Carotid and Aortic Stiffness in Patients with Heterozygous Familial Hypercholesterolemia

Lipoprotein profile assessed by 1H NMR, BMI and blood pressure are associated with vascular alterations in children with familial hypercholesterolaemia

BACKGROUND AND AIMS

Children with familial hypercholesterolaemia (FH) have elevated low-density lipoprotein cholesterol (LDL-C) concentrations since birth, which increases the risk of cardiovascular disease in adulthood. Arterial injury and stiffness parameters, including carotid intima media thickness (cIMT), pulse wave velocity (PWV) and distensibility (DIST), can be detected early in childhood. We studied the associations between cIMT, PWV and DIST with the lipoprotein profile assessed by proton nuclear magnetic resonance (1H NMR) and with influential variables such as blood pressure (BP) or body mass index (BMI) in children with FH.

METHODS AND RESULTS

In this cross-sectional study, we included 201 children (96 with FH and 105 non-FH controls). Clinical history, physical examination and standard biochemical studies were performed. FH genetic testing was performed when clinically indicated. Carotid ultrasonography and an advanced lipoprotein profile by 1H NMR were performed. Multivariate and classification methods were used. There were no differences between cIMT, PWV and DIST between FH and non-FH children. FH children presented more total LDL and large, medium and small particles. Small LDL particles, BMI and systolic BP determined the presence of pathological IMT in the FH group. LDL size, high-density lipoproteins and very low-density lipoprotein particles together with blood pressure determined the presence of pathological arterial wall elasticity.

CONCLUSIONS

Alterations in lipoprotein parameters assessed by are associated with early structural and functional arterial characteristics in children with FH. BMI and BP act as boosting factors. Cardiovascular prevention should start early in children with FH, encompassing all components of a healthy lifestyle.

What are the benefits and drawbacks of statins in carotid artery disease? A perspective review

INTRODUCTION

The prevalence of carotid artery stenosis in the general population is approximately 3%, but approximately 20% among people with acute ischemic stroke. Statins are recommended by multiple international guidelines as the drug of choice for lipid control in people with asymptomatic or symptomatic carotid artery stenosis due to their lipid-lowering and other pleiotropic effects.

AREAS COVERED

This review discusses the guidelines for statin usage as a cornerstone in the prevention and management of atherosclerotic carotid artery disease and the impact of statins on stroke incidence and mortality. Statin side effects, alternative therapy, and genetic polymorphisms are reviewed.

EXPERT OPINION

Statin therapy is associated with a decreased incidence of stroke and mortality as well as improved outcomes for patients treated with carotid revascularization. Statins are a safe and effective class of medications, but the initiation of therapy warrants close monitoring to avoid rare and potentially serious side effects. Lack of clinical efficacy or the presence of side effects suggests a need for treatment with an alternative therapy such as PCSK9 inhibitors. Understanding the interplay between the mechanisms of statins and PCSK9 inhibition therapies will allow optimal benefits while minimizing risks. Future research into genetic polymorphisms may improve patient selection for personalized therapy.

The Importance of Arterial Stiffness Assessment in Patients with Familial Hypercholesterolemia

Cardiovascular diseases are still the leading cause of mortality due to increased atherosclerosis worldwide. In the background of accelerated atherosclerosis, the most important risk factors include hypertension, age, male gender, hereditary predisposition, diabetes, obesity, smoking and lipid metabolism disorder. Arterial stiffness is a firmly established, independent predictor of cardiovascular risk. Patients with familial hypercholesterolemia are at very high cardiovascular risk. Non-invasive measurement of arterial stiffness is suitable for screening vascular dysfunction at subclinical stage in this severe inherited disorder. Some former studies found stiffer arteries in patients with familial hypercholesterolemia compared to healthy controls, while statin treatment has a beneficial effect on it. If conventional drug therapy fails in patients with severe familial hypercholesterolemia, PCSK9 inhibitor therapy should be administered; if these agents are not available, performing selective LDL apheresis could be considered. The impact of recent therapeutic approaches on vascular stiffness is not widely studied yet, even though the degree of accelerated athero and arteriosclerosis correlates with cardiovascular risk. The authors provide an overview of the diagnosis of familial hypercholesterolemia and the findings of studies on arterial dysfunction in patients with familial hypercholesterolemia, in addition to presenting the latest therapeutic options and their effects on arterial elasticity parameters.

