Characteristic cardiovascular manifestation in homozygous and heterozygous familial hypercholesterolemia

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolaemia: An expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is used for decades, lowering serum LDL-C levels by more than 70% directly after the treatment. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment goals and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Clinical practice recommendations on lipoprotein apheresis for children with homozygous familial hypercholesterolemia: an expert consensus statement from ERKNet and ESPN

Homozygous familial hypercholesterolaemia is a life-threatening genetic condition, which causes extremely elevated LDL-C levels and atherosclerotic cardiovascular disease very early in life. It is vital to start effective lipid-lowering treatment from diagnosis onwards. Even with dietary and current multimodal pharmaceutical lipid-lowering therapies, LDL-C treatment goals cannot be achieved in many children. Lipoprotein apheresis is an extracorporeal lipid-lowering treatment, which is well established since three decades, lowering serum LDL-C levels by more than 70% per session. Data on the use of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia mainly consists of case-reports and case-series, precluding strong evidence-based guidelines. We present a consensus statement on lipoprotein apheresis in children based on the current available evidence and opinions from experts in lipoprotein apheresis from over the world. It comprises practical statements regarding the indication, methods, treatment targets and follow-up of lipoprotein apheresis in children with homozygous familial hypercholesterolaemia and on the role of lipoprotein(a) and liver transplantation.

Early echocardiographic signs of cardiovascular affection in pediatric familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a rare autosomal dominant genetic disorder caused by defective low-density lipoprotein (LDL) receptors or abnormal apolipoprotein B. FH raises the risk of premature atherosclerotic disease and cardiovascular death in young adults. However, cardiovascular affection in children needs to be more adequately studied. Our study aimed to evaluate the effect of hypercholesterolemia on the cardiovascular system of pediatric patients with homozygous FH using conventional and advanced echocardiographic parameters such as tissue Doppler imaging (TDI) and 2-dimensional speckle-tracking echocardiography (2D-STE). This case-control study matched 25 healthy children with 21 patients with homozygous FH. Both groups had conventional echocardiography, TDI, and 2D-STE. Myocardial velocities of the left and right ventricles, left ventricular strain, and aortic stiffness parameters were measured. The FH group had greater systolic blood pressure, dilated coronary arteries, and hypertrophied left ventricle (LV) compared to the control (P = 0.0001, P = 0.001, P = 0.01, respectively). The mitral E/E' ratio was higher in the patient group than in the control group (P = 0.007), indicating LV diastolic dysfunction in patients. At the same time, LV systolic function evaluated by 2D-STE was comparable to that in the control group. The abdominal aorta circumferential strain and ascending aorta M-mode-derived strain were significantly lower in patients compared to those in the control (P = 0.024, P = 0.0001, respectively), indicating increased aortic stiffness in the patients' group; moreover, 85.7% of patients had mild aortic insufficiency.  Conclusion: Mild aortic insufficiency, coronary artery dilatation, left ventricular (LV) diastolic dysfunction, and increased aortic stiffness are among early cardiovascular markers in pediatric patients with homozygous FH before impaired LV systolic function. What is Known: • Familial hypercholesterolemia (FH) in adults is associated with accelerated atherosclerosis, aortic valvopathy, dilated coronary arteries, ischemic heart disease, and premature cardiovascular death. • The cardiovascular effects of FH in children require additional research. What is New: • Pediatric patients with familial hypercholesterolemia tend to have an early affection for left ventricular diastolic function before the affection for the systolic function. • The diastolic dysfunction associated with pediatric FH is correlated to the aortic stiffness and low-density lipoprotein levels.

Management and clinical outcomes of patients with homozygous familial hypercholesteremia in Saudi Arabia

We report the incidence, patient characteristic with clinical outcomes in patients with homozygous familial hypercholesterolemia (HoFH) in Saudi Arabia. This is a retrospective and prospective, single center study which included 37 patients 14 years and older enrolled and followed up between 2018-2021 for three years. 46% were females, 78% were offspring of consanguineous marriage. LDLR mutation was in 78% and LDL-C/LDLRAP in 3% of patients. Mean LDL-C at the first presentation was 14.2±3.7 mmol/L, average Dutch lipid score was 20.9±6.24. LDL apheresis was performed on 70% of patients. Most patients were on ezetimibe (92%), high-dose statins ( 84%) and  PCSK9 inhibitors (32%). 48.6% had aortic stenosis, out of which 30% had severe aortic stenosis. Ten underwent aortic valve surgery (5 mechanical valve, 3 Ross procedure, 1 aortic valve repair, 1 bioprosthetic valve) and one had transcatheter aortic valve implantation (TAVI). Coronary artery bypass surgery (CABG) was performed on 32% and percutaneous intervention (PCI) on 11% of patients. HoFH patients have complex diseases with high morbidity and mortality, and benefit from a highly specialized multidisciplinary clinic to address their clinical needs. Although there are several therapeutic agents on the horizon, early diagnosis, and treatment of HoFH remain critical to optimize patient outcomes.

Early myocardial functional abnormalities in primary dyslipidemia: clinical and echocardiographic observations in young children from a highly consanguineous population

BACKGROUND

Dyslipidemia is a major health problem among children and adolescents worldwide due to its significant association with cardiovascular disease. Primary dyslipidemias are commonly familial syndromes that can be completely asymptomatic.

PURPOSE

Apart from the risk of coronary artery disease (CAD), limited data are currently available on the direct effects of dyslipidemia on myocardial function in children.

METHODS

We recruited 25 children with primary dyslipidemia (14 with isolated hypercholesterolemia, 4 with isolated hypertriglyceridemia, and 7 with combined dyslipidemia). Relevant clinical manifestations and laboratory and radiological investigations were evaluated. Pulsed-wave Doppler and tissue Doppler imaging echocardiography were performed for all recruited patients and the results were compared with those of 15 age- and sex-matched healthy children.

RESULTS

The median age of the dyslipidemic children was 8 years (range, 1.5-16 years). A family history was documented in 13 cases (52%), while 18 (72%) had consanguineous parents. None of the dyslipidemic children had a personal history or clinical manifestations of CAD. In contrast, echocardiographic findings differed in several diastolic function parameters of both right and left ventricles in dyslipidemic children compared to controls. Based on normalized z scores, aortic valve narrowing was detected in 7 patients (28%), while narrowing of the aortic sinus (sinus of Valsalva) was detected in 15 patients (60%).

