PRET: Patients Prone to Recurrence After Endovascular Treatment

PRET: Patients Prone to Recurrence After Endovascular Treatment. A Randomized Trial Comparing Platinum and Hydrogel-coated Coils

The PRET study aims at comparing two types of coils used in the endovascular treatment of intracranial aneurysms. The first type made of platinum has been used for more than 15 years. The other, referred to as hydrocoil, containing in addition to platinum a polymer layer that expands when in contact with blood, has been in use since 2002. The hypothesis of the PRET study is that the newer hydrocoil will be more effective and yet as safe as the older platinum coil.

Inclusion Criteria:

• All patients presenting at least one aneurysm 'prone to recurrence after endovascular treatment' (PRET), defined for the sake of this study as:

  • PRET-1: One ruptured or unruptured aneurysm, never treated, with a dimension ≥10mm (longest axis, including thrombosed portions of large or giant aneurysms); for ruptured lesions, patients should be in WFNS grade I, II or III.
  • PRET-2: an Aneurysm presenting a major recurrence after previous coiling; and judged by the neurovascular team to require elective treatment.

• The anatomy of the lesion is such that endovascular treatment is possible with both types of coils (not necessarily certain or probable)

• The endovascular physician is content to use either type of coils (platinum or hydrogel-coated coils) but no other type of coils

• Patient is 18 or older

• Life expectancy is more than 2 years

Exclusion Criteria:

• Presence of other aneurysms requiring treatment during the same session
• Patients with associated cerebral arteriovenous malformations
• When parent vessel occlusion, without simultaneous endosaccular coiling of the aneurysm, is the primary intent of the procedure
• Any absolute contraindication to endovascular treatment, angiography, or anaesthesia such as severe allergies to contrast or medications