Feasibility and precision of transcutaneous very-high resolution ultrasound for quantification of arterial structures in human neonates - comparison with conventional high resolution vascular ultrasound imaging

Early Life Programming of Vascular Aging and Cardiometabolic Events: The McDonald Lecture 2022

The early life programming of adult health and disease (Developmental Origins of Adult Health and Disease; DOHaD) concept has attracted increased attention during recent years. In this review evidence is presented for epidemiological associations between early life factors (birth weight, prematurity) and cardiometabolic traits and risk of disease in adult life. Even if not all studies concur, the evidence in general is supporting such links. This could be due to either nature or nurture. There is evidence to state that genetic markers influencing birth weight could also be of importance for offspring hypertension or risk of coronary heart disease, this supporting the nature argument. On the other hand, several studies, both historical and experimental, have found that the change of maternal dietary intake or famine in pregnancy may cause permanent changes in offspring body composition as well as in hemodynamic regulation. Taken together, this also supports the strategy of preventive maternal and child health care, starting already during the preconception period, for lowering the risk of adult cardiometabolic disease in the affected offspring. Further studies are needed to better understand the mediating mechanisms, for example concerning arterial function, hemodynamic regulation, renal function, and neuroendocrine influences, related to the development of early vascular aging (EVA) and cardiovascular disease manifestations.

Arterial health during early childhood following abnormal fetal growth

Background

Abnormal fetal growth is associated with increased cardiovascular risk in adulthood. We investigated the effect of fetal programming on arterial health and morphology during early childhood.

Methods

We examined 90 children (median age 5.81 years, interquartile range: 5.67; 5.95), born small for gestational age with fetal growth restriction, large or appropriate for gestational age (SGA, N = 23, LGA, N = 19, AGA N = 48). We measured body composition, anthropometrics, blood pressure, pulse wave velocity (PWV), lipids, glucose and inflammatory markers, and assessed carotid, brachial, radial and femoral arterial morphology and stiffness using very-high resolution ultrasound (46–71 MHz).

Results

LGA showed increased anthropometry, lean body mass and body mass index. SGA displayed decreased anthropometry and lean body mass. Blood pressure, PWV, carotid artery stiffness and blood work did not differ groupwise. Differences in lumen diameters, intima-media thicknesses (IMT) and adventitia thicknesses disappeared when adjusted for lean body mass and sex. In multiple regression models arterial dimensions were mainly predicted by lean body mass, with birth weight remaining associated only with carotid and brachial lumen dimensions, and not with IMTs. Carotid-femoral PWV was predicted by height and blood pressure only. No independent effect of adiposity was observed.

Conclusions

Arterial dimensions in childhood associate with current anthropometrics, especially lean body mass, and sex, explaining differences in arterial layer thickness. We found no signs of fetal programming of cardiovascular risk or arterial health in early childhood.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02951-2.

Risk factors during first 1,000 days of life for carotid intima-media thickness in infants, children, and adolescents: A systematic review with meta-analyses

BACKGROUND

The first 1,000 days of life, i.e., from conception to age 2 years, could be a critical period for cardiovascular health. Increased carotid intima-media thickness (CIMT) is a surrogate marker of atherosclerosis. We performed a systematic review with meta-analyses to assess (1) the relationship between exposures or interventions in the first 1,000 days of life and CIMT in infants, children, and adolescents; and (2) the CIMT measurement methods.

METHODS AND FINDINGS

Systematic searches of Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica database (EMBASE), and Cochrane Central Register of Controlled Trials (CENTRAL) were performed from inception to March 2019. Observational and interventional studies evaluating factors at the individual, familial, or environmental levels, for instance, size at birth, gestational age, breastfeeding, mode of conception, gestational diabetes, or smoking, were included. Quality was evaluated based on study methodological validity (adjusted Newcastle-Ottawa Scale if observational; Cochrane collaboration risk of bias tool if interventional) and CIMT measurement reliability. Estimates from bivariate or partial associations that were least adjusted for sex were used for pooling data across studies, when appropriate, using random-effects meta-analyses. The research protocol was published and registered on the International Prospective Register of Systematic Reviews (PROSPERO; CRD42017075169). Of 6,221 reports screened, 50 full-text articles from 36 studies (34 observational, 2 interventional) totaling 7,977 participants (0 to 18 years at CIMT assessment) were retained. Children born small for gestational age had increased CIMT (16 studies, 2,570 participants, pooled standardized mean difference (SMD): 0.40 (95% confidence interval (CI): 0.15 to 0.64, p: 0.001), I2: 83%). When restricted to studies of higher quality of CIMT measurement, this relationship was stronger (3 studies, 461 participants, pooled SMD: 0.64 (95% CI: 0.09 to 1.19, p: 0.024), I2: 86%). Only 1 study evaluating small size for gestational age was rated as high quality for all methodological domains. Children conceived through assisted reproductive technologies (ART) (3 studies, 323 participants, pooled SMD: 0.78 (95% CI: -0.20 to 1.75, p: 0.120), I2: 94%) or exposed to maternal smoking during pregnancy (3 studies, 909 participants, pooled SMD: 0.12 (95% CI: -0.06 to 0.30, p: 0.205), I2: 0%) had increased CIMT, but the imprecision around the estimates was high. None of the studies evaluating these 2 factors was rated as high quality for all methodological domains. Two studies evaluating the effect of nutritional interventions starting at birth did not show an effect on CIMT. Only 12 (33%) studies were at higher quality across all domains of CIMT reliability. The degree of confidence in results is limited by the low number of high-quality studies, the relatively small sample sizes, and the high between-study heterogeneity.