CONCLUSION

Different types of primary dyslipidemia produce functional myocardial abnormalities early in childhood. Biochemical and echocardiographic screening of high-risk children is advised to minimize the incidence of serious cardiovascular complications.

Creutzfeldt–Jakob disease associated with a T188K homozygous mutation in the prion protein gene: a case report and review of the literature

Genetic Creutzfeldt–Jakob disease (gCJD) is a prion disease caused by mutations in the prion protein gene (PRNP). It has an autosomal dominant inheritance, so gCJD with homozygous mutations is extremely rare, and the influence of homozygous mutations on the gCJD phenotype is unknown. We describe the clinical and laboratory features of a patient with a PRNP T188K homozygous mutation and perform a literature review of gCJD cases with PRNP homozygous mutations. The patient was presented with cerebellum symptoms, cognitive decline and visual disturbances. Auxiliary examinations revealed restricted diffusion in magnetic resonance imaging and glucose hypometabolism on ¹⁸Fluorodeoxyglucose-positron emission tomography. No periodic sharp wave complexes were detected in electroencephalography, and the cerebrospinal fluid 14-3-3 protein was negative. PRNP sequencing revealed the presence of a homozygous T188K variant. The patient died 15 months after disease onset. A literature review revealed PRNP V203I, E200K and E200D as the only three mutations reported as homozygous in gCJD. To the best of our knowledge, this is the first report of a gCJD patient with a PRNP T188K homozygous mutation. Although the clinical manifestations of our patient were similar to those with PRNP T188K heterozygous mutations, she presented with a slightly earlier onset and had a longer survival time. This is consistent with previous observations from patients with PRNP V203I and E200K homozygous mutations. Further studies are essential to clarify the influence of homozygous mutations on the gCJD phenotype.

Supravalvular Aortic Stenosis and the Risk of Premature Death Among Patients With Homozygous Familial Hypercholesterolemia

Patients with homozygous familial hypercholesterolemia (HoFH) have a high risk for premature death. Supravalvular aortic stenosis (SVAS) is a common and the feature lesion of the aortic root in HoFH. The relation between SVAS and the risk of premature death in patients with HoFH has not been fully investigated. The present study analysis included 97 HoFH patients with mean age of 14.7 (years) from the Genetic and Imaging of Familial Hypercholesterolemia in Han Nationality Study. During the median (±SD) follow-up 4.0 (±4.0) years, 40 (41.2%) participants had SVAS and 17 (17.5%) participants experienced death. The proportion of premature death in the non-SVAS and SVAS group was 7.0% and 32.5%, respectively. Compared with the non-SVAS group, SVAS group cumulative survival was lower in the HoFH (log-rank test, p <0.001). This result was further confirmed in the multivariable Cox regression models. After adjusting for age, sex, low density lipoprotein cholesterol (LDL_C)-year-score, lipid-lowering drugs, cardiovascular disease, and carotid artery plaque, SVAS was an independent risk factor of premature death in HoFH on the multivariate analysis (hazard ratio 4.45; 95% confidence interval, 1.10 to 18.12; p = 0.037). In conclusion, a significantly increased risk of premature death was observed in HoFH patients with SVAS. Our study emphasized the importance of careful and aggressive management in these patients when appropriate.

Proteostasis Regulation in the Endoplasmic Reticulum: An Emerging Theme in the Molecular Pathology and Therapeutic Management of Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is an autosomal genetic disease characterized by high serum low-density lipoprotein (LDL) content leading to premature coronary artery disease. The main genetic and molecular causes of FH are mutations in low-density lipoprotein receptor gene (LDLR) resulting in the non-clearance of LDL from the blood by hepatocytes and consequently the formation of plaques. LDLR is synthesized and glycosylated in the endoplasmic reticulum (ER) and then transported to the plasma membrane via Golgi. It is estimated that more than 50% of reported FH-causing mutations in LDLR result in misfolded proteins that are transport-defective and hence retained in ER. ER accumulation of misfolded proteins causes ER-stress and activates unfolded protein response (UPR). UPR aids protein folding, blocks further protein synthesis, and eliminates misfolded proteins via ER-associated degradation (ERAD) to alleviate ER stress. Various studies demonstrated that ER-retained LDLR mutants are subjected to ERAD. Interestingly, chemical chaperones and genetic or pharmacological inhibition of ERAD have been reported to rescue the transport defective mutant LDLR alleles from ERAD and restore their ER-Golgi transport resulting in the expression of functional plasma membrane LDLR. This suggests the possibility of pharmacological modulation of proteostasis in the ER as a therapeutic strategy for FH. In this review, we picture a detailed analysis of UPR and the ERAD processes activated by ER-retained LDLR mutants associated with FH. In addition, we discuss and critically evaluate the potential role of chemical chaperones and ERAD modulators in the therapeutic management of FH.

NFκB (Nuclear Factor κ-Light-Chain Enhancer of Activated B Cells) Activity Regulates Cell-Type-Specific and Context-Specific Susceptibility to Calcification in the Aortic Valve

OBJECTIVE

Although often studied independently, little is known about how aortic valve endothelial cells and valve interstitial cells interact collaborate to maintain tissue homeostasis or drive valve calcific pathogenesis. Inflammatory signaling is a recognized initiator of valve calcification, but the cell-type-specific downstream mechanisms have not been elucidated. In this study, we test how inflammatory signaling via NFκB (nuclear factor κ-light-chain enhancer of activated B cells) activity coordinates unique and shared mechanisms of valve endothelial cells and valve interstitial cells differentiation during calcific progression. Approach and Results: Activated NFκB was present throughout the calcific aortic valve disease (CAVD) process in both endothelial and interstitial cell populations in an established mouse model of hypercholesterolemia-induced CAVD and in human CAVD. NFκB activity induces endothelial to mesenchymal transformation in 3-dimensional cultured aortic valve endothelial cells and subsequent osteogenic calcification of transformed cells. Similarly, 3-dimensional cultured valve interstitial cells calcified via NFκB-mediated osteogenic differentiation. NFκB-mediated endothelial to mesenchymal transformation was directly demonstrated in vivo during CAVD via genetic lineage tracking. Genetic deletion of NFκB in either whole valves or valve endothelium only was sufficient to prevent valve-specific molecular and cellular mechanisms of CAVD in vivo despite the persistence of a CAVD inducing environment.

