Surveillance Versus Treatment of Unruptured Intracranial Aneurysms of Fortuitous Discovery

NCT07817511 | Not Yet Recruiting

• 2 other identifiers: APHP2409472025-A01905-44
• Study Type: interventional
• Target: 600
• Locations: 1 country
• Sites: 1

Brief Summary

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). 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.

Conditions

Intracranial Aneurysm; Unruptured Intracranial Aneurysm

Keywords

Unruptured Intracranial Aneurysm; UIA; Incidental Intracranial Aneurysm; Endovascular Treatment; Conservative Management; Imaging Surveillance; Subarachnoid Hemorrhage; mRS

Outcome Measures

Primary Outcomes (1)

• Occurrence of a clinically significant event

  The primary outcome is the occurrence of a clinically significant event during follow-up (minimum duration 3.5 years - maximum 6.5 years, mean duration of 5 years). A clinically significant event is defined as the occurrence of a functional disability with a modified Rankin Scale (mRS) score ≥ 2, persisting for more than 90 days, attributable to the natural history of the aneurysm or to its preventive treatment, as adjudicated by an independent committee.

  From randomization until the occurrence of a mRS score ≥ 2, assessed up to 90 days after occurence by an independent neurologist, blinded to treatment allocation

Secondary Outcomes (10)

• Distribution of modified Rankin Scale

  Through study completion, an average of 5 years

• Occurrence of a transient modified Rankin Scale ≥ 3

  Up to the occurrence of a mRS score ≥ 3, assessed by an investigator

• SAH occurrence

  Through study completion, an average of 5 years

• Rupture rate

  Through study completion, an average of 5 years

• Iatrogenic complications

  Through study completion, an average of 5 years

Study Arms (2)

Watchful waiting strategy

EXPERIMENTAL

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.

Other: Clinical and imaging surveillance

Intervention strategy

ACTIVE COMPARATOR

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).

Procedure: Endovascular or neurosurgical aneurysm treatment

Interventions

Clinical and imaging surveillance OTHER

Participants undergo active surveillance of incidentally discovered unruptured intracranial aneurysms without initial preventive treatment. Management includes routine neurological follow-up and brain annual imaging according to routine clinical practice. Imaging consists of a 3D Time-of-Flight Magnetic Resonance Imaging (TOF MRI) sequence (or contrast-free CT (Computed-Tomography) and CT angiography of the circle of Willis in case of contraindications, and catheter angiogram with 3D if needed). Treatment will only be considered in the presence of predefined criteria suggestive of increased aneurysm related risk (e.g., aneurysm growth or clinical deterioration).

Watchful waiting strategy

Endovascular or neurosurgical aneurysm treatment PROCEDURE

Participants undergo immediate preventive treatment of the unruptured intracranial aneurysm according to standard clinical practice. Treatment modalities include endovascular procedures (e.g., coiling, stent-assisted coiling, flow diversion) or neurosurgical clipping, as determined by the treating physician. For patients with multiple aneurysms (≤7.9 mm), the operating investigator chooses at least one aneurysm to treat, while the treatment of any additional aneurysms is at the discretion of the team. Subsequent follow-up is performed according to standard clinical care (radiological follow-up at least annually, using the technique deemed most appropriate by the team). In case of recanalization, the choice and technique for additional treatment are left to the discretion of the team.

Intervention strategy

Eligibility Criteria

• Age: 35 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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 aged ≥ 35 years to 75 years.
• Patients must have signed informed consent.
• Patients must be affiliated with the French healthcare system.

You may not qualify if:

• Aneurysms deemed inoperable by endovascular or surgical techniques, and patients with absolute contraindications to anaesthesia.
• Patients with a disease reducing life expectancy to less than 3 years.
• Patients with a mRS score of ≥2.
• Patients with a history of prior treatment for a cerebral aneurysm (ruptured or unruptured).
• History of unexplained SAH (Subarachnoid Haemorrhage).
• 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).
• Pregnancy or a desire for pregnancy during the study period.
• Patients with autosomal dominant polycystic kidney disease (ADPKD), hereditary connective tissue disorders (HCTDs), or sickle cell disease (SCD).
• Current participation in another interventional research study.
• Patients likely to fail to attend follow-up visits or adhere to the protocol.
• Allergy to iodinated contrast material.

Sponsors & Collaborators

• Assistance Publique - Hôpitaux de Paris: lead

Study Sites (1)

Service de Neuroradiologie - Hôpital Lariboisière - APHP Nord

Paris, Île-de-France Region, 75010, France

Location

MeSH Terms

Conditions

Intracranial Aneurysm; Subarachnoid Hemorrhage

Condition Hierarchy (Ancestors)

Intracranial Arterial Diseases; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Aneurysm; Vascular Diseases; Cardiovascular Diseases; Intracranial Hemorrhages; Hemorrhage; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Alexis GUEDON, MD,PhD

  Department of Neuroradiology, Lariboisière Hospital, APHP Nord

  STUDY CHAIR

• Emmanuel HOUDART, MD

  Department of Neuroradiology, Lariboisière Hospital, APHP Nord

  STUDY DIRECTOR

Central Study Contacts

Alexis GUEDON, MD,PhD

CONTACT

+33149958117; alexis.guedon@aphp.fr

Emmanuel HOUDART, MD

CONTACT

+33149956135; emmanuel.houdart@aphp.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: This is an open-label trial; participants and treating physicians are not blinded to treatment allocation. However, outcome assessment includes blinded and independent evaluation components. The modified Rankin Scale (mRS) is assessed by an independent neurologist blinded to treatment allocation at baseline, at hospital discharge after aneurysm treatment, at the final study visit, and in case of suspected neurological deterioration identified during follow-up. In addition, all primary outcome events are reviewed by an independent adjudication committee. The committee is not blinded to treatment allocation and evaluates whether each clinically significant event (defined as mRS ≥2 persisting for more than 90 days) is attributable to the natural history of the aneurysm or to its preventive treatment.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Participants are randomized in a 1:1 ratio to one of two parallel treatment strategies. The intervention group undergoes immediate selective treatment of the unruptured intracranial aneurysm according to standard clinical practice (endovascular or neurosurgical treatment). The comparator group is managed with a watchful waiting strategy consisting of clinical and imaging surveillance without initial aneurysm treatment. Randomization is stratified by participating center, age group (35-55 years versus 56-75 years), and aneurysm size (\<5 mm versus ≥5 mm). The study uses a prospective, multicenter, open-label, parallel-group design with blinded adjudication of study outcomes (PROBE design).

Study Record Dates

• First Submitted: July 7, 2026
• First Posted: September 14, 2026
• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): May 1, 2033
• Study Completion (Estimated): May 1, 2033
• Last Updated: September 14, 2026

Record last verified: 2026-09

Data Sharing

• IPD Sharing: Will not share

Locations

FR (1)