Arterial endothelial function and wall thickness in familial hypercholesterolemia and familial combined hyperlipidemia and the effect of statins. A systematic review and meta-analysis

Evolution of the Arterial Structure and Function From Infancy to Adolescence Is related to Anthropometric and Blood Pressure Changes

Objective—

To develop a normative data set and to study the relationship among arterial structure, different anthropometric measures, blood pressure, and arterial function during healthy childhood using very-high-resolution ultrasound (25–55 MHz).

Methods and Results—

In 135 healthy children between 0 and 18 years of age, we assessed the structure of the carotid arteries, larger peripheral arteries, aorta, and left ventricle with ultrasound. Arterial stiffness was assessed by pulse wave velocity and endothelial function by brachial flow-mediated dilation. Reference curves adjusted for age and body surface area of arterial lumen diameters, intima-media thickness, and adventitia thickness were developed. Arterial walls thicken during childhood predominantly as a result of a progressive increase in intima-media thickness. There were significant associations among lumen diameter ( R 2 range, 0.20–0.88 for different arteries; P <0.001), intima-media thickness ( R 2 range, 0.47–0.85; P <0.001), left ventricular mass ( R 2 =0.90; P <0.001), and adventitia thickness ( R 2 range, 0.15–0.22; P <0.001) with sex, age, body surface, and systolic blood pressure. Arterial wall stress was associated with lumen diameter ( R 2 range, 0.52–0.83; P <0.001) and intima-media thickness ( R 2 range, 0.53–0.88; P <0.001). Limited relationships were found among arterial wall layer thickness, stiffness, and endothelial function.

Conclusion—

In healthy children, the evolution of the arterial structure is mainly related to anthropometrics and blood pressure.

Effect of fish oil supplementation on fasting vascular endothelial function in humans: a meta-analysis of randomized controlled trials

Background

Effect of fish oil supplementation on flow-mediated dilation, an index of endothelial function in humans, remains controversial. We performed a meta-analysis to determine whether fish oil supplementation could improve endothelial function.

Methods

Human intervention studies were identified by systematic searches of Medline, Embase, Cochrane's library and references of related reviews and studies. A random-effect model was applied to estimate the pooled results. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of fish oil supplementation on flow-mediated dilation.

Results

A total of sixteen records with 1,385 subjects were reviewed. The results of the pooled analysis showed that fish oil supplementation significantly improved flow-mediated dilation (weighed mean difference: 1.49%, 95% confidence interval 0.48% to 2.50%, p = 0.004). Meta-regression and subgroup analysis suggested that the quality of included studies were inversely related to the overall effect (regression coefficient  = −1.60, p = 0.04), and the significance of the effect was mainly driven by the studies with relatively poor quality. Sensitivity analysis including only double-blind, placebo-controlled studies indicated fish oil supplementation has no significant effect on endothelial function (weighed mean difference: 0.54%, 95% confidence interval −0.25% to 1.33%, p = 0.18). Besides, normoglycemic subjects or participants with lower diastolic blood pressure seemed to be associated with remarkable improvement of endothelial function after fish oil supplementation.

Conclusions

Although current evidence suggested a possible role of fish oil in improving endothelial function, large-scale and high-quality clinical trials are needed to evaluate these effects before we can come to a definite conclusion.

Increased carotid and brachial intima-media thickness is related to diffuse coronary involvement rather than focal lesions

We evaluated whether an increased carotid intima-media thickness (cIMT) and brachial artery IMT (bIMT) are related to diffuse coronary involvement rather than focal lesions. Patients (n = 88) with at least 1 significant lesion of the main epicardial coronary arteries (≥50%) were included in the present study. We used a novel score based on length and mean narrowing of all lesions in order to predict diffuse coronary involvement. Both cIMT and bIMT were higher in patients with long coronary lesion than focal lesion (P < .001). The patients with long coronary lesion had a higher rate of total coronary involvement than patients with focal lesion (P < .001). The cIMT had a higher correlation with total atherosclerotic burden in the coronary vasculature (r = .495, P < .001) and the longest lesion length (r = .489, P < .001) than cardiovascular risk factor score (r = .453, P < .001 and r = .324, P = .012, respectively). These findings may be valuable for clarifying the prognostic value of IMT measurements.