Carotid Atherosclerosis, Ultrasound and Lipoproteins

Carotid artery plaques are considered a measure of atherosclerosis and are associated with an increased risk of atherosclerotic cardiovascular disease, particularly ischemic strokes. Monitoring of patients with an elevated risk of stroke is critical in developing better prevention strategies. Non-invasive imaging allows us to directly see atherosclerosis in vessels and many features that are related to plaque vulnerability. A large body of evidence has demonstrated a strong correlation between some lipid parameters and carotid atherosclerosis. In this article, we review the relationship between lipids and atherosclerosis with a focus on carotid ultrasound, the most common method to estimate atherosclerotic load.

Carotid Pulse Wave Analysis: Future Direction of Hemodynamic and Cardiovascular Risk Assessment

Evaluation of the hemodynamic function of the cardiovascular system via measurement of the mechanical properties of the large arteries may provide a substantial improvement over present techniques. Practitioners are familiar with the problem of low reproducibility of conventional sphygmomanometry, which exhibits reasonable accuracy but low precision owing to its marked variability over time and in different circumstances (e.g., the white coat effect). Arterial wall stiffness is a consequence of atherosclerosis developing over time; thus, it has little short-term variability and is thus preferable to be used as a prognostic marker. In particular, arterial stiffness can be evaluated at the carotid artery using noninvasive approaches based on wearable sensor technologies for pulse wave analysis. These enable the assessment of central pressures and pulse waveform parameters that are expected to replace peripheral blood pressure measurement using the inflatable cuff. In this study, we discuss this simple and inexpensive technique, which has been shown to be reliable with the clinical and epidemiological evidence for its use as a biomarker of cardiovascular risk.

Stiffness of aortic arch and carotid arteries increases in ApoE-knockout mice with high-fat diet: evidence from echocardiography

Arterial stiffness is an effective predictor of atherosclerosis. Measurement of pulse-wave velocity (PWV) is a gold-standard approach to study arterial stiffness. This study aims to examine arterial stiffness and heart functions via echocardiography at an early stage of atherosclerosis. A model of atherosclerosis in ApoE-knockout (ApoE^-/- ) mice fed on high-fat diet (HFD) was used, with normal chow diet (ND) as a control. Stiffness of aortic arch and carotid arteries and left ventricular (LV) systolic/diastolic functions were measured by echocardiography. The plasma cholesterol levels and atherosclerotic plaque areas in the aortas were measured. The PWV values of aortic arch and carotid arteries were compared at 2, 4, 6 and 8 weeks with different diets. Compared with ND mice, PWV values in aortic arch and carotid arteries were significantly increased in HFD mice after 8 weeks (Aortic arch: 516.65 ± 216.89 cm/s vs. 192.53 ± 71.71 cm/s; Carotid arteries: 514.26 ± 211.01 cm/s vs. 188.03 ± 75.14 cm/s, respectively; both P < 0.01) accompanied by the decrease in LV systolic/diastolic functions. These were well correlated with the increase in plasma cholesterol levels. Echo-based PWV measurement in the aortic arch was found more sensitive to predict atherosclerosis than in the carotid arteries in ApoE^-/- mice. Measuring aortic arch PWV via echocardiography could represent a new diagnostic strategy for early detection of atherosclerosis.

Measurement of aortofemoral volume wave velocity during the routine 12-channel ECG: relation to age, physiological hemoglobin A 1C, triglycerides and SBP in healthy individuals

OBJECTIVE

Measurements of pulse wave velocity are generally thought to be too impractical for clinical routine. This study aimed to develop a method that can be performed during routine 12-channel ECG.

METHODS

A 12-channel ECG simultaneously supplies arterial impedance plethysmographic signals from the extremities beside segmental multifrequency impedance measurements for obtaining body composition. The origin of the plethysmographic signal (volume wave) at the arms and legs was determined at the level of the elbows and the knees. The volume wave velocity (VWV) at the aorta and femoral arteries was calculated from the time difference of the plethysmographic signals between arms and legs.

