LDL apheresis in Japan

LDL apheresis has been developed as the treatment for refractory familial hypercholesterolemia (FH). Currently, plasma exchange, double membrane filtration, and selective LDL adsorption are available in Japan, and selective LDL adsorption is most common method. LDL apheresis can prevent atherosclerosis progression even in homozygous (HoFH). However, in our observational study, HoFH who started LDL apheresis from adulthood had poor prognosis compared with patients who started from childhood. Therefore, as far as possible, HoFH patients need to start LDL apheresis from childhood. Although indication of LDL apheresis in heterozygous FH (HeFH) has been decreasing with the advent of strong statin, our observational study showed that HeFH patients who were discontinued LDL apheresis therapy had poor prognosis compared with patients who were continued apheresis therapy. These results suggest that high risk HeFH need to be treated by LDL apheresis even if their LDLC is controlled by lipid-lowering agents. However, by launching new class of lipid lowering agents, that is, PCSK-9 antibody and MTP inhibitor, indication of LDL-apheresis in FH may be changed near the future. LDL-apheresis can provide symptom relief of peripheral artery disease (PAD). Therefore, PAD patients who have insufficient effect by other therapeutic approach including revascularization are also treated by LDL apheresis. Thus, LDL apheresis is still one of good therapeutic options for severe atherosclerotic diseases in Japan.     

The role of low density lipoprotein apheresis in the treatment of familial hypercholesterolemia.

The chief indication for low density lipoprotein (LDL) apheresis is the treatment of homozygous familial hypercholesterolemia (FH), a potentially fatal condition that responds poorly to conventional therapy. Dextran sulfate/cellulose adsorption columns (Kaneka) and on-line heparin precipitation (HELP) are the most popular systems used in LDL apheresis. Weekly or biweekly procedures plus concomitant drug therapy enable LDL cholesterol to be maintained at 30-50% of its untreated level, with regression of xanthomas, arrest of progression of coronary atherosclerosis, and improved life expectancy. However, aortic stenosis may progress despite apheresis and necessitate valve replacement. Better control of hypercholesterolemia results from combining apheresis with a new 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, atorvastatin. LDL apheresis can also be useful in treating drug-resistant FH heterozygotes with coronary disease. However, the FH Regression Study showed no evidence that reduction by apheresis of both LDL and lipoprotein(a), was more advantageous than reduction by combination drug therapy of LDL alone.     

Treatment of hypercholesterolemia with heparin-induced extracorporeal low-density lipoprotein precipitation (HELP)

Familial hypercholesterolemia (FH) can cause early disability and death from premature atherosclerotic cardiovascular disease. Patients homozygous for the disease have very high plasma cholesterol, extensive xanthomatosis, and die from atherosclerosis in childhood or early adulthood. Past attempts to improve the prognosis included removal of cholesterol from the circulation by ileal bypass or biliary diversion. Neither treatment was successful. Direct removal by plasmapheresis of low-density lipoprotein (LDL), the primary carrier of cholesterol in plasma, was first performed on an FH homozygous patient in 1966. The treatment was well tolerated and led to rapid diminution of xanthomas. Other experimental treatments included selective LDL apheresis with monoclonal or polyclonal antibody affinity columns. A method for selective LDL apheresis was developed in 1983 by Armstrong, Seidel, and colleagues based on heparin precipitation of LDL at low pH. This method, called HELP, removes all apolipoprotein B-containing lipoproteins including LDL and lipoprotein (a), as well as some fibrinogen. LDL apheresis by HELP is well tolerated; the incidence of side effects is low, and the treatment has been associated with regression of cardiovascular disease. LDL apheresis, rather than liver transplantation, is the treatment of choice for patients with severe, life-threatening hypercholesterolemia which does not respond to diet and drug therapy. © 1996 Wiley-Liss, Inc.     