CONCLUSIONS

Our results identify NFκB signaling as an essential molecular regulator for both valve endothelial and interstitial participation in CAVD pathogenesis. Direct demonstration of valve endothelial cell endothelial to mesenchymal transformation transmigration in vivo during CAVD highlights a new cellular population for further investigation in CAVD morbidity. The efficacy of valve-specific NFκB modulation in inhibiting hypercholesterolemic CAVD suggests potential benefits of multicell type integrated investigation for biological therapeutic development and evaluation for CAVD.

Premature Valvular Heart Disease in Homozygous Familial Hypercholesterolemia

Valvular heart disease frequently occurs as a consequence of premature atherosclerosis in individuals with familial hypercholesterolemia (FH). Studies have primarily focused on aortic valve calcification in heterozygous FH, but there is paucity of data on the incidence of valvular disease in homozygous FH. We performed echocardiographic studies in 33 relatively young patients (mean age: 26 years) with homozygous FH (mean LDL of 447 mg/dL, 73% on LDL apheresis) to look for subclinical valvulopathy. Twenty-one patients had evidence of valvulopathy of the aortic or mitral valves, while seven subjects showed notable mitral regurgitation. Older patients were more likely to have aortic valve calcification (>21 versus ≤21 years: 59% versus 12.5%; p = 0.01) despite lower LDL levels at the time of the study (385 versus 513 mg/dL; p = 0.016). Patients with valvulopathy were older and had comparable LDL levels and a lower carotid intima-media thickness. Our data suggests that, in homozygous FH patients, valvulopathy (1) is present across a wide age spectrum and LDL levels and (2) is less likely to be influenced by lipid-lowering treatment. Echocardiographic studies that focused on aortic root thickening and stenosis and regurgitation are thus likely an effective modality for serial follow-up of subclinical valvular heart disease.

Calcific Aortic Valve Disease Is Associated with Layer-Specific Alterations in Collagen Architecture

Disorganization of the valve extracellular matrix (ECM) is a hallmark of calcific aortic valve disease (CAVD). However, while microarchitectural features of the ECM can strongly influence the biological and mechanical behavior of tissues, little is known about the ECM microarchitecture in CAVD. In this work, we apply advanced imaging techniques to quantify spatially heterogeneous changes in collagen microarchitecture in CAVD. Human aortic valves were obtained from individuals between 50 and 75 years old with no evidence of valvular disease (healthy) and individuals who underwent valve replacement surgery due to severe stenosis (diseased). Second Harmonic Generation microscopy and subsequent image quantification revealed layer-specific changes in fiber characteristics in healthy and diseased valves. Specifically, the majority of collagen fiber changes in CAVD were found to occur in the spongiosa, where collagen fiber number increased by over 2-fold, and fiber width and density also significantly increased. Relatively few fibrillar changes occurred in the fibrosa in CAVD, where fibers became significantly shorter, but did not otherwise change in terms of number, width, density, or alignment. Immunohistochemical staining for lysyl oxidase showed localized increased expression in the diseased fibrosa. These findings reveal a more complex picture of valvular collagen enrichment and arrangement in CAVD than has previously been described using traditional analysis methods. Changes in fiber architecture may play a role in regulating the pathobiological events and mechanical properties of valves during CAVD. Additionally, characterization of the ECM microarchitecture can inform the design of fibrous scaffolds for heart valve tissue engineering.

Surgical Challenges of Familial Hypercholesterolemia

A 21-year-old patient with familial hypercholesterolemia presented with angina caused by ostial stenosis of the left internal mammary artery and severe calcific aortic stenosis with small aortic root 9 years after coronary revascularization. The ostium of the left internal mammary artery was enlarged using a saphenous vein patch through a left supraclavicular incision, which improved left ventricular function. Successful aortic valve replacement with posterior aortic root enlargement was subsequently performed. The surgical management of this condition is discussed briefly.

Development of Aortic Valve Disease in Familial Hypercholesterolemic Swine: Implications for Elucidating Disease Etiology

Background

Familial hypercholesterolemia (FH) is a prevalent hereditary disease associated with increased atherosclerosis and calcific aortic valve disease (CAVD). However, in both FH and non‐FH individuals, the role of hypercholesterolemia in the development of CAVD is poorly understood. This study used Rapacz FH (RFH) swine, an established model of human FH, to investigate the role of hypercholesterolemia alone in the initiation and progression of CAVD. The valves of RFH swine have not previously been examined.

Methods and Results

Aortic valve leaflets were isolated from wild‐type (0.25‐ and 1‐year‐old) and RFH (0.25‐, 1‐, 2‐, and 3‐year‐old) swine. Adult RFH animals exhibited numerous hallmarks of early CAVD. Significant leaflet thickening was found in adult RFH swine, accompanied by extensive extracellular matrix remodeling, including proteoglycan enrichment, collagen disorganization, and elastin fragmentation. Increased lipid oxidation and infiltration of macrophages were also evident in adult RFH swine. Intracardiac echocardiography revealed mild aortic valve sclerosis in some of the adult RFH animals, but unimpaired valve function. Microarray analysis of valves from adult versus juvenile RFH animals revealed significant upregulation of inflammation‐related genes, as well as several commonalities with atherosclerosis and overlap with human CAVD.

Conclusions

Adult RFH swine exhibited several hallmarks of early human CAVD, suggesting potential for these animals to help elucidate CAVD etiology in both FH and non‐FH individuals. The development of advanced atherosclerotic lesions, but only early‐stage CAVD, in RFH swine supports the hypothesis of an initial shared disease process, with additional stimulation necessary for further progression of CAVD.