RESULTS

Automated measurement of VWV was highly reproducible (r = 0.96). In 107 participants in perfect health, VWV in different models was positively related to age, physiological hemoglobin A 1C, triglycerides, normal standardized unattended blood pressure, but not to physiological low-density lipoprotein-cholesterol and high-density lipoprotein-cholesterol. Aortofemoral VWV was significantly higher in patients with established coronary artery disease than in healthy controls of the same age group (18.1 ± 5.8 vs. 11.9 ± 1.7 m/s, P < 0.001). VWV in study participants was higher than tonometrically determined pulse wave velocity as muscular arteries are included (13.2 ± 5.81 vs. 8.8 ± 2.98 m/s, n = 115, P < 0.001).

CONCLUSION

These background arterial impedance plethysmographic measurements for the measurement of VWV made simultaneously during 12-channel ECG show promise for large-scale, routine clinical assessment of large artery function.

Assessment of Upper Extremity Venous Compliance in Patients With Abdominal Aortic Aneurysms

OBJECTIVE

Abdominal aortic aneurysm (AAA) is associated with morphological and functional changes in both aneurysmal and non-aneurysmal arteries. However, it remains uncertain whether similar changes also exist in the venous vasculature. The aim of this study was to evaluate global venous function in patients with AAA and controls.

METHODS

This experimental study comprised 31 men with AAA (mean ± standard deviation age 70.0 ± 2.8 years) and 29 male controls (aged 70.6 ± 3.4 years). Venous occlusion plethysmography (VOP) was used to evaluate arm venous compliance at venous pressures between 10 and 60 mmHg in steps of 5 mmHg. Compensatory mobilisation of venous capacitance blood (capacitance response) was measured with a volumetric technique during experimental hypovolaemia induced by lower body negative pressure (LBNP).

RESULTS

The VOP induced pressure-volume curve was significantly less steep in patients with AAA (interaction, p < .001), indicating lower venous compliance. Accordingly, the corresponding pressure-compliance curves displayed reduced venous compliance at lower venous pressures in patients with AAA vs. controls (interaction, p < .001; AAA vs. control, p = .018). After adjusting for arterial hypertension, diabetes mellitus, hyperlipidaemia, chronic obstructive pulmonary disease, and smoking, VOP detected differences in venous compliance remained significant at low venous pressures, that is, at 10 mmHg (p = .008), 15 mmHg (p = .013), and 20 mmHg (p = .026). Mean venous compliance was negatively correlated with aortic diameter (r = -.332, p = .010). Mobilisation of venous capacitance response during LBNP was reduced by approximately 25% in patients with AAA (p = .030), and the redistribution of venous blood during LBNP was negatively correlated with aortic diameter (r = -.417, p = .007).

CONCLUSION

Men with AAA demonstrated reduced venous compliance and, as a result, a lesser capacity to mobilise peripheral venous blood to the central circulation during hypovolaemic stress. These findings imply that the AAA disease may be accompanied by functional changes in the venous vascular wall.

Why patients with familial hypercholesterolemia are at high cardiovascular risk? Beyond LDL-C levels

Familial hypercholesterolemia (FH) is a common genetic cause of elevated low-density lipoprotein cholesterol (LDL-C) due to defective clearance of circulating LDL particles. All FH patients are at high risk for premature cardiovascular disease (CVD) events due to their genetically determined lifelong exposure to high LDL-C levels. However, different rates of CVD events have been reported in FH patients, even among those with the same genetic mutations and comparable LDL-C levels. Hence, additional CVD risk modifiers, beyond LDL-C, may contribute to increase CVD risk in the FH population. In this review, we discuss the overall CVD risk burden of the FH population. Additionally, we revise the prognostic impact of several traditional and emerging predictors of CVD risk and we provide an overview of the role of specific tools to stratify CVD risk in FH patients in order to ensure them a more personalized treatment approach.

Pulse wave velocity as a measure of arterial stiffness in patients with familial hypercholesterolemia: a systematic review and meta-analysis

INTRODUCTION

The aim of this meta-analysis was to establish whether vascular pulse wave velocity (PWV) as a measure of arterial stiffness is changed in patients with familial hypercholesterolemia (FH).

