Redefining Onyx HD 500 in the Flow Diversion Era

Abstract

We report the largest US case series results using Onyx HD-500 (EV3), a new liquid embolic agent, in the successful treatment of 21 patients with wide-neck intracranial aneurysms (mean size 4.5 mm), which are at increased risk of incomplete occlusion or recanalization with standard endovascular intervention utilizing detachable platinum coils. All aneurysms were located in the anterior circulation, and three aneurysms presented as acute subarachnoid hemorrhages. Complete aneurysm occlusion was present in 19 of 21 patients (90%). On six-month followup, one patient with an initially small residual neck progressed to total occlusion. Aneurysm recanalization was not detected in any patients on mean follow up of 8.9 months in 11 patients. Four patients experienced transient neurologic deficits in the immediate postoperative period and one in a delayed fashion. Embolization with the liquid embolic agent Onyx appears to be a safe and effective endovascular modality of treatment for wide-neck aneurysms or recurrent aneurysms that had previously failed treatment with detachable coils.

Figure 1

Angiograms showing the stages in the Onyx embolization of a 6.5 mm left ophthalmic artery aneurysm that was previously untreated. (a) Digital subtraction angiography (DSA) showing a 6.5 mm left ophthalmic artery aneurysm in the frontal and magnified frontal view (b). (c) Frontal projection of DSA showing “seal test” with Rebar 14 microcatheter in midportion of aneurysm with 4 × 30 Hyperglide balloon inflated. (d) Initial injection of Onyx HD 500. (e) Frontal and lateral. (f) DSA projection displaying immediate 95% occlusion with neck remnant. (g) Nine-month followup showing progression to complete occlusion in the frontal and lateral projections (h).

Figure 2

Angiograms displaying stages of Onyx embolization of an 85-year-old woman who presented with progressive vision loss and found to have 14 mm left ophthalmic artery aneurysm. (a) DSA showing a 14 mm L ophthalmic aneurysm in the Townes and Lateral (b) projections. (c) Magnified Townes projection showing 4 × 30 Hyperglide balloon inflated with contrast filling aneurysm. (d) Magnified frontal DSA projection showing Onyx filled aneurysm sac with complete filling. (e) DSA final runs showing completely occluded aneurysm in the frontal and lateral (f) projections.

Figure 3

Angiograms demonstrating stages of Onyx embolization of a 53-year-old man presenting with severe headaches and found to have 19 × 13 mm left anterior choroidal aneurysm with 5 mm neck as seen in the A/P (a) and 3D reconstruction (b). (c) DSA showing magnified frontal and lateral. (d) Projection after Onyx embolization and placement of Enterprise stent.