Automated detection of local artery wall thickness based on M-line signal processing

Increased diameter and stiffness of elastic but not muscular arteries in men with abdominal aortic aneurysm

It has been proposed that formation of abdominal aortic aneurysm (AAA) is part of a systemic arterial dilatative disease. However, arteries in the upper extremities are scarcely studied and it remains unclear whether both muscular and elastic arteries are affected by the proposed systemic arterial dilatation. The aim of this study was to investigate the diameter and stiffness of muscular and elastic arteries in arterial branches originating from the aortic arch. Twenty-six men with AAA (69 ± 4 yr) and 57 men without AAA (70 ± 5 yr) were included in the study. Ultrasound was used to examine the distal and proximal brachial artery, axillary artery, and common carotid artery (CCA), and measurement of diameter and diameter change was performed with wall-tracking software. Blood pressure measurements were used to calculate local arterial wall stiffness indices. The AAA cohort presented larger arterial diameters in the CCA and axillary artery after adjustment for body surface area (P = 0.002, respectively), whereas the brachial artery diameters were unchanged. Indices of increased stiffness in CCA (e.g., lower distensibility, P = 0.003) were seen in subjects with AAA after adjustments for body mass index and mean arterial blood pressure. This study supports the theory of a systemic arterial dilating diathesis in peripheral elastic, but not in muscular, arteries. Peripheral elastic arteries also exhibited increased stiffness, in analogy with findings in the aorta in AAA.NEW & NOTEWORTHY We present data partially supporting the notion of abdominal aortic aneurysm being a systemic vascular disease with focal manifestation in the abdominal aorta, from two well-defined groups recruited from a regional screening program. We show that elastic arteries distal from the aorta exhibit vascular alterations without aneurysmal formation in subjects with AAA compared with controls while muscular arteries seem unaffected.

Arterial Stiffness: From Basic Primers to Integrative Physiology

The elastic properties of conductance arteries are one of the most important hemodynamic functions in the body, and data continue to emerge regarding the importance of their dysfunction in vascular aging and a range of cardiovascular diseases. Here, we provide new insight into the integrative physiology of arterial stiffening and its clinical consequence. We also comprehensively review progress made on pathways/molecules that appear today as important basic determinants of arterial stiffness, particularly those mediating the vascular smooth muscle cell (VSMC) contractility, plasticity and stiffness. We focus on membrane and nuclear mechanotransduction, clearance function of the vascular wall, phenotypic switching of VSMCs, immunoinflammatory stimuli and epigenetic mechanisms. Finally, we discuss the most important advances of the latest clinical studies that revisit the classical therapeutic concepts of arterial stiffness and lead to a patient-by-patient strategy according to cardiovascular risk exposure and underlying disease.

The Ultrasound Window Into Vascular Ageing: A Technology Review by the VascAgeNet COST Action

Non-invasive ultrasound (US) imaging enables the assessment of the properties of superficial blood vessels. Various modes can be used for vascular characteristics analysis, ranging from radiofrequency (RF) data, Doppler- and standard B/M-mode imaging, to more recent ultra-high frequency and ultrafast techniques. The aim of the present work was to provide an overview of the current state-of-the-art non-invasive US technologies and corresponding vascular ageing characteristics from a technological perspective. Following an introduction about the basic concepts of the US technique, the characteristics considered in this review are clustered into: 1) vessel wall structure; 2) dynamic elastic properties, and 3) reactive vessel properties. The overview shows that ultrasound is a versatile, non-invasive, and safe imaging technique that can be adopted for obtaining information about function, structure, and reactivity in superficial arteries. The most suitable setting for a specific application must be selected according to spatial and temporal resolution requirements. The usefulness of standardization in the validation process and performance metric adoption emerges. Computer-based techniques should always be preferred to manual measures, as long as the algorithms and learning procedures are transparent and well described, and the performance leads to better results. Identification of a minimal clinically important difference is a crucial point for drawing conclusions regarding robustness of the techniques and for the translation into practice of any biomarker.

Coronary Volume to Left Ventricular Mass Ratio in Patients With Hypertension

The coronary vascular volume to left ventricular mass (V/M) ratio assessed by coronary computed tomography angiography (CCTA) is a promising new parameter to investigate the relation of coronary vasculature to the myocardium supplied. It is hypothesized that hypertension decreases the ratio between coronary volume and myocardial mass by way of myocardial hypertrophy, which could explain the detected abnormal myocardial perfusion reserve reported in patients with hypertension. Individuals enrolled in the multicenter ADVANCE (Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care) registry who underwent clinically indicated CCTA for analysis of suspected coronary artery disease with known hypertension status were included in current analysis. The V/M ratio was calculated from CCTA by segmenting the coronary artery luminal volume and left ventricular myocardial mass. In total, 2,378 subjects were included in this study, of whom 1,346 (56%) had hypertension. Left ventricular myocardial mass and coronary volume were higher in subjects with hypertension than normotensive patients (122.7 ± 32.8 g vs 120.0 ± 30.5 g, p = 0.039, and 3,105.0 ± 992.0 mm3 vs 2,965.6 ± 943.7 mm3, p <0.001, respectively). Subsequently, the V/M ratio was higher in patients with hypertension than those without (26.0 ± 7.6 mm3/g vs 25.3 ± 7.3 mm3/g, p = 0.024). After correcting for potential confounding factors, the coronary volume and ventricular mass remained higher in patients with hypertension (least square) mean difference estimate: 196.3 (95% confidence intervals [CI] 119.9 to 272.7) mm3, p <0.001, and 5.60 (95% CI 3.42 to 7.78) g, p <0.001, respectively), but the V/M ratio was not significantly different (least square mean difference estimate: 0.48 (95% CI -0.12 to 1.08) mm3/g, p = 0.116). In conclusion, our findings do not support the hypothesis that the abnormal perfusion reserve would be caused by reduced V/M ratio in patients with hypertension.

Detectable Bias between Vascular Ultrasound Echo-Tracking Systems: Relevance Depends on Application

The Esaote MyLab70 ultrasound system has been extensively used to evaluate arterial properties. Since it is reaching end-of-service-life, ongoing studies are forced to seek an alternative, with some opting for the Esaote MyLabOne. Biases might exist between the two systems, which, if uncorrected, could potentially lead to the misinterpretation of results. This study aims to evaluate a potential bias between the two devices. Moreover, by comparing two identical MyLabOne systems, this study also aims to investigate whether biases estimated between the MyLabOne and MyLab70 employed in this study could be generalized to any other pair of similar scanners. Using a phantom set-up, we performed n = 60 measurements to compare MyLab70 to MyLabOne and n = 40 measurements to compare the two MyLabOne systems. Comparisons were performed to measure diameter, wall thickness, and distension. Both comparisons led to significant biases for the diameter (relative bias: −0.27% and −0.30% for the inter- and intra-scanner model, respectively, p < 0.05) and wall thickness (relative bias: 0.38% and −1.23% for inter- and intra-scanner model, respectively p < 0.05), but not for distension (relative bias: 0.48% and −0.12% for inter- and intra-scanner model, respectively, p > 0.05). The biases estimated here cannot be generalized to any other pair of similar scanners. Therefore, longitudinal studies with large sample sizes switching between scanners should perform a preliminary comparison to evaluate potential biases between their devices. Furthermore, caution is warranted when using biases reported in similar comparative studies. Further work should evaluate the presence and relevance of similar biases in human data.

Time-warping for robust automated arterial wall-recognition and tracking from single-scan-line ultrasound signals

Current ultrasound methods for recognition and motion-tracking of arterial walls are suited for image-based B-mode or M-mode scans but not adequately robust for single-line image-free scans. We introduce a time-warping-based technique to address this need. Its performance was validated through simulations and in-vivo trials on 21 subjects. The method recognized wall locations with 100 % precision for simulated frames (SNR > 10 dB). Clustering detections for multiple frames achieved sensitivity >98 %, while it was ∼90 % without clustering. The absence of arterial walls was predicted with 100 % specificity. In-vivo results corroborated the performance outcomes yielding a sensitivity ≥94 %, precision ≥98 %, and specificity ≥98 % using the clustering scheme. Further, excellent frame-to-frame tracking accuracy (absolute error <3 %, RMSE <2 μm) was demonstrated. Image-free measurements of peak arterial distension agreed with the image-based ones, within an error of 1.08 ± 3.65 % and RMSE of 38 μm. The method discerned the presence of arterial walls in A-mode frames, robustly localized, and tracked them even when they were proximal to hyperechoic regions or slow-moving tissue structures. Unification of delineation techniques with the proposed methods facilitates a complete image-free framework for measuring arterial dynamics and the development of reliable A-mode devices.

Single M-Line Is as Reliable as Multiple M-Line Ultrasound for Carotid Artery Screening

Purpose: Carotid artery properties can be evaluated with high accuracy and reproducibility using multiple M-line ultrasound. However, the cost of multiple M-line-based imaging modalities and the extensive operator expertise requirements hamper the large-scale application for arterial properties assessment, particularly in resource-constrained settings. This study is aimed to assess the performance of a single M-line approach as an affordable and easy-to-use alternative to multiple M-line imaging for screening purposes.

