Extra-Cranial Carotid Artery Stenosis: An Objective Analysis of the Available Evidence

Radiomics and artificial intelligence: General notions and applications in the carotid vulnerable plaque

Carotid atherosclerosis plays a substantial role in cardiovascular morbidity and mortality. Given the multifaceted impact of this disease, there has been increasing interest in harnessing artificial intelligence (AI) and radiomics as complementary tools for the quantitative analysis of medical imaging data. This integrated approach holds promise not only in refining medical imaging data analysis but also in optimizing the utilization of radiologists' expertise. By automating time consuming tasks, AI allows radiologists to focus on more pertinent responsibilities. Simultaneously, the capacity of AI in radiomics to extract nuanced patterns from raw data enhances the exploration of carotid atherosclerosis, advancing efforts in terms of (1) early detection and diagnosis, (2) risk stratification and predictive modeling, (3) improving workflow efficiency, and (4) contributing to advancements in research. This review provides an overview of general concepts related to radiomics and AI, along with their application in the field of carotid vulnerable plaque. It also offers insights into various research studies conducted on this topic across different imaging techniques.

Association between hospital ownership and patient selection, management, and outcomes after carotid endarterectomy or carotid artery stenting : - Secondary data analysis of the Bavarian statutory quality assurance database

BACKGROUND

This study analyses the association between hospital ownership and patient selection, treatment, and outcome of carotid endarterectomy (CEA) or carotid artery stenting (CAS).

METHODS

The analysis is based on the Bavarian subset of the nationwide German statutory quality assurance database. All patients receiving CEA or CAS for carotid artery stenosis between 2014 and 2018 were included. Hospitals were subdivided into four groups: university hospitals, public hospitals, hospitals owned by charitable organizations, and private hospitals. The primary outcome was any stroke or death until discharge from hospital. Research was funded by Germany's Federal Joint Committee Innovation Fund (01VSF19016 ISAR-IQ).

RESULTS

In total, 22,446 patients were included. The majority of patients were treated in public hospitals (62%), followed by private hospitals (17%), university hospitals (16%), and hospitals under charitable ownership (6%). Two thirds of patients were male (68%), and the median age was 72 years. CAS was most often applied in university hospitals (25%) and most rarely used in private hospitals (9%). Compared to university hospitals, patients in private hospitals were more likely asymptomatic (65% vs. 49%). In asymptomatic patients, the risk of stroke or death was 1.3% in university hospitals, 1.5% in public hospitals, 1.0% in hospitals of charitable owners, and 1.2% in private hospitals. In symptomatic patients, these figures were 3.0%, 2.5%, 3.4%, and 1.2% respectively. Univariate analysis revealed no statistically significant differences between hospital groups. In the multivariable analysis, compared to university hospitals, the odds ratio of stroke or death in asymptomatic patients treated by CEA was significantly lower in charitable hospitals (OR 0.19 [95%-CI 0.07-0.56, p = 0.002]) and private hospitals (OR 0.47 [95%-CI 0.23-0.98, p = 0.043]). In symptomatic patients (elective treatment, CEA), patients treated in private or public hospitals showed a significantly lower odds ratio compared to university hospitals (0.36 [95%-CI 0.17-0.72, p = 0.004] and 0.65 [95%-CI 0.42-1.00, p = 0.048], respectively).

CONCLUSIONS

Hospital ownership was related to patient selection and treatment, but not generally to outcomes. The lower risk of stroke or death in the subgroup of electively treated patients in private hospitals might be due to the right timing, the choice of treatment modality or actually to better structural and process quality.

Imaging of intracranial arterial disease: a comparison between MRI and unenhanced CT

Background and purpose

Arterial calcifications on unenhanced CT scans and vessel wall lesions on MRI are often used interchangeably to portray intracranial arterial disease. However, the extent of pathology depicted with each technique is unclear. We investigated the presence and distribution of these two imaging findings in patients with a history of cerebrovascular disease.

Materials and methods

We analyzed CT and MRI data from 78 patients admitted for stroke or TIA at our institution. Vessel wall lesions were assessed on 7 T MRI sequences, while arterial calcifications were assessed on CT scans. The number of vessel wall lesions, severity of intracranial internal carotid artery (iICA) calcifications, and overall presence and distribution of the two imaging findings were visually assessed in the intracranial arteries.

