(1) to estimate the prevalence of Circle of Willis (CoW) variants in patients undergoing carotid endarterectomy, (2) to correlate these variants to controls and (3) cerebral ischemia depicted by computed tomography (CT).

The Circle of Willis (CoW) is the main collateral system, and its morphological variants are more common in patients who have severe carotid artery stenosis. Earlier data suggest that optical coherence tomography angiography (OCTA) may help to assess the changes in cerebral vascular perfusion by imaging the retinal blood flow. In this single-center prospective clinical study, patients scheduled for carotid endarterectomy (CEA) underwent preoperative computed tomography angiography (CTA) of the extra- and intracranial cerebral circulation. OCTA imaging was performed one week before surgery and postoperatively one month later. The patients were divided into two subgroups based on CTA evaluation of CoW: compromised CoW or non-compromised CoW (containing hypoplastic and normal segments). The effect of the patient’s age, OCTA scan quality (SQ), CoW morphology, laterality, and surgery on superficial capillary vessel density (VD) in the macula were assessed in multivariable regression models using linear mixed models. We found that VD significantly decreased with aging (−0.12%; 95%CI: −0.07–−0.15; p < 0.001) and was significantly higher in patients with non-compromised CoW morphology (by 0.87% 95%CI (0.26–1.50); p = 0.005). After CEA, retinal blood flow significantly improved by 0.71% (95%CI: 0.18–1.25; p = 0.01). These results suggest that in the case of carotid artery occlusion, patients with non-compromised CoW have more preserved ocular blood flow than subjects with compromised CoW due to remodeling of the intra-orbital blood flow. Measuring the retinal blood flow might be used as a relevant and sensitive indicator of collateral cerebrovascular circulation.

(1) Study purpose: The aim of our prospective single-center, matched case–control study was to compare the number and volume of acute ischemic brain lesions following carotid endarterectomy (CEA) versus carotid artery stenting (CAS) using a propensity-matched design. (2) Methods: Carotid bifurcation plaques were analyzed by using VascuCAP software on CT angiography (CTA) images. The number and volume of acute and chronic ischemic brain lesions were assessed on MRI scans taken 12–48 h after the procedures. Propensity score-based matching was performed at a 1:1 ratio to compare the ischemic lesions on postinterventional MR. (3) Results: A total of 107 patients (CAS, N = 33; CEA, N = 74) were included in the study. There were significant differences in smoking (p = 0.003), total calcification plaque volume (p = 0.004), and lengths of the lesion (p = 0.045) between the CAS and CEA groups. Propensity score matching resulted in 21 matched pairs of patients. Acute ischemic brain lesions were detected in ten patients (47.6%) of the matched CAS group and in three patients (14.2%) in the matched CEA group (p = 0.02). The volume of acute ischemic brain lesions was significantly larger (p = 0.04) in the CAS group than in the CEA group. New ischemic brain lesions were not associated with neurological symptoms in either group. (4) Conclusions: Procedure-related new acute ischemic brain lesions occurred significantly more frequently in the propensity-matched CAS group.

Purpose: We assessed diffusion tensor imaging (DTI) metric changes of the corpus callosum and cingulum correlated to postprocedural ischemic lesion load (ILL) and cognitive performance in transcatheter aortic valve replacement (TAVR). Methods: TAVR subjects had DTI post-TAVR (≤ 8 days) and at 6 months (78 participants, males 56%, age 78.8 years ± 6.3) and four neurocognitive tests (pre-TAVR, post-TAVR, 6 months, 1 year). DTI metrics (fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD)) were calculated for 7 regions: corpus callosum (genu, body, splenium) and cingulum (cingulate gyrus, parahippocampal cingulum bilaterally). DTI metrics post-TAVR and at 6 months were compared with Student’s t-test (p < 0.0071) and ANOVA covarying for sex, ILL (p < 0.05) with post hoc analysis of ILL groups (p < 0.0167). Repeated-measures linear mixed-effect model (p < 0.05) was performed to investigate the effect of time and ILL on cognition. Results: At 6 months, significant decrease of the following DTI metrics was detected: AD (genu, body, splenium, right parahippocampal cingulum: p ≤ 0.0046); MD (body, both cingulate gyri: p ≤ 0.0050); RD (left cingulate gyrus: p = 0.0021); FA (splenium: p < 0.0001). ANOVA confirmed significant effect of female sex on AD + MD reduction (body, right cingulate gyrus) and AD reduction (left cingulate gyrus) (p ≤ 0.0254). Significant negative effect of ILL on some DTI metric changes was found (AD + MD-body: p ≤ 0.0050; MD-left cingulate gyrus: p = 0.0087). Cognitive performance remained stable with significant negative correlation of ILL and retrograde memory and visual scores (p ≤ 0.0483). Conclusion: Significant effect of TAVR on cerebral microstructural integrity was found with reduced diffusivities opposite to the trends reported in various neurodegenerative conditions/ageing, notably in women and lower ILL, and with preserved/improved cognition. Trial registration number. NCT02826200 at ClinicalTrials.gov; date of registration: 07. July 2016.

