Measuring the Interaction Between the Macro- and Micro-Vasculature

ECG-gated retinal vessel calibre as a novel measure of aberrant pulsatile retinal flow in diabetes mellitus: a cross-sectional study

Purpose

To evaluate ECG-gated retinal vessel calibre as a novel measure of aberrant pulsatile retinal flow in diabetes mellitus.

Methods

A novel mydriatic ECG-gated fundoscope was used to acquire retinal vessel calibre measurements at four cardiac cycle time points from end diastole to early diastole. An inhouse software recorded the exact time when an image was captured to corroborate ECG-synchronisation. Arterial applanation tonometry, an alternative method of assessing aberrant blood flow, was used to measure carotid-femoral pulse wave velocity (cPWV) and augmentation index (AIx). The intraclass correlation (ICC) was used to perform intra- and inter-observer reliability analyses. Two reviewers measured the retinal vessel calibre in single retinal arterioles and venules. A receiver operating characteristic curve determined associations with diabetes mellitus.

Results

In this study 119 controls and 120 participants with diabetes mellitus were recruited. Mean peak change in retinal arteriolar calibre from baseline was higher in diabetes mellitus compared with controls (controls: 0.92%, IQR 0.63 vs diabetes mellitus: 2.05%, IQR 1.25, p<0.0001). In a subset of 9 controls and 11 participants, the intra-and inter-observer reliability was high (ICC 0.87-0.97) in mean peak changes in retinal vascular responses from baseline. In a subset of 36 controls and 95 participants with diabetes mellitus, diabetes mellitus was more strongly associated with retinal arteriolar pulsatility (AUC 0.85, 95%CI 0.76-0.93) than applanation tonometry (cfPWV AUC 0.72, 95%CI 0.62-0.82 vs AIx AUC 0.56, 95%CI 0.45-0.68).

Conclusion

Higher retinal arteriolar pulsatility appears to be more strongly correlated with diabetes mellitus than arterial applanation tonometry.

Impact of thoracic endovascular aortic repair following blunt traumatic thoracic aortic injury on blood pressure

BACKGROUND

Blunt traumatic thoracic aortic injuries (BTAIs) are associated with a high mortality rate. Thoracic endovascular aortic repair (TEVAR) is the most frequently used surgical strategy in patients with BTAI, as it offers good short- and middle-term results. Previous studies have reported an abnormally high prevalence of hypertension (HT) in these patients. This work aimed to describe the long-term prevalence of HT and provide a comprehensive evaluation of the biomechanical, clinical, and functional factors involved in HT development.

METHODS

Twenty-six patients treated with TEVAR following BTAI with no history of HT at the time of trauma were enrolled. They were matched with 37 healthy volunteers based on age, sex, and body surface area and underwent a comprehensive follow-up study, including cardiovascular magnetic resonance, 24-hour ambulatory blood pressure monitoring, and assessment of carotid-femoral pulse wave velocity (cfPWV, a measure of aortic stiffness) and flow-mediated vasodilation.

RESULTS

The mean patient age was 43.5 ± 12.9 years, and the majority were male (23 of 26; 88.5%). At a mean of 120.2 ± 69.7 months after intervention, 17 patients (65%) presented with HT, 14 (54%) had abnormal nighttime blood pressure dipping, and 6 (23%) high cfPWV. New-onset HT was related to a more proximal TEVAR landing zone and greater distal oversizing. Abnormal nighttime blood pressure was related to high cfPWV, which in turn was associated with TEVAR length and premature arterial aging.

CONCLUSIONS

HT frequently occurs otherwise healthy subjects undergoing TEVAR implantation after BTAI. TEVAR stiffness and length, the proximal landing zone, and distal oversizing are potentially modifiable surgical characteristics related to abnormal blood pressure.

Regular Physical Activity Seems to Eliminate Lower Limb Perfusion Asymmetries in Sedentary Non-Healthy Older Individuals

Perfusion asymmetries have been associated with vascular pathology. Physical activity is a component of vascular health. Here, we investigate the impact of a thirty-day regular home-based physical activity program in older individuals with multiple age-related comorbidities. Eleven participants of both sexes were included. Skin perfusion was assessed in both feet by laser Doppler flowmetry (LDF, for deeper perfusion) and polarized light spectroscopy (PSp, for superficial perfusion). At baseline, participants had significant perfusion differences between right and left feet (p = 0.005 with LDF; p = 0.028 with PSp), which disappeared with activity and reappeared in recovery. After 30 days, both feet showed significant perfusion increases as assessed with LDF (p = 0.005) compared to D0. At this point, the perfusion asymmetry observed at D0 was no longer present. However, the superficial perfusion asymmetry assessed by PSp persisted at D30 (p = 0.028). Data show that regular physical activity positively altered the lower limb perfusion pattern. Systolic pressure and mean arterial pressure were also significantly reduced at D30. These impacts seem to be directly related to the physical activity program introduced in the day-by-day routines of these participants. These also encourage further research on the role of symmetry-asymmetry in prevention, treatment, and rehabilitation in vascular medicine.

Relationship between atherosclerotic burden and depressive symptoms in hypertensive patients: A cross-sectional study based on the NHANES database

OBJECTIVE

The relationship between atherosclerotic burden, depressive symptoms, and clinically relevant depression (CRD) in hypertensive patients is unclear. In this study, we used the atherosclerotic index of plasma (AIP) to quantify atherosclerotic burden and explore its association with depressive symptoms and CRD in hypertensive patients.

METHODS

Hypertension-diagnosed patients were extracted from the National Health and Nutrition Examination Survey (NHANES) database. The relationships between AIP and depressive symptoms and CRD risk in patients were examined through the weighted logistic regression and the weighted linear regression models. Restrictive cubic spline curves were employed to analyze potential nonlinear associations between AIP and outcome indicators. Additionally, subgroup analyses and intergroup interaction tests were conducted.