Homozygous autosomal dominant hypercholesterolaemia: prevalence, diagnosis, and current and future treatment perspectives

PURPOSE OF REVIEW

Homozygous autosomal dominant hypercholesterolemia (hoADH) is a rare genetic disorder caused by mutations in LDL receptor, apolipoprotein B, and/or proprotein convertase subtilisin-kexin type 9. Both the genetic mutations and the clinical phenotype vary largely among individual patients, but patients with hoADH are typically characterized by extremely elevated LDL-cholesterol (LDL-C) levels, and a very high-risk for premature cardiovascular disease. Current lipid-lowering therapies include bile acid sequestrants, statins, and ezetimibe. To further decrease LDL-C levels in hoADH, lipoprotein apheresis is recommended, but this therapy is not available in all countries.

RECENT FINDINGS

Recently, the microsomal triglyceride transfer protein inhibitor lomitapide and the RNA antisense inhibitor of apolipoprotein B mipomersen were approved by the Food and Drug Administration/European Medicine Agency and the Food and Drug Administration, respectively. Several other LDL-C-lowering strategies and therapeutics targeting the HDL-C pathway are currently in the clinical stage of development.

SUMMARY

Novel therapies have been introduced for LDL-C-lowering and innovative drug candidates for HDL-C modulation for the treatment of hoADH. Here, we review the current available literature on the prevalence, diagnosis, and therapeutic strategies for hoADH.

Calcific Aortic Valve Disease: Molecular Mechanisms and Therapeutic Approaches

Calcification occurs in atherosclerotic vascular lesions and In the aortic valve. Calcific aortic valve disease (CAVD) is a slow, progressive disorder that ranges from mild valve thickening without obstruction of blood flow, termed aortic sclerosis, to severe calcification with impaired leaflet motion, termed aortic stenosis. In the past, this process was thought to be 'degenerative' because of time-dependent wear and tear of the leaflets, with passive calcium deposition. The presence of osteoblasts in atherosclerotic vascular lesions and in CAVD implies that calcification is an active, regulated process akin to atherosclerosis, with lipoprotein deposition and chronic inflammation. If calcification is active, via pro-osteogenic pathways, one might expect that development and progression of calcification could be inhibited. The overlap in the clinical factors associated with calcific valve disease and atherosclerosis provides further support for a shared disease mechanism. In our recent research we used an in vitro porcine valve interstitial cell model to study spontaneous calcification and potential promoters and inhibitors. Using this model, we found that denosumab, a human monoclonal antibody targeting the receptor activator of nuclear factor-κB ligand may, at a working concentration of 50 μg/mL, inhibit induced calcium deposition to basal levels.

Aortic stenosis: a general overview of clinical, pathophysiological and therapeutic aspects

Aortic stenosis is the most prevalent valve pathology and calcific aortic valve disease (CAVD) is its most frequent etiology in developed countries. There is extensive evidence that CAVD represents an active disease process similar to that of atherosclerosis with similar classical cardiovascular risk factors and pathological mechanisms. Given that in the vast majority of situations the only treatment available is valve replacement there is a need to develop pharmacological therapies that retard the disease progression. Lipid-lowering therapies have been the focus of research, however, so far with negative results. Future studies, including animal models, shall provide an opportunity to further evaluate the disease mechanisms of CAVD and to discover potential disease biomarkers and pharmacological interventions that can reduce the need for valve replacement.

Fatal myocardial infarction at 4.5 years in a case of homozygous familial hypercholesterolaemia

Management of homozygous familial hypercholesterolaemia is notoriously difficult. For these patients, LDL apheresis is considered the treatment of choice. Treatment initiation is advocated generally from the age of seven years onwards (Thompson et al., Atherosclerosis 198:247-255, 2008). Here, we present the case of a young girl from a large inbred family of Turkish descent with homozygous familial hypercholesterolaemia and fatal outcome at the early age of 4½ years.In conclusion, this case suggests that management of homozygous familial hypercholesterolaemia may require earlier and more aggressive treatment, including LDL apheresis before the age of seven years.

Lipid lowering on progression of mild to moderate aortic stenosis: meta-analysis of the randomized placebo-controlled clinical trials on 2344 patients

BACKGROUND

Aortic stenosis (AS) is believed to develop through an inflammatory similar to the atherosclerosis process. Based on findings from animal studies and uncontrolled clinical studies, lipid-lowering therapy with a statin is postulated to slow this process. Randomized trials, however, reported neutral results. This meta-analysis of randomized lipid trials on patients with AS examined the effects of treatment on AS progression and clinical outcomes.

METHODS

Echocardiographic measures of AS (aortic valve jet velocity, peak and mean valve gradients, and aortic valve area) were pooled and clinical outcomes were evaluated in 4 randomized placebo controlled trials (N=2344).

RESULTS

Although active treatment with statin therapy was associated with highly significant 50% reduction in low-density lipoprotein cholesterol levels, there were no statistical differences between active and placebo groups in any of the echocardiographic indicators of AS severity: annual increase in AS velocity was 0.16±0.28 m/sec, and mean gradient was 2.8±3.0 mm Hg. Each trial reported no differences in clinical outcomes between the 2 treatment groups. Substantial events rates (6.6% aortic valve surgery and 1.2% cardiovascular deaths per year in SEAS with follow-up of 4.4 years and 5.8% aortic valve surgery and 0.7% cardiovascular deaths per year in ASTRONOMER over 3.5 years) were observed in these patients despite the relatively mild disease.

CONCLUSION

The current data do not support the hypothesis that statin therapy reduces AS progression. Patients with mild to moderate AS may require closer follow-up because despite the less severe disease in these trials, event rates remain substantial.

Causes and histopathology of ascending aortic disease in children and young adults

BACKGROUND

Ascending aortic diseases (aneurysms, dissections, and stenosis) and associated aortic valve disease are rare but important causes of morbidity and mortality in children and young adults. Certain genetic causes, such as Marfan syndrome and congenital bicuspid aortic valve disease, are well known. However, other rarer genetic and nongenetic causes of aortic disease exist.

METHODS

We performed an extensive literature search to identify known causes of ascending aortic pathology in children and young adults. We catalogued both aortic pathologies and other defining systemic features of these diseases.

RESULTS

We describe 17 predominantly genetic entities that have been associated with thoracic aortic disease in this age group.