Methods: We used triplicate longitudinal common carotid artery (CCA) ultrasound recordings (17 M-lines covering about 16 mm, at 500 frames per second) of 500 subjects from The Maastricht Study to assess the validity and reproducibility of a single against multiple M-line approach. The multiple M-line measures were obtained by averaging over all available 17 lines, whereas the middle M-line was used as a proxy for the single M-line approach.

Results: Diameter, intima-media thickness (IMT), and Young's elastic modulus (YEM) were not significantly different between the single and multiple M-line approaches (p > 0.07). Distension and distensibility coefficient (DC) did differ significantly (p < 0.001), however, differences were technically irrelevant. Similarly, Bland-Altman analysis revealed good agreement between the two approaches. The single M-line approach, compared to multiple M-line, exhibited an acceptable reproducibility coefficient of variation (CV) for diameter (2.5 vs. 2.2%), IMT (11.9 vs. 7.9%), distension (10 vs. 9.4%), DC (10.9 vs. 10.2%), and YEM (26.5 vs. 20.5%). Furthermore, in our study population, both methods showed a similar capability to detect age-related differences in arterial stiffness.

Conclusion: Single M-line ultrasound appears to be a promising tool to estimate anatomical and functional CCA properties with very acceptable validity and reproducibility. Based on our results, we might infer that image-free, single M-line tools could be suited for screening and for performing population studies in low-resource settings worldwide. Whether the comparison between single and multiple M-line devices will yield similar findings requires further study.

Training responsiveness of cardiorespiratory fitness and arterial stiffness following moderate-intensity continuous training and high-intensity interval training in adults with intellectual and developmental disabilities

BACKGROUND

Cardiorespiratory fitness (CRF) prompts antiatherogenic adaptations in vascular function and structure. However, there is an extraordinary interindividual variability in response to a standard dose of exercise, wherein a substantial number of adults with intellectual and developmental disabilities (IDD) do not improve CRF. We (1) evaluated the effects of 12-month of moderate-intensity continuous training (MICT) on CRF and arterial stiffness and (2) tested whether an additional 3-month of high-intensity interval training (HIIT) would add to improvements in CRF responsiveness and arterial stiffness.

METHODS

Fifteen adults with mild-to-moderate IDD (male adults = 9, 30.1 ± 7.5 years old) met 3 days per week for 30 min MICT for 12 months, after which the incidence of CRF responsiveness was calculated (≥5.0% change in absolute peak VO₂ ). Thereafter, responders and non-responders started HIIT for 3 months with identical daily training load/frequency. Peak VO₂ , local and regional indices of arterial stiffness were assessed prior to and after each period.

RESULTS

Sixty per cent of the participants were non-responders following MICT, but the incidence dropped to 20% following HIIT (P = 0.03). Absolute peak VO₂ values reached significant difference from pre-intervention (+0.38 ± 0.08 L min^-1 , P = 0.001) only when HIIT was added. Lower limb pulse wave velocity (PWV) decreased following MICT (-0.8 ± 1.1 m s^-1 , P = 0.049), whereas central PWV only decreased following HIIT (-0.8 ± 0.9 m s^-1 , P = 0.013).

CONCLUSIONS

Cardiorespiratory fitness responsiveness and reductions in PWV to a 12-month MICT period in adults with IDD improved following a period of HIIT programme inducing higher metabolic stress.

Interindividual Variability in Fat Mass Response to a 1-Year Randomized Controlled Trial With Different Exercise Intensities in Type 2 Diabetes: Implications on Glycemic Control and Vascular Function

Purpose: Little is known about the interindividual variability in fat mass (FM) loss in response to high-intensity interval training (HIIT) and moderate continuous training (MCT) in individuals with type 2 diabetes mellitus (T2DM). Moreover, the impact on health-related outcomes in those who fail to reduce FM is still unclear. The aims of this investigation were (1) to assess if the individuals with T2DM who FM differed across MCT, HIIT, and control groups over a 1-year intervention and (2) to assess the changes on glycemic control and vascular function in the exercising patients who failed to lose FM.

Methods: Adults with T2DM were randomized into a 1-year intervention involving a control group (n=22), MCT with resistance training (RT; n=21), and HIIT with RT (n=19). FM was assessed using dual-energy X-ray absorptiometry and a change in total body FM above the typical error was used to categorize FM responders. Glycemic control and vascular stiffness and structure were assessed. A chi-square test and generalized estimating equations were used to model the outcomes.

Results: Both MCT (n=10) and HIIT (n=10) had a similar proportion of individuals who were categorized as high responders for FM, with the percent change in FM on average −5.0±9.6% for the MCT and −6.0±12.1% for the HIIT, which differed from the control group (0.2±7.6%) after a 1-year intervention (p<0.05). A time-by-group interaction for carotid artery intima-media thickness (cIMT) (p for interaction=0.042) and lower-limb pulse wave velocity (LL PWV; p for interaction=0.010) between those categorized as low FM responders and the control group. However, an interaction was observed between the high responders for FM loss and controls for both brachial and carotid hemodynamic indices, as well as in cIMT, carotid distensibility coefficient, carotid beta index, and LL PWV (p for interactions <0.05). No interactions were found for glycaemic indices (p for interaction >0.05).

Conclusion: Our results suggest that the number of FM responders did not differ between the MCT or HIIT, compared to the control, following a 1-year exercise intervention in individuals with T2DM. However, low responders to FM may still derive reductions in arterial stiffness and structure.

Clinical Trial Registration: Comparing Moderate and High-intensity Interval Training Protocols on Biomarkers in Type 2 Diabetes Patients (D2FIT study) – number: NCT03144505 (https://clinicaltrials.gov/ct2/show/NCT03144505).

Carotid IMT and Stiffness in the KiGGS 2 National Survey: Third-Generation Measurement, Quality Algorithms and Determinants of Completeness

Carotid intima-media thickness (cIMT) and carotid stiffness (CS) are important markers of atherosclerotic risk in the young. We assessed a novel third-generation method for its applicability in large population-based epidemiologic studies to determine strengths, limitations, completeness and predictors of unsuccessful measurement. Four thousand seven hundred ninety-eight 14- to 31-y-old participants of the German KiGGS cohort, which is based on a nationally representative sample with 11-y follow-up, underwent B-mode ultrasound examinations of the left and right common carotid artery with semi-automatic edge detection and automatic electrocardiogram-gated real-time quality control based on a sophisticated snake algorithm and subpixel interpolation. Overall completeness was 98% for far wall cIMT and 89% for CS parameters. Plane-specific completeness varied from 92%-96% for far wall and from 64%-69% for near-wall cIMT. Obesity independently predicted unsuccessful cIMT and CS measurements with odds ratios of 12.67 (95% confidence interval: 5.50-29.19) and 7.30 (4.87-10.94) compared with non-overweight after adjustment for blood pressure, cholesterol, smoking, hazardous drinking, age, sex and sonographer. Inter- and intra-rater reliabilities of cIMT and CS parameters in a sample of 15 young adults were good or excellent. Third-generation cIMT and CS measurements in the young with semi-automatic edge-detection and automatic real-time quality control has been successfully standardized with high reliability and very high completeness in a national survey setting. This provides a strong methodological foundation for further validation of the predictive value of cIMT and CS for atherosclerotic risk in the young.

Carotid artery stiffness in rural adult Chinese: a cross-sectional analysis of the community-based China stroke cohort study

OBJECTIVES

To derive normative carotid artery stiffness data in rural adult Chinese population-based study of ultrasound measurements of carotid elasticity by using quality arterial stiffness (QAS), and to assess the changes of relevant parameters in Chinese adults 40 years of age and older.

DESIGN

A China stroke cohort study (total number: 1586) in the northern countryside were carried out between June 2013 and April 2016, designed to investigate the risk factors of cardiovascular and age-related diseases.

SETTING

The present study was a cross-sectional analysis of an ongoing community-based Shunyi cohort study in China.

PARTICIPANTS

A total of 583 participants (227 men and 356 women; aged 40-80 years) with ultrasound carotid QAS examination were retrieved from the study to analyse.

PRIMARY AND SECONDARY OUTCOME MEASURES

Arterial stiffness parameters included diastolic diameter (Dd), pulse wave velocity (PWV), stiffness indices α and β were calculated by QAS. Other clinical indicators included physical measurements, medical histories and blood biochemical test.