Low-density lipoprotein apheresis for the treatment of refractory hyperlipidemia

The advent of treatment with 3-hydroxy-3-methylglutaryl coenzyme A inhibitors has meant that, with a combination of diet and drug therapy, adequate control of serum cholesterol concentrations can be achieved in most patients with hypercholesterolemia. However, some patients, primarily those with familial hypercholesterolemia (FH), may require additional therapy to lower their cholesterol levels. In recent years, low-density lipoprotein (LDL) apheresis has emerged as an effective method of treatment in these patients. The criteria for commencement of LDL apheresis are LDL cholesterol levels of 500 mg/dL or higher for homozygous FH patients, 300 mg/dL or higher for heterozygous FH patients in whom medical therapy has failed, and 200 mg/dL or higher for heterozygous FH patients with documented coronary disease and in whom medical therapy has failed. In addition to cholesterol lowering in patients with FH, other indications for LDL apheresis are emerging. These include its use in the treatment of graft vascular disease in patients receiving cardiac transplants as well as in the treatment of certain glomerulonephritides. This review examines the role of LDL apheresis in the management of lipid disorders and the evidence available to support its use in clinical practice.     

Lipid apheresis, indications, and principles

Low-density lipoprotein apheresis (LDL apheresis) is a term that describes a group of apheresis techniques and devices that selectively remove apolipoprotein B containing lipoproteins. A number of different devices are available worldwide, which all effectively remove low-density lipoprotein cholesterol while sparing other important plasma components. LDL apheresis is used to treat familial hypercholesterolemia (FH), an inherited condition of accelerated atherosclerosis and severe coronary artery disease resulting in premature death. It has also been used to treat other disorders, although the evidence for its use is limited. This review describes the underlying pathophysiology of FH, the mechanism of action of the various LDL apheresis devices available, and how LDL apheresis is used to treat this uncommon metabolic condition.     

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.     

The effect of selective low-density lipoprotein apheresis on plasma lipoperoxides and antioxidant vitamins in familial hypercholesterolemic patients.

Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder characterized by a lifelong elevation in the concentration of low-density lipoprotein (LDL) bound cholesterol in blood by cholesterol deposits and by early coronary artery disease. The LDL apheresis technique has been introduced with the goal of reducing LDL cholesterol levels, thereby preventing the development of atherosclerosis. The literature on LDL apheresis reports 2 different facets, the therapeutic aspect associated with the lessening of LDL concentration and the initiation of a peroxidation process associated with the biocompatibility of the artificial membrane. Lipid and protein peroxidation gives rise to toxic and atherogenic hydroperoxide, mostly lipid hydroperoxides, and derivative compounds, which may offset the benefit of the procedure. In this paper, plasma hydroperoxide levels are determined along with the elevation of the serum and LDL antioxidant status in hypercholesterolemic patients before and following repeated LDL apheresis sessions. Hydroperoxide concentration has been expressed both in terms of plasma volume and LDL concentration. A highly significant increase in LDL lipid hydroperoxides is demonstrated when expressed in terms of LDL concentration and is associated with the LDL apheresis procedure. The usefulness of antioxidant supplementation in LDL apheresis is discussed.     

The retardation of progression, stabilization, and regression of coronary and carotid atherosclerosis by low-density lipoprotein apheresis in patients with familial hypercholesterolemia.

