate treatment? * How do the two strategies compare in terms of aneurysm rupture, treatment-related complications, quality of life, anatomical outcomes, and healthcare costs?

Researchers will compare two management strategies:

* Immediate selective treatment of the aneurysm (endovascular or neurosurgical treatment according to standard practice). * Watchful waiting with regular clinical and imaging follow-up and no initial aneurysm treatment.

Participants will:

* Be randomly assigned to either immediate treatment or watchful waiting. * Undergo routine clinical assessments and annual brain imaging for at least 42 months. * Complete quality-of-life questionnaires (EQ-5D-5L) at baseline and annually during follow-up. * Participate in annual telephone follow-up assessments, including evaluation of functional outcome using the modified Rankin Scale (mRS). * Undergo a blood or urine pregnancy test at enrollment if they are women of childbearing potential.

The study includes adults aged 35 years or older with incidentally discovered, non-infectious, intradural saccular UIAs measuring between 2.0 mm and 7.9 mm and no history of subarachnoid hemorrhage. The primary objective is to compare the impact of the two management strategies on neurological dependency during follow-up.

The 2 groups in the trial

Watchful waiting strategyTreatment being tested
Participants randomized to the watchful waiting strategy will receive no immediate preventive treatment of the unruptured intracranial aneurysm. This strategy consists of initial non-interventional management with standard clinical follow-up and annual brain imaging according to standard care. In the case of patients with multiple aneurysms, all aneurysms will be monitored under the same watchful waiting protocol. Selective treatment is not performed at baseline, but may be considered during follow-up if clinically indicated.
Treatment: Clinical and imaging surveillance
Intervention strategyExisting treatment, for comparison
Participants undergo immediate preventive treatment of the incidentally discovered unruptured intracranial aneurysm using standard endovascular or neurosurgical techniques. Post-procedural follow-up is conducted according to standard care (clinical follow-up and annual brain imaging).
Treatment: Endovascular or neurosurgical aneurysm treatment