Vertebral tandem occlusion - SLICE Worldwide 2021

Vertebral tandem occlusion - small clot burden and severe symptoms

Presentations of case resolutions in the form of a “serious game”. Vertebral tandem stroke with early recurrence from the stump of artery with unclear etiology (clot migration vs. hemodynamic). You will find also tips and tricks of dealing with this type of occlusion during mechanical thrombectomy.

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Posterior stroke:

• can mimic anterior circulation stroke with hemiparesis and hemianopia
• but has some characteristic features: fluctuation of consciousness, drowsiness, neglect, but NO eyes deviation

Small clot burden (for example P2 occlusion) and severe and fluctuating symptoms:

2 Theories:

• Hemodynamic threat (single vertebral artery = basilar like artery, PCoMs aplasia/hypoplasia) with hypoperfusion of bilateral posterior territory. Recurrence when hemodynamic instability - change of position, physical exertion.
• Clot migration from BA à P1 à P2 - gradual improvement of consciousness, new symptoms from thalamic and cerebral pedunculi involvement – neglect, hemiparesis. The clot can cause temporal damage in previously occupied territory or can damage both territories irreversibly. Recurrence when new emboli from vertebral stump.

To know: 

PCoMs preserve the flow through the top of basilar artery so it is not so much in danger when occluded as in the cases of PCoM aplasia/hypoplasia where there is no backflow.

Treatment of posterior stroke in publications and guidelines:

• IVT + EVT - should be strongly considered (ESO guidelines)
• EVT - may be reasonable for carefully selected patients with occlusion of VA, BA or PCA (AHA/ASA guidelines)
• IVT - the risk of bleeding was half that of anterior circulation stroke with similar functional outcomes and higher risk of death

P2 occlusions in publications:

• conservative vs. agressive therapy 
• conservative:  ~50% patients with mrs <2 ; ~50% patients with cognitive dysfunction, only 10% patients have <2 cognitive domains impaired

VERTEBRAL TANDEM OCCLUSION STRATEGY:

R. Nogueira: proximal aspiration, distal lesion treated first, stenting of proximal lesion

E. Abergel: balloon angioplasty of proximal lesion, while partially deflate go up with base catheter over the balloon, stent if needed after

T. Jovin: balloon angioplasty of proximal lesion, base catheter to distal lesion, if stenting - balloon-mounted stent

D. Lopes: proximal aspiration, balloon angioplasty of proximal lesion, distal lesion treated, balloon-mounted stent

T. Anderson: BCG, peripheral balloon angioplasty over 0,035 in wire and balloon-mounted stenting of proximal lesion, distal lesion treated

TIPs and TRICKs:

• use BCG as a prevention of clot migration facing vertebral tandem: à inflation of BCG in subclavian artery can create a subclavian steal = proximal protection with flow reversal 
• once PTA of proximal lesion is made go up over the balloon angioplasty catheter with base catheter, while the balloon is partially deflate and still gives you some support - you can cross the lesion that way with neither need of recatheterization nor risk of embolization while recrossing 
• block the wire of stent-retriever with torquer to better control the position of stent-retriever while opening and retrieving of the stent
• you can gain some centimeters of microcatheter length by removing the plastic sheath from it
• it is better to herniate with stent to subclavian artery than to be too short within the lesion
• in the way back before stenting you should clear up the lesion to avoid clot trapping in between the stent and vessel wall