Results

At least one vessel wall lesion or arterial calcification was assessed in 69 (88%) patients. Only the iICA and vertebral arteries (VA) showed a substantial number of both calcifications and vessel wall lesions. The other vessels showed almost exclusively vessel wall lesions. The number of vessel wall lesions was associated with the severity of iICA calcification (p = 0.013).

Conclusions

The number of vessel wall lesions increases with the severity of iICA calcifications. Nonetheless, the distribution of vessel wall lesions on MRI and arterial calcifications on CT shows remarkable differences. These findings support the need for a combined approach to examine intracranial arterial disease.

[Advisability of carotid endarterectomy in asymptomatic patients]

OBJECTIVE

To determine the optimal treatment strategy for patients with asymptomatic carotid stenosis.

MATERIAL AND METHODS

The authors reviewed clinical guidelines for the management of patients with asymptomatic carotid stenosis 60-99%, as well as medical studies and meta-analyses comparing carotid endarterectomy and optimal drug therapy in asymptomatic patients between 1993 and 2023.

RESULTS

The choice of treatment strategy for patients with asymptomatic carotid artery stenosis is still a controversial issue. There were several large randomized clinical trials comparing carotid endarterectomy with optimal medical therapy in asymptomatic patients at the end of the 20th century. However, drug therapy has undergone significant changes calling into question the relevance of previous results. This review highlights the evolution of management of patients with asymptomatic carotid stenosis and also presents modern approaches to the treatment of these patients.

CONCLUSION

Patients younger 75 years old gain an advantage from carotid endarterectomy with small perioperative risk compared to optimal drug therapy and yearly risk of cerebral embolism. Patients with asymptomatic carotid stenosis 80-99% are candidates for carotid endarterectomy due to higher risk of acute cerebrovascular accident at least until more data are available. The choice of the best tactics for a particular patient should be made individually depending on own experience and patient's adherence to therapy and lifestyle correction. The results of the ACTRIS (2025) and CREST-2 (2026) studies are expected to clarify this issue.

Quantifying Carotid Stenosis: History, Current Applications, Limitations, and Potential: How Imaging Is Changing the Scenario

Carotid artery stenosis is a major cause of morbidity and mortality. The journey to understanding carotid disease has developed over time and radiology has a pivotal role in diagnosis, risk stratification and therapeutic management. This paper reviews the history of diagnostic imaging in carotid disease, its evolution towards its current applications in the clinical and research fields, and the potential of new technologies to aid clinicians in identifying the disease and tailoring medical and surgical treatment.

Role of carotid duplex in the assessment of carotid artery restenosis after endarterectomy or stenting

Introduction

Redo carotid endarterectomy (CEA) and carotid stenting (CAS) are often performed when there is evidence of post-procedural restenosis. The incidence of restenosis after carotid reconstruction is not negligible, ranging from 5 to 33%. The diagnosis of significant internal carotid artery (ICA) restenosis is usually based on duplex ultrasound (US) criteria, mostly on peak-systolic flow velocity (PSV). However, there have been no generally accepted duplex US criteria for carotid restenosis after CAS or CEA.

Methods

In this systematic review, the PubMed/ Medline and Scopus databases were screened to find trials that reported duplex US criteria for significant restenosis after CEA and/or CAS. Only those reports were analyzed in which the restenoses were also assessed by CT/MR or digital subtraction angiography as comparators for duplex US.

Results

Fourteen studies met the predetermined search criteria and were included in this review. In most studies, PSV thresholds for significant in-stent ICA restenosis after CAS were higher than those for significant stenosis in non-procedurally treated (native) ICA. Many fewer studies investigated the US criteria for ICA restenosis after CEA. Despite the heterogeneous data, there is a consensus to use higher flow velocity thresholds for assessment of stenosis in stented ICA than in native ICA; however, there have been insufficient data about the flow velocity criteria for significant restenosis after CEA. Although the flow velocity thresholds for restenosis after CAS and CEA seem to be different, the large studies used the same duplex criteria to define restenosis after the two procedures. Moreover, different studies used different flow velocity thresholds to define ICA restenosis, leading to variable restenosis rates.

Discussion

We conclude that (1) further examinations are warranted to determine appropriate duplex US criteria for restenosis after CAS and CEA, (2) single duplex US parameter cannot be used to reliably determine the degree of ICA restenosis, (3) inappropriate US criteria used in large studies may have led to false restenosis rates, and (4) studies are required to determine if there is a benefit from redo carotid artery procedure, such as redo-CEA or redo-CAS, starting with prospective risk stratification studies using current best practice non-invasive care alone.

