Ocular signs of carotid stenosis in ipsi- and contralateral eyes before and after carotid endarterectomy: a prospective study.

PURPOSE: We describe hypoperfusion-related and embolic ocular signs of carotid stenosis (CS) before and six months after carotid endarterectomy (CEA) in a CS population. METHODS: We enrolled prospectively 70 CEA patients (81% male, mean age 69) and 41 non-medicated control subjects (76%, 68), from March 2015 to December 2018, assessing intraocular pressure (IOP), best-corrected visual acuity (BCVA) in logMAR units and performing a bio-microscopy examination. RESULTS: Main index symptoms included amaurosis fugax (Afx) (29, 41%) and hemispheric TIA (17, 24%), and 17 (24%) were asymptomatic. Of the 70, 17 patients (24%, 95% CI 16-36) showed ocular signs of CS. Of four embolic (Hollenhorst plaques) findings, one small macular plaque disappeared postoperatively. Four had hypoperfusion, that is ocular ischaemic syndrome (OIS), requiring panretinal photocoagulation: one for multiple mid-peripheral haemorrhages, two for iris neovascularization and one for neovascular glaucoma (NVG); only the NVG proved irreversible. Nine (de novo in three) showed mild OIS, that is only few mid-peripheral haemorrhages, ranging pre- /postoperatively in ipsilateral eyes from one to eleven (median two)/ one to two (median one), and in contralateral eyes from three to nine (median five)/ one to six (median three). Pre- and postoperative median BCVA was 0 or better, and mean IOP was normal, except in the NVG patient. Temporary visual impairment from 0 to 0.3 occurred in one eye soon after CEA due to ocular hyperperfusion causing macular oedema. CONCLUSIONS: Ocular signs of CS are common in CEA patients, ranging from few mid-peripheral haemorrhages to irreversible NVG. Clinicians should be aware of these signs in detecting CS.

Recognizing subtle near-occlusion in carotid stenosis patients: a computed tomography angiographic study.

INTRODUCTION: Near-occlusion of the internal carotid artery (ICA) is a significant luminal diameter (LD) reduction beyond a tight atherosclerotic carotid stenosis (CS). Recognition of even subtle near-occlusions is essential to prevent underestimation of the stenosis degree. Our goal was to investigate the prevalence of near-occlusion among CS patients using a single standard criterion to facilitate its recognition, even when distal ICA LD reduction is not visually evident in computed tomography angiography (CTA). METHODS: We analysed carotid artery CTAs of 467 patients with moderate-to-severe CS scheduled for endarterectomy. We performed measurements of the bilateral distal ICA LDs from thin axial source images and utilized a 1.0 mm intra-individual side-to-side distal ICA LD difference to distinguish near-occlusions, based on a previous study, aware of the vagaries of measurement. For analysis stratification, we excluded cases with significant carotid pathology affecting LD measurements. RESULTS: We discovered 126 near-occlusions fulfilling our criterion of ipsilateral near-occlusion: the mean LD side-to-side difference (mm) with 95% confidence interval being 1.8 (1.6, 1.9) and a standard deviation of 0.8 mm. Among the 233 cases not meeting our near-occlusion criterion, we found 140 moderate (50-69%) and 93 severe (70-99%) ipsilateral stenoses. CONCLUSION: The utilization of 1.0 mm cut-off value for the intra-individual distal ICA LD side-to-side difference to distinguish atherosclerotic ICA near-occlusion leads to a relatively high incidence of near-occlusion. In CTA, recently suggested to be used for near-occlusion diagnosis, a discriminatory 1.0 mm cut-off value could function as a pragmatic tool to enhance the detection of even subtle near-occlusions.

The normal internal carotid artery: a computed tomography angiographic study.

INTRODUCTION: Systematic computed tomography angiographic (CTA) studies investigating variation in internal carotid artery (ICA) luminal diameters (LDs) are scarce. Knowledge of the normal intra-individual LD variability would provide a cut-off value for detection of more subtle collapses. In addition, low intra-individual variability would allow using contralateral LD as a reference for estimation of stenosis degree in cases where ipsilateral measurement is hampered. Therefore, our aim was to investigate intra-individual LD variation of normal ICA. METHODS: We retrospectively collected multidetector high-speed CTAs of 104 patients younger than 40 years who were considered not to have carotid pathology. We carried out independent measurements of the common carotid artery (CCA) and ICA LDs bilaterally from axial source images by two observers, analysing side-to-side LD differences from averaged double measurements with a paired t test. RESULTS: We discovered no significant side-to-side LD differences. In the female group, the mean differences (mm) with 95% confidence intervals were 0.08 (0.00, 0.17) for CCA and 0.03 (-0.04, 0.11) for ICA, with ICA LD standard deviation of 0.4 mm. In the male group, these were: 0.06 (-0.04, 0.17), 0.02 (-0.07, 0.11) and 0.4 mm, respectively. We detected no ICA agenesis. CONCLUSION: The intrinsic intra-individual variation of the LD of normal ICA is minimal. This uniformity may serve as the basis for detection of subtle grades of side-to-side variation caused by pathology.