RESULTS

The AIP was considerably associated with the severity of depressive symptoms in hypertensive patients, according to the findings of weighted linear regression. Weighted logistic regression analysis showed that high AIP was significantly associated with a high risk of clinically relevant depression in hypertensive patients. This trend was consistent across various subgroups within the population.

CONCLUSION

AIP was observed to be a significant risk factor for clinically relevant depression in hypertensive patients. Atherosclerotic burden in hypertensive patients was significantly associated with the severity of their depressive symptoms.

Hemodynamic parameters and diabetes mellitus in community-dwelling middle-aged adults and elders: a community-based study

Hemodynamic parameters have been correlated with stroke, hypertension, and arterial stenosis. While only a few small studies have examined the link between hemodynamics and diabetes mellitus (DM). This case-control study enrolled 417 DM patients and 3475 non-DM controls from a community-based cohort. Peak systolic velocity (PSV), end-diastolic velocity (EDV), blood flow velocity (MFV), pulsatility index (PI), and the resistance index (RI) of the common carotid arteries were measured by color Doppler ultrasonography. Generalized linear regression analyses showed that as compared to the non-DM controls, the age-sex-adjusted means of PSV, EDV, and MFV were - 3.28 cm/sec, - 1.94 cm/sec, and - 2.38 cm/sec, respectively, lower and the age-sex-adjusted means of RI and PI were 0.013 and 0.0061, respectively, higher for the DM cases (all p-values < 0.0005). As compared to the lowest quartiles, the multivariable-adjusted ORs of DM for the highest quartiles of PSV, EDV, MFV, RI, and PI were 0.59 (95% confidence interval [CI] 0.41-0.83), 0.45 (95% CI 0.31-0.66), 0.53 (95% CI 0.37-0.77), 1.61 (95% CI 1.15-2.25), and 1.58 (95% CI 1.12-2.23), respectively. More importantly, the additions of EDV significantly improved the predictabilities of the regression models on DM. As compared to the model contained conventional CVD risk factors alone, the area under the receiver operating curve (AUROC) increased by 1.00% (95% CI 0.29-1.73%; p = 0.0059) and 0.80% (95% CI 0.15-1.46%; p = 0.017) for models that added EDV in continuous and quartile scales, respectively. Additionally, the additions of PSV and MFV also significantly improved the predictabilities of the regression models (all 0.01 < p-value < 0.05). This study reveals a significant correlation between DM and altered hemodynamic parameters. Understanding this relationship could help identify individuals at higher risk of DM and facilitate targeted preventive strategies to reduce cardiovascular complications in DM patients.

Retinal microcirculation: A window into systemic circulation and metabolic disease

The retinal microcirculation system constitutes a unique terminal vessel bed of the systemic circulation, and its perfusion status is directly associated with the neural function of the retina. This vascular network, essential for nourishing various layers of the retina, comprises two primary microcirculation systems: the retinal microcirculation and the choroidal microcirculation, with each system supplying blood to distinct retinal layers and maintaining the associated neural function. The blood flow of those capillaries is regulated via different mechanisms. However, a range of internal and external factors can disrupt the normal architecture and blood flow within the retinal microcirculation, leading to several retinal pathologies, including diabetic retinopathy, macular edema, and vascular occlusions. Metabolic disturbances such as hyperglycemia, hypertension, and dyslipidemia are known to modify retinal microcirculation through various pathways. These alterations are observable in chronic metabolic conditions like diabetes, coronary artery disease, and cerebral microvascular disease due to advances in non-invasive or minimally invasive retinal imaging techniques. Thus, examination of the retinal microcirculation can provide insights into the progression of numerous chronic metabolic disorders. This review discusses the anatomy, physiology and pathophysiology of the retinal microvascular system, with a particular emphasis on the connections between retinal microcirculation and systemic circulation in both healthy states and in the context of prevalent chronic metabolic diseases.

Cerebrovascular Phenotype in Fabry Disease Patients Assessed by Ultrasound

OBJECTIVES

Fabry disease (FD) is a rare X-linked lysosomal storage disorder with variable phenotypes, including neurological symptoms. These can be influenced by vascular impairment. Extracranial and transcranial vascular sonography is an effective and noninvasive method for measuring arterial structures and blood flow. The study aims to investigate cerebrovascular phenotype characteristics in FD patients compared to controls using neurosonology.

METHODS

This is a single-center, cross-sectional study of 130 subjects-65 patients (38 females), with genetically confirmed FD, and 65 sex- and age-matched controls. Using ultrasonography, we measured structural and hemodynamic parameters, including distal common carotid artery intima-media thickness, inner vertebral artery diameter, resting blood flow velocity, pulsatility index, and cerebral vasoreactivity (CVR) in the middle cerebral artery. To assess differences between FD and controls and to identify factors influencing investigated outcomes, unadjusted and adjusted regression analyses were performed.

RESULTS

In comparison to sex- and age-matched controls, FD patients displayed significantly increased carotid artery intima-media thickness (observed FD 0.69 ± 0.13 mm versus controls 0.63 ± 0.12 mm; Padj  = .0014), vertebral artery diameter (observed FD 3.59 ± 0.35 mm versus controls 3.38 ± 0.33 mm; Padj  = .0002), middle cerebral artery pulsatility index (observed FD 0.98 ± 0.19 versus controls 0.87 ± 0.11; Padj  < .0001), and significantly decreased CVR (observed FD 1.21 ± 0.49 versus controls 1.35 ± 0.38; Padj  = .0409), when adjusted by age, BMI, and sex. Additionally, FD patients had significantly more variable CVR (0.48 ± 0.25 versus 0.21 ± 0.14; Padj  < .0001).

CONCLUSIONS

Our results suggest the presence of multiple vascular abnormalities and changes in hemodynamic parameters of cerebral arteries in patients with FD.