The long-term effects of low-density lipoprotein (LDL) apheresis (LA) on the progression and regression of atherosclerosis were evaluated by angiographic and pathological findings as well as ultrasonography based studies, and the clinical significance of the treatment was evaluated. We studied 11 patients with familial hypercholesterolemia (FH), 2 with homozygous FH and 9 with severe heterozygous FH who received combined LA and drug therapy for a mean of 7.7 years. During the treatment period, the mean time-averaged level of LDL cholesterol was 181+/-52 mg/dl. According to the coronary angiographic results, 3 patients showed regression, 6 patients showed progression, and 2 patients showed no change. Cardiac events occurred in 6 patients. We pathologically examined at autopsy the coronary arteries of 1 FH patient who had received long-term LA therapy before death. The results revealed the process of scarring of atheromatous plaque, suggesting pathological regression correlated with the angiographic regression shown in serial angiograms taken during LA treatment. It was further suggested that the formation of an eccentric thick end wall lesion rich in collagen fiber prevented atheromatous plaque from tearing off. However, the annual progression rate of the mean maximal intima-media thickness in the common carotid artery was 0.0002 mm/year in the LA group, which was significantly lower than the mean of 0.251 mm/year seen in the control group (drug therapy only group). In the patients with heterozygous FH (9 patients), the annual progression rate was lowered to 0.0023 mm/year, suggesting regression. The findings of the present study indicate that patients with severe FH refractory to drug treatment may benefit from more aggressive cholesterol lowering treatments such as LA combined with cholesterol lowering drug therapy. The progression of atherosclerosis may be prevented, plaque may be stabilized (regressed), and clinical events may be reduced as seen with patients with non-FH hypercholesterolemia.     

Ex vivo gene therapy of familial hypercholesterolemia.

Familial hypercholesterolemia (FH) is an autosomal dominant disorder caused by a deficiency in the receptor that clears low density lipoprotein (LDL) from the serum (reviewed in Ref. 1 and 2). Patients with one abnormal LDL receptor allele have moderate elevations in plasma LDL and suffer premature coronary artery disease (CAD). Approximately 5% of all patients under 45 who have had a myocardial infarction carry this trait. Patients with two abnormal LDL receptor genes (homozygous deficient patients) have severe hypercholesterolemia and life-threatening coronary artery disease in childhood. Strategies for treating patients with FH are directed at lowering the plasma level of LDL. In heterozygotes, this is accomplished through the administration of drugs that stimulate the expression of LDL receptor from the normal allele (2). This therapeutic approach is not effective in the treatment of homozygous deficient patients, especially those that retain less than 2% of residual LDL receptor activity. Partial amelioration of hyperlipidemia has been achieved in some homozygous deficient patients by diverting the portal circulation through a portacaval anastomosis (3) and by chronic plasmapheresis therapy (4). A more direct approach has been to correct the deficiency of hepatic LDL receptor by transplanting a liver that expresses normal levels of LDL receptor. Three patients that survived this procedure normalized their serum LDL-cholesterol (5-9). We have used an authentic animal model for FH, the Watanabe Heritable Hyperlipidemic rabbit (WHHL), to develop gene therapies for the homozygous form of FH (10-13). The WHHL rabbit has a mutation in its LDL receptor gene which renders the receptor completely dysfunctional (12) leading to severe hypercholesterolemia, diffuse atherosclerosis, and premature death. The potential efficacy of gene therapy for FH is supported by a series of studies we have performed in the WHHL rabbit in which we have achieved metabolic improvement (14-18). Liver tissue was removed from WHHL rabbits and used to isolate hepatocytes and establish primary cultures. A functional rabbit LDL receptor gene was transduced into a high proportion of hepatocytes using recombinant retroviruses, and the genetically corrected cells were transplanted into the animal from which they were derived. Transplantation of the genetically corrected, autologous hepatocytes was associated with a 30-40% decrease in serum cholesterol that persisted for the duration of the experiment (4 months, Ref. 18). Recombinant derived LDL receptor RNA was detected in liver for at least 6 months. There was no apparent immunological response to the recombinant derived LDL receptor.(ABSTRACT TRUNCATED AT 400 WORDS)     

Characterization of a novel cellular defect in patients with phenotypic homozygous familial hypercholesterolemia