MATERIAL AND METHODS

Studies comparing PWV between patients with FH and controls were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (up to November 26, 2017). A meta-analysis was conducted using Comprehensive Meta-Analysis V2 software. A random-effects model (using the DerSimonian-Laird method) and the generic inverse variance method were used to compensate for the heterogeneity of studies concerning demographic characteristics and differences in the studies' design.

RESULTS

This meta-analysis of 8 studies involving 317 patients with FH and 244 non-FH individuals did not suggest a significantly altered PWV in FH patients versus controls (weighted mean difference (WMD): 0.17 m/s, 95% confidence interval (CI): -0.31, 0.65, p = 0.489; I ² = 80.15%). The result was robust in the sensitivity analysis and its significance was not influenced after omitting each of the included studies from the meta-analysis. Subanalysis of 6 of these studies which had data on intima-media thickness (IMT) indicated an increased IMT in FH patients when compared with controls (WMD = 0.03 mm, 95% CI: 0.003, 0.06, p = 0.034; I ² = 48.95%). However, the effect size was sensitive to some of the included studies.

CONCLUSIONS

This meta-analysis suggests that FH patients do not have significantly altered PWV when compared with normocholesterolemic individuals. However, a subanalysis of studies in which IMT was measured indicated that IMT is increased in FH patients compared with controls.

Neural Crest Cells Differentiate Into Brown Adipocytes and Contribute to Periaortic Arch Adipose Tissue Formation

OBJECTIVE

Periaortic arch adipose tissue (PAAT) plays critical roles in regulating vascular homeostasis; however, its anatomic features, developmental processes, and origins remain unclear. Approach and Results: Anatomic analysis and genetic lineage tracing of Wnt1 (wingless-type MMTV [mouse mammary tumor virus] integration site family member 1)-Cre⁺;Rosa26^RFP/+ mice, Myf5 (myogenic factor 5)-Cre⁺;Rosa26^RFP/+ mice, and SM22α-Cre⁺;Rosa26^RFP/+ mice are performed, and the results show that PAAT has unique anatomic features, and the developmental processes of PAAT are independent of the others periaortic adipose tissues. PAAT adipocytes are mainly derived from neural crest cells (NCCs) rather than from Myf5⁺ progenitors. Most PAAT adipocyte progenitors expressed SM22α⁺ (smooth muscle protein 22-alpha) during development. Using Wnt1-Cre⁺;PPARγ^flox/flox mice, we found that knockout of PPAR (peroxisome proliferator-activated receptor)-γ in NCCs results in PAAT developmental delay and dysplasia, further confirming that NCCs contribute to PAAT formation. And we further indicated PAAT dysplasia aggravates Ang II (angiotensin II)-induced inflammation and remodeling of the common carotid artery close to aorta arch. We also found that NCCs can be differentiated into both brown and white adipocytes in vivo and in vitro. RNA sequencing results suggested NCC-derived adipose tissue displays a distinct transcriptional profile compared with the non-NCC-derived adipose tissue in PAAT.

CONCLUSIONS

PAAT has distinctive anatomic features and developmental processes. Most PAAT adipocytes are originated from NCCs which derive from ectoderm. NCCs are progenitors not only of white adipocytes but also of brown adipocytes. This study indicates that the PAAT is derived from multiple cell lineages, the adipocytes derived from different origins have distinct transcriptional profiles, and PAAT plays a critical role in Ang II-induced common carotid artery inflammation and remodeling.Visual OvervieW: An online visual overview is available for this article.

LDL cholesterol is associated with systemic vascular resistance and wave reflection in subjects naive to cardiovascular drugs

BACKGROUND AND AIM

Low density lipoprotein cholesterol (LDL-C) is a primary risk factor for atherosclerosis, but it is also associated with elevated blood pressure (BP) and future development of hypertension. We examined the relationship between LDL-C and haemodynamic variables in normotensive and never-treated hypertensive subjects.

METHODS

We recruited 615 volunteers (19-72 years) without lipid-lowering and BP-lowering medication. Supine haemodynamics were recorded using continuous radial pulse wave analysis, whole-body impedance cardiography, and single channel electrocardiogram. The haemodynamic relations of LDL-C were examined using linear regression analyses with age, sex, body mass index (BMI) (or height and weight as appropriate), smoking status, alcohol use, and plasma C-reactive protein, sodium, uric acid, high density lipoprotein cholesterol (HDL-C), triglycerides, estimated glomerular filtration rate, and quantitative insulin sensitivity check index as the other included variables.