Cellular cholesterol efflux and cholesterol loading capacity of serum: effects of LDL-apheresis

High LDL-cholesterol (LDL-C) characterizes familial hypercholesterolemia (FH) and familial combined hyperlipidemia (FCH). LDL-apheresis, used in these patients to reduce LDL-C levels, has been shown to also affect HDL levels and composition. We studied LDL-apheresis effects on six FH and nine FCH subjects' serum capacity to modulate cellular cholesterol efflux, an index of HDL functionality, and to load macrophages with cholesterol. Serum cholesterol efflux capacity (CEC) and macrophage cholesterol loading capacity (CLC) were measured before, immediately after, and two days after LDL-apheresis. The procedure reduced total cholesterol (TC), LDL-C, and apoB plasma levels (-69%, -80% and -74%, respectively), parameters only partially restored two days later. HDL-C and apoA-I plasma levels, reduced after LDL-apheresis (-27% and -16%, respectively), were restored to almost normal levels two days later. LDL-apheresis reduced serum aqueous diffusion (AD) CEC, SR-BI-CEC, and ABCA1-CEC. AD and SR-BI were fully restored whereas ABCA1-CEC remained low two days later. Sera immediately and two days after LDL-apheresis had a lower CLC than pre-LDL-apheresis sera. In conclusion, LDL-apheresis transiently reduces HDL-C levels and serum CEC, but it also reduces also serum capacity to deliver cholesterol to macrophages. Despite a potentially negative effect on HDL levels and composition, LDL-apheresis may counteract foam cells formation.

Endothelial dysfunction and cardiovascular disease in early-stage chronic kidney disease: cause or association?

Chronic kidney disease (CKD) is strongly associated with cardiovascular disease (CVD); a graded inverse relationship between estimated glomerular filtration rate (eGFR) and cardiovascular event rates has emerged from large-scale observational studies. Chronic kidney disease is also associated with endothelial dysfunction (ED) although the precise relationship with GFR and the "threshold" at which ED begins are contentious. Abnormal endothelial function is certainly present in late-stage CKD but data in early-stage CKD appear confounded by disease states such as diabetes and hypertension which themselves promote ED. Thus, the direct effect of a reduction in GFR on endothelial function and, therefore, cardiovascular (CV) risk is far from completely established. In human studies, the precise duration of kidney impairment is seldom known and the onset of CVD often insidious, making it difficult to determine exactly when CVD first appears in the context of CKD. Kidney donors provide a near-ideal experimental model of CKD; subjects undergo an acute change from normal to modestly impaired renal function at the time of nephrectomy and lack the confounding co-morbidity that has made observational studies of CKD patients so challenging to interpret. By examining changes in endothelial function in living kidney donors before and after nephrectomy, useful insight might be gained into the pathophysiology of CVD in CKD and help determine whether targeting ED or the renal disease itself has the potential to reduce CV risk.

Atherosclerosis in systemic sclerosis: a systematic review and meta-analysis

OBJECTIVE

Systemic sclerosis (SSc) is characterized by calcification, vasculopathy, and endothelial wall damage, all of which can increase the risk of developing atherosclerosis and cardiovascular disease. The aim of this study was to perform a systematic review and meta-analysis to determine whether the risk of atherosclerosis is increased in SSc patients compared to healthy individuals.