Comparative effect of antihypertensive drugs in improving arterial stiffness in adults with hypertension (RIGIPREV study). A network meta-analysis

Aims: To synthesize and evaluate the available scientific evidence on the efficacy of antihypertensive drugs on arterial stiffness in patients with hypertension by using a network meta-analysis approach. Methods: A systematic search of the MEDLINE (via PubMed), Scopus, and Web of Science databases was conducted to identify experimental studies addressing the effect of different antihypertensive drugs on arterial stiffness parameters (pulse wave velocity [PWV] and augmentation index [AIx]) in adults with hypertension. Comparative evaluation of the effect of antihypertensive drugs was performed by conducting a standard pairwise meta-analysis and a network meta-analysis for direct and indirect comparisons between antihypertensive drugs and placebo/other antihypertensive drugs. Analyses were performed including studies of any duration and only studies longer than 6 months length. Results: Seventy-six studies were included in the main analysis and considering only studies longer than 6 months length, thiazide diuretics, ACEIs, ARBs, the ACEI/ARB combination, the ACEI/CCB combination, and the ARB/CCB combination showed a higher effect on reducing PWV, and ACEIs and ARBs on reducing AIx. Conclusion: Our research provides evidence that antihypertensive medications are an effective way to treat arterial stiffness in adults with hypertension. Based on our findings, patients with hypertension who have greater levels of arterial stiffness may benefit from using thiazide diuretics, ACEIs, ARBs, the ACEI/ARB combination, the ACEI/CCB combination, and the ARB/CCB combination. Systematic Review Registration: PROSPERO (CRD42021276360).

Vascular ageing: moving from bench towards bedside

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, sub-clinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vascular ageing (VA) involves the deterioration in vascular structure and function over time and ultimately leads to damage in the heart, brain, kidney, and other organs. Vascular ageing encompasses the cumulative effect of all cardiovascular risk factors on the arterial wall over the life course and thus may help identify those at elevated cardiovascular risk, early in disease development. Although the concept of VA is gaining interest clinically, it is seldom measured in routine clinical practice due to lack of consensus on how to characterize VA as physiological vs. pathological and various practical issues. In this state-of-the-art review and as a network of scientists, clinicians, engineers, and industry partners with expertise in VA, we address six questions related to VA in an attempt to increase knowledge among the broader medical community and move the routine measurement of VA a little closer from bench towards bedside.

Vascular mechanisms leading to progression of mild cognitive impairment to dementia after COVID-19: Protocol and methodology of a prospective longitudinal observational study

INTRODUCTION

Mild cognitive impairment (MCI) is a prodromal stage to dementia, affecting up to 20% of the aging population worldwide. Patients with MCI have an annual conversion rate to dementia of 15-20%. Thus, conditions that increase the conversion from MCI to dementia are of the utmost public health concern. The COVID-19 pandemic poses a significant impact on our aging population with cognitive decline as one of the leading complications following recovery from acute infection. Recent findings suggest that COVID-19 increases the conversion rate from MCI to dementia in older adults. Hence, we aim to uncover a mechanism for COVID-19 induced cognitive impairment and progression to dementia to pave the way for future therapeutic targets that may mitigate COVID-19 induced cognitive decline.

METHODOLOGY

A prospective longitudinal study is conducted at the University of Oklahoma Health Sciences Center. Patients are screened in the Department of Neurology and must have a formal diagnosis of MCI, and MRI imaging prior to study enrollment. Patients who meet the inclusion criteria are enrolled and followed-up at 18-months after their first visit. Visit one and 18-month follow-up will include an integrated and cohesive battery of vascular and cognitive measurements, including peripheral endothelial function (flow-mediated dilation, laser speckle contrast imaging), retinal and cerebrovascular hemodynamics (dynamic vessel retinal analysis, functional near-infrared spectroscopy), and fluid and crystalized intelligence (NIH-Toolbox, n-back). Multiple logistic regression will be used for primary longitudinal data analysis to determine whether COVID-19 related impairment in neurovascular coupling and increases in white matter hyperintensity burden contribute to progression to dementia.

The renal resistive index is associated with microvascular remodeling in patients with severe obesity

BACKGROUND

Renal hemodynamics is impaired since the early stage of cardiometabolic disease. However, in obesity, its noninvasive ultrasound assessment still fails to provide pathophysiologic and clinical meaningfulness. We aimed to explore the relationship between peripheral microcirculation and renal hemodynamics in severe obesity.

METHODS

We enrolled fifty severely obese patients with an indication for bariatric referring to our outpatient clinic. Patients underwent an extensive reno-metabolic examination, paired with Doppler ultrasound and measurement of the renal resistive index (RRI). On the day of the surgery, visceral fat biopsies were collected to perform an ex-vivo complete microcirculatory assessment. Media-to-lumen ratio (M/L) and vascular response to acetylcholine (ACh), alone or co-incubated with N G -nitro arginine methyl ester (L-NAME), were measured.

RESULTS

Patients were stratified according to their normotensive (NT) or hypertensive (HT) status. HT had lower estimated glomerular filtration rate and higher RRI compared to NT, while the presence and extent of albuminuria were similar between the two groups. Concerning microcirculatory assessment, there were no differences between groups as regards the microvascular structure, while the vasorelaxation to ACh was lower in HT ( P = 0.042). Multivariable analysis showed a relationship between M/L and RRI ( P  = 0.016, St. β 0.37) and between albuminuria and the inhibitory response of L-NAME to Ach vasodilation ( P   =  0.036, St. β = -0.34). Notably, all these correlations were consistent also after adjustment for confounding factors.

CONCLUSIONS

The RRI and albuminuria relationship with microvascular remodeling in patients affected by severe obesity supports the clinical implementation of RRI to improve risk stratification in obesity and suggests a tight pathophysiologic connection between renal haemodynamics and microcirculatory disruption.