CONCLUSIONS

In our meta-analyses, we found several risk factors in the first 1,000 days of life that may be associated with increased CIMT during childhood. Small size for gestational age had the most consistent relationship with increased CIMT. The associations with conception through ART or with smoking during pregnancy were not statistically significant, with a high imprecision around the estimates. Due to the large uncertainty in effect sizes and the limited quality of CIMT measurements, further high-quality studies are needed to justify intervention for primordial prevention of cardiovascular disease (CVD).

Non-Invasive Vascular Very-High Resolution Ultrasound to Quantify Artery Intima Layer Thickness: Validation of the Four-Line Pattern

Preliminary findings suggest that very-high resolution ultrasound (VHRU, 55 MHz) could differentiate arterial intima layer thickness (IT) non-invasively in vivo. We aimed to validate ultrasound-derived IT measurements and describe a four-line pattern consistent with intimal thickening. VHRU was applied to temporal arteries of 37 patients with suspected giant cell arteritis without inflammation on histology. Anatomically matched ultrasound-derived measurements of arterial layer thickness with the leading-edge method was compared to histology. Intimal thickening (IT >0.06 mm on histology) was identified as a four-line pattern in VHRU with a sensitivity of 96.3% and a specificity of 100%. Histologic and VHRU IT measurement agreement was excellent (mean difference 0.007 mm; 95% limits of agreement, -0.043 to 0.057) and intra-class coefficient (ICC) 0.923 (95% confidence interval [CI], 0.833-0.964). Intra- and inter-observer agreements for VHRU IT were high: ICC 0.946 (95% CI, 0.877-0.976) and 0.872 (95% CI, 0.773-0.943). VHRU utilizing the leading-to-leading edge method allows accurate and reliable measurements of arterial IT in patients with IT >0.06 mm. Measurements of IT will provide the opportunity to explore early subclinical structural intimal changes in the arterial wall increasing with age.

Maternal obesity and gestational diabetes: Impact on arterial wall layer thickness and stiffness in early childhood - RADIEL study six-year follow-up

BACKGROUND AND AIMS

Gestational diabetes (GDM) and maternal obesity are linked to weight gain in childhood and an increased risk of cardiovascular disease later in life. We assessed the effects of GDM and maternal obesity on arterial function and morphology in relation to body anthropometrics and composition in early childhood.

METHODS

We assessed body size and composition, blood pressure (BP), arterial morphology and stiffness in 201 pairs of obese mothers (pre-pregnancy BMI 30.7 ± 5.6 kg/m², 96 with GDM) and their children at 6.1 years (SD 0.5).

RESULTS

Child BMI (z-score 0.45 ± 0.92; p < 0.001) and common carotid intima-media thickness (IMT, z-score 0.15 ± 0.75, p = 0.003) were increased compared with a healthy Finnish reference population. No associations with maternal GDM was found. Carotid IMT and pulse wave velocity were unrelated to child sex, anthropometrics, body composition, BP, as well as maternal anthropometrics and body composition. Carotid stiffness was independently predicted by second trimester fasting glucose. Child lean body mass was the strongest independent predictor for radial (RA), and brachial artery (BA) lumen diameter (LD) and BA IMT (LD: RA: r² = 0.068, p < 0.001; BA: r² = 0.108, p < 0.001; IMT: BA: r² = 0.161, p < 0.001) and carotid LD (r² = 0.066, p < 0.001).

CONCLUSIONS

Children of obese mothers have increased BMI, blood pressure and carotid IMT suggesting a transgenerational effect of maternal obesity and clustering of cardiovascular risk factors in the population. Arterial dimensions were mainly predicted by child LBM, and not associated with maternal or child adiposity, or GDM. There was a weak association with maternal gestational fasting glucose and increased carotid artery stiffness.