RESULTS

In the entire study sample, mean Dd was 7.93±0.88 mm, mean PWV was 9.4±2.4 m/s, mean α was 7.65±5.13 and mean β was 15.53±10.29. PWV was significant higher in participants with hypertension (9.9 m/s vs 9.2 m/s in those without, p=0.002), and with diabetes (10.3 m/s vs 9.2 m/s in those without, p=0.003). PWV were significantly higher in participants with HbA1c at 5.8%-6.4% versus <5.8%, but no difference was found between subjects with glycohaemoglobin (HbA1c) at 5.8%-6.4% versus >6.4% (p=0.005, p=0.955, respectively). Age increase by every 10 years was associated with Dd increased by 0.27 mm, PWV increased by 1.2 m/s, α increased by 1.34 and β increased by 2.71. Systolic blood pressure (SBP) increase by every 10 mm Hg was associated with Dd increased by 0.15 mm, PWV increased by 0.35 m/s, α increased by 0.13 and β increased by 0.15.

CONCLUSION

Among the participants older than 40 years, stiffness of the carotid artery had differences between hypertension and non-hypertension adults, as well as between diabetes and non-diabetes adults. Stiffness of the carotid artery also have differences between adults with HbA1c at 5.8%-6.4% versus <5.8%. Stiffness of the carotid artery increases with increasing age and increasing SBP at a range from 40 and up.

Automated measurement of compression-decompression in arterial diameter and wall thickness by image-free ultrasound

BACKGROUND AND OBJECTIVE

The manual measurement of arterial diameter and wall thickness using imaging modalities demand expertise, and the state-of-art automated or semi-automated measurement features are seldom available in the entry-level systems. The advanced ultrasound modalities are expensive, non-scalable, and less favorable for field and resource-constrained settings. In this work, we present a novel method to measure arterial diameter (D), surrogate intima-media thickness (sIMT), and with them their intra-cardiac cycle changes by employing an affordable image-free ultrasound technology.

METHODS

The functionality of the method was systematically validated on a simulation testbed, phantoms and, 40 human subjects. The accuracy, agreement, inter-beat, and inter-operator variabilities were quantified. The in-vivo measurement performance of the method was compared against two reference B-mode tools - Carotid Studio and CAROLAB.

RESULTS

Simulations revealed that for the A-mode frames with SNR > 10 dB, the proposed method identifies the desired arterial wall interfaces with an RMSE < 20 μm. The RMSE for the diameter and wall thickness measurements from the static phantom were 111 μm and 14 μm, and for the dynamic phantom were 117 μm and 18 μm, respectively. Strong agreement was seen between the in-vivo measurements of the proposed method and the two reference tools. The mean absolute errors against the two references and the inter-beat variability were smaller than 0.18 mm for D and smaller than 36 μm for sIMT measurements. Likewise, the respective inter-observer variabilities were 0.16 ± 0.23 mm and 43 ± 25 μm.

CONCLUSION

Acceptable accuracy and repeatability were observed during the validation, that were on a par with the recently reported B-mode techniques in the literature. The technology being real-time, automated, and relatively inexpensive, is promising for field and low-resource settings.

Vascular improvements in individuals with type 2 diabetes following a 1 year randomised controlled exercise intervention, irrespective of changes in cardiorespiratory fitness

AIMS/HYPOTHESIS

Vascular changes in individuals with type 2 diabetes mellitus majorly contribute to the development of cardiovascular disease. Increased cardiorespiratory fitness (CRF) has been associated with improvements in vascular health. Although CRF tends to improve with exercise training, there remains a portion of participants with little or no improvement. Given the importance of vascular function in individuals with type 2 diabetes, we assessed whether individuals who failed to improve CRF following a 1 year exercise intervention also failed to improve arterial stiffness and structural indices.

METHODS

Individuals with type 2 diabetes with no major micro- and macrovascular complications and aged between 30 and 75 years old (n = 63) participated in a three-arm, 1 year, randomised controlled exercise intervention in Lisbon, Portugal. The study involved a non-exercise control group, a moderate continuous training combined with resistance training (RT) group and a high-intensity interval training with RT group. Allocation of participants into the intervention and control groups was done using a computer-generated list of random numbers. An improvement in CRF was defined as a change in [Formula: see text] ≥5%. Vascular stiffness and structural indices were measured using ultrasound imaging and applanation tonometry. Generalised estimating equations were used to compare changes in vascular measures across individuals in the control group (n = 22) and those in the exercise groups who either had improved CRF (CRF responders; n = 14) or whose CRF did not improve (CRF non-responders; n = 27) following 1 year of exercise training.

RESULTS

Compared with the control group, exercisers, with and without improvements in CRF, had decreased carotid intima-media thickness (IMT) (CRF responders: β = -2.84 [95% CI -5.63, -0.04]; CRF non-responders: β = -5.89 [95% CI -9.38, -2.40]) and lower-limb pulse wave velocity (PWV) (CRF responders: β = -0.14 [95% CI -0.25, -0.03]; CRF non-responders: β = -0.14 [95% CI -0.25, -0.03]), the latter being an indicator of peripheral arterial stiffness. Only CRF responders had decreased PWV of the upper limb compared with control participants (β = -0.12 [95% CI -0.23, -0.01]). As for central stiffness, CRF non-responders had increased aortic PWV compared with CRF responders (β = 0.19 [95% CI 0.07, 0.31]), whereas only the CRF non-responders had altered carotid distensibility coefficient compared with the control group (β = 0.00 [95% CI 3.01 × 10^-5, 0.00]). No interaction effects between the CRF responders and non-responders vs control group were found for the remaining stiffness or haemodynamic indices (p>0.05).

CONCLUSIONS/INTERPRETATION

Regardless of improvements in CRF, individuals with type 2 diabetes had significant improvements in carotid IMT and lower-limb arterial stiffness following a 1 year exercise intervention. Thus, a lack of improvement in CRF following exercise in people with type 2 diabetes does not necessarily entail a lack of improvement in vascular health.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03144505 FUNDING: This work was supported by fellowships from the Portuguese Foundation for Science and Technology. This work is also financed by a national grant through the Fundação para a Ciência e Tecnologia (FCT), within the unit I&D 472.

Aortic stiffness is not only associated with structural but also functional parameters of retinal microcirculation

OBJECTIVE

The aim of the study was to test the hypothesis that alterations in large arteries are associated with microvascular remodelling and decreased retinal capillary blood flow.

METHODS

The study group comprised of 88 patients with essential hypertension and 32 healthy controls. Retinal microcirculation was evaluated by scanning laser Doppler flowmetry. Macrovascular changes were assessed on the basis of arterial stiffness measurement (carotid-femoral pulse wave velocity), its hemodynamic consequences (central pulse pressure, augmentation pressure, augmentation index) and intima media thickness of common carotid artery.

RESULTS

Pulse wave velocity was inversely correlated to mean retinal capillary blood flow in hypertensive patients (R = -0.32, p < 0.01). This relationship remained significant in multivariate regression analysis after adjustment for age, sex, central systolic blood pressure (BP) and body mass index (β = -31.27, p < 0.001). Lumen diameter (LD) of retinal arterioles was significantly smaller in hypertensive then normotensive subjects (79.4 vs. 83.8, p = 0.03). Central and brachial systolic, diastolic and mean BPs were significantly correlated with LD and outer diameter of retinal arterioles. The relationship between LD and central BPs remained significant in multivariate analysis (β = -0.15, p = 0.03 for cSBP; β = -0.22, p = 0.04 for cDBP; β = -0.21, p = 0.03 for cMBP). Moreover, in a subgroup with cardiac damage central and brachial pulse pressure were positively associated with retinal wall thickness, wall cross sectional area, and wall to lumen ratio.

CONCLUSION

In conclusion, the study provides a strong evidence that microcirculation is coupled with macrocirculation not only in terms of structural but also functional parameters.

Shortening telomere is associated with subclinical atherosclerosis biomarker in omnivorous but not in vegetarian healthy men

Telomere length is considered to be a biomarker of biological aging and age-related disease. There are few studies that have evaluated the association between telomere length and diet, and none of them have evaluated the impact of a vegetarian diet on telomere length and its correlation with cardiovascular biomarkers in apparently healthy subjects. Therefore, our objectives were to evaluate leukocyte telomere length (LTL) in vegetarians and omnivorous subjects and its association with classical cardiovascular risk biomarkers. From the total of 745 participants initially recruited, 44 omnivorous and 44 vegetarian men apparently healthy were selected for this study and LTL was measured in 39 omnivorous and 41 vegetarians by Real-Time Quantitative PCR reaction. Although telomere length was not different between omnivorous and vegetarians, we found a strong negative correlation between LTL and IMT (intima-media thickness) in omnivorous, but not in vegetarian group. In addition, omnivorous who were classified with short telomere length had higher carotid IMT compared to vegetarians. Our data suggest that telomere length can be a marker of subclinical atherosclerosis in the omnivorous group.

Effects of combined training with different intensities on vascular health in patients with type 2 diabetes: a 1-year randomized controlled trial

Background

Exercise, when performed on a regular basis, is a well-accepted strategy to improve vascular function in patients with type 2 diabetes. However, the exercise intensity that yields maximal adaptations on structural and functional indices in patients with type 2 diabetes remains uncertain. Our objective was to analyze the impact of a 1-year randomized controlled trial of combined high-intensity interval training (HIIT) with resistance training (RT) vs. a combined moderate continuous training (MCT) with RT on structural and functional arterial indices in patients with type 2 diabetes.

