Large and Giant Aneurysms

Abstract

The large (>1 cm) and giant (>2.5 cm) aneurysms constitute a unique group of intracranial aneurysms due to the difficulty of the treatment with both surgical and endovascular approaches. The high risk of rupture and other mass effect symptoms and complications associated with the endovascular treatment make it a significant challenge for endovascular physicians. With the flow diverter becoming a major treatment of the large and giant aneurysm, many other strategies are still valid in many situations and are discussed. The common complications associated with large and giant aneurysm treatment, such as device migrations/retraction, flow-diverter stent occlusion, and in-stent stenosis, delayed aneurysm rupture, new or worsening of presenting symptoms of mass effect, etc., are reviewed. Many specific techniques for large and giant aneurysm embolization are introduced in detail.

Case Presentation

Case 11.1 Intravascular Flow Diversion Treatment for Large/Giant Aneurysms

Case Pearls

• 1. Initial FDA-approved indication for PED includes large or giant wide-necked ICA aneurysm from the petrous to the superior hypophyseal segments.

• 2. The new indication expands to small or medium, wide-necked brain aneurysms from the petrous to the terminus of ICA in 2019.

(a): 3D angiogram of left ICA for a patient with known bilateral ICA aneurysms showing a large left paraclinoid ICA aneurysm; (b): pre-embo 2D embo view; (c): immediate post-PED treatment; (d): single shot for PED contour; (e): 3D angiogram of right ICA showing another wide-neck smaller ophthalmic artery aneurysm; (f–h): embolization with PED 1 month later. (i, j): 6-month follow-up, small entrance remnants of left-side large aneurysm, complete obliteration of right ICA aneurysm

Case 11.2 FD Device Plus Additional Coiling for Large Supraglenoid ICA Aneurysm

Case Pearls

• 1. Addition of coiling to FD embolization of large wide-neck aneurysm is preferred by many providers.

• 2. Added coiling is believed to facilitate the thrombosis of the aneurysm.

• 3. Coils occupy the aneurysm space and decrease the fresh clot size and risk of delayed aneurysm rupture.

(a, b): Pre-embo 3D, large right paraclinoid ICA aneurysm; the parent vessel convexed at the neck of the aneurysm with near 90° angle turn; (c, d): pre-embo 2D embo views for better view of the distal landing zone and neck of the aneurysm; (e, f): before deploying the FD stent completely, jail the coiling catheter and partially deploy the coil to prevent the FD stent from collapsing when deployed; especially when advancing the stent, pushing wire is needed; (g, h): final run shows the coil mass and stent position; (i–l): 4-month follow-up, complete obliteration of the aneurysm

Case 11.3 Mechanical Support for FD Device From Additional Coil Mass

Case Pearls

Mechanical support from additional coil mass can be pivotal in two situations:

• Large aneurysm with parent artery convex toward the dome carries the risk of collapse of the FD stent into the anuerysm sac.

• For large aneurysms located more distal in the paraclinoid ICA, the distal landing zone for the FD stent may not be long enough to safely hold the FD device. In a ruptured situation, the support from the additional coil mass is more important as vasospasm can squeeze the stent into the aneurysm sac.

(a): 3D angiogram showing a large wide-neck paraclinoid ICA aneurysm with ICA convexed toward the aneurysm sac; (b): pre-embo 2D view for the best view of the neck to watch the FD stent interaction with the coils; (c): angiogram after embolization is finished; (d): 7-month follow-up showing complete obliteration of the aneurysm; (e): single-shot X-ray showing the relationship of PED with coils and support of the coil mass to the PED (double arrow)

Case 11.4 Destructive Treatment of the Distal Large Aneurysm

Case Pearls

• 1. For distal large aneurysm/or small aneurysm, parent vessel sacrifice can be the treatment option if located beyond the major perforator segment.

• 2. Baby or kids can tolerate the destructive treatment better than adult.

• 3. Simple treatment is better for the infant from the radiation injury standpoint.

(a): Head CT for work-up of somnolence on a new infant baby showing posterior fossa hemorrhagic lesion; (b, c): AP and lateral angiogram performed with 4 Fr dilator as a femoral sheath and XT-27 microcatheter (Stryker) as diagnostic catheter showing a 13x8mm distal PICA aneurysm; (d, e): selective angiogram with microcatheter tip positioned at the takeoff of the left PICA showing clear contour of the aneurysm; due to short PICA segment and big sac of the aneurysm, the onyx was not considered for embolization; occlusion of proximal PICA with coil was planned; (f, g): due to a sharp turn at the takeoff of left PICA, catheterization of left PICA more distally was unsuccessful. Unable to pass the microwire further distally; one Target Nano 1x3 coil for occlusion of the proximal PICA; (h): POD#3 MRA; (i): 7-month MRA follow-up

Case 11.5 Management of Large Active Bleeding Aneurysm

Case Pearls

• 1. Early re-rupture (within 24 hours from initial rupture) is more common in the large/giant aneurysms.

• 2. The outcome of early re-rupture is usually dismal.

• 3. Intraoperative bleeding during diagnostic angiogram is rare. Quick coiling if possible is a practical and effective option.

• 4. Balloon or coil occlusion of the parent artery is the last option.

(a): Middle-aged female presented with syncope and seizure with CT SAH; (b): CTA: large right paraclinoid ICA aneurysm; (c): head CT after EVD placement showing new hemorrhage; (d, e): first diagnostic angiogram showing active bleeding; (f): sequential and quick coiling processes (Target XL standard 12x45, 10x40, 9x30, XL Soft, 5x15, Soft: 5x15x2, 6x20); (g): post-embo CT: slightly increased SAH/IVH. The patient subsequently underwent hemicraniectomy for decompression; (h, i): 1-week angiogram showing vasospasm (h) and improvement after treatment (i); j: 3-week angiogram showing coil compaction. Patient eventually passed away