The acute adaptation of skin microcirculatory perfusion in vivo does not involve a local response but rather a centrally mediated adaptive reflex

Introduction: Cardiovascular homeostasis involves the interaction of multiple players to ensure a permanent adaptation to each organ's needs. Our previous research suggested that changes in skin microcirculation-even if slight and distal-always evoke an immediate global rather than "local" response affecting hemodynamic homeostasis. These observations question our understanding of known reflexes used to explore vascular physiology, such as reactive hyperemia and the venoarteriolar reflex (VAR). Thus, our study was designed to further explore these responses in older healthy adults of both sexes and to potentially provide objective evidence of a centrally mediated mechanism governing each of these adaptive processes. Methods: Participants (n = 22, 52.5 ± 6.2 years old) of both sexes were previously selected. Perfusion was recorded in both feet by laser Doppler flowmetry (LDF) and photoplethysmography (PPG). Two different maneuvers with opposite impacts on perfusion were applied as challengers to single limb reactive hyperemia evoked by massage and a single leg pending to generate a VAR. Measurements were taken at baseline (Phase I), during challenge (Phase II), and recovery (Phase III). A 95% confidence level was adopted. As proof of concept, six additional young healthy women were selected to provide video imaging by using optoacoustic tomography (OAT) of suprasystolic post-occlusive reactive hyperemia (PORH) in the upper limb. Results: Modified perfusion was detected by LDF and PPG in both limbs with both hyperemia and VAR, with clear systemic hemodynamic changes in all participants. Comparison with data obtained under the same conditions in a younger cohort, previously published by our group, revealed that results were not statistically different between the groups. Discussion: The OAT documentary and analysis showed that the suprasystolic pressure in the arm changed vasomotion in the forearm, displacing blood from the superficial to the deeper plexus vessels. Deflation allowed the blood to return and to be distributed in both plexuses. These responses were present in all individuals independent of their age. They appeared to be determined by the need to re-establish hemodynamics acutely modified by the challenger, which means that they were centrally mediated. Therefore, a new mechanistic interpretation of these exploratory maneuvers is required to better characterize in vivo cardiovascular physiology in humans.

Association of Pressure Wave Reflections With Left Ventricular Mass: a Systematic Review and Meta-Analysis

BACKGROUND

Pressure wave reflections (PWRs) within the circulation are assessed at various arterial sites by various noninvasive methods. We aimed at reviewing the conflicting data regarding the hypothesis that higher PWRs are associated with higher left ventricular mass and tested whether this association stands for all available indices of PWRs, all (proximal or distal to the heart) sites of assessment, and is modified by sex, age and heart rate.

METHODS

Based on a predefined protocol applying the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines, we identified eligible for meta-analysis data regarding: augmentation index, augmentation pressure, backward pressure (Pb), reflection index, and their association with left ventricular mass index (19 studies, total population n=8686).

RESULTS

We found statistically significant associations, independent from blood pressure level, for all indices of PWRs at all arterial sites (carotid augmentation index; odds ratio; standardized beta coefficient [β]: 0.14 [95% CI, 0.07% to 0.21%], per SD increase), radial augmentation index (β: 0.21; 0.11 to 0.31), central augmentation pressure (β: 0.15; 0.03 to 0.27), central Pb (β: 0.23; 0.05 to 0.42), and central reflection index (β: 0.14; 0.06 to 0.22), except for aortic augmentation index as estimated by generalized transfer functions. Meta-regression analysis showed that the association between carotid augmentation index and left ventricular mass was higher among populations with higher heart rate (P=0.036, beta: 0.017 [95% CI, 0.001 to 0.033]) and tended to be higher in middle-aged (P=0.07, beta: -0.001; -0.021 to 0.001).

CONCLUSIONS

A clinically meaningful association between PWRs and left ventricular mass, assessed at either central or peripheral arterial sites by most available methods was shown, suggesting that PWR reduction strategies might be useful. Based on the present evidence, such trials should target middle-aged populations with high normal heart rate.

Essential Hypertension and Oxidative Stress: Novel Future Perspectives

Among cardiovascular diseases, hypertension is one of the main risk factors predisposing to fatal complications. Oxidative stress and chronic inflammation have been identified as potentially responsible for the development of endothelial damage and vascular stiffness, two of the primum movens of hypertension and cardiovascular diseases. Based on these data, we conducted an open-label randomized study, first, to evaluate the endothelial damage and vascular stiffness in hypertense patients; second, to test the effect of supplementation with a physiological antioxidant (melatonin 1 mg/day for 1 year) in patients with essential hypertension vs. hypertensive controls. Twenty-three patients of either gender were enrolled and randomized 1:1 in two groups (control and supplemented group). The plasmatic total antioxidant capacity (as a marker of oxidative stress), blood pressure, arterial stiffness, and peripheral endothelial function were evaluated at the beginning of the study and after 1 year in both groups. Our results showed that arterial stiffness improved significantly (p = 0.022) in supplemented patients. The endothelial function increased too, even if not significantly (p = 0.688), after 1 year of melatonin administration. Moreover, the supplemented group showed a significative reduction in TAC levels (p = 0.041) correlated with the improvement of arterial stiffness. These data suggest that melatonin may play an important role in reducing the serum levels of TAC and, consequently, in improving arterial stiffness.

Arterial Stiffness and Long-Term Risk of Health Outcomes: The Framingham Heart Study

BACKGROUND

Arterial stiffness increases with age and is associated with an increased risk of adverse outcomes on short-term follow-up (typically <10 years). Data regarding associations of arterial stiffness with health outcomes on longer-term follow-up are lacking.

METHODS

We evaluated 7283 Framingham Study participants (mean age 50 years, 53% women) who underwent assessment of carotid-femoral pulse wave velocity (a marker of arterial stiffness) via applanation tonometry at one or more routine examinations. We used time-dependent Cox proportional hazards regression models to relate carotid-femoral pulse wave velocity to the incidence of health outcomes (updating carotid-femoral pulse wave velocity and all covariates at serial examinations).

