General Description

Cerebral aneurysms located at bifurcations often provide a unique challenge for endovascular treatment. They require protection of at least three parent vessels. Additionally, the hemodynamic forces acting in these locations may increase the risk of coil compaction. Wide-necked bifurcation aneurysms add an additional layer of complexity. Stent-assisted coiling of bifurcation aneurysms requires unique stent constructs, such as Y or X stenting. These complex stenting configurations have been reported to increase the rate of procedure-related complications compared to coiling alone.

The PulseRider (Pulsar Vascular) is a self-expanding nitinol implant that is intended to serve as a “neck bridge for wide-necked aneurysms arising at or near a vessel bifurcation.” It is designed to minimize metal exposure while serving a buttress to maintain coils within the aneurysm sac.

The Barrel vascular reconstruction device (VRD) (Medtronic) is a self-expanding nitinol stent. Its unique design, with a bulged central component, is intended to allow for greater neck coverage. It is constructed with a double spiral strut, which is meant to conform to the tortuous anatomy encountered at vessel branch points. It has 12 platinum marker bands.

Evidence

Both the PulseRider and Barrel VRD are novel devices, and their longevity and long-term success are yet to be determined.

The Adjunctive Neurovascular Support of Wide-neck Aneurysm Embolization and Reconstruction (ANSWER) Trial included 34 patients with wide-necked carotid terminus or basilar apex aneurysms treated with the PulseRider. ¹ Immediate Raymond-Roy occlusion grade 1 or 2 was achieved in 82.4% and increased to 87.9% at the 6-month follow-up. Good neurologic outcome (modified Rankin Scale [mRS] score < 2) occurred in 94% at 6 months.

A multicenter, prospective postmarket study of the Barrel VRD included 20 patients with wide-necked bifurcation aneurysms. ² The primary effectiveness endpoint (Raymond-Roy occlusion grade 1 or 2 in the absence of retreatment, parent artery stenosis [> 50%], or target aneurysm rupture) was achieved in 78.9% of study patients, with a morbidity rate of 5.3%. The German experience echoed these findings with 95% of patients achieving a Raymond-Roy occlusion grade of 1 after a median follow-up of 282 days. ³

Indications

Novel neck reconstruction devices have been specifically designed to address the challenge of wide-necked aneurysms encountered in endovascular management. PulseRider and Barrel VRD are indicated for these aneurysms when they occur at bifurcations or branch points.

Neuroendovascular Anatomy

Anatomy pertinent to the use and deployment of neck reconstruction devices relates to aneurysm neck shape and the angle that it forms with the arteries of parent(s), which is very variable. The devices must be sized appropriately and deployed in such a way as to cover the aneurysm neck to maintain the coil mass within the aneurysm.

For use of the Barrel VRD, it is important to measure the diameter of the parent vessel and the triangle formed by the parent vessel, bifurcation vessels, and the neck of the aneurysm. The diameter of this triangle would provide the size of the bulged central component needed ( Fig. 28.1–28.3, Video 28.1–28.3 ).

For use of the PulseRider device, it is important to measure the diameter of the inflow vessel and the angle formed by the inflow vessel (e.g., basilar artery) and the bifurcation arteries (e.g., posterior cerebral arteries). The diameter of the inflow vessel should be between 2.7–4.5 mm. The device comes in “Y” and “T” shapes. A Y-shaped device fits best where the aneurysm and branch vessels are angled 90–120° relative to the axis parent vessel (inflow vessel). A T-shaped device fits best where both of the branch artery angles are < 90° relative to the axis of the parent vessel ( Fig. 28.4, 28.5, Video 28.4, 28.5 ).

An understanding of the complex vascular anatomy and hemodynamics occurring at bifurcations and branch points is critical when considering use of these novel devices. For the PulseRider, it is important to understand the landing zones for the limbs of the device. For the Barrel VRD, appreciating the angle of branch vessels is critical to allow for correct deployment of the device and coverage of the neck.

Periprocedure Medications

Both these neck reconstruction devices necessitate that patients be placed on dual antiplatelet therapy. The ANSWER trial maintained patients on dual antiplatelet therapy for 6 months after treatment. It is our practice to begin the dual antiplatelet regimen 5–7 days prior to the procedure with aspirin 325 mg daily and clopidogrel 75 mg daily. When this is not possible, loading doses of both medications (aspirin 650 mg and clopidogrel 600 mg) are administered immediately prior to the procedure. We continue dual antiplatelet therapy for 6 months after the procedure, whereas the aspirin is continued indefinitely.