Familial hypercholesterolemia (FH) is characterized by a raised concentration of LDL in plasma that results in a significantly increased risk of premature atherosclerosis. In FH, impaired removal of LDL from the circulation results from inherited mutations in the LDL receptor gene or, more rarely, in the gene for apo B, the ligand for the LDL receptor. We have identified two unrelated clinically homozygous FH patients whose cells exhibit no measurable degradation of LDL in culture. Extensive analysis of DNA and mRNA revealed no defect in the LDL receptor, and alleles of the LDL receptor or apo B genes do not cosegregate with hypercholesterolemia in these families. FACS((R)) analysis of binding and uptake of fluorescent LDL or anti-LDL receptor antibodies showed that LDL receptors are on the cell surface and bind LDL normally, but fail to be internalized, suggesting that some component of endocytosis through clathrin-coated pits is defective. Internalization of the transferrin receptor occurs normally, suggesting that the defective gene product may interact specifically with the LDL receptor internalization signal. Identification of the defective gene will aid genetic diagnosis of other hypercholesterolemic patients and elucidate the mechanism by which LDL receptors are internalized.     

Comparison of different treatment regimens in a case of homozygous familial hypercholesterolemia.

The laboratory results of five periods of different treatment regimens were compared in a 19-year-old girl with homozygous familial hypercholesterolemia (FH): weekly low-density lipoprotein (LDL) apheresis sessions with dextran sulfate columns (LA 15, Kaneka Corporation, Osaka, Japan) without statin administration; weekly LDL apheresis with polyacrylate columns (DALI, Fresenius Adsorber Technology, Bad Homburg, Germany) without statin; LDL apheresis as in Period 2 with 40 mg atorvastatin daily; LDL apheresis as in Period 2 with 80 mg atorvastatin daily; and fortnightly LDL apheresis sessions with polyacrilate and administration of 80 mg atorvastatin daily. The five treatments were given in the above order, and each lasted at least 2 months. To compare the effectiveness of the different methods, the blood levels of total cholesterol, LDL-cholesterol and high-density lipoprotein (HDL)-cholesterol were measured before each session, and the percentage decreases in the blood levels of total cholesterol and LDL-cholesterol were recorded during sessions in Periods 1 and 2. In Periods 1 and 2, the biological effectiveness of LDL apheresis was comparable. Atorvastatin (40 mg daily) improved the blood levels of total cholesterol and LDL-cholesterol, but lowered HDL-cholesterol values. Increasing the daily dose of atorvastatin from 40 mg to 80 mg did not significantly improve LDL-cholesterol levels. When the time between two sessions was longer (Period 5), the total cholesterol and LDL-cholesterol values worsened and were comparable to those of Period 2 during which there was no atorvastatin treatment. In this case of homozygous FH, weekly sessions of LDL apheresis in association with atorvastatin at dose of 40 mg per day gave the best results.     

Low-density lipoprotein apheresis for prevention and regression of atherosclerosis: clinical results.

