Short- and intermediate-term angiographic and clinical outcomes of patients with various grades of coil protrusions following embolization of intracranial aneurysms

Abstract

Background and purpose: An infrequent occurrence during endovascular treatment is protusion of detachable coils into the parent lumen with a subsequent thrombosis within in the parent vessel or embolic events. We report the short- and intermediate-term angiographic and clinical outcomes of patients who experience coil or loop protrusions and are managed with medical or additional endovascular treatments.

Materials and methods: The coil protrusions were identified by retrospective review of 256 consecutive patients treated at 3 centers with endovascular embolizations for intracranial aneurysms and subsequently categorized as grade I when a single loop or coil protruded into the parent vessel lumen less than half the parent artery diameter; grades II and III were assigned when a single coil or loop protruded more than half the parent artery diameter, respectively.

Results: There were 19 patients with grade I (n = 9), grade II (n = 4), or grade III (n = 6) coil protrusions. Patients with active hemodynamic compromise (n = 6) had intracranial stents placed in addition to aspirin (indefinitely) and clopidogrel (range, 1-12 months; mean, 4.5 months) treatment. The remaining patients were placed on aspirin indefinitely. Complete aneurysm obliteration was achieved in all patients except in 3 in whom near-complete obliteration was achieved. Two patients had intraprocedural aneurysm ruptures, both of whom survived hospitalization. There were 4 deaths (4-21 days), all due to major strokes in different vascular distributions related to vasospasm (unrelated to the coil protrusion).

Conclusions: Management of coil protrusions with antiplatelet therapy and placement of stents (in selected patients) appears efficacious in preventing vessel thrombosis.

Fig 1.

Grade I, Loop or coil protrudes into the main lumen less than half of parent artery diameter. Grade II, Coil protrudes into the main lumen exceeding more than half of parent artery diameter. Grade III, Loop protrudes into the main lumen exceeding more than half of parent artery diameter.

Fig 2.

Serial angiographic images of a 48-year-old man who underwent endovascular treatment for a ruptured left ICA terminus aneurysm. A, Immediate postprocedural image demonstrates a grade I protrusion. B, Six-month follow-up corresponding image demonstrates spontaneous resolution of the coil protrusion.

Fig 3.

Serial angiographic images of a 40-year-old woman who underwent endovascular treatment for a ruptured paraophthalmic segment ICA aneurysm. A, Immediate postprocedure image demonstrates a grade II coil protrusion into the parent vessel lumen. B, At 18-month follow-up, angiographic images demonstrate persistent but unchanged grade II coil protrusion.