Acoustic Properties of Small Animal Soft Tissue in the Frequency Range 12-32 MHz

Quality assurance phantoms are made of tissue-mimicking materials (TMMs) the acoustic properties of which mimic those of soft tissue. However, the acoustic properties of many soft tissue types have not been measured at ultrasonic frequencies >9 MHz. With the increasing use of high-frequency ultrasound for both clinical and pre-clinical applications, it is of increasing interest to ensure that TMMs accurately reflect the acoustic properties of soft tissue at these higher frequencies. In this study, the acoustic properties of ex vivo brain, liver and kidney samples from 50 mice were assessed in the frequency range 12-32 MHz. Measurements were performed within 6 min of euthanasia in a phosphate-buffered saline solution maintained at 37.2 ± 0.2 °C. The measured mean values for the speed of sound for all organs were found to be higher than the International Electrotechnical Commission guideline recommended value for TMMs. The attenuation coefficients measured for brain, liver and kidney samples were compared with the results of previous studies at lower frequencies. Only the measured kidney attenuation coefficient was found to be in good agreement with the International Electrotechnical Commission guideline. The information provided in this study can be used as a baseline on which to manufacture a TMM suitable for high-frequency applications.

Feasibility and reliability of carotid intima-media thickness measurements in nonsedated infants

INTRODUCTION

Carotid intima-media thickness (CIMT) is a surrogate marker for atherosclerosis. It is increased in adolescents and young adults at risk for future cardiovascular disease. However, it remains unclear if it can be considered as a surrogate marker for atherosclerosis in infancy as very few studies have been performed in infants.

OBJECTIVES

Our objective was to assess the feasibility and interobserver reproducibility of CIMT measurement in nonsedated infants.

METHODS

We measured CIMT in 81 infants less than 1 year of age. Repeated measurements were obtained by a second observer in 24 children. The analysis was performed with semiautomated edge detection software. Measurements with over 95% edge detection over a length of 1 cm were considered as valid. We further compared the measurements using the semiautomated method with measurements using the manual electronic caliper method in a subgroup of 10 infants.

RESULTS

Carotid ultrasound recordings and intima-media thickness measurements were obtained in 79% of infants (n = 64). Mean CIMT of the 64 infants measured by the first observer was 0.44 mm (SD: 0.04). In the 24 participants with measurements by two observers, the mean interobserver difference was 0.001 mm (SD: 0.026). The interobserver coefficient of variation was 5.9%. CIMT measurements obtained with the manual method (mean: 0.35; range: 0.29-0.39) were slightly lower than measurements obtained with the semiautomated method (mean: 0.38; range: 0.32-0.44). Measurements with both methods were highly correlated (r: 0.87).

CONCLUSION

Measurement of CIMT in nonsedated infants less than 1 year of age is feasible in the majority of infants with good interobserver variability.

Broadband Acoustic Measurement of an Agar-Based Tissue-Mimicking-Material: A Longitudinal Study

Commercially available ultrasound quality assurance test phantoms rely on the long-term acoustic stability of the tissue-mimicking-material (TMM). Measurement of the acoustic properties of the TMM can be technically challenging, and it is important to ensure its stability. The standard technique is to film-wrap samples of TMM and to measure the acoustic properties in a water bath. In this study, a modified technique was proposed whereby the samples of TMM are measured in a preserving fluid that is intended to maintain their characteristics. The acoustic properties were evaluated using a broadband pulse-echo substitution technique over the frequency range 4.5-50 MHz at 0, 6 and 12 months using both techniques. For both techniques, the measured mean values for the speed of sound and attenuation were very similar and within the International Electrotechnical Commission-recommended value. However, the results obtained using the proposed modified technique exhibited greater stability over the 1-y period compared with the results acquired using the standard technique.

Neonatal Arterial Morphology Is Related to Body Size in Abnormal Human Fetal Growth

BACKGROUND

Restriction in fetal growth is associated with cardiovascular disease in adulthood. It is unclear whether abnormal intrauterine growth influences arterial morphology during the fetal or neonatal stage. The objective was to study the regional arterial morphology with respect to gestational age and abnormal fetal body size.

METHODS AND RESULTS

We studied body anthropometrics and arterial morphology and physiology in 174 neonates born between 31 and 42 weeks of gestation, including neonates with birth weights appropriate, small, and large for age, with very high resolution vascular ultrasound (35-55 MHz). In simple linear regressions, parameters of body size (body weight, body surface area, and organ circumference) and gestational age were statistically significantly associated with common carotid, brachial, femoral arterial parameters (lumen diameter [LD], wall layer thickness [intima-media thickness and intima-media-adventitia thickness], and carotid artery wall stress [CAWS]). Male sex was statistically significantly associated with LD and CAWS. In multiple linear regression models, body size, gestational age, and sex explained a large proportion of the arterial variance (R( 2) range, 0.37-0.47 for LD; 0.09-0.35 for intima-media thickness; 0.21-0.41 for intima-media-adventitia thickness; and 0.23 for CAWS; all models P<0.001). Arterial wall layer thickness, LDs, and CAWS were independently and strongly predicted by body size, and no effect of maternal disease was observed when added to the models. Gestational age and male sex were also independently but more weakly associated with arterial LDs and CAWS (P<0.01), but not with arterial wall layers.

CONCLUSIONS

These results indicate that the intrauterine growth of fetal arterial LD and wall layer thickness are primarily attributed to body growth overall. LD and CAWS show weaker association with gestational age and sex.