Chronic Total Occlusion - Ep.2/2 - SLICE WorldWide 2022

Best technique

Clinical applications of OCT

Introduction

Complete occlusion of the internal carotid artery (ICA) by atherosclerotic disease causes approximately 15-25% of ischemic strokes in the carotid artery distribution. Patients treated with medical therapy have a risk of recurrent stroke of 7-10% per year for all stroke and 5-8% per year for ipsilateral ischemic stroke during the first two years following ICA occlusion[1].

Patient 1

Normal findings of CTA, MRI and ultrasound Doppler despite 2 previous ischemic strokes in right ICA territory, new TIA now

-> searching for the etiology

-> OCT

-> thrombosed carotid web with thrombus attenuation

Patient 2

Chronic total occlusion with recurrent watershed infarcts, total carotid artery reconstruction in 2020, CTA in 2021 showing focal intimal hyperplasia

-> discussion regarding antiplatelet regimen

-> OCT

-> stent not fully covered by the endothelium cells (stent fracture) + neointimal hyperplasia

the decision to continue with DAPT
sometimes angioplasty or another stent may be required

Patient 3

2 episodes of transient right side dysesthesia, MRI showing right carotid occlusion with normal brain perfusion raising suspicion of right ICA dissection sequelae, aspirin treatment + clinical follow up, then another episode of left sided infarct with left ICA occlusion but spontaneous recanalization during hospitalization

+normal findings in CTA, scintigraphy, MRI, ultrasound Doppler, PET

-> searching for the etiology

-> OCT

-> fibrodysplasia (thick media and intima, may be bilateral)

treatment decision based on this result

Bothering problem in total carotid occlusion: timing – often it is difficult to evaluate when the occlusion has occurred

Imaging findings to predict if the occlusion is subacute or chronic:

Subacute (weeks)	Chronic (late)
No brain atrophy Recent ischemia that may be territorial or embolic Occlusion level - petrous segment opacification on late CTA Few ECA collaterals Flair negative Origin of ICA is irregular	Brain atrophy Watershed sequelae Cognitive impairment Occlusion level - very high occlusion, no petrous segment opacification Flair positive Origin of ICA is smooth

To distinguish you need to perform: angiogram, MR, CT perfusion, cognitive impairment evaluation, CTA late phase.

Short treatment protocol:

Evidence of total carotid occlusion à 3 weeks of medical therapy (DAPT or anticoagulation)

If there is still occlusion à CT perfusion à if there is hypoperfusion + stress test positive:

-> subacute occlusion: perform the revascularization

-> chronic occlusion: consider medical therapy first and perform the revascularization only if persisting symptoms and salvageable brain tissue to preserve

Literature:

Xu, B., Li, C., Guo, Y., Xu, K., Yang, Y., & Yu, J. (2018). Current understanding of chronic total occlusion of the internal carotid artery. Biomedical Reports, 8(2), 117-125.