RESULTS

On long-term follow-up (median 15 years; minimum-maximum, 0-20), participants developed cardiometabolic disease (hypertension [1255 events]; diabetes [381 events]), chronic kidney disease (529 events), dementia (235 events), cardiovascular disease (684 events) and its components (coronary heart disease [314 events], heart failure [191 events], transient ischemic attacks or stroke [250 events]), and death (1086 events). In multivariable-adjusted models, each SD increment in carotid-femoral pulse wave velocity was associated with increased risk of hypertension (hazard ratio [HR], 1.32 [95% CI, 1.21-1.44]), diabetes (HR, 1.32 [95% CI, 1.11-1.58]), chronic kidney disease (1.19 [95% CI, 1.05-1.34]), dementia (HR 1.27 [95% CI, 1.06-1.53]), cardiovascular disease (HR, 1.20 [95% CI, 1.06-1.36]) and its components (coronary heart disease, HR 1.37 [95% CI, 1.13-1.65]; transient ischemic attack/stroke, HR, 1.24 [95% CI, 1.00-1.53]), and death (HR, 1.29 [95% CI, 1.17-1.43]). The association with heart failure was borderline nonsignificant (HR, 1.21 [95% CI, 0.98-1.51], P=0.08).

CONCLUSIONS

Our prospective observations of a large community-based sample establish the long-term prognostic importance of arterial stiffness for multiple health outcomes.

Validation and Feasibility of an Automated System for the Assessment of Vascular Structure and Mechanical Properties in the Digital Arteries: An Ultrahigh-Frequency Ultrasound Study

Ultrahigh-frequency ultrasound (UHFUS) allows sharp visualization of human small muscular arteries. This may help in elucidating some aspects of the pathophysiology of arterial aging, such as the stiffness gradient between large and small conduit arteries and its consequences on the microcirculation, as well as vascular diseases affecting medium-sized arteries. However, UHFUS use is still limited, partly because of the lack of validated tools to quantify vascular structure and mechanical properties of small muscular arteries. In this validation study, scans of digital arteries were obtained with UHFUS (VevoMD, Visualsonics-Fujifilm, Toronto, ON, Canada), analyzed using Carotid Studio software (Quipu, Pisa, Italy) and compared with the manual measurement. Agreement between the two techniques on measures of diameter, distension and intima-media thickness (IMT) was evaluated using Bland-Altman analyses; inter- and intra-operator reproducibility was evaluated using coefficients of variation (CVs). Overall, no trend or significant bias was observed between Carotid Studio and manual analysis. All limits of agreement were acceptable. The intra-observer CV of diastolic diameter and IMT were 4.1% and 4.2%, respectively. The inter-observer CV for diastolic diameter and IMT were 7.3% and 5.4%, respectively. Intra- and inter-observer CVs for distension were higher (25.7% and 26.7%, respectively). These results suggest that the Carotid Studio software is a valid and reproducible tool to study UHFUS scans of digital arteries, with potential utility both in rare vascular diseases of medium-sized arteries and in the study of the pathophysiology of arterial aging in general.

Center-To-Periphery Arterial Stiffness Gradient Is Attenuated and/or Reversed in Pregnancy-Associated Hypertension

Background: Non-pregnant (NP) women have a progressive increase in arterial stiffness from central-to-peripheral arteries [“stiffness gradient” (SG)], which is of physiologic importance since excessive pulsatility is filtered by the creation of wave reflections. If the aorta gets stiff with minimal or no change in the periphery, the SG is dissipated transmitting pressure disturbances to the microcirculation. It remains unknown the status of the SG in both women with healthy pregnancies (HP) and complicated by pregnancy-associated hypertension (PAH).

Objective: To determine whether HP and PAH are associated with changes in SG. Secondarily, we aim at identifying potential differences between the subgroups of PAH (pre-eclampsia and gestational hypertension).

Methods: HP (n = 10), PAH (n = 16), and healthy NP women (n = 401, to be matched for age, and cardiovascular risk with the pregnant women) were included. Carotid-to-femoral (cfPWV) and carotid-to-radial pulse wave velocity (crPWV), common carotid artery (CCA) and brachial artery (BA) diameters and elastic modulus (EM), and regional (cfPWV/crPWV or “PWV ratio”) and local (CCA EM/BA EM or “EM ratio”) SG were quantified.

Results: HP showed no changes in PWV ratio compared with NP, in the presence of significantly lower cfPWV and crPWV. HP exhibited higher arterial diameters and lower CCA EM/BA EM compared to NP, without differences with PAH. PAH was associated with a significant increase in the PWV ratio that exceeded the levels of both NP and HP, explained by a lower (although significant) reduction of cfPWV with respect to that observed in HP with respect to NP, and a higher reduction in crPWV with respect to that observed between HP and NP. The blunted reduction in cfPWV observed in PAH coincided with an increase in the CCA EM.

Conclusions: Compared with NP, HP was associated with unchanged PWV ratio but with a reduction in CCA EM/BA EM, in the setting of a generalized drop in arterial stiffness. Compared with NP and HP, PAH was associated with an “exaggerated rise” in the PWV ratio without changes in CCA EM/BA EM, in the setting of a blunt reduction in cfPWV but exaggerated crPWV drop. The SG attenuation/reversal in PAH was mainly driven by pre-eclampsia.

Examination of Large Artery Atherosclerosis could Reveal Small Artery Retinopathy in Untreated Middle-Aged Individuals

AIMS

Small arteries can be visualized in the ocular fundus, and findings of retinopathy based on Scheie classification are often applied to evaluate the impact of hypertension and atherosclerosis. However, the relationship between damage in the large and small arteries has not been investigated sufficiently, especially in the early stages. The present study investigated possible associations between large artery atherosclerosis and small artery retinopathy in untreated middle-aged individuals.

