Trends and controversies in carotid artery stenosis treatment

Correlation between intravascular pressure gradients and ultrasound velocities in carotid artery stenosis: An exploratory study

INTRODUCTION

Grading of carotid stenosis is routinely performed with non-invasive techniques, such as carotid ultrasound (CUS) and computerized tomography angiography (CTA), which have limitations in grading definition. Moreover, the actual hemodynamic impact of a stenosis remains poorly defined. Preliminary studies explored the application of the resting full-cycle ratio (RFR), measured with pressure wire (PW), but the correlation between RFR and morphological/hemodynamic parameters is still undefined. This study aims to test the correlation between RFR and CUS-CTA-DSA based degree of stenosis, to define the suitability of RFR as carotid stenosis index.

METHODS

We included patients with symptomatic carotid stenosis receiving carotid artery stenting (CAS), between November 2022 and May 2023. We performed CUS and PW measurements before and after stenting, at four different sites (trans-lesion, distal cervical, petrous and supraclinoid internal carotid artery [ICA] segments). We compared CUS and PW parameters by Pearson's or Spearman test for continuous variables.

RESULTS

Among 15 patients included the mean stenosis degree was 81.3%. Trans-lesion RFR was significantly higher than other sites (0.72 ± 0.2 trans-lesion vs. 0.69 ± 0.18 distal cervical ICA vs. 0.66 ± 0.2 petrous ICA vs. 0.6 ± 0.2 intracranial ICA, p < 0.05). All RFR values significantly increased after treatment; the highest relative increase was registered at stenosis site (0.72 ± 0.2 pre-stent vs. 1.01 ± 0.1 post-stent, p < 0.01). Trans-lesion RFR was significantly associated with the CTA and DSA stenosis degree and CUS measurements.

CONCLUSIONS

Pressure wire in carotid artery stenosis seems safe and suitable. Resting full-cycle ratio has a significant correlation with CUS values and stenosis degree and might be used as carotid stenosis index during CAS.

Carotid Artery Stenosis: A Look Into the Diagnostic and Management Strategies, and Related Complications

Carotid stenosis (CS) is a buildup of atherosclerotic plaque within the artery leading to a wide range of symptoms, from mild symptoms, including blurred vision and confusion, to much more life-threatening presentations, including paralysis due to stroke. The presentation is insidious, with symptoms exhibiting predominantly at severe stenosis; hence the emphasis is placed on the importance of early diagnosis, treatment, and lifestyle modifications. CS is seen undergoing almost the same pathogenesis of any atherosclerotic plaque formation, from endothelial damage of the artery lumen to the formation of a fibrous cap with a foam cell, lipid-filled core. The findings of our review article were consistent with the recent literature, depicting that comorbid hypertension, diabetes, and chronic kidney disease (CKD), and lifestyle aspects, including smoking and diet, played the most salient role in plaque development. Among several imaging modalities, duplex ultrasound (DUS) imaging is the widely preferred method in clinical practice. Carotid endarterectomy (CEA) and carotid stenting are the primarily advocated procedures for symptomatic severe stenosis, with similar long-term outcomes. Although, earlier clinical trials showed promising results in mitigating the risk of stroke among asymptomatic severe CS with surgical intervention. However, recent advancements have shifted the focus to medical management alone due to comparable results among the asymptomatic population. Both surgical and medical regimens are beneficial in treating patients, but it is still an ongoing debate as to which is predominantly superior. The currently advancing trials and research will help elucidate definitive guidelines. However, the massive impact of lifestyle modifications advocates some degree of individualized multidisciplinary management strategies.

Application of laser speckle flowgraphy to evaluate cerebral perfusion after carotid endarterectomy

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy (CEA) is devastating, and postoperative monitoring of cerebral perfusion is essential to prevent CHS. We report two cases of successful measurement of ocular blood flow using laser speckle flowgraphy (LSFG) for bedside assessment of the changes in cerebral perfusion after CEA. An 18.7% (case 1) and 47.7% (case 2) increase in ocular blood flow were measured postoperatively using LSFG compared with the baseline. LSFG might be applicable to evaluate cerebral perfusion after CEA.

A magnetic resonance imaging-based computational analysis of cerebral hemodynamics in patients with carotid artery stenosis

Management of asymptomatic carotid artery stenosis (CAS) relies on measuring the percentage of stenosis. The aim of this study was to investigate the impact of CAS on cerebral hemodynamics using magnetic resonance imaging (MRI)-informed computational fluid dynamics (CFD) and to provide novel hemodynamic metrics that may improve the understanding of stroke risk. CFD analysis was performed in two patients with similar degrees of asymptomatic high-grade CAS. Three-dimensional anatomical-based computational models of cervical and cerebral blood flow were constructed and calibrated patient-specifically using phase-contrast MRI flow and arterial spin labeling perfusion data. Differences in cerebral hemodynamics were assessed in preoperative and postoperative models. Preoperatively, patient 1 demonstrated large flow and pressure reductions in the stenosed internal carotid artery, while patient 2 demonstrated only minor reductions. Patient 1 exhibited a large amount of flow compensation between hemispheres (80.31%), whereas patient 2 exhibited only a small amount of collateral flow (20.05%). There were significant differences in the mean pressure gradient over the stenosis between patients preoperatively (26.3 vs. 1.8 mmHg). Carotid endarterectomy resulted in only minor hemodynamic changes in patient 2. MRI-informed CFD analysis of two patients with similar clinical classifications of stenosis revealed significant differences in hemodynamics which were not apparent from anatomical assessment alone. Moreover, revascularization of CAS might not always result in hemodynamic improvements. Further studies are needed to investigate the clinical impact of hemodynamic differences and how they pertain to stroke risk and clinical management.

Risk Stratification and Management of Extracranial Carotid Artery Disease

Stroke is the fifth leading cause of death in the United States and is a leading cause of disability. Extracranial internal carotid artery stenosis is a major cause of ischemic stroke, as it is estimated to cause 8% to 15% of ischemic strokes. It is critical to improve our strategies for stroke prevention and treatment in order to reduce the burden of this disease. Herein, we review approaches for the diagnosis and risk stratification of carotid artery disease as well as interventional strategies for the prevention and treatment of strokes caused by carotid artery disease.