Effects of Liver Transplantation on Lipids and Cardiovascular Disease in Children With Homozygous Familial Hypercholesterolemia

Consensus document on diagnosis and management of familial hypercholesterolemia from the Italian Society for the Study of Atherosclerosis (SISA)

AIMS

Familial Hypercholesterolemia (FH) is a genetic disorder of lipoprotein metabolism that causes an increased risk of premature atherosclerotic cardiovascular disease (ASCVD). Although early diagnosis and treatment of FH can significantly improve the cardiovascular prognosis, this disorder is underdiagnosed and undertreated. For these reasons the Italian Society for the Study of Atherosclerosis (SISA) assembled a Consensus Panel with the task to provide guidelines for FH diagnosis and treatment.

DATA SYNTHESIS

Our guidelines include: i) an overview of the genetic complexity of FH and the role of candidate genes involved in LDL metabolism; ii) the prevalence of FH in the population; iii) the clinical criteria adopted for the diagnosis of FH; iv) the screening for ASCVD and the role of cardiovascular imaging techniques; v) the role of molecular diagnosis in establishing the genetic bases of the disorder; vi) the current therapeutic options in both heterozygous and homozygous FH. Treatment strategies and targets are currently based on low-density lipoprotein cholesterol (LDL-C) levels, as the prognosis of FH largely depends on the magnitude of LDL-C reduction achieved by lipid-lowering therapies. Statins with or without ezetimibe are the mainstay of treatment. Addition of novel medications like PCSK9 inhibitors, ANGPTL3 inhibitors or lomitapide in homozygous FH results in a further reduction of LDL-C levels. LDL apheresis is indicated in FH patients with inadequate response to cholesterol-lowering therapies.

CONCLUSION

FH is a common, treatable genetic disorder and, although our understanding of this disease has improved, many challenges still remain with regard to its identification and management.

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.

Long-term outcomes of liver transplantation for homozygous familial hypercholesterolaemia in Australia and New Zealand

BACKGROUND AND AIMS

Homozygous familial hypercholesterolaemia (FH) causes severe cardiovascular disease from childhood. Conventional drug therapy is usually ineffective; lipoprotein apheresis (LA) is often required. Liver transplantation (LT) can correct the metabolic defect but is considered a treatment of last resort. Newer drugs including lomitapide and evinacumab might reduce the need for apheresis and LT. We sought to determine the long-term outcomes following LT in Australia and New Zealand.

METHODS

We analysed demographic, biochemical and clinical data from all patients in Australia and New Zealand who have received LT for homozygous FH, identified from the Australia and New Zealand Liver and Intestinal Transplant Registry.

RESULTS

Nine patients (five female; one deceased; seven aged between 3 and 6 years at the time of LT and two aged 22 and 26 years) were identified. Mean follow-up was 14.1 years (range 4-27). Baseline LDL-cholesterol off all treatment was 23 ± 4.1 mmol/L. Mean LDL-cholesterol on medical therapy (including maximal statin therapy in all patients, ezetimibe in three and LA in five) was 11 ± 5.7 mmol/L (p < 0.001). After LT, mean LDL-cholesterol was 2.6 ± 0.9 mmol/L (p = 0.004) with three patients remaining on statin therapy and none on LA. One patient died from acute myocardial infarction (AMI) three years after LT. Two patients required aortic valve replacement, more than 10 years after LT. The remaining six patients were asymptomatic after eight to 21 years of follow-up. No significant adverse events associated with immunosuppression were reported.

CONCLUSIONS

LT for homozygous FH was highly effective in achieving substantial long-term reduction in LDL-cholesterol concentrations in all nine patients. LT remains an option for severe cases of homozygous FH where drug therapy combined with apheresis is ineffective or unfeasible.

International Atherosclerosis Society guidance for implementing best practice in the care of familial hypercholesterolaemia

This contemporary, international, evidence-informed guidance aims to achieve the greatest good for the greatest number of people with familial hypercholesterolaemia (FH) across different countries. FH, a family of monogenic defects in the hepatic LDL clearance pathway, is a preventable cause of premature coronary artery disease and death. Worldwide, 35 million people have FH, but most remain undiagnosed or undertreated. Current FH care is guided by a useful and diverse group of evidence-based guidelines, with some primarily directed at cholesterol management and some that are country-specific. However, none of these guidelines provides a comprehensive overview of FH care that includes both the lifelong components of clinical practice and strategies for implementation. Therefore, a group of international experts systematically developed this guidance to compile clinical strategies from existing evidence-based guidelines for the detection (screening, diagnosis, genetic testing and counselling) and management (risk stratification, treatment of adults or children with heterozygous or homozygous FH, therapy during pregnancy and use of apheresis) of patients with FH, update evidence-informed clinical recommendations, and develop and integrate consensus-based implementation strategies at the patient, provider and health-care system levels, with the aim of maximizing the potential benefit for at-risk patients and their families worldwide.