METHODS

Untreated middle-aged workers undergoing periodic health check-ups (n=7,730, 45±8 years) were enrolled in this study. The absence or presence and extent of retinopathy were characterized by ophthalmologists as hypertensive (H0-4) and atherosclerotic grades (S0-4) based on Scheie classification. Large artery atherosclerosis was examined based on functional assessment of the cardio-ankle vascular index (CAVI) and morphological assessment of the carotid intima-media thickness (IMT) by ultrasound.

RESULTS

We found significant differences in CAVI and carotid IMT between individuals with and without hypertensive or atherosclerotic retinopathy. Multivariable regression analysis showed that the presence of hypertensive and atherosclerotic retinopathy was significantly associated with CAVI and carotid IMT. Logistic regression analysis with the endpoint of a hypertensive or atherosclerotic lesion revealed that CAVI and carotid IMT are independent determinants of retinopathy.

CONCLUSIONS

CAVI and carotid IMT were significantly associated with the presence of retinopathy based on Scheie classification in untreated middle-aged subjects, implying that atherosclerotic examination in large arteries could reveal early-stage small artery retinopathy.

Comparison of the usefulness of the cardio-ankle vascular index and augmentation index as an index of arteriosclerosis in patients with essential hypertension

Arteriosclerosis leads to various serious diseases that substantially reduce the quality of life. When treating hypertension, it is important to evaluate the degree of arteriosclerosis. In recent years, the cardio-ankle vascular index and augmentation index have been frequently used as indicators of arterial wall sclerosis. However, the superiority of either the cardio-ankle vascular index or the augmentation index as an index of arteriosclerosis remains unclear. Therefore, the present study compared the usefulness of these two indices as an index of arteriosclerosis. Associations between the cardio-ankle vascular index or augmentation index and risk factors for arteriosclerosis and other indices of arteriosclerosis in 535 consecutive patients with essential hypertension were evaluated. The cardio-ankle vascular index was significantly correlated with age, hemoglobin A1c, brain natriuretic peptide, and estimated glomerular filtration rate. In contrast, the augmentation index showed significant correlations only with age, brain natriuretic peptide, and estimated glomerular filtration rate. In addition, these correlations with the augmentation index were generally weaker than those with the cardio-ankle vascular index. The cardio-ankle vascular index, but not the augmentation index, was significantly correlated with flow-mediated dilation, an index of vascular endothelial function, and carotid intima-media thickness, an index of carotid atherosclerosis. Similar results were observed in subgroups stratified by sex and age. These data indicate that the cardio-ankle vascular index is more closely associated with risk factors for arteriosclerosis and other indices of arteriosclerosis than the augmentation index, suggesting that the cardio-ankle vascular index may be superior to the augmentation index as an index of arteriosclerosis.

Chronic Kidney Disease and Arterial Stiffness: A Two-Way Path

The kidney-heart relationship has raised interest for the medical population since its vast and complex interaction significantly impacts health. Chronic kidney disease (CKD) generates vascular structure and function changes, with significant hemodynamic effects. The early arterial stiffening in CKD patients is a consequence of the interaction between oxidative stress and chronic vascular inflammation, leading to an accelerated deterioration of left ventricular function and alteration in tissue perfusion. CKD amplifies the inflammatory cascade's activation and is responsible for altering the endothelium function, increasing the vascular tone, wall thickening, and favors calcium deposits in the arterial wall. Simultaneously, the autonomic imbalance, and alteration in other hormonal systems, also favor the overactivation of inflammatory and fibrotic mediators. Thus, hormonal disarrangement also contributes to structural and functional lesions throughout the arterial wall. On the other hand, a rise in arterial stiffening and volume overload generates high left ventricular afterload. It increases the left ventricular burden with consequent myocardial remodeling, development of left ventricular hypertrophy and, in turn, heart failure. It is noteworthy that reduction in glomerular mass of renal diseases generates a compensatory glomerular filtration overdriven associated with large-arteries stiffness and high cardiovascular events. Furthermore, we consider that the consequent alterations of the arterial system's mechanical properties are crucial for altering tissue perfusion, mainly in low resistance. Thus, increasing the knowledge of these processes may help the reader to integrate them from a pathophysiological perspective, providing a comprehensive idea of this two-way path between arterial stiffness and renal dysfunction and their impact at the cardiovascular level.

Lower Limb Perfusion Asymmetries in Humans at Rest and Following Activity—A Collective View

The significance of lower limb perfusion asymmetries remains unknown in healthy individuals. Our study aims to understand how factors such as posture, sex, age, and body weight relate to perfusion. Data from studies previously published by our group, including experiments using laser Doppler flowmetry as the gold standard for perfusion measurements in baseline, (various) challenge, and recovery phases was assembled from a total of 139 healthy participants. Body position was shown to be a primary determinant of perfusion asymmetry, especially in women. Effects of sex and age were also analyzed. In a supine position, perfusion asymmetries seemed to relate negatively in the aged group of participants, where challenge and recovery seemed to follow different processes. In the upright position, young men and women have shown comparable distributions and asymmetry ratios at baseline and recovery. In the aged group, differences between sexes were observed at baseline, but again, the course of the asymmetry ratios with challenge was essentially similar in men and women. Our analysis suggests that ageing is a critical determinant in our upright study sample, as higher baseline asymmetries and longer recoveries after challenge were linked in older males with higher body mass index (BMI).