Methods

Patients with type 2 diabetes (n = 80) were randomized into an exercise intervention with three groups: control, combined HIIT with RT and combined MCT with RT. The 1-year intervention had 3 weekly exercise sessions. High-resolution ultrasonography of the common carotid artery and central and peripheral applanation tonometry were used to assess the changes in structural and functional arterial indices. Generalized estimating equations were used to model the corresponding outcomes.

Results

After adjusting the models for sex, baseline moderate-to-vigorous physical activity, and mean arterial pressure changes, while using the intention-to-treat analysis, a significant interaction was observed on the carotid intima-media thickness (cIMT) for both the MCT (β = − 4.25, p < 0.01) and HIIT group (β = − 3.61, p < 0.01). However, only the HIIT observed favorable changes from baseline to 1-year on peripheral arterial stiffness indices such as carotid radial arterial pulse wave velocity (β = − 0.10, p = 0.044), carotid to distal posterior tibial artery pulse wave velocity (β = − 0.14, p < 0.01), and on the distensibility coefficient (β = − 0.00, p < 0.01). No effect was found for hemodynamic variables after the intervention.

Conclusions

Following a 1-year intervention in patients with type 2 diabetes, both the MCT and HIIT group reduced their cIMT, whereas only the HIIT group improved their peripheral arterial stiffness indices and distensibility coefficient. Taken together, HIIT may be a meaningful tool to improve long-term vascular complications in type 2 diabetes.

Trial registration clinicaltrials.gov ID: NCT03144505

Subclinical parameters of arterial stiffness and arteriosclerosis correlate with QRISK3 in systemic lupus erythematosus

It is well known that cardiovascular diseases (CVD) are a major contributor of death in systemic lupus erythematosus (SLE) as well in other rheumatic illness. In the last decades, there has been a growing development of different methodologies with the purpose of early detection of CVD. Objective: The aim of this study is to correlate the usefulness of subclinical parameters of vascular aging and QRISK 3–2017 score for early detection of CVD in SLE. Methods: Clinical assessment including systemic lupus erythematosus disease activity index (SLEDAI) and systemic lupus international collaborating clinics / american college of rheumatology damage index (SLICC/ACR DI), laboratory measurements, carotid ultrasound examination, carotid intima media thickness (cIMT) measurement, carotid distention and diameter analysis, arterial stiffness measurement measured by tonometry and QRISK 3–2017 were done. All results were analyzed by SPSS 24 software. Results: We observed correlation between QRISK3 and mean cIMT (rs = 0.534, P < 0.001), PWV (rs = 0.474, P < 0.001), cfPWV (rs = 0.569, P < 0.001) and distensibility (rs = -0.420, P = 0.006). Consistent with above, SLE patients in middle and high risk QRISK 3–2017 showed increased arterial stiffness versus low risk group. Conclusions: We encourage to the rheumatology community to assess cardiovascular risk in SLE patients with QRISK 3–2017 risk calculator as an alternative method at the outpatient clinic along a complete cardiovascular evaluation when appropriate.

Relation between age and carotid artery intima-medial thickness: a systematic review

Carotid artery intima-medial thickness (cIMT) represents a popular measure of atherosclerosis and is predictive of future cardiovascular and cerebrovascular events. Although older age is associated with a higher cIMT, little is known about whether this increase in cIMT follows a linear relationship with age or it is affected under influence of cardiovascular diseases (CVD) or CVD risk factors. We hypothesize that the relationship between cIMT and age is nonlinear and is affected by CVD or risk factors. A systematic review of studies that examined cIMT in the general population and human populations free from CVD/risk factors was undertaken. The literature search was conducted in PubMed, Scopus, and Web of Science. Seventeen studies with 32 unique study populations, involving 10,124 healthy individuals free from CVD risk factors, were included. Furthermore, 58 studies with 115 unique study populations were included, involving 65,774 individuals from the general population (with and without CVD risk factors). A strong positive association was evident between age and cIMT in the healthy population, demonstrating a gradual, linear increase in cIMT that did not differ between age decades (r = 0.91, P < 0.001). Although populations with individuals with CVD demonstrated a higher cIMT compared to populations free of CVD, a linear relation between age and cIMT was also present in this population. Our data suggest that cIMT is strongly and linearly related to age. This linear relationship was not affected by CVD or risk factors.

Carotid artery intima-media thickness measurement in children with normal and increased body mass index: a comparison of three techniques

BACKGROUND

Common carotid artery intima-media thickness is a marker of subclinical atherosclerosis. In children, increased intima-media thickness is associated with obesity and the risk of cardiovascular events in adulthood.

OBJECTIVE

To compare intima-media thickness measurements using B-mode ultrasound, radiofrequency (RF) echo tracking, and RF speckle probability distribution in children with normal and increased body mass index (BMI).

MATERIALS AND METHODS

We prospectively measured intima-media thickness in 120 children randomly selected from two groups of a longitudinal cohort: normal BMI and increased BMI, defined by BMI ≥85th percentile for age and gender. We followed Mannheim recommendations. We used M'Ath-Std for automated B-mode imaging, M-line processing of RF signal amplitude for RF echo tracking, and RF signal segmentation and averaging using probability distributions defining image speckle. Statistical analysis included Wilcoxon and Mann-Whitney tests, and Pearson correlation coefficient and intra-class correlation coefficient (ICC).

RESULTS

Children were 10-13 years old (mean: 11.7 years); 61% were boys. The mean age was 11.4 years (range: 10.0-13.1 years) for the normal BMI group and 12.0 years (range: 10.1-13.5 years) for the increased BMI group. The normal BMI group included 58% boys and the increased BMI group 63% boys. RF echo tracking method was successful in 79 children as opposed to 114 for the B-mode method and all 120 for the probability distribution method. Techniques were weakly correlated: ICC=0.34 (95% confidence interval [CI]: 0.27-0.39). Intima-media thickness was significantly higher in the increased BMI than normal BMI group using the RF techniques and borderline for the B-mode technique. Mean differences between weight groups were: B-mode, 0.02 mm (95% CI: 0.00 to 0.04), P=0.05; RF echo tracking, 0.03 mm (95% CI: 0.01 to 0.05), P=0.01; and RF speckle probability distribution, 0.03 mm (95% CI: 0.01 to 0.05), P=0.002.

CONCLUSION

Though techniques are not interchangeable, all showed increased intima-media thickness in children with increased BMI. RF echo tracking method had the lowest success rate at calculating intima-media thickness. For patient follow-up and cohort comparisons, the same technique should be used throughout.

Reduced subclinical carotid vascular disease and arterial stiffness in vegetarian men: The CARVOS Study

BACKGROUND

Dietary habits play an important role in the development of atherosclerosis, the most important cause of morbidity and mortality in the world. The objective of this study was to verify if vegetarian (VEG) diet could be related a better profile of subclinical vascular disease evaluated by arterial stiffness and functional and structural properties of carotid arteries, compared to omnivorous (OMN) diet.

METHODS

In this cross-sectional study, 44 VEG and 44 OMN apparently healthy men ≥35years of age, in order to not have confounding risk factors of subclinical atherosclerosis, were assessed for anthropometric data, blood pressure, blood lipids, glucose, C reactive protein (CRP), and arterial stiffness determined by carotid-femoral pulse wave velocity (PWV). Also, carotid intima-media thickness (c-IMT) and distensibility were evaluated.

RESULTS

VEG men had lower body mass index, systolic and diastolic blood pressures, fasting serum total cholesterol, LDL and non-HDL-cholesterol, apolipoprotein B, glucose and glycated hemoglobin values in comparison with OMN individuals (all p values <0.05). Markers of vascular structure and function were different between VEG and OMN: PWV 7.1±0.8m/s vs. 7.7±0.9m/s (p<0.001); c-IMT 593±94 vs. 661±128μm (p=0.003); and relative carotid distensibility 6.39±1.7 vs. 5.72±1.8% (p=0.042), respectively. After a multivariate linear regression analysis, a VEG diet was independently and negatively associated with PWV (p value 0.005).

CONCLUSIONS

A VEG diet is associated with a more favorable cardiovascular diseases biomarker profile and better vascular structural and functional parameters.

An ultrasonographic technique to assess the jugular venous pulse: a proof of concept

The purpose of the work described here was to investigate the feasibility of assessing the jugular venous pulse (JVP) using ultrasound (US) equipment. Three young healthy subjects underwent a B-mode US scan of the internal jugular vein (IJV) to acquire a sonogram sequence in the transverse plane. On each acquired sonogram, the IJV contour was manually traced, and both the cross-sectional area (CSA) and the perimeter were measured. The CSA data set represents the US jugular diagram (USJD). The arterial distension waveform of the subjects was compared with its USJD. The correlation between the CSA and the perimeter was assessed during the cardiac cycle to verify IJV distension. For each subject, a short sonogram sequence of a few seconds was recorded, and the USJD obtained exhibited periodic behavior. Furthermore, for all subjects, the CSA was found to be correlated with the perimeter (Pearson coefficient, R > 0.9), indicating that the IJV in supine position is distended. We compared 390 manually traced contours of the IJV cross-sectional area with corresponding values semi-automatically calculated by an algorithm developed in-house. For all subjects, the sensitivity, specificity and accuracy were around 95%, 85% and 90% respectively. We found that a diagram reflecting the JVP can be obtained by analyzing a B-mode sonogram sequence of the IJV; such a diagram can result in a new methodology to assess the IJV functionality.