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.

Recent advances in the management and implementation of care for familial hypercholesterolaemia

Familial hypercholesterolaemia (FH) is a common autosomal semi-dominant and highly penetrant disorder of the low-density lipoprotein (LDL) receptor pathway, characterised by lifelong elevated levels of low-density lipoprotein cholesterol (LDL-C) and increased risk of atherosclerotic cardiovascular disease (ASCVD). However, many patients with FH are not diagnosed and do not attain recommended LDL-C goals despite maximally tolerated doses of potent statin and ezetimibe. Over the past decade, several cholesterol-lowering therapies such as those targeting proprotein convertase subtilisin/kexin type 9 (PCSK9) or angiopoietin-like 3 (ANGPTL3) with monoclonal antibody or ribonucleic acid (RNA) approaches have been developed that promise to close the treatment gap. The availability of new therapies with complementary modes of action of lipid metabolism has enabled many patients with FH to attain guideline-recommended LDL-C goals. Emerging therapies for FH include liver-directed gene transfer of the LDLR, vaccines targeting key proteins involved in cholesterol metabolism, and CRISPR-based gene editing of PCSK9 and ANGPTL3, but further clinical trials are required. In this review, current and emerging treatment strategies for lowering LDL-C, and ASCVD risk-stratification, as well as implementation strategies for the care of patients with FH are reviewed.

2023 Update on European Atherosclerosis Society Consensus Statement on Homozygous Familial Hypercholesterolaemia: new treatments and clinical guidance

This 2023 statement updates clinical guidance for homozygous familial hypercholesterolaemia (HoFH), explains the genetic complexity, and provides pragmatic recommendations to address inequities in HoFH care worldwide. Key strengths include updated criteria for the clinical diagnosis of HoFH and the recommendation to prioritize phenotypic features over genotype. Thus, a low-density lipoprotein cholesterol (LDL-C) >10 mmol/L (>400 mg/dL) is suggestive of HoFH and warrants further evaluation. The statement also provides state-of-the art discussion and guidance to clinicians for interpreting the results of genetic testing and for family planning and pregnancy. Therapeutic decisions are based on the LDL-C level. Combination LDL-C-lowering therapy-both pharmacologic intervention and lipoprotein apheresis (LA)-is foundational. Addition of novel, efficacious therapies (i.e. inhibitors of proprotein convertase subtilisin/kexin type 9, followed by evinacumab and/or lomitapide) offers potential to attain LDL-C goal or reduce the need for LA. To improve HoFH care around the world, the statement recommends the creation of national screening programmes, education to improve awareness, and management guidelines that account for the local realities of care, including access to specialist centres, treatments, and cost. This updated statement provides guidance that is crucial to early diagnosis, better care, and improved cardiovascular health for patients with HoFH worldwide.

Contemporary Homozygous Familial Hypercholesterolemia in the United States: Insights From the CASCADE FH Registry

Background Homozygous familial hypercholesterolemia (HoFH) is a rare, treatment-resistant disorder characterized by early-onset atherosclerotic and aortic valvular cardiovascular disease if left untreated. Contemporary information on HoFH in the United States is lacking, and the extent of underdiagnosis and undertreatment is uncertain. Methods and Results Data were analyzed from 67 children and adults with clinically diagnosed HoFH from the CASCADE (Cascade Screening for Awareness and Detection) FH Registry. Genetic diagnosis was confirmed in 43 patients. We used the clinical characteristics of genetically confirmed patients with HoFH to query the Family Heart Database, a US anonymized payer health database, to estimate the number of patients with similar lipid profiles in a "real-world" setting. Untreated low-density lipoprotein cholesterol levels were lower in adults than children (533 versus 776 mg/dL; P=0.001). At enrollment, atherosclerotic cardiovascular disease and supravalvular and aortic valve stenosis were present in 78.4% and 43.8% and 25.5% and 18.8% of adults and children, respectively. At most recent follow-up, despite multiple lipid-lowering treatment, low-density lipoprotein cholesterol goals were achieved in only a minority of adults and children. Query of the Family Heart Database identified 277 individuals with profiles similar to patients with genetically confirmed HoFH. Advanced lipid-lowering treatments were prescribed for 18%; 40% were on no lipid-lowering treatment; atherosclerotic cardiovascular disease was reported in 20%; familial hypercholesterolemia diagnosis was uncommon. Conclusions Only patients with the most severe HoFH phenotypes are diagnosed early. HoFH remains challenging to treat. Results from the Family Heart Database indicate HoFH is systemically underdiagnosed and undertreated. Earlier screening, aggressive lipid-lowering treatments, and guideline implementation are required to reduce disease burden in HoFH.

