The endovascular treatment of intracranial aneurysms has become an accepted alternative to surgical repair given the many recent advances with neurointerventional devices and procedures. The introduction of GDC coils in 1993 provided physicians and their patients a less invasive treatment option. Additionally, the results of two large international trials, ISAT and ISUIA, have shown the benefits of endovascular treatment over surgery for treatment of specific types of aneurysms. One limitation of endovascular coil embolization is aneurysm recurrence or recanalization which is not infrequently observed angiographically at follow up. Aneurysm recanalization may be a result of aneurysm morphology, anatomic location and flow orientation, aneurysm regrowth or the degree of coil compaction. Despite the widespread adoption of endovascular aneurysm coiling, there remains much to be learned about the efficacy and optimization of this treatment modality.

The goal of endovascular embolization of intracranial aneurysms is to prevent rupture or re-rupture. Fortunately, the incidence of aneurysm rupture following coil embolization is very low. Follow-up angiographic analysis to evaluate the occlusion and stability of the treated aneurysm provides a surrogate endpoint against which to weigh the likelihood of rupture/re-rupture. However, angiographic interpretation is subjective, operator dependent and can be influenced by multiple confounding variables.

The MAPS trial will examine Target Aneurysm Recurrence Rates: clinically relevant recurrence rates resulting in target aneurysm reintervention, rupture/re-rupture and/or death from an unknown cause for Matrix 2® and GDC® Coils used for the treatment of intracranial saccular aneurysms. The trial will compare TAR rates to recurrences measured by angiographic analysis and assess the utility of angiographic analysis for predicting clinically relevant recurrences.