Flow Diversion, BA Trunk Aneurysm
HPI:
- PMHx: neurofibromatosis, HTN
- Presented to ED with slurred speech and dizzy spells intermittently for 1 year
- Workup: CT head -> CTA head -> MRI brain
Imaging
CT Head without Contrast - Axial/Coronal/Sagittal
There is a large, slightly calcified mass located at the basal cistern - aneurysm vs. tumor.
CTA Head - Axial/Coronal/Sagittal
Axial Brain MRI - DWI/ADC/SWI/Black Blood (-C)
Axial Brain MRI - T1/T2/T1 (+C)/Black Blood (+C)
Coronal Brain MRI - Black Blood (+C)
Enhancement was observed in the walls of both the bilateral VA (orange arrow: right VA; green arrow: left VA) and the aneurysm (red arrow).
CTA Neck - Coronal (A)/Axial (B)
It appeared that there was calcification and stenosis at the right VA origin (orange arrow), which might pose a challenge for catheterization.
Pre-Op Consideration
- Diagnostic cerebral angiography was performed under moderate sedation
- Co-dominant bilateral VAs -> radial access -> right VA
- A large unruptured irregular basilar trunk aneurysm, 21 mm
- Black blood MRI illustrates bilateral VA vessel wall and aneurysm wall enhancement -> high risk of rupturing
- Plan for flow diversion embolization
- Triple therapy[1] for anti-thrombotic management
- Daily 81 mg of aspirin (ARU: 369)
- Daily 75 mg of clopidogrel (PRU: 78)
- Daily 10 mg of rivaroxaban
Flow Diversion Embolization
Intervention Specifics
- Intra-operative neuro-monitoring: SSEP, MEP, EEG
- General anesthesia
- Access: Right radial artery access
- Sheath: Terumo 7F slender sheath, 10 cm[2]
- Guide catheter: 7F Rist, 95 cm[3]
- Select catheter: Vert, 125 cm[4]
- Intermediate catheter: Vecta 0.046, 125 cm[5]
- Microcatheter: Excelsior XT-27, 150 cm, straight[6][7]
- Microwire: Aristotle 0.024, 200 cm[8]
- Stent:
- Findings:
- Large unruptured distal basilar trunk aneurysm, 21 mm
- Adjacent small aneurysms
- Successful flow diverter embolization with excellent contrast stasis
- ACT was maintained between 250-300
Labelling
- Orange arrow: right VA.
- Red arrow: The aneurysm.
- Green arrow: left VA.
- Pink arrow: Rist tip.
- Plum arrow: Adjacent small aneurysms.
- White arrow: BA apex.
- Blue arrow: right PCA.
- Cyan arrow: left PCA.
- Brown arrow: Vecta 0.046 tip.
- Black arrow: XT-27 tip.
- Magenta arrow: Proximal marker.
- Teal arrow: Recapture marker.
- Maroon arrow: Distal marker.
Intra-Operative Imaging
(A): Right radial artery DSA showed favorable anatomy.
(B): Right brachiocephalis roadmap through the Vert catheter revealed slight stenosis at the right VA origin, as seen on pre-operative CTA.
(C): The tip of the Rist catheter (pink arrow) was advanced into the distal V2 segment.
Angiogram without Subtraction - Right VA Injection (PA and Lateral)
An angiogram, conducted through the Rist catheter (pink arrow), without subtraction, revealed the aneurysm and its exact position relative to the skull.
DSA - Right VA Injection (PA and Lateral)
The same angiogram with subtraction.
DSA - Right VA Injection (PA and Lateral)
This zoomed-in run, focused on the aneurysm, allowed us to obtain the measurements.
Roadmap - Right VA Injection (PA and Lateral)
Roadmap - Right VA Injection (PA and Lateral)
Following the microwire, both the XT-27 (black arrow) and Vecta 0.046 (brown arrow) catheters were positioned in the proximal basilar artery.
Roadmap - Right VA Injection (PA and Lateral)
The microwire was gently advanced into the right PCA using the "around the world" technique, which is our preferred approach for distal stent landing due to its larger size than the left PCA. However, due to the acute turn at its origin, the mcirocatheter couldn't follow the microwire without exerting excessive pressure on the aneurysm wall, posing a high risk of intra-operative rupture. As a result, we decided to select the left PCA instead.
Roadmap - Right VA Injection (PA and Lateral)
The left PCA was successfully catheterized and the XT-27 was advanced into the distal P2.
Roadmap - Right VA Injection (PA and Lateral)
The microwire was removed, and a 4.5 mm x 40 mm Surpass Evolve stent[12] was inserted inside the XT-27 and advanced to its tip. Initially, a Surpass Evolve 5 mm x 40 mm stent was attempted, but it was removed due to the ribbon effect at the aneurysm curve.
Fluoroscopy - PA and Lateral
After unloading the whole system, the microcatheter was reduced to the inner curve. The stent was then partially unsheathed and landed in the left P1. As it was continuously unsheathed, the Vecta 0.046 advanced and sheathed both the stent and the XT-27. The latter was then utilized as a delivery wire for the Vecta 0.046 to unsheath the stent.
Fluoroscopy - PA and Lateral
The stent was unsheathed all the way just shy of deployment. There was an overlapping of the Vecta 0.046 and XT-27 tips.
Fluoroscopy - PA and Lateral
With gentle loading, the stent opened up slightly more. It was then deployed without issues.
Fluoroscopy - PA and Lateral
A post-deployment fluoroscopy showed no complications and there was excellent contrast stasis in the aneurysm.
DSA - Right VA Injection (PA and Lateral)
A repeat angiogram during the early arterial phase revealed continuous contrast stasis (white star) which was subtracted and a total of three aneurysms (1, 2, and 3) covered by the stent.
DSA - Right VA Injection (PA and Lateral)
The same angiogram beyond venous phase showed excellent contrast stasis in aneurysms 1 and 3. Notably, there was distinct layering of the contrast within aneurysm 1.
DSA - Right VA Injection (PA and Lateral)
A delayed, zoomed-out angiogram showed patent bilateral PCAs.
Final Fluoroscopy - PA and Lateral
The final fluoroscopy showed the stent position and contrast stasis.
Post-Operative Course
- Extubated without complications
- No new neurological deficits
- ICU overnight
- Continued triple therapy
- Discharged home with assistance on POD3
- No issued at one-week phone follow-up
- Long-term outcome to follow
ED Visit (POD14)
- Ground level fall
- CTA head: stable aneurysm, patent stent
- Anemia -> GI bleeding (non-active on EGD) -> transfusion and PPI -> stabilized -> discharged home
- Continued on triple therapy
- Steroid taper for presumed post-embolization inflammation
Follow-Up DSA (6m)
Patient recovered well without new neurological deficits. Six-month follow-up angiogram demonstrated occlusion of the No. 2 small aneurysm. The large BA trunk (No. 1) and No. 3 aneurysms were of similar sizes and shapes. Patient stopped clopidogrel while continued aspirin and rivaroxaban.
Left column: 6-month follow-up angiogram.
Right column: Pre-interventional angiogram.
Discussion
- Outcome without treatment
- Ischemic events: up to 68.2%
- Progression of brainstem compression: 45.7%
- Aneurysm rupture: 6%
- Mortality: 40%
- Outcome with treatment: better, but still poor
- Triple therapy was used to lower the risk of basilar artery perforators ischemic stroke.
- Adjunctive coil embolization was not attempted to simplify the process and lower the risks of intra-operative complications.
- Future stent with anti-platelet coating which may not need triple therapy?