Homozygous Familial Hypercholesterolemia in Canada: An Observational Study

Background

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disease characterized by very high levels of low-density lipoprotein cholesterol (LDL-C). Untreated patients present with extensive xanthomas and premature atherosclerosis. Lipid-lowering therapy is highly efficacious and has dramatically increased life expectancy of patients with HoFH.

Objectives

The aim of the study was to obtain a comprehensive registry of HoFH in Canada, known to have several founder effect regions, and describe the clinical characteristics and cardiovascular outcomes of this population over time.

Methods

Clinical and genetic data on patients with HoFH were collected via a standardized questionnaire sent to academic sites participating in the Familial Hypercholesterolemia Canada network.

Results

A total of 48 patients with HoFH were enrolled. The median age at diagnosis was 12 years (interquartile range [IQR]: 5-24) and untreated LDL-C levels were 15.0 mmol/L (IQR: 10.5-18.6 mmol/L; 580 mg/dL IQR: 404-717 mg/dL). At last follow-up visit, median age was 40 years (IQR: 26-54 years). Treated LDL-C levels were 6.75 mmol/L (IQR: 4.73-9.51 mmol/L; 261 mg/dL IQR: 183-368 mg/dL) with 95.5% of patients on statins, 88.6% on ezetimibe, 34.1% on proprotein convertase subtilisin/kexin type 9 inhibitors, 27.3% on lomitapide, 13.6% on evinacumab, and 56.8% were treated with low-density lipoprotein apheresis or plasmapheresis. Deaths were reported in 7 (14.5%) and major adverse cardiovascular events were observed in 14.6% of patients with the average onset at 30 years (IQR: 20-36 years). Aortic stenosis was reported in one-half the patients (47.9%) and 10 (20.8%) underwent aortic valve replacement.

Conclusions

This HoFH patient registry in Canada will provide important new health-related knowledge about the phenotypic manifestations and determinants of cardiovascular risk in this population, allowing for closer examination of quality of life and burden to the health care system.

Concurrent Living Donor Liver Transplantation and Off-Pump Coronary Artery Bypass in a Five-Year-Old Child With Homozygous Familial Hypercholesterolemia: A Case Report

BACKGROUND

Homozygous familial hypercholesterolemia (FH) is a rare disease that causes serious cardiovascular problems and may be fatal even at an early age. Because this disease variant is rather aggressive, the effect of lipid-lowering agents and lipid apheresis remains inadequate in most cases. In patients who are not responding or tolerating available treatments, liver transplantation (LT) is the last and definitive solution. In addition to LT, the need for cardiac surgery is often substantial.

CASE REPORT

This study presents the first pediatric case of FH who underwent off-pump coronary artery bypass (OPCAB) surgery concurrent with live-donor LT (LDLT). The early postoperative period was uneventful. After a 1-year follow-up period, the patient is alive and well with normal liver functions and cholesterol levels remaining within the normal range without any lipid-lowering medical therapy.

CONCLUSION

Performing simultaneous coronary bypass and LT may be safe and feasible even for pediatric patients.