Linking cardiorespiratory fitness classification criteria to early subclinical atherosclerosis in children

It is unclear if cardiorespiratory fitness (CRF) can be used as a screening tool for premature changes in carotid intima-media thickness (cIMT) in paediatric populations. The purpose of this cross-sectional study was 3-fold: (i) to determine if CRF can be used to screen increased cIMT; (ii) to determine an optimal CRF cut-off to predict increased cIMT; and (iii) to evaluate its ability to predict increased cIMT among children in comparison with existent CRF cut-offs. cIMT was assessed with high-resolution ultrasonography and CRF was determined using a maximal cycle test. Receiver operating characteristic analyses were conducted in boys (n = 211) and girls (n = 202) aged 11-12 years to define the optimal sex-specific CRF cut-off to classify increased cIMT (≥75th percentile). Logistic regression was used to examine the association between the CRF cut-offs with the risk of having an increased cIMT. The optimal CRF cut-offs to predict increased cIMT were 45.81 and 34.46 mL·kg(-1)·min(-1) for boys and girls, respectively. The odds-ratios for having increased cIMT among children who were unfit was up to 2.8 times the odds among those who were fit (95% confidence interval: 1.40-5.53). Considering current CRF cut-offs, only those suggested by Adegboye et al. 2011. (Br. J. Sports Med. 45(9): 722-728) and Boddy et al. 2012 (PLoS One, 7(9): e45755) were significant in predicting increased cIMT. In conclusion, CRF cut-offs (boys: ≤ 45.8; girls: ≤ 34.5 mL·kg(-1)·min(-1)) are associated with thickening of the arterial wall in 11- to 12-year-old children. Low CRF is an important cardiovascular risk factor in children and our data highlight the importance of obtaining an adequate CRF.

Noninvasive method for measuring local pulse wave velocity by dual pulse wave Doppler: in vitro and in vivo studies

Objectives

To evaluate the validity and reproducibility of a noninvasive dual pulse wave Doppler (DPWD) method, which involves simultaneous recording of flow velocity of two independent sample volumes with a measurable distance, for measuring the local arterial pulse wave velocity (PWV) through in vitro and in vivo studies.

Methods

The DPWD mode of Hitachi HI Vision Preirus ultrasound system with a 5–13MHz transducer was used. An in vitro model was designed to compare the PWV of a homogeneous rubber tubing with the local PWV of its middle part measured by DPWD method. In the in vivo study, local PWV of 45 hypertensive patients (25 male, 49.8±3.1 years) and 45 matched healthy subjects (25 male, 49.3±3.0 years) were investigated at the left common carotid artery (LCCA) by DPWD method.

Results

In the in vitro study, the local PWV measured by DPWP method and the PWV of the homogeneous rubber tubing did not show statistical difference (5.16 ± 0.28 m/s vs 5.03 ± 0.15 m/s, p = 0.075). The coefficient of variation (CV) of the intra- and inter- measurements for local PWV were 3.46% and 4.96%, for the PWV of the homogeneous rubber tubing were 0.99% and 1.98%. In the in vivo study, a significantly higher local PWV of LCCA was found in the hypertensive patients as compared to that in healthy subjects (6.29±1.04m/s vs. 5.31±0.72m/s, P = 0.019). The CV of the intra- and inter- measurements in hypertensive patients were 2.22% and 3.94%, in healthy subjects were 2.07% and 4.14%.

Conclusions

This study demonstrated the feasibility of the noninvasive DPWD method to determine the local PWV, which was accurate and reproducible not only in vitro but also in vivo studies. This noninvasive echocardiographic method may be illuminating to clinical use.

A constitutive modeling interpretation of the relationship among carotid artery stiffness, blood pressure, and age in hypertensive subjects

Aging has a profound influence on arterial wall structure and function. We have previously reported the relationship among pulse wave velocity, age, and blood pressure in hypertensive subjects. In the present study, we aimed for a quantitative interpretation of the observed changes in wall behavior with age using a constitutive modeling approach. We implemented a model of arterial wall biomechanics and fitted this to the group-averaged pressure-area ( P-A) relationship of the “young” subgroup of our study population. Using this model as our take-off point, we assessed which parameters had to be changed to let the model describe the “old” subgroup’s P-A relationship. We allowed elastin stiffness and collagen recruitment parameters to vary and adjusted residual stress parameters according to published age-related changes. We required wall stress to be homogeneously distributed over the arterial wall and assumed wall stress normalization with age by keeping average “old” wall stress at the “young” level. Additionally, we required axial force to remain constant over the cardiac cycle. Our simulations showed an age-related shift in pressure-load bearing from elastin to collagen, caused by a decrease in elastin stiffness and a considerable increase in collagen recruitment. Correspondingly, simulated diameter and wall thickness increased by about 20 and 17%, respectively. The latter compared well with a measured thickness increase of 21%. We conclude that the physiologically realistic changes in constitutive properties we found under physiological constraints with respect to wall stress could well explain the influence of aging in the stiffness-pressure-age pattern observed.

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Background

Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients.

Objective

To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations.

Methods

This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior^® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound.

Results

The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03).

Conclusion

In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure. The carotid artery structure was directly related to aortic stiffness, which was inversely related to the carotid artery functional property.

Ultrasound study of carotid and cardiac remodeling and cardiac-arterial coupling in normal pregnancy and preeclampsia: a case control study

BACKGROUND

Cardiovascular adaptions, such as cardiac and uterine spiral arterial remodeling, and aortic arterial stiffening during pregnancy have been extensively investigated, while the interactions between the elastic artery and the left ventricle are poorly understood. This study was to evaluate the cardiac-arterial coupling in both normal pregnancy and preeclampsia using ultrasound techniques.

METHODS

Twenty-three preeclamptic women with no antihypertensive treatment prior to admission, and 40 age- (27.2 ± 3.0 y vs. 29.1 ± 5.7 y, p = 0.0805) and gestational week- (35.6 ± 3.4 wk vs. 34.8 ± 3.6 wk, p = 0.3573) matched normotensive pregnant women were included. All women signed informed consent. All were nulliparas, had singleton pregnancies, and had no other risk factors for arterial stiffening. Carotid and cardiac ultrasound was performed using a MylabTwice ultrasound unit (Esaote, Italy). Cardiac and carotid remodeling and their associations were analyzed. Left ventriculo-carotid coupling was characterized by the ratio between the arterial elastance (Ea) and the left ventricular systolic elastance (Ees). Follow-up study was performed 16-20 months after parturition.

RESULTS

Left ventricular and carotid arterial remodeling was seen more frequently in preeclamptic women than in normal pregnant controls (96% vs. 40%, 82% vs. 48%, both p < 0.0001). The relative carotid arterial wall thickness showed no significant difference between the two groups. However, the carotid cross-sectional area, a surrogate for carotid arterial mass, was significantly greater in preeclampsia than that in normal controls (11.23 ± 0.17 mm2 vs. 8.58 ± 1.88 mm2, p < 0.00001). Carotid arterial stiffness and intima-media thickness correlated significantly with cardiac diastolic function parameters and blood pressures (p < 0.05). Both Ea and Ees were significantly greater in preeclampsia, compared with values in normal pregnant controls (Ea: 2.41 ± 0.57 mmHg/ml vs. 1.98 ± 0.46 mmHg/ml, p = 0.0005; Ees: 11.68 ± 9.51 m/s2 vs. 6.91 ± 6.13 m/s2, p = 0.002). However, there was no significant difference in the left ventriculo-carotid coupling index, Ea/Ees, between the two groups. Carotid remodeling persisted in both preeclamptic women and normal pregnant controls 16-20 months after parturition.

CONCLUSIONS

Significant cardiac and carotid remodeling and similar left ventriculo-carotid coupling were observed in both preeclampsia and normal pregnancy. Carotid remodeling may persist postpartum. Further studies with larger populations are needed to confirm these findings.