CONCLUSIONS

While extensive literature on the common causes of ascending aortic disease exists, there is a need for better histologic documentation of aortic pathology in rarer diseases.

Effect of Lipid lowering with rosuvastatin on progression of aortic stenosis: results of the aortic stenosis progression observation: measuring effects of rosuvastatin (ASTRONOMER) trial

BACKGROUND

Aortic stenosis (AS) is an active process with similarities to atherosclerosis. The objective of this study was to assess the effect of cholesterol lowering with rosuvastatin on the progression of AS.

METHODS AND RESULTS

This was a randomized, double-blind, placebo-controlled trial in asymptomatic patients with mild to moderate AS and no clinical indications for cholesterol lowering. The patients were randomized to receive either placebo or rosuvastatin 40 mg daily. A total of 269 patients were randomized: 134 patients to rosuvastatin 40 mg daily and 135 patients to placebo. Annual echocardiograms were performed to assess AS progression, which was the primary outcome; the median follow-up was 3.5 years. The peak AS gradient increased in patients receiving rosuvastatin from a baseline of 40.8+/-11.1 to 57.8+/-22.7 mm Hg at the end of follow-up and in patients with placebo from 41.6+/-10.9 mm Hg at baseline to 54.8+/-19.8 mm Hg at the end of follow-up. The annualized increase in the peak AS gradient was 6.3+/-6.9 mm Hg in the rosuvastatin group and 6.1+/-8.2 mm Hg in the placebo group (P=0.83). Treatment with rosuvastatin was not associated with a reduction in AS progression in any of the predefined subgroups.

CONCLUSIONS

Cholesterol lowering with rosuvastatin 40 mg did not reduce the progression of AS in patients with mild to moderate AS; thus, statins should not be used for the sole purpose of reducing the progression of AS. Clinical Trial Registration Information- URL: http://www.controlled-trials.com/.

CLINICAL TRIAL REGISTRATION NUMBER

ISRCTN 32424163.

Biventricular adaptation to volume overload in mice with aortic regurgitation

BACKGROUND

Aortic valve regurgitation is usually caused by impaired coaptation of the aortic valve cusps during diastole. Hypercholesterolemia produces aortic valve lipid deposition, fibrosis, and calcification in both mice and humans, which could impair coaptation of cusps. However, a link between hypercholesterolemia and aortic regurgitation has not been established in either species. The purpose of this study was to ascertain the prevalence of aortic regurgitation in hypercholesterolemic mice and to determine its impact on the left and right ventricles.

METHODS AND RESULTS

Eighty Ldlr-/-/Apob100/100/Mttpfl/fl/Mx1Cre+/+ ("Reversa") hypercholesterolemic mice and 40 control mice were screened for aortic regurgitation (AR) with magnetic resonance imaging at age 7.5 months. The prevalence of AR was 40% in Reversa mice, with moderate or severe regurgitation (AR+) in 19% of mice. In control mice, AR prevalence was 13% (p = 0.004 vs. Reversa), and was invariably trace or mild in severity. In-depth evaluation of cardiac response to volume overload was performed in 12 AR-positive and 12 AR-negative Reversa mice. Regurgitant fraction was 0.34 +/- 0.04 in AR-positive vs. 0.02 +/- 0.01 in AR-negative (mean +/- SE; p < 0.001). AR-positive mice had significantly increased left ventricular end-diastolic volume and mass and reduced ejection fraction in both ventricles. When left ventricular ejection fraction fell below 0.60 in AR-positive (n = 7) mice, remodeling occurred and right ventricular systolic function progressively worsened.

CONCLUSION

Hypercholesterolemia causes aortic valve regurgitation with moderate prevalence in mice. When present, aortic valve regurgitation causes volume overload and pathological remodeling of both ventricles.

Aortic calcifications in familial hypercholesterolemia: potential role of the low-density lipoprotein receptor gene

BACKGROUND

We have previously reported premature, extensive aortic calcifications in patients with homozygous familial hypercholesterolemia (hmzFH) due to mutations in the low-density lipoprotein receptor gene (LDL-R). The objective of this study was to measure the degree of aortic calcification in heterozygous FH (htzFH) compared to both hmzFH and controls. We hypothesized that the LDL-R gene may contribute to aortic calcifications in a gene-dosage effect.

METHOD

Patients with htzFH due to the French Canadian mutation (Delta15 kb del. null allele) were selected. All patients underwent computed tomographic scan to measure vascular calcification. We used 22 hmzFH patients from our previous study and patients undergoing computed tomographic virtual colonoscopy as controls.

RESULTS

Mean age for htzFH was 50 +/- 15 years; initial cholesterol level before treatment was 10.45 +/- 1.73 mmol/L. Major cardiovascular events occurred in 9 of 17 patients. A strong correlation between age and calcium score was found (r = 0.72, P = .0016). There was a strong correlation between the cholesterol-year score (an index of lifelong cholesterol burden) and the aortic calcium score (r = 0.62, P = .0105). Aortic calcifications in htzFH subjects occurred later than in hmzFH patients, but much earlier than in controls, suggesting a gene-dosage effect of LDL-R mutations and aortic calcium deposition.

CONCLUSION

Aortic calcification was observed in patients with htzFH but presented at a later time and were less extensive than in hmzFH (34 vs 14 years, respectively). Because aortic calcifications may be partly independent of serum cholesterol levels in patients with familial hypercholesterolemia, implications for screening and the timing of treatment initiation may need reassessment.