Current Treatment Options in Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is the rare form of familial hypercholesterolemia causing extremely high low-density lipoprotein cholesterol (LDL-C) levels, leading to atherosclerotic cardiovascular disease (ASCVD) in the first decades of life, if left untreated. Early diagnosis and effective lipid lowering therapy (LLT) are crucial for the prevention of early ASCVD in patients with HoFH. On-treatment LDL-C levels are the best predictor of survival. However, due to the absent or defective LDL-receptor activity, most individuals with HoFH are resistant to conventional LLT, that leads to LDL-C clearance by upregulating LDL-receptors. We are at the dawn of a new era of effective pharmacotherapies for HoFH patients, with new agents providing an LDL-receptor independent cholesterol reduction. In this context, the present review provides a summary of the currently available therapies and emerging therapeutic agents for the management of patients with HoFH, in light of recent evidence and guideline recommendations.

Perioperative Management and Clinical Outcomes of Liver Transplantation for Children with Homozygous Familial Hypercholesterolemia

Background and Objectives: Liver transplantation (LT) has been accepted as a life-saving option as a last resort for children with homozygous familial hypercholesterolemia (HoFH). Perioperative management of LT for HoFH poses extra challenges for clinicians largely due to premature atherosclerotic cardiovascular diseases (ASCVDs). We aimed to analyze our data of pediatric LT recipients with HoFH, with special attention paid to perioperative management and clinical outcomes. Materials and Methods: After obtaining approval from the local ethics committee, the clinical data of pediatric patients with HoFH who underwent LT at our institution between January 2014 and February 2021 were retrospectively studied. Results: Six pediatric LT recipients with HoFH were included in the analysis. Although ASCVDs were common before LT, all children with HoFH survived the perioperative period without in-hospital mortality. However, one patient experienced acute myocardial infarction two months following LT and was successfully treated with medical interventions. Post-LT metabolic improvement was shown by declines in serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) levels in the early post-LT period (for TC: 14.7 ± 3.2 mmol/L vs. 5.5 ± 1.8 mmol/L, p < 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 3.6 ± 1.2 mmol/L, p < 0.001, respectively) and at the last follow-up (for TC: 14.7 ± 3.2 mmol/L vs. 4.5 ± 0.9 mmol/L, p = 0.001; for LDL-C: 10.6 ± 2.2 mmol/L vs. 2.8 ± 0.6 mmol/L, p = 0.001, respectively). Dietary restrictions could be lifted after LT. However, three patients required restarting lipid-lowering therapy after LT due to suboptimal LDL-C levels and progression of ASCVDs. Conclusions: Our data suggest that LT can be a safe and feasible therapeutic option for well-selected patients with HoFH, offering relaxed dietary restrictions and remarkable reductions in LDL-C levels. However, concerns remain regarding progression of ASCVDs after LT.

From supravalvular to valvular aortic stenosis: are statins contributing to the phenotypic shift in homozygous familial hypercholesterolaemia?

Graphical Abstract LLT, lipid lowering therapies; Lp(a), lipoprotein(a); VAS, valvular aortic stenosis; SVAS, supravalvular aortic stenosis.

Aortic stenosis in homozygous familial hypercholesterolaemia: a paradigm shift over a century

AIMS

Homozygous familial hypercholesterolaemia (HoFH) is an orphan disease defined by extreme elevations in low-density lipoprotein cholesterol, cutaneous xanthomas, and pre-mature atherosclerotic cardiovascular disease. Survival has more than doubled over the past three decades. Aortic stenosis (AS) [supravalvular aortic stenosis (SVAS) or valvular aortic stenosis (VAS)] is commonly encountered. There are no medical treatments available and complex high-risk surgeries represent the only available option in severe cases. A systematic review was performed to summarize the current evidence on AS in HoFH and to determine whether pharmacological treatment (statins) have had an impact on clinical presentation, phenotype and clinical course over the past nine decades (PROSPERO CRD42021250565).

METHODS AND RESULTS

MEDLINE, Embase Classic + Embase, Cochrane Central Register of Controlled Trials, PubMed, AfricaWide, and Scopus were searched from inception to 10 November 2021. Searches identified 381 publications, of which 19 were retained; they were cross-sectional or retrospective studies. Separately, 108 individual case reports were described. Within the 424 HoFH cases, AS was identified in 57% of patients in the pre-statin era vs. 35% in patients reported more recently (>2000, long-term statin period). With an increase in longevity due to statins and lipoprotein apheresis, a change in the proportion of patients with SVAS and VAS with a SVAS:VAS ratio of 47:53 and 10:90 for HoFH patients not on statin and on long-term statin, respectively, was noted.

CONCLUSION

These data suggest that SVAS and VAS are frequent in HoFH and that the phenotype has shifted towards calcific VAS as statins and lipoprotein apheresis improve survival in these patients.