Body composition phenotypes and carotid intima-media thickness in 11-13-year-old children

Early detection of impairment in vascular structure is an important clinical pursuit. However, it is unknown which measure of body composition best predicts vascular wall changes. We assess the differences in body composition among intima-media thickness (IMT) tertiles and determined which measures of body composition are associated with IMT in 385 children aged 11-13 years (196 girls). In this cross-sectional study, body mass index (BMI), waist circumference (WC), body fat mass (BFM), and trunk fat mass (TFM) from dual-energy radiographic absorptiometry and IMT through high-resolution ultrasonography were collected. Differences in body composition measures among IMT tertiles [low IMT (LIMT), ≤ 0.46 mm; middle IMT, 0.46-0.53 mm; higher IMT (HIMT), ≥0.53 mm] were assessed with ANOVA/ANCOVA after categorization. Regression analysis was used to assess the relationships between body composition and IMT. The groups were similar for sex, age, and maturity (p > 0.05). As compared with LIMT group, subjects with HIMT had higher mean values of BMI, BFM, TFM, and WC (p < 0.05). Significant differences were found for WC even when controlling for BMI (p < 0.05). Combining all subjects, IMT was significantly correlated to BMI, BFM, TFM, and WC (p < 0.05). In multiple regression, WC was the only predictor of IMT (β = 0.22, p < 0.001).

CONCLUSION

Differences exist in body composition variables among IMT tertiles. In the overall model, WC was the only obesity-related predictor of increased IMT in 11-13-year-old children.

Carotid arterial intima–media thickness and arterial stiffness in pre-eclampsia: analysis with a radiofrequency ultrasound technique

OBJECTIVE

Whether arterial elasticity is reduced in preeclampsia has been investigated only rarely. This study aimed to characterize in vivo the carotid arterial intima–media thickness (IMT) and mechanical properties in women with pre-eclampsia by employing a radiofrequency ultrasound technique.

METHODS

We included 22 late-onset pre-eclamptic pregnant women and 28 normotensive pregnant women who were matched for age (29 ± 6 vs. 27 ± 3, P=0.09) and gestational age (36.0 ± 3.2 vs. 35.8 ± 2.4 weeks, P=0.802). All women were nulliparous with singleton pregnancy. The pre-eclamptic women had a significantly higher arterial pressure than did the normotensive women (P<0.0001). All women underwent right common carotid arterial measurements with an ultrasound machine equipped with automatic Quality IMT (QIMT) and Quality Arterial Stiffness (QAS) capability. At follow-up examination 18 months after parturition, measurements were repeated in 10 of the pre-eclamptic women and 11 of the normotensive women.

RESULTS

In pre-eclamptic compared with normotensive pregnancy, carotid arterial IMT (459 ± 95 vs. 351 ± 85 μm, P=0.0001), internal diameter (7.8 ± 0.5 vs. 7.2 ± 0.4 mm, P<0.0001), pulse wave velocity (7.1 ± 1.7 vs. 6.0 ± 1.5 m/s, P=0.007), augmentation index (7.9 ± 9.2 vs. −5.0 ± 5.6%, P<0.0001) and arterial wall tension (55.0 ± 6.5 vs. 38.6 ± 4.9 mmHg/cm, P<0.0001) were significantly greater, and the distensibility coefficient (0.020 ± 0.009 vs. 0.029 ± 0.011 1/kPa, P=0.006) was significantly smaller, remaining so after adjusting for body mass index and carotid arterial pressure. Eighteen months after parturition, carotid arterial internal diameter, pressure and wall tension remained greater in the pre-eclamptic group.

CONCLUSION

Carotid arterial remodeling, including changes in arterial internal diameter and wall thickness, and arterial stiffening occur in pre-eclampsia but this may reverse, to some extent, postpartum. QIMT and QAS techniques together could provide a comprehensive assessment of carotid arterial remodeling.

Surface roughness detection of arteries via texture analysis of ultrasound images for early diagnosis of atherosclerosis

There is a strong research interest in identifying the surface roughness of the carotid arterial inner wall via texture analysis for early diagnosis of atherosclerosis. The purpose of this study is to assess the efficacy of texture analysis methods for identifying arterial roughness in the early stage of atherosclerosis. Ultrasound images of common carotid arteries of 15 normal mice fed a normal diet and 28 apoE^−/− mice fed a high-fat diet were recorded by a high-frequency ultrasound system (Vevo 2100, frequency: 40 MHz). Six different texture feature sets were extracted based on the following methods: first-order statistics, fractal dimension texture analysis, spatial gray level dependence matrix, gray level difference statistics, the neighborhood gray tone difference matrix, and the statistical feature matrix. Statistical analysis indicates that 11 of 19 texture features can be used to distinguish between normal and abnormal groups (p<0.05). When the 11 optimal features were used as inputs to a support vector machine classifier, we achieved over 89% accuracy, 87% sensitivity and 93% specificity. The accuracy, sensitivity and specificity for the k-nearest neighbor classifier were 73%, 75% and 70%, respectively. The results show that it is feasible to identify arterial surface roughness based on texture features extracted from ultrasound images of the carotid arterial wall. This method is shown to be useful for early detection and diagnosis of atherosclerosis.

Maternal carotid remodeling and increased carotid arterial stiffness in normal late-gestational pregnancy as assessed by radio-frequency ultrasound technique

BACKGROUND

The adaption of elastic arteries to transient increase in hemodynamic load in normal pregnancy (NP) remains controversial. The purpose of this study was to investigate the NP carotid remodeling and regional arterial stiffness before and after parturition.

METHODS

Fifty-one NP women and 30 age-matched non-pregnant women were included. All women underwent right common carotid artery (RCCA) measurements with MylabTwice ultrasound instrument (Esaote, Italy). Carotid intima-medial thickness (IMT), pulse wave velocity (PWV, m/s), distensibility coefficient (DC, 1/KPa), α, β, augmentation index (AIx, %) and carotid arterial pressure were obtained by the newly developed ultrasound vascular wall tracking methods: automatic QAS (Quality Arterial Stiffness) and QIMT (Quality Intima-Medial Thickness) Follow up study was performed.

RESULTS

Compared to the non-pregnant controls, the arterial pressures were significantly increased and RCCA diameter was significantly enlarged in late gestational NP women. Twenty months after parturition, carotid diameter, DC, AIx, PWV and arterial wall tension were significantly decreased and had no significant difference with those in non-pregnant controls.

CONCLUSIONS

Carotid arterial remodeling and stiffening could be seen in the normal pregnant women, which seems to be a physiological adaption and could be recovered post partum. QIMT and QAS together could provide a comprehensive assessment of the maternal carotid arterial changes during pregnancy.

Carotid ultrasound is useful for the cardiovascular risk stratification of patients with rheumatoid arthritis: results of a population-based study

OBJECTIVE

To determine if the use of carotid ultrasonography (US) may improve the stratification of the cardiovascular (CV) risk in rheumatoid arthritis (RA).

METHODS

A set of 370 consecutive patients without history of CV events were studied to assess carotid intima-media thickness (cIMT) and plaques. As previously proposed, CV risk was calculated according to the modified EULAR systematic coronary risk evaluation (mSCORE) for RA that was adapted by the application of a multiplier factor of 1.5 in those patients fulfilling ≥ 2 of 3 specific criteria.

RESULTS

The mean disease duration was 9.8 years, 250 (68%) had rheumatoid factor/anticyclic citrullinated peptide positivity and 61 (17%) extra-articular manifestations. 43 were excluded because they had type 2 diabetes mellitus or severe chronic kidney disease. CV risk was categorised in the remaining 327 RA patients according to the mSCORE: mild (96 cases; 29.3%), moderate (201; 61.5%) and high/very high risk (30; 9.2%). Only five patients were reclassified as having high/very high CV risk when the mSCORE was applied. Severe carotid US abnormalities (cIMT >0.90 mm and/or plaques) were uncommon in patients with low mSCORE (13%). Nevertheless, in patients with moderate mSCORE, severe carotid US abnormalities were observed in 63% of cases. A model that included a chart mSCORE risk ≥ 5% plus the presence of severe carotid US findings in patients with moderate mSCORE risk (≥ 1% and <5%) yielded high sensitivity for high/very high CV risk (93 (95% CI 88 to 96)).

CONCLUSIONS

Our results support the use of carotid US in the assessment of CV risk in patients with RA.

Evaluation of carotid artery stiffness in obese children using ultrasound radiofrequency data technology

OBJECTIVES

The goals of this study were to investigate the difference in carotid arterial stiffness in obese children compared to healthy children and to study the correlation between carotid arterial stiffness parameters and obesity using ultrasound (US) radiofrequency (RF) data technology.

METHODS

Carotid artery stiffness parameters, including the compliance coefficient, stiffness index, and pulse wave velocity, were evaluated in 71 obese patients and 47 healthy controls with US RF data technology. In addition, all participants were evaluated for fat thickness in the paraumbilical abdominal wall and fatty liver using abdominal US.

RESULTS

Compared to the control group, the blood pressure (BP), body mass index (BMI), fat thickness in the paraumbilical abdominal wall, presence of fatty liver, and carotid stiffness parameters (stiffness index and pulse wave velocity) were significantly higher in the obese group, whereas the compliance coefficient was significantly lower in the obese group. Furthermore, the pulse wave velocity was weakly positively correlated with the BMI, systolic BP, diastolic BP, and paraumbilical abdominal wall fat thickness, whereas the compliance coefficient was weakly negatively correlated with the systolic BP, BMI, and paraumbilical abdominal wall fat thickness. The presence of a fatty liver was moderately positively correlated with the BMI and weakly positively correlated with the pulse wave velocity.