As we do with all intracranial endovascular interventions, it is our practice to systemically heparinize the patient. This is confirmed by an activated coagulation time of 250–300 s.

Specific Technique and Key Steps

1. 
   

   A 6 or 8 French (F) sheath is placed in the femoral artery.

   
   
2. 
   

   A guide catheter is placed in the distal cervical segment of the appropriate vessel (e.g., internal carotid artery [ICA] or vertebral artery).

   
   
3. 
   

   A 3D angiogram is performed to assess aneurysm and parent vessel morphology.

   
   
4. 
   

   Under roadmap guidance, the microcatheters (and intermediate catheter, if used) are advanced.

   
   
5. 
   

   A second microcatheter is advanced into the aneurysm. We routinely deploy one or two loops of coil into the aneurysm prior to deployment of the neck reconstruction device ( Video 28.1–28.3 ).

   
   
6. 
   

   Control injections are performed at the working angles to ensure aneurysm obliteration, stent patency, and adequate wall apposition.

   
   
7. 
   

   Control injections are performed with full views of the intracranial vasculature to assess for delayed capillary filling, distal emboli, or vessel extravasation.

Device Selection

The following devices are typically selected when using aneurysm neck reconstruction devices.

• 
  

  6 or 8 F sheath.

  
  
• 
  

  6F guide catheter (Envoy XB, DePuy Synthes; Benchmark, Penumbra) or 8F guide catheter (Neuron MAX, Penumbra).

  
  
• 
  

  Intermediate catheter (Distal Access Catheter, Stryker).

  
  
• 
  

  PulseRider—Selection of T- or Y-shaped device based on bifurcation anatomy ( Fig. 28.4, 28.5, Video 28.4, 28.5 ).

  
  
  
  
  • 
    

    0.021-inch microcatheter.

  
  
• 
  

  Barrel VRD. ( Fig. 28.1–28.3, Video 28.1–28.3 )

  
  
  
  
  • 
    

    0.021-inch microcatheter.

  
  
• 
  

  Coils.

Pearls

• 
  

  The PulseRider device is indicated for the treatment of wide-necked aneurysms with a neck width ≥ 4 mm or a dome-to-neck ratio < 2 that originate on or near a vessel bifurcation of the basilar tip or ICA ( Fig. 28.4, 28.5, Video 28.4, 28.5 ). Other aneurysm locations (anterior communicating artery and middle cerebral artery) for the use of this device are under investigation (NAPA Study, https://www.clinicaltrials.gov/ct2/show/NCT03383666).

  
  
• 
  

  The PulseRider is not indicated for patients with severe intracranial vessel tortuosity or anatomy that would preclude a safe introduction of the device.

  
  
• 
  

  The Barrel VRD can be used on wide-necked aneurysms at any anatomical location ( Fig. 28.1–28.3, Video 28.1–28.3 ).

  
  
• 
  

  Be cautious when maneuvering the coiling microcatheter through the tines of the PulseRider device because it can move and dislodge from a previously adequate position ( Video 28.4, 28.5 ).

  
  
• 
  

  Do not torque or rotate the PulseRider delivery wire unless the implant distal markers are constrained within the microcatheter. Torquing the device with the implant deployed and engaged in the vasculature can cause vessel damage or dissection.

  
  
• 
  

  Carefully observe while deploying coils to ensure that the coils do not prolapse through the neck of the aneurysm or implant arch (applies to the PulseRider and Barrel VRD).

References

Case Overview: CASE 28.1 Wide-Necked Middle Cerebral Artery Aneurysm: Neck Reconstruction (Barrel)

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  A 62-year-old male presented with a rupture anterior communicating artery aneurysm treated with endovascular coil embolization. The patient recovered completely. He also had a past medical history of hypertension, obesity, and smoking.

  
  
• 
  

  Four-year follow-up computed tomography (CT) angiogram demonstrated a de novo right wide-necked middle cerebral artery (MCA) aneurysm.

Related posts:

30 Endovascular Vasospasm Treatment 24 Balloon-Assisted Coiling 27 Intrasaccular Flow Diverter for Intracranial Aneurysms (WEB) 29 Aneurysm Embolization with Liquid Embolic Agents 25 Stent-Assisted Coiling Part V Intracranial Aneurysms

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