Is Liver Transplant Curative in Homozygous Familial Hypercholesterolemia? A Review of Nine Global Cases

INTRODUCTION

Homozygous familial hypercholesterolemia (HoFH) is a rare, life-threatening, inherited condition characterized by extremely elevated levels of low-density lipoprotein cholesterol (LDL-C). Patients are at high risk of atherosclerotic cardiovascular disease, adverse cardiovascular events, and associated early mortality. Liver transplant is sometimes used with curative intent. The objective of the current case series was to evaluate the follow-up of a range of patients who have undergone liver transplant for the treatment of HoFH.

METHODS

Patients with clinical and/or genetic diagnoses of HoFH were treated according to local practices in four units in Europe and the Middle East. All patients underwent liver transplantation. Baseline and long-term follow-up data were collected, including LDL-C levels, DNA mutations, lipid-lowering medications, and complications due to surgery and immunosuppressive therapy.

RESULTS

Nine patients were included with up to 22 years' follow-up (mean ± SD 11.7 ± 11.7 years; range 0.5-28 years). Three of the patients died as a result of complications of transplant surgery (mortality rate 33%). Among the surviving six patients, four required continued lipid-lowering therapy (LLT) to maintain LDL-C levels and two patients show signs of increasing LDL-C levels that require management. One case (11%) required two consecutive transplants to achieve a viable graft and is awaiting a third transplant because of graft failure.

CONCLUSIONS

Liver transplant did not enable attainment of recommended LDL-C targets in most patients with HoFH, and the majority of patients still required post-transplant LLT. Liver transplant was not curative in most of the patients with HoFH followed. Guidelines suggest that transplant is a treatment of last resort if contemporary treatments are not available or possible.

Advancements in the Treatment of Homozygous Familial Hypercholesterolemia

Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder with extreme elevations of low-density lipoprotein cholesterol (LDL-C) leading to premature atherosclerotic cardiovascular disease (ASCVD) as early as in childhood. Management of HoFH centers around aggressive and adequate reduction of LDL-C levels to slow the trajectory of ASCVD development. Historically, lowering LDL-C levels in HoFH has been challenging because of both the markedly elevated LDL-C levels (often ＞400 mg/dL) and reduced response to treatment options, such as statins, for which the mechanism of action requires a functional LDL receptor. However, the treatment landscape for HoFH has rapidly progressed over the last decade. While statins and ezetimibe remain first-line treatment, patients often require addition of multiple therapies to achieve goal LDL-C levels. The PCSK9 inhibitors are an important recent addition to the available treatment options, along with lomitapide, bile acid sequestrants, and, possibly, bempedoic acid. Additionally, ANGPTL3 has emerged as an important therapeutic target, with evinacumab being the first available ANGPTL3 inhibitor on the market for the treatment of patients with HoFH. For patients who cannot achieve adequate LDL-C reduction, lipoprotein apheresis may be necessary, with the added benefit of reducing lipoprotein(a) levels that carries an added risk if also elevated in patients with HoFH. Finally, gene therapy and genome editing using CRISPR/Cas-9 are moving through clinical development and may dramatically alter the future landscape of treatment for HoFH.

Novel therapies for familial hypercholesterolemia

PURPOSE OF REVIEW

Familial hypercholesterolemia is a genetic disorder of defective clearance and subsequent increase in serum LDL cholesterol (LDL-C) with a resultant increased risk of premature atherosclerotic cardiovascular disease. Despite treatment with traditional lipid-lowering therapies (LLT), most patients with familial hypercholesterolemia are unable to achieve target LDL-C. We review current and future novel therapeutic options available for familial hypercholesterolemia.

RECENT FINDINGS

The use of proprotein convertase subtilisin kexin type 9 (PCSK9) inhibitors are effective in lowering LDL-C in patients with familial hypercholesterolemia, with a reduction in LDL-C of 60% in heterozygous familial hypercholesterolemia (HeFH) and up to 35% in homozygous familial hypercholesterolemia (HoFH). Inclisiran, another novel agent, is a small-interfering ribonucleic acid that reduces hepatic production of PCSK9 to provide a prolonged and sustained reduction in LDL-C of nearly 50% in HeFH. However, both agents require LDL receptor (LDLR) activity. Evinacumab, a novel monoclonal antibody against angiopoetin-like 3 (ANGPTL3), reduces LDL-C by 50% independent of LDLR activity.