Early Vascular Aging in Children With Tuberous Sclerosis Complex

Objectives: Experimental data indicate that activating mutations in the mTOR (mammalian target of rapamycin) pathway may lead to abnormal arterial wall structure. Vascular anomalies like arterial stenoses are reported in pediatric patients with tuberous sclerosis complex (TSC). In addition, large renal lesions (angiomyolipoma-AML and cysts) are risk factors for arterial hypertension in adult patients with TSC. This study aimed to assess blood pressure, including central blood pressure and arterial damage (early vascular aging-EVA) in children with TSC. Materials and Methods: In a group of 33 pediatric patients with TSC (11.13 ± 4.03 years, 15 boys, 18 girls), we evaluated peripheral and central office blood pressure, 24-h ambulatory blood pressure, and arterial damage: aortic pulse wave velocity (aPWV) [m/s], [Z-score], augmentation index (AIx75HR [%]), common carotid artery intima-media thickness (cIMT) [mm], [Z-score], stiffness of common carotid artery (E-tracking), renal lesions in magnetic resonance and ultrasonography, and selected biochemical parameters. The control group consisted of 33 healthy children (11.23 ± 3.28 years, 15 boys, 18 girls). Results: In TSC group 7 (21.2%) children had arterial hypertension, 27 (81.8%) children had renal angiomyolipomas, 26 (78.8%)-renal cysts, and 4 (12.1%) patients were treated with mTOR inhibitors (2 patients with everolimus and 2 patients with sirolimus) at the moment of evaluation. Children with TSC had higher central systolic blood pressure (AoSBP) (98.63 ± 9.65 vs. 90.45 ± 6.87 [mm Hg], p < 0.001), cIMT (0.42 ± 0.05 vs. 0.39 ± 0.03 [mm], p = 0.011), cIMT Z-score (0.81 ± 1.21 vs. 0.16 ± 0.57, p = 0.007), aPWV (4.78 ± 0.81 vs. 4.25 ± 0.56 [m/s], p = 0.003) and aPWV Z-score (-0.14 ± 1.15 vs. -0.96 ± 0.87, p = 0.002) compared to healthy children, without differences in AIx75HR (8.71 ± 15.90 vs. 5.24 ± 11.12 [%], p = 0.319) and stiffness of common carotid artery. In children with TSC AoSBP correlated positively with serum cystatin C concentration (r = 0.377, p = 0.030) and with maximum diameter of renal cyst (R = 0.419, p = 0.033); mean arterial pressure (MAP) 24 h Z-score correlated with serum cystatin C concentration (R = 0.433, p = 0.013); and aPWV Z-score with daily urinary albumin loss [mg/24 h] (R = 0.412, p = 0.029). Conclusions: Children with tuberous sclerosis complex are at risk of elevated central blood pressure and early vascular aging. In children with TSC, blood pressure and arterial stiffness are related to renal involvement.

Glycaemic Control in Diabetes

Reduction of glucose is the hallmark of diabetes therapy proven to reduce micro- and macro-vascular risk in patients with type 1 diabetes. However glucose-lowering efficacy trials in type 2 diabetes didn't show major cardiovascular benefit. Then, a paradigm change in the treatment of patients with type 2 diabetes has emerged due to the introduction of new blood glucose-lowering agents. Cardiovascular endpoint studies have proven HbA1c-independent cardioprotective effects for GLP-1 receptor agonists and SGLT-2 inhibitors. Furthermore, SGLT-2 inhibitors reduce the risk for heart failure and chronic kidney disease. Mechanisms for these blood glucose independent drug target-related effects are still an enigma. Recent research has shown that GLP-1 receptor agonists might have anti-inflammatory and plaque stabilising effects whereas SGLT-2 inhibitors primarily reduce pre- and after-load of the heart and increase work load efficiency of the heart. In addition, reduction of intraglomerular pressure, improved energy supply chains and water regulation appear to be major mechanisms for renoprotection by SGLT-2 inhibitors. These studies and observations have led to recent changes in clinical recommendations and treatment guidelines for type 2 diabetes. In patients with high or very high cardio-renal risk, SGLT-2 inhibitors or GLP-1 receptor agonists have a preferred recommendation independent of baseline HbA1c levels due to cardioprotection. In patients with chronic heart failure, chronic kidney disease or at respective risks SGLT-2 inhibitors are the preferred choice. Therefore, the treatment paradigm of glucose control in diabetes has changed towards using diabetes drugs with evidence-based organ protection improving clinical prognosis.

Vascular Ageing in Youth: A Call to Action

Extensive evidence shows that risk factors for cardiovascular disease (CVD) begin to develop early in life. Childhood obesity and elevated blood pressure (BP) have become overwhelmingly challenging, with 57% of today's children predicted to be obese by the age of 35 years, and global rates of hypertension in children and adolescents increasing by 75% from 2000 to 2015. Thus, there is an urgent need for tools that can assess early CVD risk in youth, which may lead to better risk stratification, preventative intervention, and personalised medicine. Vascular ageing (the deterioration in vascular structure and function) is a pivotal progenitor of health degeneration associated with elevated BP. Exposure to adverse environmental and genetic factors from fetal life promotes the development and accumulation of subclinical vascular changes that direct an individual towards a trajectory of early vascular ageing (EVA)-an independent predictor of target organ damage in the heart, brain, and kidneys. Therefore, characterising vascular ageing from youth may provide a window into cardiovascular risk later in life. However, vascular ageing measurements only have value when techniques are accurate/validated and when reliable thresholds are available for defining normal ranges and ranges that signal increased risk of disease. The aim of this paper is to summarise current evidence on the importance of vascular ageing assessment in youth and the impact of interventions to prevent or delay EVA, to highlight the need for standardisation and validation of measurement techniques in children and adolescents, and the importance of establishing reference values for vascular ageing measures in this population.

Role of increased central arterial stiffness in macro and microvascular damage in patients with coronary artery disease

BACKGROUND

Patients with heart disease frequently have renal dysfunction manifested by a decrease in glomerular filtration rate (GFR) and / or increase of albuminuria.

OBJECTIVES

The objective was to study the possible role of increased aortic stiffness in the presence and extent of coronary artery disease (CAD) and kidney dysfunction in a group of patients with suspected CAD.

PATIENTS AND METHODS

We studied forty-eight patients undergoing coronariography for suspected coronary disease (CAD). Using applanation tonometry on the radial artery and applying a transfer function, central blood pressure values were calculated. The study of aortic stiffness was done by determining the carotid-femoral pulse velocity (Pv_c-f).

