The pitfalls and challenges in the diagnosis and treatment of patients with carotid near-occlusion: a narrative review

Abstract

Background and objective: Carotid near-occlusion (CNO) is defined as a severe stenosis of the internal carotid artery (ICA) resulting in a reduction in the distal diameter. It is a specific type of carotid stenosis accounting for 34% of the patients with symptomatic carotid stenosis ≥50%. The current guidelines recommend the best medical treatment (BMT) as the treatment of choice. Therefore, it is of the utmost importance to accurately diagnose CNO to avoid unnecessary surgical treatment. Although imaging can detect the majority of cases, there are still a few cases that remain unexplained. The purpose of this review is to discuss the mechanism of stroke, diagnostic imaging, and therapeutic approaches in patients with CNO and to examine the importance of diagnostic imaging in determining the treatment and prognosis of patients with CNO.

Methods: The PubMed database was searched for clinical studies on CNO published in English from 1950 to 2024. The selected literature was screened for articles related to the formation mechanism of CNO, clinical diagnosis, and the latest developments in treatment methods.

Key content and findings: The primary mechanisms of stroke in CNO include embolism and hypoperfusion. Imaging techniques such as computed tomography angiography (CTA) and digital subtraction angiography (DSA) can identify most instances of CNO; however, anatomical variations may pose challenges in accurately diagnosing this condition. Currently, revascularization offers limited benefits for patients with CNO. According to the 2023 European Society for Vascular Surgery (ESVS) guideline update, BMT is the preferred treatment for CNO, and patients with CNO and distal vessel collapse with recurrent carotid territory symptoms may be considered for revascularization after multidisciplinary team discussion.

Conclusions: The diagnosis of CNO based on feature interpretation necessitates a cautious approach. It is imperative to conduct large prospective clinical trials to identify the optimal treatment for patients with various types of CNO.

Keywords: Carotid stenosis; carotid artery endarterectomy; carotid artery stenting (CAS); medical imaging; near occlusion.