Aims To test utility of diffusion MRI-derived indices in carotid endarterectomy (CEA), change of diffusion tensor imaging (DTI) metrics, cerebral white matter (WM) volumes were evaluated and predictors of overall mortality determined. Methods Prospectively enrolled participants had preoperative, immediate and late postoperative DTI after CEA. WM volumes, DTI metrics (fractional anisotropy, FA; axial, radial, mean diffusivities; AD, RD, MD, respectively) were calculated for the index/contralateral hemispheres at all time points. Temporal changes, predictors of log₂-transformed WM volumes, DTI values were analyzed using linear mixed model. Uni- and multivariable Cox proportional hazards models were used to identify predictors of mortality. Results 60 subjects (57% male, 69.5 ± 7.2years) were included. Significantly increased AD and MD was observed in both hemispheres comparing the preoperative and immediate postoperative DTI metrics (index AD: β = 0.02 [95%CI:0.01,0.02], p < 0.001; index MD: β = 0.02 [95%CI:0.01,0.03], p < 0.001; contralateral AD: β = 0.01 [95%CI:0.01,0.02], p = 0.001; contralateral MD: β = 0.02 [95%CI:0.01,0.03], p = 0.003). The index MD decreased (β = 0.01 [95%CI:0.01,0.001], p = 0.04), bilateral WM volumes (index WM: β = 0.04 [95%CI:0.02,0.07], p < 0.001; contralateral WM: β = 0.05 [95%CI:0.03,0.07], p < 0.001) decreased significantly between the immediate and late postoperative scans. Postoperative contralateral FA correlated significantly with lower mortality (HR = 0.001 [95%CI:0.001,0.19], p = 0.02); postoperative contralateral RD (HR = 3.74 × 10⁴ [95%CI:1.62,8.60 × 10⁸], p = 0.04) and MD (HR = 1.19 × 10⁵ [95%CI:1.03,1.37 × 10¹⁰], p = 0.049) were significant predictors of mortality. Conclusion The increase of various DTI metrics from pre-to-postoperative may be indicative of microstructural deterioration following CEA. Temporal changes between the immediate and late postoperative scans suggest, however, reversal of detrimental WM changes and clearance of presumed subclinical WM edema. Our results also imply, that preserved cerebral properties are protective after CEA.

Introduction: Many cardiovascular parameters of sport adaptation have become an area of detailed research in recent decades. However, details of local circulatory and metabolic processes ongoing in the working muscles during physical exercise need to be revealed. Purpose: Our aim was to extend cardiopulmonary exercise testing with near-infrared spectroscopy measurements to focus on observing local changes in the contracting muscles during running. Methods: Mixed muscle oxygen saturation values (SmO2) measured in the left vastus lateralis muscle of athletes were analyzed by near-infrared spectroscopy during vita maxima treadmill cardiopulmonary exercise testing with 2-min fingertip lactate measurements. Body composition analysis was carried out with bioimpedance method. One-way repeated measures ANOVA, Tukey post-hoc test, Shapiro–Wilk test and Pearson correlation were used for statistical analysis. Results: The results of 66 elite athletes (male: 40; age: 17.9±3.6 y; training: 17.7±6.6 h/w; water polo player: 56, wrestler: 8, basketball player: 2) were analyzed. The 10-second averaged values of the measured saturation values were examined at rest (65.8±11.1%), at the anaerobic threshold (40.7±22.8%), at maximum load (30.2±20.5%) and after 5 minutes of cool-down (70.9±12.8%). Significant differences were measured between the four measurement time points in all pairings. A negative correlation was found between the achieved maximal oxygen uptake and the muscle oxygen saturation values measured at the anaerobic threshold and at the maximal load (respectively r=−0.30, p<0.02; r=−0.32, p<0.01). Oxygen uptake at the end of cool-down was also negatively correlated with muscle oxygen saturation values measured at the anaerobic threshold and at the peak of exercise (respectively r=−0.27, p<0.05; r=−0.27, p<0.05). The fat-free mass of the identical limb showed negative correlation with the muscle oxygen saturation values measured at the anaerobic threshold, at the maximal load and at the cool-down (respectively r=−0.43, p<0.01; r=−0.44, p<0.01; r=−0.35, p<0.01), while positive interactions were observed between the body-fat mass of the same limb and the muscle oxygen saturation values (respectively r=0.51, p<0.01; r=0.55, p<0.01; r=0.41, p<0.01). Muscle oxygen saturation values showed no significant correlations with exercise time, lactate levels, or heart rate measurements. Conclusions: By our results, muscle oxygen saturation measurements can be reliably applied during exercise physiological measurements. During exercise, muscle oxygen saturation values negatively correlated with oxygen uptake. At the cool-down phase, a rebound effect could be observed compared to the resting measurements. On the identical limb, the higher the muscle mass was, the higher muscle desaturation could be measured. This easy-to-perform test provides insight into muscle metabolism processes and can help with training planning and athlete follow-up. Funding Acknowledgement: Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This project was supported by a grant from the National Research, Development and Innovation Office (NKFIH) of Hungary (K 135076). Supported by the ÚNKP-21-3-I-SE-68 New National Excellence Program of the Ministry for Innovation and Technology from the Source of the National Research, Development and Innovation fund.