SUMMARY

Achieving a target LDL-C in familial hypercholesterolemia can be challenging with standard LLT; however, novel therapeutic modalities show remarkable reductions in LDL-C allowing nearly all patients with HeFH and a significant proportion of patients with HoFH to achieve acceptable LDL-C levels.

Calcified Aortic Valve Disease in Patients With Familial Hypercholesterolemia

Familial hypercholesterolemia (FH) is a rare autosomal gene deficiency disease with increased low-density lipoprotein cholesterol, xanthoma, and premature coronary heart disease. Calcified aortic valve disease (CAVD) is prevalent in FH patients, resulting in adverse events and heavy health care burden. Aortic valve calcification is currently considered an active biological process, which shares several common risk factors with atherosclerosis, including aging, hypertension, dyslipidemia, and so on. Unfortunately, the pathogenesis and therapy of CAVD in FH are still controversial. There is no pharmacological intervention recommended to delay the development of CAVD in FH, and the only effective treatment for severe CAVD is aortic valve replacement. In this review, we summarize the detailed description of the pathophysiology, molecular mechanism, risk factors, and treatment of CAVD in FH patients.

Case Report: Liver Transplantation in Homozygous Familial Hypercholesterolemia (HoFH)-Long-Term Follow-Up of a Patient and Literature Review

Homozygous familial hypercholesterolemia (HoFH) is a rare inherited metabolic disorder, frequently leading to an early cardiovascular death if not adequately treated. Since standard medications usually fail to reduce LDL-cholesterol (LDL-C) levels satisfactorily, LDL-apheresis is a mainstay of managing HoFH patients but, at the same time, very burdensome and suboptimally effective. Liver transplantation (LT) has been previously shown to be a promising alternative. We report on a 14 year-long follow-up after LT in a HoFH patient. At the age of 4, the patient was referred to our institution because of the gradually increasing number of xanthomas on the knees, elbows, buttocks, and later the homozygous mutation c.1754T>C (p.Ile585Thr) on the LDL-receptor gene was confirmed. Despite subsequent intensive treatment with the combination of diet, statins, bile acid sequestrant, probucol, and LDL-apheresis, the patient developed valvular aortic stenosis and aortic regurgitation by 12 years. At 16 years, the patient successfully underwent deceased-donor orthotopic LT. Nine years post-LT, we found total regression of the cutaneous xanthomas and atherosclerotic plaques and with normal endothelial function. Fourteen years post-LT, his clinical condition remained stable, but LDL-C levels have progressively risen. In addition, a systematic review of the literature and guidelines on the LT for HoFH patients was performed. Six of the 17 identified guidelines did not take LT as a treatment option in consideration at all. But still the majority of guidelines suggest LT as an exceptional therapeutic option or as the last resort option when all the other treatment options are inadequate or not tolerated. Most of the observed patients had some kind of cardiovascular disease before the LT. In 76% of LT, the cardiovascular burden did not progress after LT. According to our experience and in several other reported cases, the LDL-C levels are slowly increasing over time post LT. Most of the follow-up data were short termed; only a few case reports have followed patients for 10 or more years after LT. LT is a feasible therapeutic option for HoFH patients, reversing atherosclerotic changes uncontrollable by conservative therapy, thus importantly improving the HoFH patient's prognosis and quality of life.

Familial Hypercholesterolaemia in 2020: A Leading Tier 1 Genomic Application

Familial hypercholesterolaemia (FH) is caused by a major genetic defect in the low-density lipoprotein (LDL) clearance pathway. Characterised by LDL-cholesterol elevation from birth, FH confers a significant risk for premature coronary artery disease (CAD) if overlooked and untreated. With risk exposure beginning at birth, early detection and intervention is crucial for the prevention of CAD. Lowering LDL-cholesterol with lifestyle and statin therapy can reduce the risk of CAD. However, most individuals with FH will not reach guideline recommended LDL-cholesterol targets. FH has an estimated prevalence of approximately 1:250 in the community. Multiple strategies are required for screening, diagnosing and treating FH. Recent publications on FH provide new data for developing models of care, including new therapies. This review provides an overview of FH and outlines some recent advances in the care of FH for the prevention of CAD in affected families. The future care of FH in Australia should be developed within the context of the National Health Genomics Policy Framework.

