Keywords:
Head and neck, Neuroradiology brain, Interventional vascular, CT-Angiography, MR-Angiography, Experimental, Catheters, Angioplasty, Stents, Arteriosclerosis, Cardiac Assist Devices, Haemodynamics / Flow dynamics
Authors:
R. Gandini, M. Chiocchi, G. Loreni, A. Chiaravalloti, D. Morosetti, G. Simonetti; Rome/IT
DOI:
10.1594/ecr2013/C-0782
Purpose
Carotid artery stenting (CAS) is a viable alternative treatment to carotid endarterectomy.
Stroke is one of the most important complications of CAS and is mostly caused by intraprocedural distal embolization of plaque components.1 In order to prevent procedure-related cerebrovascular accidents,
a careful assessment of carotid plaque morphology is required.
Large studies demonstrated that necrotic core,
mainly if superficial and surrounded by a thin or ruptured fibrous cap,
is the predominant histological finding in carotid plaque related to cerebrovascular accidents.2 So,
it is fundamental to have a technique able to identify vulnerable
and prone to rupture plaques.3,4 Duplex ultrasound (DUS) proved to be a good technique to identify necrotic cores plaques; in fact,
hypoechogenic
signals are associated with a predominant lipidic core, correlated with an higher risk of embolization and stroke during carotid artery interventions.2,5,6 Nevertheless,
use of transcutaneous ultrasound remains highly subjective and operator dependent. Multislice spiral Computed Tomography (CT) and High Resolution Magnetic Resonance (HR-MR) are able to identify lipid-rich tissues,
calcifications and thrombus with high diagnostic accuracy,
except for small plaques which remain undetectable.2 Intravascular ultrasound (IVUS) and Virtual histology –
IVUS (VH-IVUS) have been extensively validated in the coronary arteries imaging,
with a high vessel and plaque resolution,
which is essential in the endovascular procedures planning.7 As CT-angiography (CTA) and Magnetic Resonance Angiography (MRA),
VH-IVUS is able to demonstrate the proportion of hard and soft plaque constituents and the amount of fibrous and necrotic lipid core.
Thus,
this technique may provide useful information on how the plaque may behave at the moment of treatment and which stent should be deployed.2–7 Even if the diagnostic accuracy of VH-IVUS for the imaging of the carotid arteries resulted good in many
available studies,
it is lower in resolution and does not provide three-dimensional images,
when compared with diagnostic techniques such as CTA or MRA,
which are widely used for the carotid arteries imaging.8–10
VH-IVUS has,
however,
the advantage of the real-time intraprocedural evaluation over both CTA and MRA. The primary aim of this prospective study is to evaluate the usefulness of IVUS in the identification of otherwise un-noticed complications during carotid stenting.
The secondary aim is the evaluation of the impact of IVUS-assisted stenting in the procedural outcomes and long-term patency rates.