CONCLUSIONS

Ultrasound RF data technology may be a sensitive noninvasive method that can be used to accurately and quantitatively detect the difference in carotid artery stiffness in obese children compared to healthy children. The detection of carotid functional abnormalities and nonalcoholic fatty liver disease in obese children should allow early therapeutic intervention, which may prevent or delay the development of atherosclerosis in adulthood.

Reference intervals for common carotid intima-media thickness measured with echotracking: relation with risk factors

AIMS

Common carotid artery intima-media thickness (CCIMT) is widely used as a surrogate marker of atherosclerosis, given its predictive association with cardiovascular disease (CVD). The interpretation of CCIMT values has been hampered by the absence of reference values, however. We therefore aimed to establish reference intervals of CCIMT, obtained using the probably most accurate method at present (i.e. echotracking), to help interpretation of these measures.

METHODS AND RESULTS

We combined CCIMT data obtained by echotracking on 24 871 individuals (53% men; age range 15-101 years) from 24 research centres worldwide. Individuals without CVD, cardiovascular risk factors (CV-RFs), and BP-, lipid-, and/or glucose-lowering medication constituted a healthy sub-population (n = 4234) used to establish sex-specific equations for percentiles of CCIMT across age. With these equations, we generated CCIMT Z-scores in different reference sub-populations, thereby allowing for a standardized comparison between observed and predicted ('normal') values from individuals of the same age and sex. In the sub-population without CVD and treatment (n = 14 609), and in men and women, respectively, CCIMT Z-scores were independently associated with systolic blood pressure [standardized βs 0.19 (95% CI: 0.16-0.22) and 0.18 (0.15-0.21)], smoking [0.25 (0.19-0.31) and 0.11 (0.04-0.18)], diabetes [0.19 (0.05-0.33) and 0.19 (0.02-0.36)], total-to-HDL cholesterol ratio [0.07 (0.04-0.10) and 0.05 (0.02-0.09)], and body mass index [0.14 (0.12-0.17) and 0.07 (0.04-0.10)].

CONCLUSION

We estimated age- and sex-specific percentiles of CCIMT in a healthy population and assessed the association of CV-RFs with CCIMT Z-scores, which enables comparison of IMT values for (patient) groups with different cardiovascular risk profiles, helping interpretation of such measures obtained both in research and clinical settings.

Comparison of B-mode, M-mode and Hough transform methods for measurement of arterial diastolic and systolic diameters

Measurements of arterial diameter during the cardiac cycle are increasingly used to study the mechanical properties of the arterial wall and changes associated with disease. In this paper, diastolic and systolic diameters of the carotid arteries were estimated from ultrasound imaging using the following three different procedures: a/ B-mode imaging with region tracking and block-matching, b/ M-mode imaging with automated edge detection and c/ automatic segmentation of the arterial lumen at diastole and systole using the Hough transform. Transverse images of the carotid artery were used, in which the arterial lumen has an almost circular appearance. The values for systolic and diastolic diameters estimated with the Hough transform, 0.69&#177;0.04 and 0.61&#177;0.06, respectively, were closer to those estimated with B-mode and motion tracking, 0.75&#177;0.07 and 0.67&#177;0.09. A large difference was found for a subject with an atherosclerotic vessel wall. It is concluded that the Hough transform can be efficiently used to automatically segment healthy arterial wall lumen from B-mode ultrasound images of the carotid artery, assuming a circular shape. In atherosclerotic vessel walls the assumption for circular shape may no longer be valid, and thus the use of an elliptical shape may be more appropriate.

An automated, interactive analysis system for ultrasound sequences of the common carotid artery

Structural parameters of the common carotid artery (CCA) have shown to correlate with the risk of cardiovascular disease, but their precise measurement is challenging. We developed an automatic detection system with manual interaction capabilities that can reliably analyze B-mode ultrasound sequences of the CCA over several heart cycles. We evaluated 3824 frames from 40 sequences in two data qualities. Two readers measured the intima media thickness (IMT) and the lumen diameter at two evaluation times (T1/T2). A Bland-Altman analysis of the average IMT showed a bias ± SD of 0.002 ± 0.010 mm (T1), -0.004 ± 0.008 mm (T2) for completely automatic detections and -0.004 ± 0.010 mm (T1), -0.003 ± 0.010 mm (T2) for clips with manual corrections. The combination of automated analysis and manual intervention provides precise parameters as biomarkers for the atherosclerotic process and makes the system suitable for large scale epidemiological research, diagnostic and clinical practice.

Peripheral endothelial function and arterial stiffness in women with migraine with aura: a case-control study

BACKGROUND

Vascular dysfunction may be involved in migraine pathophysiology and contribute to the increased risk of ischemic stroke in migraine, particularly in women with migraine with aura (MA). However, data on endothelial function in MA are controversial. Here, we investigated whether systemic endothelial function and arterial stiffness are altered in women with MA, using a novel peripheral arterial tonometry device for the first time.

METHODS

Twenty-nine female MA patients without comorbidities and 30 healthy women were included, and carotid intima-media thickness was assessed by a standardized procedure. Endothelial function was assessed using peripheral arterial tonometry. Reactive hyperaemic response of digital pulse amplitude was measured following 5 minutes of forearm occlusion of the brachial artery. Arterial stiffness was assessed by fingertip tonometry derived and heart-rate-adjusted augmentation index.

RESULTS

No differences were found in peripheral arterial tonometry ratio (2.3 ± 0.6 vs 2.2 ± 0.8; p = 0.58) and left carotid intima-media thickness (in µm: 484 ± 119 vs 508 ± 60; p = 0.37). Women with MA had higher heart-rate-averaged augmentation index [median (interquartile range, IQR) of 5 (IQR 0.5 to 18) vs -5 (IQR -16.8 to 8.3), p = 0.005] and heart-rate-adjusted augmentation index [1 (IQR -6 to 12.5) vs -8 (IQR -20.3 to 2.5), p = 0.008] than healthy controls.

CONCLUSION

Peripheral endothelial function is not impaired in women with MA, but they have greater arterial stiffness. This may contribute to the increased stroke risk in women with MA.

Increased arterial stiffness assessed by pulse wave velocity in Behçet's disease and its association with the lipid profile

OBJECTIVE

To evaluate the structural and functional properties of vessels in Behçet's Disease (BD) using carotid-femoral pulse wave velocity (PWV) and an echo-tracking system.

METHODS

BD patients without traditional cardiovascular risk factors were selected. All BD patients performed PWV and carotid ultrasound. BD patients were divided into groups based on the presence of systemic (vascular and/or ocular and/or central nervous system involvement) and vascular involvement. Healthy controls age- and sex-matched with the same exclusion criteria were selected.

RESULTS

A total of 23 BD patients (mean age 35.0 ± 7.6 years) had significantly higher PWV levels compared with controls (8.48 ± 1.14 vs. 7.53 ± 1.40 m/s, P = 0.017). Intima-media thickness (594.87 ± 138.61 vs. 561.08 ± 134.26 μm, P = 0.371), diastolic diameter (6383.78 ± 960.49 vs. 6447.65 ± 1159.73 μm, P = 0.840), distension (401.95 ± 117.72 vs. 337.91 ± 175.36 μm, P = 0.225) and relative distension (6.26 ± 2.83 vs. 5.42 ± 2.46 μm, P = 0.293) were similar in both groups. The systemic disease group had significantly higher levels of PWV (8.79 ± 1.21 vs. 7.88 ± 0.72 m/s, P = 0.036) compared to those with exclusive mucocutaneous manifestations. BD patients with vascular involvement had similar PWV and echo-tracking parameters compared to those without vascular involvement (P > 0.05), but had higher total and LDL cholesterol levels (P = 0.019 and P = 0.012, respectively). The multivariate linear regression analysis identified triglycerides as the most important factor in increasing PWV levels (P = 0.001) in BD.

CONCLUSIONS

PWV is more useful than carotid ultrasound in detecting structural and functional vascular damage in BD and emphasizes the role of the disease itself in promoting these alterations. Our findings also reinforce the need for rigorous control of all risk factors in BD, particularly lipoproteins.

Is there an underestimation of intima-media thickness based on M-mode ultrasound technique in the abdominal aorta?

