International Subarachnoid Aneurysm Trial II (ISATII)

Centre hospitalier de l'Université de Montréal (CHUM)

Status: Active, not recruiting

Conditions: Intracranial Hemorrhage Ruptured Aneurysm

Treatments: Procedure: surgical management; Procedure: Endovascular management

Study type: Interventional

Funder types: Other

Identifiers

NCT01668563

CE 12.136

Details and patient eligibility

About

The purpose of this study is to compare the clinical outcome of surgical clipping and endovascular coiling for ruptured intracranial aneurysms not included in the original ISAT Study.

Full description

The International Subarachnoid Aneurysm Trial (ISAT) was a turning point in modern neurosurgical history (1). The trial showed that for 2143 subarachnoid hemorrhage (SAH)patients eligible for both surgery and endovascular coiling, randomized allocation to coiling was associated with better one year clinical outcomes, defined as survival without dependency (absolute risk reduction (ARR) of 7.4% (95%CI; 3.6 - 11.2, p=0.0001). Because ISAT was a positive pragmatic trial, the interpretation of the trial results was that coiling should be adopted as the first-line treatment for ruptured lesions, for patients with the types of aneurysms included in ISAT, of which the great majority were small (≥10 mm) anterior circulation aneurysms.

Although ISAT was well-designed, conducted, and reported, trial results were not always properly interpreted, and endovascular coiling was perhaps inappropriately extrapolated beyond what ISAT demonstrated. Endovascular treatment for ruptured aneurysms has now become first-line treatment in many centers (2), which may be appropriate for small, anterior circulation lesions, but there is no evidence to support this practice for the wide spectrum of non-ISAT patients and aneurysms. A recent pre-randomized study of coiling as first-intention (3)showed better results for those ruptured aneurysms felt to be readily coilable; however, the optimal management of more difficult-to-coil ruptured aneurysms remains unclear.

Further compounding the problem are the concerns that aneurysm coiling may not be as durable in the long-term as surgical clipping, leading many neurosurgeons to continue to clip most ruptured aneurysms in spite of ISAT results.

Proponents of endovascular treatment sometimes justify this extrapolation of ISAT results on the basis of improved catheter and coil technology, although this has never been demonstrated. However, the addition of stents and flow-diverters, which were not tested in ISAT, may increase endovascular treatment risks, especially when combined with dual anti-platelet agents. The introduction of these devices allowed for the expansion of indications of EVT to include wide-necked aneurysms, lesions which would not have been included in ISAT. The wider spectrum of patients and aneurysms now considered for EVT may not all experience the same degree of benefit as seen in the original ISAT trial (4). Considering the relatively small ARR of 7.4% favouring coiling, when the additional risks due to stents are included, the balance may have tipped to favour surgical clipping.

These new questions deserve formal study in the context of a randomized clinical trial.

Enrollment: 1,724 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients at least 18 years of age
• At least one documented, intradural, intracranial aneurysm, ruptured within last 30 days
• SAH WFNS grade 4 or less
• The patient and aneurysm are considered appropriate for either surgical or endovascular treatment by the treating team

Exclusion criteria

• Patients with absolute contraindications administration of contrast material (any type)
• Patients with AVM-associated aneurysms
• Aneurysm located at basilar apex

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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1,724 participants in 2 patient groups

Endovascular management

Active Comparator group

Description:

Endovascular treatment will be performed as soon as possible following randomization, according to standards of practice, and under general anesthesia. Details regarding type of coils, use of adjunctive techniques such as balloon-remodeling, stents or flow-diverters, as well as post-treatment medical management issues, will be left up to the physician performing the endovascular treatment.

Treatment:

Procedure: Endovascular management

Surgical management

Active Comparator group

Description:

Surgical clipping will be performed as soon as possible following randomization, according to standards of practice, and under general anesthesia. Aneurysms thought by the treating physicians to require deliberate permanent proximal vessel occlusion, construction of a surgical bypass, or other flow-redirecting treatments that do not directly clip the aneurysm will not be excluded; these non-ISAT aneurysms are expected to be more difficult lesions to manage surgically as well as endovascularly.

Treatment:

Procedure: surgical management