METHODS

A systematic search was performed to identify studies published in PubMed and the Cochrane database up to May 2010, and recently published abstracts were also reviewed. Two reviewers independently screened articles to identify studies comparing the rate of atherosclerosis in SSc patients to that in healthy controls. The studies utilized one of the following methods: angiography, Doppler ultrasound to assess plaque and carotid intima-media thickness (IMT), computed tomography, magnetic resonance imaging, flow-mediated vasodilation (assessed as the FMD%), the ankle-brachial index, or autopsy. For carotid IMT and FMD% values, we computed a pooled estimate of the summary mean difference and explored predictors of carotid IMT using random-effects meta-regression.

RESULTS

Of the 3,156 articles initially identified, 31 were selected for systematic review. The meta-analysis included 14 studies assessing carotid IMT and 7 assessing brachial artery FMD%. Compared to healthy controls, SSc patients had a higher prevalence of coronary atherosclerosis, peripheral vascular disease, and cerebrovascular calcification. Meta-analysis showed that SSc patients had increased carotid IMT (summary mean difference 0.11 mm, 95% confidence interval [95% CI] 0.05 mm, 0.17 mm; P = 0.0006) and lower FMD% (summary mean difference -3.07%, 95% CI -5.44%, -0.69%; P = 0.01) compared to controls. There was marked heterogeneity between the studies, which was mainly attributable to variations in disease duration and differences in the mean/median age between SSc patients and controls.

CONCLUSION

Patients with SSc have an increased risk of atherosclerosis compared to healthy subjects. Further studies should elucidate the mechanism of this increased risk.

Feasibility of very-high resolution ultrasound to assess elastic and muscular arterial wall morphology in adolescents attending an outpatient clinic for obesity and lipid abnormalities

OBJECTIVE

Atherosclerosis begins during early life and is accelerated in individuals with cardiovascular risk factors. We hypothesized that very-high resolution ultrasound (VHRU, 25-55 MHz) could feasibly detect early arterial changes in adolescents with risk factors.

METHODS

We prospectively imaged the carotid, brachial and radial arterial morphology (far wall intima-media thickness, IMT; adventitia thickness, AT) by VHRU in 58 youths (age 14 ± 2 years) attending a Pediatric Preventive Cardiology Clinic for assessment and management of cardiovascular risk factors and compared the findings to those from an age-matched group of 67 controls.

RESULTS

Brachial and radial imaging was successful for all subjects. The carotid far wall could not be imaged in 7% of the patients due to limitations in penetration. VHRU image quality was related to body size and imaging depth. Imaging and analysis time were 12 ± 3 and 18 ± 3 min, respectively. Carotid IMT was increased in patients (0.42 ± 0.05 vs. 0.40 ± 0.06 mm, p = 0.05). No differences were found in brachial or radial IMT or AT vs. controls. Age, male gender, body mass index, systolic blood pressure (BP), but not lipid levels, were associated with arterial IMT in regression analyses.

CONCLUSION

VHRU is feasible in imaging carotid and peripheral muscular artery IMT in adolescents. The arterial IMT is associated with age, gender, adiposity and systolic BP, but not lipid levels, in this adolescent population. Further studies including patients with manifest clinical atherosclerosis are needed to assess if VHRU has applications in atherosclerosis research.

Modern ultrasound methods and atherosclerosis assessment in patients with familial hypercholesterolemia

Familial hypercholesterolemia (FHCH) is characterised by early atherosclerosis development and its fast progression. The prevalence of FHCH inRussiahas been increasing, therefore, it is important to evaluate the potential of various methods for atherosclerosis diagnostics. Arterial ultrasound is an informative, accessible, and safe method for evaluating atherosclerotic vascular changes. The modern ultrasound methods allow describing vascular wall status in detail, including qualitative and quantitative characteristics of its structure and function. At the same time, most ultrasound characteristics of arterial wall are used in research settings or are under development, and not implemented into clinical practice. The most promising parameters, applicable for clinical use in FHCH patients, simultaneously describe atherosclerosis severity and its localization, such as total plaque height, ankle-brachial index, and plaque number.