Hypercholesterolemia can be adequately controlled by appropriate diet and maximum lipid lowering drug therapy in most patients. Nevertheless, there exists a group of patients, including those with familial hypercholesterolemia (FH), who remain at high risk for the development or progression of premature coronary heart disease (CHD). For these patients additional measures such as surgery and low-density lipoprotein (LDL) apheresis have to be considered. The objective of this multicenter trial, which included 30 clinical centers (28 in Germany and one each in Scotland and Luxembourg), was to determine if repeated LDL apheresis using the Liposorber LA-15 system (Kaneka Corporation, Osaka, Japan) could lead to an additional acute and time averaged lowering of total cholesterol (TC) and LDL-cholesterol (LDL-C) in severely hypercholesterolemic patients whose cholesterol levels could not be controlled by appropriate diet and maximum drug therapy. A total of 6,798 treatments were performed on 120 patients, including 8 with homozygous FH, 75 with heterozygous FH, and 37 with unclassified FH or other hyperlipidemias from 1988 through 1994. The mean TC and mean LDL-C levels at baseline were 410.0 mg/dl and 333.9 mg/dl, respectively. LDL apheresis was performed once a week or at least once every 2 weeks in all patients. During treatment with the Liposorber system the mean acute percentage reduction was 52.6% for TC and 63.1% for LDL-C. Very low density lipoprotein cholesterol (VLDL-C) and triglycerides (TG) were also substantially reduced to 60.6% and 47.5%, respectively. Fibrinogen, a potential risk factor for CHD, was reduced by 26.2%. In contrast, the mean acute reduction of high density lipoprotein (HDL) was only 3.4%. During the course of the treatment, the time averaged levels of TC and LDL-C were reduced by approximately 39% and 50%, respectively, compared to baseline levels. The adverse events (AEs) were those generally associated with extracorporeal treatments. The most common AE was hypotension, with 69 episodes corresponding to 1% of all treatments reported in 44 of the 120 patients treated. All other kinds of AEs occurred in less than 0.2% of the treatments. The treatment with the Liposorber LA-15 system was overall well tolerated. It should be noted, however, that a more severe type of hypotensive reaction associated with flush, bradycardia, and dyspnea was reported in patients taking concomitant angiotensin converting enzyme (ACE) inhibitor medication. Except for such anaphylactoid-like reactions associated with the intake of ACE inhibitors, the Liposorber LA-15 system represents a safe and effective therapeutic option for patients suffering from severe hypercholesterolemia that could not be adequately controlled by diet and maximum drug therapy.     

Clinical applications of long-term LDL-apheresis on and beyond refractory hypercholesterolemia

Premature coronary heart disease (CHD) can result from high LDL cholesterol levels even in the absence of any other risk factors. A striking example is found in children who have the homozygous form of familial hypercholesterolemia (FH) with extremely high levels of LDL-cholesterol, and severe atherosclerosis and CHD often develop during the first decades of life. LDL-apheresis was developed for the treatment of severe type of FH patients who are resistant to lipid-lowering drug therapy. Clinical efficacy and safety of the therapeutic tool which directly removes LDL from circulation have already been established in the treatment for refractory hypercholesterolemia in FH patients. The most recently developed method enables lipoproteins to be adsorbed directly from whole blood, using polyacrylate column. In addition to benefits derived from the stabilization or regression of arterial lesions, we highlight other possible clinical applications of LDL-apheresis. However, most of these clinical benefits came from case reports or retrospective studies. Mechanisms related these clinical improvement remain unclear, and prospective randomized controlled trials should be performed for the new clinical indications of LDL-apheresis.     

Malondialdehyde (MDA) and protein carbonyl (PCO) levels as biomarkers of oxidative stress in subjects with familial hypercholesterolemia

ObjectiveFamilial hypercholesterolemia (FH) is clinically characterized by elevated total and low-density lipoprotein (LDL) cholesterol levels in plasma, which has high risk for developing atherosclerosis. Increased oxidative stress (OS) and FH have been related to atherosclerosis. The study aims to evaluate oxidative stress in patients with hypercholesterolemia by measuring lipid peroxidation and protein carbonyl (PCO) levels in these patients. PCO in these patients may provide a new diagnostic biomarker for oxidative damage in atherosclerosis.Design and methodTotal cholesterol (Tc), low-density lipoprotein-cholesterol (LDL-c), triglyceride (TG), high-density lipoprotein-cholesterol (HDL-c), lipoprotein(a) (Lp-a) levels and carotid intima-media thickness were measured to evaluate characteristics of patients (11 homozygous and 25 heterozygous) with FH. 25 age–gender–BMI matched healthy control subjects were included in the study for comparison.ResultsMDA and PCO levels were significantly higher in homozygous patients compared with those of heterozygous and controls and it was found that they are positively correlated with LDL-c, Tc, Lp-a and IMT while negatively correlated with HDL-c. The heterozygous group also had significantly higher MDA and PCO levels compared with controls.ConclusionThe data obtained could be important for understanding the alterations presented by FH and could be related to their increased risk of developing atherosclerosis. To our knowledge, measurements of PCO in patients with FH are not recorded before and this may be used as a biomarker for protein oxidation, which may play a role in the increased cardiovascular risk of patients with FH.     