Measuring intima-media thickness (IMT) in the common carotid artery (CCA) is a valuable resource for the evaluation of subclinical atherosclerosis. The main objective of this study was to explore whether a B-mode ultrasound technique, Philips ATL, and an M-mode ultrasound technique, Wall Track System (WTS), show interchangeable results when measured in CCA and the abdominal aorta (AA). A total of 24 healthy, young subjects were examined. IMT and lumen diameter (LD) of the AA and the CCA were measured twice by two skilled ultrasonographers with two different ultrasound equipment B-mode: (Philips, ATL and M-mode: WTS).The intra-observer variability of IMT in CCA and AA using B-mode showed a coefficient of variation 8% and 9%, and with M-mode 11% and 15%, respectively. Interobserver variability of IMT in CCA and AA using B-mode was 6% and 12%, and with M-mode 11% and 18%, respectively. CCA IMT was 0·53 ± 0·07 and 0·53 ± 0·09 mm using B-mode and M-mode, respectively. However, in AA, IMT was 0·61 ± 0·05 and 0·54 ± 0·10 mm using B-mode and M-mode, respectively. Thus, AA IMT was 11·5% thicker using B-mode (P < 0·01). We received adequate IMT readings from the carotid artery as well as the AA using two commonly used B-mode and M-mode techniques. B-mode technique seems to show less variability, especially in the AA. More importantly, the two techniques measured different IMT thickness in the aorta, emphasizing the importance of using similar technique when comparing the impact of absolute values of IMT on cardiovascular disease.

Pharmacological modulation of arterial stiffness

Arterial stiffness has emerged as an important marker of cardiovascular risk in various populations and reflects the cumulative effect of cardiovascular risk factors on large arteries, which in turn is modulated by genetic background. Arterial stiffness is determined by the composition of the arterial wall and the arrangement of these components, and can be studied in humans non-invasively. Age and distending pressure are two major factors influencing large artery stiffness. Change in arterial stiffness with drugs is an important endpoint in clinical trials, although evidence for arterial stiffness as a therapeutic target still needs to be confirmed. Drugs that independently affect arterial stiffness include antihypertensive drugs, mostly blockers of the renin-angiotensin-aldosterone system, hormone replacement therapy and some antidiabetic drugs such as glitazones. While the quest continues for 'de-stiffening drugs', so far only advanced glycation endproduct cross-link breakers have shown promise.

Circulating endothelial progenitor cells and large artery structure and function in young subjects with uncomplicated type 1 diabetes

Background

Carotid intima-media thickness (IMT), indices of large artery stiffness and measures of endothelium function may be used as markers of early atherosclerosis in type 1 diabetes mellitus (T1DM). The aim of the present study was to compare the indices of large artery structure and function as well as endothelial function and regenerating capacity between adolescents with T1DM and healthy control of similar age. In addition, the associations of different vascular measures with endothelial progenitor cells (EPCs), glyco-metabolic control and serum levels of advanced glycation endproducts (AGEs), soluble receptors for AGEs (sRAGE) and adiponectin were evaluated.

Methods

Sixteen uncomplicated young T1DM patients (mean age 18 ± 2 years, history of disease 11 ± 5 years, HbA1c 7.7 ± 1.1%) and 26 controls (mean age 19 ± 2 years) were studied. A radiofrequency-based ultrasound system (Esaote MyLab 70) was used to measure carotid IMT and wave speed (WS, index of local stiffness), applanation tonometry (PulsePen) was applied to obtain central pulse pressure (PP) and augmentation index (AIx), and carotid-femoral pulse wave velocity (PWV, Complior) was used as index of aortic stiffness. Peripheral endothelium-dependent vasodilation was determined as reactive hyperemia index (RHI, EndoPAT). Circulating EPCs, glycometabolic profile, AGEs (autofluorescence method), sRAGE and adiponectin were also measured.

Results

After adjusting for age, sex and blood pressure, T1DM adolescents had significantly higher carotid IMT (456 ± 7 vs. 395 ± 63 μm, p < 0.005), carotid WS (p < 0.005), PWV (p = 0.01), AIx (p < 0.0001) and central PP (p < 0.01) and lower EPCs (p = 0.02) as compared to controls. RHI was reduced only in diabetic patients with HbA1c ≥7.5% (p < 0.05). In the overall population, EPCs were an independent determinant of carotid IMT (together with adiponectin), while fasting plasma glucose was an independent determinant of carotid WS, AIx and central PP.

Conclusions

Our findings suggest that young subjects with relatively long-lasting T1DM have a generalized preclinical involvement of large artery structure and function, as well as a blunted endothelium regenerating capacity. Hyperglycemia and suboptimal chronic glycemic control seem to deteriorate the functional arterial characteristics, such as large arteries stiffness, wave reflection and peripheral endothelium-dependent vasodilation, whereas an impaired endothelium regenerating capacity and adiponectin levels seem to influence arterial structure.

Association of menopause and hormone replacement therapy with large artery remodeling

OBJECTIVE

To evaluate the remodeling of large arteries according to age at menopause, duration of menopause, and use of hormone therapy (HT).

DESIGN

A cross-sectional study consisting of baseline measurements of a multicentric randomized trial were used to evaluate arterial parameters.

SETTING

The study was conducted in France, Belgium, and the Netherlands in academic hospitals and private clinics.

PATIENT(S)

Postmenopausal women (n = 538) with mild hypercholesterolemia.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Common carotid artery intima-media thickness (CCA-IMT), central pulse pressure, and aortic stiffness (carotid-femoral pulse wave velocity) were measured and centrally controlled for quality. Multivariate regression analysis was used to assess the possible covariates associated with arterial parameters.

RESULT(S)

Women were 58 ± 6 (mean ± SD) years of age with an age of 50 ± 5 at menopause and a mean duration of menopause of 8 ± 7 years. Lower age at menopause, time since menopause, and absence of HT use were independently associated with worsening of the arterial parameters. After multivariate analysis, HT was associated with a lower CCA-IMT (-40 μm [range -64 to -1]), whereas lower age at menopause and menopause duration were respectively associated with a CCA-IMT increase (25 μm/5 y and 27 μm/5 y). Similarly, values of central pulse pressure and pulse wave velocity were lower in HT users (-3.1 mm Hg [-5.1 to -0.9] and -0.31 m/s [-0.63 to -0.02], respectively) but worsened with age at menopause and menopause duration.

CONCLUSION(S)

The age at menopause, the time since menopause, and the use of HT are independently associated with the thickening and stiffening of the large arteries.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00163163.

Gender-specific association of the plasminogen activator inhibitor-1 4G/5G polymorphism with central arterial blood pressure

BACKGROUND

The functional plasminogen activator inhibitor-1 (PAI-1) 4G/5G polymorphism has previously been associated with hypertension. In recent years, central blood pressure, rather than brachial has been argued a better measure of cardiovascular damage and clinical outcome. The aim of this study was to investigate the possible influence of the 4G/5G polymorphism on central arterial blood pressure in a cohort of elderly individuals.

METHODS

We studied 410 individuals, 216 men and 194 women, aged 70-88. Central pressures and pulse waveforms were calculated from the radial artery pressure waveform by the use of the SphygmoCor system and a generalized transfer function. Brachial pressure was recorded using oscillometric technique (Dinamap, Critikon, Tampa, FL). PAI-1 antigen was determined in plasma.

RESULTS

The results showed that central pressures were higher in women carrying the PAI-1 4G/4G genotype compared to female carriers of the 5G/5G genotype, (P = 0.025, P = 0.002, and P = 0.002 for central systolic-, diastolic-, and mean arterial pressure, respectively). The association remained after adjustment for potentially confounding factors related to hypertension. No association of the PAI-1 genotype with blood pressure was found in men. Multiple regression analysis revealed an association between PAI-1 genotype and plasma PAI-1 levels (P = 0.048).

CONCLUSIONS

Our findings show a gender-specific association of the PAI-1 4G/5G polymorphism with central arterial blood pressure. The genotype effect was independent of other risk factors related to hypertension, suggesting that impaired fibrinolytic potential may play an important role in the development of central hypertension in women.

Impaired abdominal aortic wall integrity in elderly men carrying the angiotensin-converting enzyme D allele

OBJECTIVE

A polymorphism in the angiotensin-converting-enzyme gene (ACE I/D) has been associated with abdominal aortic aneurysm and a link between aortic aneurysm and aortic stiffness has been suggested. This study aimed to explore the links between ACE I/D polymorphism, circulating ACE and abdominal aortic wall integrity as reflected by abdominal aortic wall stiffness.

MATERIAL

A total of 212 men and 194 women, aged 70-88 years, were studied.

METHODS

Mechanical properties of the abdominal aorta were determined using the Wall Track System, ACE genotype using the polymerase chain reaction (PCR) and circulating ACE level by enzyme-linked immunosorbent assay (ELISA).

RESULTS

In men, pulsatile diameter change differed between genotypes (II 0.70, ID 0.55 and DD 0.60 mm, P = 0.048), whereas a tendency was seen for distensibility coefficient (DC) (II 10.38, ID 7.68 and ID 8.79, P = 0.058). Using a dominant model (II vs. ID/DD), men carrying the ACE D allele had lower pulsatile diameter change (P = 0.014) and DC (P = 0.017) than II carriers. Multiple regression analyses showed additional associations between the D allele and increased stiffness β, and reduced compliance coefficient.

CONCLUSION

Men carrying the ACE D allele have stiffer abdominal aortas compared with II carriers. Deranged abdominal aortic stiffness indicates impaired vessel wall integrity, which, along with other local predisposing factors, may be important in aneurysmal disease.