Rates of Stroke in Patients With Different Presentations of Carotid Artery Stenosis

OBJECTIVE

Carotid artery stenosis may present without the classical symptoms of transient ischaemic attack or stroke but the rates of stroke for these presentations is unknown. The aim of this study was to examine the rates of stroke in patients with different presentations of carotid artery stenosis.

METHODS

A multicentre prospective cohort study was conducted across three Australian vascular centres with low rates of surgical treatment of patients without transient ischaemic attack or stroke. Patients with a 50 - 99% carotid artery stenosis presenting with non-focal symptoms (e.g., dizziness or syncope; n = 47), prior contralateral carotid endarterectomy (n = 71), prior ipsilateral symptoms more than six months earlier (n = 82), and no symptoms (n = 304) were recruited. The primary outcome was ipsilateral ischaemic stroke. Secondary outcomes were any ischaemic stroke and cardiovascular death. Data were analysed using Cox proportional hazard and Kaplan-Meier analyses.

RESULTS

Between 2002 and 2020, 504 patients were enrolled (mean age 71 years, 30% women) and followed for a median of 5.1 years (interquartile range 2.5, 8.8; 2 981 person years). Approximately 82% were prescribed antiplatelet therapy, 84% were receiving at least one antihypertensive drug, and 76% were prescribed a statin at entry. After five years the incidence of ipsilateral stroke was 6.5% (95% confidence interval [CI] 4.3 - 9.5). There were no statistically significant differences in the annual rate of ipsilateral stroke among people with non-focal symptoms (2.1%; 95% CI 0.8 - 5.7), prior contralateral carotid endarterectomy (0.2%; 0.03 - 1.6) or ipsilateral symptoms > 6 months prior (1.0%; 0.4 - 2.5) compared with those with no symptoms (1.2%; 0.7 - 1.8; p = .19). There were no statistically significant differences in secondary outcomes across groups.

CONCLUSION

This cohort study showed no large differences in stroke rates among people with different presentations of carotid artery stenosis.

Carotid artery stenting for asymptomatic stenosis is associated with decreased 30-day readmission at very high volume centers

Endovascular carotid artery stenting (CAS) is a common treatment for carotid artery stenosis and stroke prevention. Previous studies have shown that high procedural volume centers are associated with improved patient outcomes. Unplanned 30-day readmissions, which are associated with significant expenses, are increasingly used as a metric of patient outcome. Despite prior studies evaluating associations between procedural volume and multiple outcomes, the association between very high CAS volume and short-term (30-day) readmission has not yet been evaluated in a large multicenter study. The National Readmissions Database (NRD) was analyzed retrospectively from 2010 to 2015 to evaluate the association between hospital procedural volume and patient outcomes in asymptomatic and symptomatic CAS patients. Very high volume centers (VHVC) were defined as the top 10% hospitals in terms of procedural volume, performing >= 79 procedures a year. Univariate and multivariate analyses of patient and hospital characteristics evaluated associations with short-term (30-day) readmissions (SR), long-term (90-day) readmissions (LR), index mortality, discharge disposition, major complications, and neurological complications. A total of 36,128 asymptomatic patients and 8,390 symptomatic patients who underwent CAS were identified. Asymptomatic CAS patients treated at VHVCs were associated with decreased likelihood of SR (OR 0.88, 95% CI 0.80-0.95, p = 0.003) and LR (OR 0.91, 95% CI 0.85-0.99, p = 0.037) compared to asymptomatic patients at non-VHVCs. There was no significant difference in SR or LR between symptomatic CAS patients treated at a VHVC vs. non-VHVC. Our findings provide additional evidence to support the role of experience in improved CAS treatment outcomes.

Trends in mortality and postoperative complications among octogenarian patients undergoing carotid endarterectomy

BACKGROUND

Elderly patients represent a large portion of patients undergoing vascular surgery. This study aims to assess the contemporary frequency of octogenarians undergoing carotid endarterectomy (CEA) and to evaluate their postoperative complications and survival rates.