Coronary artery disease in a child with homozygous familial hypercholesterolemia: Regression after liver transplantation

Children with homozygous familial hypercholesterolemia are at risk for early cardiovascular events secondary to coronary artery disease. Current medical therapy does not ameliorate this risk. Liver transplantation offers the most effective option to reduce circulating levels of low-density lipoprotein cholesterol and thereby reduce risk of cardiovascular events. Angiographic evidence of regression of coronary artery disease is presented.

Liver Transplantation for Homozygous Familial Hypercholesterolemia

Pharmacological treatments to decrease low-density lipoprotein (LDL) cholesterol (LDL-C) have limited effects on patients with homozygous familial hypercholesterolemia (HoFH). Since LDL receptors are located mainly in the liver, liver transplantation is considered to be the only way to correct the hepatic cholesterol metabolism abnormalities in HoFH. Liver transplantations, including those combined with heart transplantation, for HoFH have been increasing since 1984, making this a globally established therapeutic option for HoFH. Plasma LDL-C is reported to be dramatically lowered, by 80%, after transplantation, with the rapid regression of cutaneous and tendinous xanthomas. However, long-term cardiovascular benefits remain unclear. The major concerns about liver transplantation include surgical complications, the need for lifelong immunosuppressive therapy, and rejection. In addition, organ transplantations from deceased donors are extremely rare in Japan. We experienced two pediatric siblings with HoFH who received living-donor liver transplantations from their heterozygous parents. Their plasma LDL-C levels decreased immediately and stabilized at approximately 200 mg/dL. Both developed normally with the administration of lipid-lowering medications and have been free of severe problems for more than 10 years, to date, since transplantation. In Japan, where the shortage of deceased donors is critical, the combination of living-donor liver transplant from a heterozygous donor, that is, usually a parent, and medication is regarded as a valid therapeutic option for HoFH. Further studies and clinical experience are required to establish liver transplantation as a safe and effective treatment for HoFH.

Familial Hypercholesterolemia: New Horizons for Diagnosis and Effective Management

Familial hypercholesterolemia (FH) is a common genetic cause of premature cardiovascular disease (CVD). The reported prevalence rates for both heterozygous FH (HeFH) and homozygous FH (HoFH) vary significantly, and this can be attributed, at least in part, to the variable diagnostic criteria used across different populations. Due to lack of consistent data, new global registries and unified guidelines are being formed, which are expected to advance current knowledge and improve the care of FH patients. This review presents a comprehensive overview of the pathophysiology, epidemiology, manifestations, and pharmacological treatment of FH, whilst summarizing the up-to-date relevant recommendations and guidelines. Ongoing research in FH seems promising and novel therapies are expected to be introduced in clinical practice in order to compliment or even substitute current treatment options, aiming for better lipid-lowering effects, fewer side effects, and improved clinical outcomes.

Homozygous familial hypercholesterolaemia: update on management

Homozygous familial hypercholesterolaemia (HoFH) is an inherited disease causing an approximately fourfold increase in blood low-density lipoprotein cholesterol (LDLC) from birth compared with the age-matched normal population owing to reduced low-density lipoprotein receptor (LDLR) activity. Such elevated cholesterol is associated with accelerated atheromatous disease, particularly of the aortic root and coronary arteries. However, HoFH is clinically heterogeneous, reflecting residual low-density lipoprotein receptor (LDLR) activity. The main objective in treating children may be stated to be the avoidance of irreversible cardiac damage requiring heart transplantation by sufficient lowering of blood cholesterol. Lipoprotein apheresis or plasmapheresis are safe means of lowering cholesterol but may be insufficient on their own. Statin drugs, PCSK9 inhibitors ezetimibe and bile acid sequestrants are relatively ineffective if LDLR activity is lacking, but should be used if effective. Two new drugs, lomitapide and mipomersen, have been licensed specifically for HoFH by some regulatory authorities. They work by reducing LDL production rate. They have been associated with fatty liver in adults. Evidence of safety in children is lacking. An alternative is liver transplantation, which replaces the missing LDLR and normalises cholesterol. Clinicians are faced with a dilemma in choosing between these options or deferring such treatment associated with potential harm. Individual case descriptions are an important means of informing clinical judgement. Management of the two cases described in this issue is discussed in the light of modern developments in transplantation and pharmacotherapy.