RESULTS

The mean (SD) characteristics of the subjects were: age 45 (12) years, BMI 27 (4) kg/m², office BP 141/89 (21/13) mmHg, creatinine 74 (14) µmol/l, total cholesterol 5.2 (1.0), LDL-C 3.1 (0.6), triglycerides 1.2 (0.8), and HDL-C 1.6 (0.4) mmol/l. LDL-C was an independent explanatory factor for aortic systolic and diastolic BP, augmentation index, pulse wave velocity (PWV), and systemic vascular resistance index (p < 0.05 for all). When central BP was included in the model for PWV, LDL-C was no longer an explanatory factor for PWV.

CONCLUSIONS

LDL-C is independently associated with BP via systemic vascular resistance and wave reflection. These results suggest that LDL-C may play a role in the pathogenesis of primary hypertension.

High-density lipoprotein 3 cholesterol is a predictive factor for arterial stiffness: a community-based 4.8-year prospective study

Background

Although drug trials with niacin and cholesteryl ester transfer protein inhibitors that substantially increase high-density lipoprotein-cholesterol (HDL-C) failed to reduce the risk of coronary heart disease, HDL protection of the cardiovascular system cannot be easily denied. Hence, it may be HDL subfractions that are responsible for the long-held and consistent cardioprotective association of HDL. Arterial stiffness has been increasingly recognized as a strong predictor of subclinical vascular disease, atherosclerotic disease, and cardiovascular mortality. As the association of HDL subfractions and arterial stiffness is not well characterized, we aimed to determine the relations between these two entities in a community-based longitudinal Chinese population sample.

Methods

We evaluated the associations of plasma HDL2-C and HDL3-C subfractions with arterial stiffness measured using carotid-femoral pulse wave velocity (cf-PWV) and then multivariate logistic regression in 1447 subjects (mean age 61.3 years) from a community-based population in Beijing, China.

Results

After a median follow-up of 4.8 years, Pearson’s correlation analysis revealed that HDL3-C was negatively associated with follow-up cf-PWV (r = −0.114; P = 0.001), and there was no correlation between HDL2-C and follow-up cf-PWV (r = −0.045; P = 0.181). In the multivariate logistic regression analysis, each standard deviation (SD) increase in HDL3-C was associated with a 1.490-increased likelihood of the presence of follow-up cf-PWV [odds ratio (per SD increase in HDL3-C) 1.490; 95% confidence interval 1.021–1.470; P = 0.039), whereas there was no relation between HDL2-C and follow-up cf-PWV.

Conclusions

HDL3-C subfractions were significantly and inversely associated with arterial stiffness, suggesting that HDL subfractions are likely more important than HDL-C in preventing cardiovascular disease.

Comparison of arterial stiffness/compliance in the ascending aorta and common carotid artery in healthy subjects and its impact on left ventricular structure and function

Arterial stiffness and compliance parameters from two adjacent elastic arteries [aorta and common carotid artery (CCA)] were compared and their relationship with left ventricular (LV) structure and function and clinical parameters was assessed. 584 healthy subjects were prospectively enrolled [mean age 47.8 ± 18.4 years, range 16-94; 318 (54.4%) men]. They underwent comprehensive transthoracic echocardiography; M-mode diameters were measured at the level of the ascending aorta in systole and diastole and by echo-tracking at the level of the left CCA. The β-stiffness, pressure-strain elastic modulus, arterial compliance and one-point pulse wave velocity were derived. A significant correlation was observed between aortic and CCA stiffness and compliance parameters (p < 0.0001 for all). At multiple regression analysis, CCA stiffness parameters were constantly correlated with age and systolic blood pressure, and accounted for up to 56% of the variability (vs. only 29% in aortic stiffness and compliance). CCA stiffness parameters were found to better predict LV structure, diastolic function than aortic stiffness parameters. Aortic and CCA stiffness and compliance were found to correlate with each other and with age, with the correlation being higher for CCA stiffness. At multiple regression analysis, CCA stiffness parameters were better predictors of LV structure and function than aortic stiffness.