Efficacy and safety measures for low density lipoprotein apheresis treatment using dextran sulfate cellulose columns.

Long-term low density lipoprotein (LDL) apheresis using dextran sulfate cellulose (DSC) columns is a well tolerated treatment for drug refractory hypercholesterolemia with coronary heart disease (CHD). Hypercholesterolemic patients may benefit from LDL apheresis combined with cholesterol lowering drug therapy in terms of the prevention of the progression of atherosclerosis, stabilization of atheromatous plaque, and reduction of cardiac events. The major adverse reaction of LDL apheresis is temporal hypotension caused by hypovolemia or vasovagal reactions due to extracorporeal circulation. Anaphylactoid reactions in patients administered angiotensin converting enzyme inhibitors (ACE-I) are other dextran sulfate cellulose column related adverse reactions, which must be carefully prevented by ceasing the administration of ACE-I before LDL apheresis treatment. ACE-I must not be administered to patients undergoing LDL apheresis.     

Apheresis technology for prevention and regression of atherosclerosis.

Familial hypercholesterolemia (FH) is a congenital disorder of cholesterol metabolism, which is due to a deficiency in low-density lipoprotein (LDL) receptors. The homozygous form of FH is especially liable to coronary artery disease (CAD) in youth because of the very high LDL-cholesterol levels. It is resistant to drug therapy, and LDL-apheresis is the only practical way of treatment for these patients. Some patients with heterozygous FH also have high LDL-cholesterol levels that cannot be brought down into the optimum range by any combination drug therapy. We have treated or are treating 10 homozygous and 28 heterozygous FH patients in our hospital or in affiliated hospitals expert in blood purification. Among the 10 homozygous patients, 2 died of myocardial infarction. Only one young female patient is still free of symptoms, and the other patients have been suffering from regurgitation through the aortic valve although they have not experienced myocardial infarction. Rapid rebound of LDL-cholesterol after each apheresis treatment limits the period during which LDL-cholesterol is in the optimum range. The use of atorvastatin at a high dose (40 mg/day) was attempted to suppress this rebound. In contrast with good results in receptor-defective-type patients, receptor-negative-type patients did not show a response in LDL-cholesterol levels to the statin therapy although there was a slight increase in high-density lipoprotein (HDL)-cholesterol with a decrease in very-low-density lipoprotein-triglyceride and -cholesterol. Follow-up study of the patients with heterozygous FH revealed that LDL-apheresis was effective in lengthening the life expectancy of the patients with pre-existing CAD, especially those who had received intervention coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA). It was also shown that the use of probucol in combination with LDL-apheresis was effective in reducing coronary events as shown by the necessity of CABG or PTCA. Clinical data on the effect of LDL-apheresis, recently reported from some other institutions in Japan, will also be reviewed.     

Genetic and biochemical analyses in dyslipidemic patients undergoing LDL apheresis

Objective : Familial hypercholesterolemia (FH) can be due to mutations in LDLR, PCSK9, and APOB. In phenotypically defined patients, a subset remains unresponsive to lipid‐lowering therapies and requires low density‐lipoprotein (LDL) apheresis treatment. In this pilot study, we examined the genotype/phenotype relationship in patients with dyslipidemia undergoing routine LDL apheresis. Design : LDLR, APOB, and PCKS9 were analyzed for disease‐causing mutations in seven patients undergoing routine LDL apheresis. Plasma and serum specimens were collected pre‐ and post‐apheresis and analyzed for lipid concentrations, Lp(a) cholesterol, and lipoprotein particle concentrations (via NMR). Results : We found that four patients harbored LDLR mutations and of these, three presented with xanthomas. While similar reductions in LDL‐cholesterol (LDL‐C), apolipoprotein B, and LDL particles (LDL‐P) were observed following apheresis in all patients, lipid profile analysis revealed the LDLR mutation‐positive cohort had a more pro‐atherogenic profile (higher LDL‐C, apolipoprotein B, LDL‐P, and small LDL‐P) pre‐apheresis. Conclusion : Our data show that not all clinically diagnosed FH patients who require routine apheresis have genetically defined disease. In our small cohort, those with LDLR mutations had a more proatherogenic phenotype than those without identifiable mutations. This pilot cohort suggests that patients receiving the maximum lipid lowering therapy could be further stratified, based on genetic make‐up, to optimize treatment. J. Clin. Apheresis 29:256–265, 2014. © 2014 Wiley Periodicals, Inc.     