Longitudinal evaluation and assessment of cardiovascular disease in patients with homozygous familial hypercholesterolemia

Homozygous familial hypercholesterolemia (hoFH) is caused by mutations in the low-density lipoprotein receptor gene and is characterized by severe hypercholesterolemia from birth and onset of premature cardiovascular disease (CVD) during childhood. The onset and progression of CVD using currently available testing methods in children with hoFH have not been fully characterized. A large cohort of patients with hoFH referred to our subspecialty clinic was studied. Thirty-nine patients (22 aged < or =16 years) underwent extensive cardiovascular, lipid, and genetic evaluation. Sixteen children < or =16 years without known CVD when first evaluated were followed up longitudinally for up to 8 years. CVD was clinically evident in 88% of subjects aged >16 years and 9% of those < or =16 years. Markers of atherosclerosis correlated significantly with age at which lipid-lowering treatment was initiated (abnormal coronary angiogram, abnormal aortic valve using echocardiography, and high calcium score using electron beam computed tomography; all p <0.01; abnormal carotid Doppler result; p = 0.03). Twenty of 22 children had no clinical evidence of coronary artery disease, yet 7 of these children had angiographically confirmed mild coronary artery disease (<50%) and 8 had mild to moderate aortic regurgitation using echocardiography. Of noninvasive tests, only evaluation of aortic valve regurgitation using echocardiography predicted the presence of angiographic coronary stenosis (p <0.001). During follow-up, 7 children developed progression of coronary and/or aortic valvular disease during their teenage years and 4 required surgical interventions. In conclusion, in these patients aggressive lipid-lowering treatment initiated in early childhood is warranted. Careful coronary and valvular surveillance strategies and coronary revascularization when appropriate are also warranted in this high-risk population.

Calcific aortic stenosis: lessons learned from experimental and clinical studies

Calcific aortic stenosis is the most common indication for surgical valve replacement in the United States. For years this disease has been described as a passive degenerative process during which serum calcium attaches to the valve surface and binds to the leaflet to form nodules. Therefore, surgical treatment of this disease has been the approach toward relieving outflow obstruction in these patients. Recent studies demonstrate an association between atherosclerosis and its risk factors for aortic valve disease. In 2008, there are increasing number of epidemiology and experimental studies to provide evidence that this disease process is not a passive phenomena. There is an active cellular process that develops within the valve leaflet and causes a regulated bone formation to develop. If the atherosclerotic hypothesis is important in the initiation of aortic stenosis, then treatments used in slowing the progression of atherosclerosis may be effective in patients with aortic valve disease. This review will discuss the pathogenesis and the potential for medical therapy in the management of patients with calcific aortic stenosis by examining the lessons provided from the experimental research.

Non-invasive detection of aortic and coronary atherosclerosis in homozygous familial hypercholesterolemia by 64 slice multi-detector row computed tomography angiography

Homozygous familial hypercholesterolemia (HoFH) is a rare disorder characterized by the early onset of atherosclerosis, often at the ostia of coronary arteries. In this study we document for the first time that aortic and coronary atherosclerosis can be detected using 64 slice multiple detector row computed tomographic coronary angiography (CTCA). We studied five HoFH patients (three females, two males, mean age 19.8+/-2.9 years, age range 15-23 years, with a mean low density lipoprotein (LDL) cholesterol 618+/-211 mg/dL) using 64 slice CTCA. None of the patients showed evidence of ischemia with standard exercise testing. Calcified and mixed atherosclerotic plaques adjacent to or compromising the coronary artery ostia were found in all study subjects. Coronary plaques causing significant obstruction were found in one patient, who had previously undergone coronary artery bypass surgery and aortic valve replacement. Two other patients were noted to have non-obstructive calcified, mixed and non-calcified coronary artery plaques. Our data suggest that CTCA could be a useful non-invasive method for detection of early aortic and coronary atherosclerosis specifically affecting the coronary ostia in HoFH subjects.

Monogenic pediatric dyslipidemias: classification, genetics and clinical spectrum

Monogenic disorders that cause abnormal levels of plasma cholesterol and triglycerides have received much attention due to their role in metabolic dysfunction and cardiovascular disease. While these disorders often present clinically during adulthood, some present most commonly in the pediatric population and can have serious consequences if misdiagnosed or untreated. This review provides an overview of monogenic lipid disorders that present with unusually high or low levels of plasma cholesterol and/or triglycerides during infancy, childhood and adolescence. Biochemical and genetic findings, clinical presentation and treatment options are discussed with an emphasis upon recent advances in our understanding and management of these monogenic disorders.

Vascular calcifications in homozygote familial hypercholesterolemia

BACKGROUND

Patients with homozygous familial hypercholesterolemia (hmzFH) attributable to LDL receptor gene mutations have shown a remarkable increase in survival over the last 20 years. Early onset coronary heart disease (CHD) and calcific aortic valve stenosis are the major complications of this disorder. We now report extensive premature calcification of the aorta in patients with hmzFH.

METHODS AND RESULTS

We examined 25 hmzFH patients from Canada; mean age was 32 years (range 5 to 54), and mean baseline cholesterol before treatment was 19+/-5 mmol/L (737+/-206 mg/dL). Aortic calcification was quantified using computed tomography (CT). An elevated mean calcium score was found in patients by age 20 and correlated with age (r(2)=0.53, P=0.001). One quarter (24%) of patients underwent aortic valve surgery.

CONCLUSIONS

We document premature severe aortic calcifications in all adult hmzFH patients studied. These presented considerable surgical management challenges. Strategies to identify and monitor aortic calcification in hmzFH by noninvasive techniques are required, as are clinical trials to determine whether additional or more intensive therapies will prevent the progression of such calcifications. Whether vascular calcifications in hmzFH subjects are related to sustained increases in LDL-C levels or to other mechanisms, such as abnormal osteoblast activity, remains to be determined.

Severe supravalvar aortic stenosis in familial homozygous hypercholesterolemia

Familial homozygous hypercholesterolemia is a rare disease with diverse clinical presentations. Patients often present with cutaneous xanthomas, particularly in the Achilles' tendon. They may have significant cardiovascular involvement, including premature atherosclerotic coronary artery disease and valvar and supravalvar aortic stenosis. Standard therapy includes diet modulation, pharmacotherapy, and lipid apheresis. Rarely, patients require surgical intervention for coronary artery bypass grafting and/or relief of the aortic stenosis. We present the case of a patient with severe progressive supravalvar aortic stenosis that ultimately required surgical resection despite aggressive medical therapy.

Is aortic stenosis a preventable disease?