METHODS

The Vascular Quality Initiative (VQI) dataset was queried for patients who underwent elective CEA between 2012 and 2021. Patients aged >90 years were excluded, as well as emergent and combined cases. The population was divided into two age groups: <80 years and ≥80 years. Frailty scores were generated using Vascular Quality Initiative variables grouped into 11 domains historically associated with frailty. Patients with scores within the first 25th percentile, between the 25th and 50th percentile, and above the 75th percentile were categorized into low, medium, and high frailty classes, respectively. Procedural indications were defined as hard (stenosis ≥80% or ipsilateral neurologic symptoms) or soft. Primary outcomes of interest were 2-year stroke-free and 2-year overall survival comparing (i) octogenarians with nonoctogenarians and (ii) octogenarians by frailty class. Standard statistical methods were used.

RESULTS

Overall, 83,745 cases were included in this analysis. Between 2012 and 2021, a consistent proportion averaging 17% of CEA patients were octogenarians. Among this age group, the proportion of patients undergoing CEA for hard indications increased over time from 43.7% to 63.8% (P < .001). This increase was accompanied by a statistically significant increase in the combined 30-day perioperative stroke and mortality rate from 1.56% in 2012 to 2.96% in 2021 (P = .019). A Kaplan-Meier analysis showed a significantly lower 2-year stroke-free survival among octogenarians compared with the younger group (78.1% vs 87.6%; P < .001). Similarly, there was a significantly lower 2-year overall survival among octogenarians compared with the younger group (90.5% vs 95.1%; P < .001). Multivariate Cox proportional hazard analyses showed that high frailty class was associated with increased 2-year stroke risk (hazard ratio, 2.26; 95% confidence interval, 1.61-3.17; P < .001) and 2-year mortality (hazard ratio, 2.43; 95% confidence interval, 1.71-3.47; P < .001). Repeat Kaplan-Meier analysis stratifying octogenarians by frailty class revealed that octogenarians with low frailty can have stroke-free and overall survival rates comparable with nonoctogenarians (88.2% vs 87.6% [P = .158] and 96.0% vs 95.1% [P = .151], respectively).

CONCLUSIONS

Chronological age should not be regarded as a contraindication for CEA. Frailty score calculation is a better predictor for postoperative outcomes and is an appropriate tool to risk stratify octogenarians, aiding in the decision between best medical treatment or intervention. The risk benefit assessment for high frailty class octogenarians is paramount because the postoperative risks may outweigh the long-term survival benefits of the prophylactic CEA.

Optimal Management of Asymptomatic Carotid Artery Stenosis: A Systematic Review and Network Meta-Analysis

OBJECTIVE

Management of asymptomatic carotid artery stenosis (ACAS), including carotid endarterectomy (CEA), carotid artery stenting (CAS), and best medical treatment (BMT), remains inconsistent in current practice. Early studies reported a benefit of CEA vs. BMT; however, the current risk-benefit profile of invasive therapy lacks consensus. By evaluating the effects of modern BMT vs. invasive intervention on patient outcomes, this study aimed to influence the future management of ACAS.

METHODS

A systematic review and series of network meta-analyses were performed assessing peri-operative (within 30 days) and long term (30 days - 5 years) stroke and mortality risk between ACAS interventions. Total stroke, major, minor, ipsilateral, and contralateral stroke subtypes were assessed independently. Traditional (pre-2000) and modern (post-2000) BMT were compared to assess clinical improvements in medical therapy over the previous two decades. Risks of myocardial infarction (MI) and cranial nerve injury (CNI) were also assessed.

RESULTS

Seventeen reports of 14 310 patients with > 50% ACAS were included. CEA reduced the odds of a peri-operative stroke event occurring vs. CAS (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.1 - 2.2 [0 - 20 fewer/1 000]). CEA and CAS reduced the long term odds of minor strokes (OR 0.35, 95% CI 0.21 - 0.59 [20 fewer/1 000]) and ipsilateral strokes (OR 0.27, 95% CI 0.19 - 0.39 [30 fewer/1 000]) vs. all BMT. CEA reduced the odds of major strokes and combined stroke and mortality vs. traditional BMT; however, no difference was found between CEA and modern BMT. CAS reduced the odds of peri-operative MI (OR 0.49, 95% CI 0. 26 - 0.91) and CNI (OR 0.07, 95% CI 0.01 - 0.42) vs. CEA.

CONCLUSION

Modern BMT demonstrates similar reductions in major stroke, combined stroke, and mortality to CEA. The overall risk reductions are low and data were unavailable to assess subgroups which may benefit from intervention. However, BMT carries the potential to reduce the requirement for surgical intervention in patients with ACAS.