RESULTS

Of the 48 patients, 11 had no significant coronary lesions, 24 showed significant lesions in 1 or 2 coronary arteries and 13 in ≥ 3 arteries. The group with a higher degree of CD had significantly higher cPP values than the group without CD. The Pv_c-f increased progressively and significantly with the degree of CD. The logistic regression showed that Pv_c-f independently predicted the presence of CD. The relative risk of CD increased 2.5 times for each meter of increase in Pv_c-f. The GFR was negatively and significantly correlated with age and Pv_c-f was associated with albuminuria.

CONCLUSIONS

In patients with stable CD, Pv_c-f, expression of aortic stiffness, is independently associated with the existence of CD and its degree of extension. The increase in arterial stiffness also participates in the decrease in GFR and in the increase in albuminuria.

Reference values of retinal microcirculation parameters derived from a population random sample

Retinal microcirculation reflects retinal perfusion abnormalities and retinal arterial structural changes at relatively early stages of various cardiovascular diseases. Our objective has been to establish reference values for major functional and structural parameters of retinal microcirculation in a randomly selected urban population sample. A total of 398 randomly selected individuals from an urban population aged 25 to 65 years, resident in Pilsen, Czech Republic, were screened for major cardiovascular risk factors. Retinal microcirculation was assessed using scanning laser Doppler flowmetry (SLDF), with data evaluable in 343 patients. Of this number, complete data were available for 256 individuals free from manifest cardiovascular disease, diabetes and drug treatment for hypertension and/or dyslipidemia, constituting the reference value population. Juxtapapillary retinal capillary blood flow has increased significantly with age whereas vessel and luminal diameters have decreased. No sex differences in retinal microcirculation parameters have been found. Therefore, reference values for retinal microcirculation parameters have been established by age groups. Unattended automated office systolic BP, after adjusting for age, correlated significantly with wall-to-lumen ratio (WLR) and wall thickness (WT). Moreover, after adjusting for age and mean BP, a positive relationship has been found between carotid femoral pulse wave velocity and WT, WLR and wall cross-sectional area, indicating the interaction between micro- and macro-vasculature. In conclusion, our study is the first to provide reference values of retinal microcirculation parameters in a random Caucasian population sample. Our results have shown that, at the population level, the first structural changes in retinal microcirculation are those in lumen diameters. Of note, a close relationship between BP and vascular remodeling of retinal arterioles and between aortic stiffness and WLR of retinal arterioles suggests an interaction between micro- and macro-vasculature.

Oscillatory interstitial fluid pressure and velocity in a solid tumor with partial surface fluid leakage

This work investigates the interstitial fluid flow characteristics in a solid tumor with partial fluid leakage at the tumor surface subjected to oscillatory microvascular pressure. Solutions of the pore fluid pressure and velocity in a spherical tumor are obtained using the poroelasticity theory for small strains. It is found that partial fluid leakage at the tumor surface reduces the pore pressure drop and decreases the fluid velocity near the surface compared with those in a tumor with a fully leaking surface. Both the pore pressure and the fluid velocity decrease dramatically with an increase in the vascular frequency. The pore pressure at a vascular frequency of 1 Hz is two orders of magnitude smaller than the amplitude of the vascular pressure, and the fluid velocity at the same frequency is one order of magnitude smaller than that produced by the steady constant vascular pressure. The pore pressure amplitude may reach that of the vascular pressure under the steady state vascular pressure condition.

Vasculo-Neuronal Coupling and Neurovascular Coupling at the Neurovascular Unit: Impact of Hypertension

Components of the neurovascular unit (NVU) establish dynamic crosstalk that regulates cerebral blood flow and maintain brain homeostasis. Here, we describe accumulating evidence for cellular elements of the NVU contributing to critical physiological processes such as cerebral autoregulation, neurovascular coupling, and vasculo-neuronal coupling. We discuss how alterations in the cellular mechanisms governing NVU homeostasis can lead to pathological changes in which vascular endothelial and smooth muscle cell, pericyte and astrocyte function may play a key role. Because hypertension is a modifiable risk factor for stroke and accelerated cognitive decline in aging, we focus on hypertension-associated changes on cerebral arteriole function and structure, and the molecular mechanisms through which these may contribute to cognitive decline. We gather recent emerging evidence concerning cognitive loss in hypertension and the link with vascular dementia and Alzheimer’s disease. Collectively, we summarize how vascular dysfunction, chronic hypoperfusion, oxidative stress, and inflammatory processes can uncouple communication at the NVU impairing cerebral perfusion and contributing to neurodegeneration.

Ultrasonic Assessment of the Medial Temporal Lobe Tissue Displacements in Alzheimer’s Disease

We aim to estimate brain tissue displacements in the medial temporal lobe (MTL) using backscattered ultrasound radiofrequency (US RF) signals, and to assess the diagnostic ability of brain tissue displacement parameters for the differentiation of patients with Alzheimer’s disease (AD) from healthy controls (HC). Standard neuropsychological evaluation and transcranial sonography (TCS) for endogenous brain tissue motion data collection are performed for 20 patients with AD and for 20 age- and sex-matched HC in a prospective manner. Essential modifications of our previous method in US waveform parametrization, raising the confidence of micrometer-range displacement signals in the presence of noise, are done. Four logistic regression models are constructed, and receiver operating characteristic (ROC) curve analyses are applied. All models have cut-offs from 61.0 to 68.5% and separate AD patients from HC with a sensitivity of 89.5% and a specificity of 100%. The area under a ROC curve of predicted probability in all models is excellent (from 95.2 to 95.7%). According to our models, AD patients can be differentiated from HC by a sharper morphology of some individual MTL spatial point displacements (i.e., by spreading the spectrum of displacements to the high-end frequencies with higher variability across spatial points within a region), by lower displacement amplitude differences between adjacent spatial points (i.e., lower strain), and by a higher interaction of these attributes.