Aortic stenosis (AS) is the most common valvular disease requiring valve replacement. Its prevalence increases with age. When the severity of AS is only mild to moderate, it is well tolerated. When it becomes severe, AS confers significant morbidity and mortality. Adverse events can be avoided if it is possible to prevent or retard the progression from mild or moderate AS to severe AS. Progression of AS parallels the progression of sclerotic changes involving the aortic valve, which share histological and immunochemical similarities with the process of atherosclerosis. Far from being just a degenerative process, the development of AS is a complex and highly regulated process with a number of modifiable factors. One of the key factors appears to be lipoproteins, which are intimately involved in several pathways crucial to the development of AS. The importance of lipoproteins is further supported by epidemiological and clinical studies showing a strong association between lipoproteins and AS. The time has come to initiate prospective studies to assess the effect of cholesterol lowering on the progression of AS.

Hypercholesterolemic valvulopathy: an aspect of malignant atherosclerosis

Hypercholesterolemia affects not only the coronary artery, but also the aortic root, particularly the aortic valve. Aortic stenosis is critical in the prognosis for most patients with homozygous familial hypercholesterolemia (FH) and some heterozygous FH patients who result in aortic valve replacement (AVR). Histopathological examination of their valves shows lipid deposition, inflammatory cell infiltration and calcification in the aortic cusps. These pathological findings are common in non-FH patients with AVR. In homozygous FH patients, the aortic valves are injured by extreme hypercholesterolemia in a relatively short period of time, whereas in heterozygous FH patients with additional risk factors, the damage to the valves occurs over an intermediate time period. In the non-FH population with several risk factors, an underlying raised serum cholesterol level results in gradual impairment over a number of years. Aortic valvular dysfunction caused by hypercholesterolemia, which we termed hypercholesterolemic valvulopathy is recognized to be a life-threatening complication as the primary clinical characteristic of malignant atherosclerosis.

Genetic influence on cigarette-induced cardiovascular disease

Cigarette smoking as an addictive habit has accompanied human beings for more than 4 centuries. It is also one of the most potent and prevalent environmental health risks human beings are exposed to, and it is responsible for more than 1000 deaths each day in the United States. With recent research progress, it becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. These detrimental effects are not only present in active smokers who choose the risk, but also to innocent bystanders, as passive smokers, who are exposed to cigarettes not-by-choice. While the cigarette-induced harm to human health is indiscriminate and severe, the degree of damage also varies from individual to individual. This intersubject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification process, eg, cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development. Through population studies, we have learned that certain CYP1A1 variants, such as Mspl polymorphism, may render the carriers more susceptible to cigarette-induced lung cancer or severe coronary atherosclerosis. The endothelial nitric oxide synthase intron 4 rare allele homozygotes are more likely to have myocardial infarction if they also smoke. In vitro experimental approach has further demonstrated that cigarettes may specifically regulate these genes in genotype-dependent fashion. While we still know little about genetic basis and molecular pathways for cigarette-induced pathological changes, understanding these mechanisms will be of great value in designing strategies to further reduce smoking in targeted populations, and to implement more effective measures in prevention and treatment of cigarette-induced diseases.

Long-term treatment effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients

AIM

To assess the effect of atorvastatin on aortic stiffness in hypercholesterolaemic patients free of arterial hypertension and diabetes mellitus.

METHODS AND RESULTS

The study included 36 patients (25 men and 11 women, mean age 56 +/- 12 years); 18 patients had stable coronary heart disease (CHD) and 18 were free of CHD at baseline. All patients received atorvastatin (20 mg/day) for a 2-year period. Aortic stiffness was assessed by transthoracic echocardiography at baseline and 2 years later. At baseline, total cholesterol, low density lipoprotein cholesterol (LDL-C) and LDL-C/high density lipoprotein cholesterol (HDL-C) ratio were positively related to aortic stiffness (p < 0.001 for all). The mean change in lipid parameters during treatment was: total cholesterol -38%, LDL-C -46%, triglycerides -29%, and HDL-C +6%, all significant (p = 0.029 to < 0.0001). After the 2-year treatment with atorvastatin, aortic stiffness was significantly reduced by 14% (p = 0.019). An improvement of left ventricular (LV) ejection fraction by 13% (p < 0.001) and a reduction of LV mass index by 9% (p = 0.008) were also recorded. The change in aortic stiffness was similar in patients with or without CHD.

CONCLUSION

Long-term treatment with atorvastatin improves aortic stiffness; this index is related to total and coronary mortality. Moreover, assessment of aortic stiffness may be useful in identifying which hypercholesterolaemic patients should be treated aggressively, regardless of CHD. The aortic stiffness effect may eventually become an index of the efficacy of lipid lowering treatment.

Hyperlipidemia in HIV-infected children treated with protease inhibitors: relevance for cardiovascular diseases

Cases of severely hypercholesterolemic HIV-infected children taking protease inhibitors (PIs) have been reported. Because high cholesterol levels (> or =15 mmol/L), as seen in homozygous familial hypercholesterolemia (FH), may lead to heart disease in childhood, the authors performed a systematic retrospective survey of all plasma lipid levels recorded for children who had received ritonavir or nelfinavir between 1995 and 2001 in Switzerland. Administration of PIs was associated with a significant increase in plasma cholesterol levels, which was more pronounced for those given ritonavir (from 3.3 +/- 0.7 mmol/L, n = 5 to 6.3 +/- 2.8 mmol/L, n = 19 [mean +/- SD]; p =.03) than for nelfinavir (from 3.0 +/- 0.7 mmol/L, n = 11 to 4.9 +/- 1.0 mmol/L, n = 30; p = <.001). Cholesterol levels exceeded 10.0 mmol/L in 3 of 49 (6%) PI-treated children and culminated at 13.8 mmol/L. Plasma cholesterol levels in PI-treated children were comparable with levels reported for heterozygous FH children but were all lower than in homozygous FH children. Because heterozygous FH patients usually develop heart disease in middle age, the authors conclude that the risk for heart disease in PI-treated children is minimal. Long-term monitoring of these children, however, will be necessary.

