Aneurysm recanalization after coiling

After endovascular coiling, an aneurysm that was occluded on the first angiogram can fill again months or years later. This is called recanalization or recurrence. It happens when coils compact into the dome, when the aneurysm wall grows around the coil mass, or when thrombus between the coils resolves.

Recanalization is usually graded with the Raymond-Roy classification, and major recanalization (a residual aneurysm, class 3) is the outcome most prediction work focuses on. Pooled series have reported recurrence in roughly one in five coiled aneurysms, with about half of those retreated, but the rate varies widely with aneurysm size, neck width, location, rupture status and how densely the aneurysm was packed.

Because the risk unfolds over time, recanalization is best modeled with survival (time-to-event) methods that account for patients who have not yet been imaged at later time points.