Familial hypercholesterolemia: Review of diagnosis,screening, and treatment

Objective

To summarize the pathophysiology, epidemiology, screening, diagnosis, and treatment of familial hypercholesterolemia (FH).

Quality of evidence

A PubMed search was conducted (inception to July 2014) for articles on pathophysiology, screening, diagnosis, and management of FH, supplemented with hand searches of bibliographies of guidelines and reviews. A supporting level of evidence for each recommendation was categorized as level I (randomized controlled trial or systematic review of randomized controlled trials), level II (observational study), or level III (expert opinion). The best available evidence is mostly level II or III.

Main message

Familial hypercholesterolemia affects 1 in 500 Canadians. Risk of a coronary event is high in these patients and is underestimated by risk calculators (eg, Framingham). Clinicians should screen patients according to guidelines and suspect FH in any patient with a premature cardiovascular event, physical stigmata of hypercholesterolemia, or an elevated plasma lipid level. Physicians should diagnose FH using either the Simon Broome or Dutch Lipid Network criteria. Management of heterozygous FH includes reducing low-density lipoprotein levels by 50% or more from baseline with high-dose statins and other lipid-lowering agents. Clinicians should refer any patient with homozygous FH to a specialized centre.

Conclusion

Familial hypercholesterolemia represents an important cause of premature cardiovascular disease in Canadians. Early identification and aggressive treatment of individuals with FH reduces cardiovascular morbidity and mortality.Familial hypercholesterolemia (FH) is an autosomal dominant genetic disorder that produces elevations in low-density lipoprotein (LDL) cholesterol.¹ High levels of circulating LDL lead to the rapid development of atherosclerosis early in life, which results in the premature development of atherosclerotic cardiovascular disease (ASCVD). In practice, clinicians underrecognize FH and frequently only make the diagnosis once patients present with an ASCVD event at a young age.^1,2 Patients with FH require aggressive treatment, often with multiple pharmacologic agents, to reduce their levels of circulating LDL cholesterol in order to curtail ASCVD risk. In this review, we aim to summarize the pathophysiology, epidemiology, screening, diagnosis, and treatment of FH.     

Low-density lipoprotein apheresis using the Liposorber system: features of the system and clinical benefits.

LDL apheresis using the Liposorber system is indicated for use to remove selectively LDL from the plasma of hypercholesterolemic patients for whom diet and maximum cholesterol-lowering drug therapy have been ineffective or not tolerated. The dextran sulfate immobilized to porous cellulose beads is contained in the adsorption column as the adsorbent. The dextran sulfate has a structure similar to that of the LDL receptor and seems to act as a type of pseudoreceptor for LDL. There have been reported a number of clinical benefits using the Liposorber system for drug refractory hypercholesterolemic patients. Among them, the improvement of endothelial cell function of coronary and brachial arteries by a single treatment is the focus of the world's attention. Moreover, it is also noteworthy that LDL apheresis reduced the incidence of the cardiac events by 70% compared to drug therapy alone. In addition to the clinical benefits of the Liposorber system on familial hypercholesterolemia (FH), the preliminary data suggest that LDL apheresis may improve arteriosclerosis obliterans (ASO) of the lower extremities and focal glomerular sclerosis (FGS).