The role of risk factors in the development of atherosclerosis

Our understanding of risk factors for atherogenesis has changed significantly over the last decade. In addition to better grasp of the mechanism of action of the "classic" (causal) risk factors, a number of potentially important new factors has emerged. In this review we briefly summarize the evidence of the relation between atherosclerosis and the currently recognized causal risk factors, namely, age, smoking, LDL cholesterol, HDL cholesterol, hypertension, and diabetes. More emphasis has been put on description of the emerging entities such as atherogenic profile of plasma lipoproteins with discussion of LDL and HDL subclasses, Lp(a), homocysteine, and, last but not least, on the role of infection and inflammation in atherogenesis. Whenever possible, we tried to summarize the relevant lines of evidence such as epidemiological, pathological, genetic, and clinical trial data linking the specific factor with atherosclerosis.

Effects of low-density lipoprotein apheresis on coronary and carotid atherosclerosis and diabetic scleredema in patients with severe hypercholesterolemia

Correlations between serum cholesterol levels and progression of coronary and peripheral atherosclerosis have been found in many recent studies. It has also been demonstrated that aggressive cholesterol-lowering therapy with low-density lipoprotein (LDL) apheresis, a method of LDL elimination by extracorporeal circulation, is effective not only for coronary artery disease, but also for systemic circulatory disturbance in severe hypercholesterolemic patients with familial hypercholesterolemia (FH) in particular. We found that LDL apheresis treatment with medical therapy improved coronary atherosclerotic lesions, based on coronary angiography evaluation and histopathological observation, suppressed progression of early carotid atherosclerotic lesions on annual B-mode ultrasonography, and improved diabetic scleredema in FH patients. This effectiveness of LDL apheresis appears to be due to recovery of vascular endothelial function and improvement of blood rheology. For diseases that are possibly due to circulation disturbance and that are intractable with drugs alone. LDL apheresis may be worth trying, particularly for patients complicated by hyperlipemia.

Leg edema, ST-T abnormalities, and high BNP values are important signs of heart failure in the elderly

This study was aimed at the mechanism of the circulatory failure characteristic of the elderly through elucidating the cause of leg edema frequently found in patients under treatment in health care facilities for physical or mental handicaps. ECG and measurement of atrial (ANP) and brain (BNP) natriuretic peptides were carried out on 156 patients (mostly females aged 84 years on average) and echocardiographic assessment was done on 44 patients. Non-specific ST-T abnormalities were frequently found in patients with moderate or severe leg edema (61 vs. 37% in those with slight or no edema). BNP levels were markedly increased in patients with either leg edema or ECG abnormalities (Group B) and with both (Group C) compared with those without either (Group A), with averages of 35.5+/-23.9, 91.3+/-80.1, and 184.3+/-139.0 pg/ml, respectively, for Group A, B, and C. UCG examination revealed marked regurgitation of cardiac valves, more frequently in patients with BNP over 50 pg/ml than in those with less (14/24 vs. 2/20), with a difference in extent of 5.7 versus 1.6 on an arbitrary scale. In addition to left ventricular hypertrophy, dilatation of the left atrium and inferior vena cava was frequently observed in patients with higher BNP levels. It is concluded that both cardiac valve regurgitation and myocardial damage represented by ST-T abnormalities on ECG result in heart failure characteristic of the elderly, and that an increase in BNP is an important sign of such heart failure.

MR Virtual Angioscopy of Thoracic Aortic Atherosclerosis in Homozygous Familial Hypercholesterolemia

PURPOSE

The thoracic aorta is an important site of atherosclerotic disease in patients with homozygous familial hypercholesterolemia (HFH). Thoracic aortic atherosclerosis in patients with HFH was assessed with contrast-enhanced MR angiograms using exoscopic and endoscopic virtual angioscopy reconstructions and maximum intensity projections (MIPs).

METHOD

Contrast-enhanced MR angiograms of the thoracic aorta of 15 patients with HFH and 8 normal volunteers were obtained. Perspective surface reconstructions of the MR angiograms including virtual angioscopy views were evaluated by three radiologists blinded to the diagnosis.

RESULTS

Thoracic wall irregularity was depicted on 8 of 15 (53%) patient scans and only 1 of 8 (13%) normal subject scans using surface reconstructions. Wall irregularity scores of patients with HFH were significantly increased compared with controls (2.0 +/- 0.9 vs. 1.0 +/- 0.6; p = 0.008). There was excellent interobserver agreement (weighted kappa = 0.82 +/- 0.12). Virtual endoscopy views added diagnostic confidence compared with exoscopic surface renderings alone. MIP reconstructions were unable to depict wall irregularity.

CONCLUSION

MR angiography with virtual angioscopy of the thoracic aorta depicts nonstenotic wall irregularity of thoracic aortic atherosclerosis in patients with HFH. This may be important for assessing disease progression and response to treatment and may be generalizable to routine (non-HFH) atherosclerosis.

The effect of atorvastatin on serum lipids and lipoproteins in patients with homozyous familial hypercholesterolemia undergoing LDL-apheresis therapy

The efficacy of atorvastatin, a new hydroxymethylglutaryl (HMG)-CoA reductase inhibitor, in reducing serum lipid levels, modifying lipoprotein composition, and suppressing cholesterol synthesis was evaluated in patients with homozygous familial hypercholesterolemia (homozygous FH) undergoing LDL-apheresis therapy. Atorvastatin was given in escalating doses (10, 20, and 40 mg/day) to nine patients with homozygous FH. Five of nine patients responded well to atorvastatin; four of these patients were receptor-defective and the remaining one was receptor-negative. The change in LDL-cholesterol in the receptor-defective patients averaged -20.6% compared to the baseline level at the highest dose of atorvastatin. Of five receptor-negative type patients, only one showed good response to atorvastatin therapy with a LDL-cholesterol reduction of 14.9%. Although the other four receptor-negative patients did not show a change in LDL-cholesterol, all of them exhibited a considerable increase in HDL-cholesterol. All patients showed reduced urinary excretion of mevalonic acid, suggesting that atorvastatin decreases LDL-cholesterol by inhibiting cholesterol biosynthesis even where LDL-receptor activity is not present. Atorvastatin also decreased serum triglycerides in both receptor-negative and defective patients, especially in the latter. As cholesterol level rebounds quickly after each apheresis procedure, a combination therapy using atorvastatin and apheresis may increase the efficacy of the apheresis treatment, improving cost-benefit effectiveness by reducing the frequency of the apheresis treatment.