Low–Density Lipoprotein Removal Methods by Membranes and Future Perspectives

Abstract: Since the application by Thompson et al. in 1975 of plasma exchange for the treatment of 2 patients with familial hyperlipidemia, plasma purification techniques for selective low–density lipoprotein (LDL) removal (i.e., LDL apheresis) have been developed and adopted for the management of this disease. Thermofil–tration is one of the LDL apheresis systems that utilizes membrane techniques developed by Nose and Malchesky's group in 1985. This article reviews its rationale, in vitro studies, animal studies, and clinical investigation. Thermofiltration effectively and selectively removes LDL cholesterol while retaining in the plasma physiologically important macromolecules such as albumin and high–density lipoprotein (HDL) cholesterol. Based on the global view of the treatment of atherosclerosis by LDL apheresis, membrane techniques are as effective, safe, and simpler to apply than other methods. Additionally, these methods are effective for the removal of lipoprotein (a) and fibrinogen; thus, they can address the needs in these application areas.     

Lipid Apheresis: From a Heroic Treatment to Routine Clinical Practice

Abstract: Lipid apheresis has developed from a heroic treatment into a routine clinical therapy and currently is the major indication for performing extracorporeal plasma therapy. Whereas it was once reserved for patients with homozygous familial hypercholesterolemia, today it has a place in the secondary prevention of severe coronary heart disease when low-density lipoprotein (LDL)-cholesterol levels exceed 150 mg/dl, despite conservative treatment, in any type of primary hypercholesterolemia. Unselective plasma exchange has been replaced by a variety of selective procedures. The efficacy of the treatment can be maximized by combining LDL apheresis with the use of cholesterol synthesis enzyme inhibitors. Clinical studies have shown that drastic cholesterol reduction can result in regression of coronary atherosclerosis as well as in reduced cardiac morbidity and mortality. Technical progress comprises improved selectivity, online regeneration of adsorbers, and LDL adsorption from whole blood. Recently, a new LDL hemoper-fusion procedure was successfully tested in a clinical pilot study; blood is passed directly over a lipid sorbent without prior plasma separation. If this system is demonstrated to be safe and effective in clinical Phase III trials, a further qualitative step in the rapid development of LDL apheresis will have been made.     

LDL Hemoperfusion-A New Procedure for LDL Apheresis: First Clinical Application of an LDL Adsorber Compatible with Human Whole Blood

Abstract: To date, lipid apheresis procedures can remove low-density lipoprotein (LDL) cholesterol (LDL-C) only from plasma. Thus, initially plasma has to be separated from the blood cells, which increases the costs and complexity of the extracorporeal circuit. This paper describes the first clinical application of a new LDL adsorber that eliminates LDL directly from whole blood. The goal of this pilot study was to test the efficacy, safety, and feasibility of direct lipoprotein adsorption in patients. In a 2 center Phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation consisted of an initial heparin bolus followed by an acid citrate dextrose (ACD)-A infusion during the treatment. The processing of nearly 1 patient blood volume resulted in a reduction of LDL-C by 45 ± 8% and triglycerides by 23 ± 20%. HDL-C, fibrinogen, and cell counts were not significantly influenced. In a subgroup of 5 patients who exhibited elevated lipoprotein (a) (Lp[a]) levels, Lp(a) reduction was 43 ± 15% (all results corrected for plasma volume shifts). The sessions were clinically uneventful; the system was technically safe and easily handled. In conclusion, short-term LDL hemoperfusion by the DALI proved to be a safe, effective, and simple procedure for the treatment of patients suffering from symptomatic recalcitrant hypercholesterolemia. The present study represents a solid basis for the clinical long-term evaluation of this new technique in the future.     

State of the Art of Lipid Apheresis

Abstract: Currently, 5 different lipid apheresis procedures are available for routine clinical treatment of hy–percholesterolemic patients. Unselective plasma exchange is a technically simple extracorporeal circuit, but albumin substitution fluid must be used and there is no high–density lipoprotein (HDL) recovery. Semiselective double filtration with improved size selectivity because of a small–pore secondary filter combines good elimination of low–density lipoprotein (LDL), lipoprotein (a) (Lp[a]), and fibrinogen with adequate HDL recovery; modifications such as thermofiltration, predilution/backflush, or pulsatile flow have been proposed for the improvement of this system. Three highly selective procedures are basedon immunologic or electrostatic interactions: immunoad–sorption using anti–low–density lipoprotein (LDL) antibodies, chemoadsorption onto dextran sulfate, and hep–arin–induced LDL precipitation (HELP) apheresis. The features of each system are discussed critically. Lastly, two new developments, Lp(a) immunoadsorption and LDL hemoperfusion using a polyacrylate LDL adsorber compatible with whole blood, are described     

Treatment of Homozygous Familial Hypercholesterolemia with Low Density Lipoprotein Apheresis: A 4 Year Follow-Up Study

Abstract: Hypercholesterolemia and elevated lipoprotein (a) (Lp[a]) levels are considered to be risk factors for the development and progression of premature atherosclerosis. The purpose of our report is to describe the effects of low density lipoprotein (LDL) apheresis (Liposorber system, Kanegafuchi Chemical Industrial Company LTD, Osaka, Japan) on serum lipoprotein concentrations and the clinical status in 2 male patients with homozygous familial hypercholesterolemia. Compared with pretreatment values, the posttreatment concentrations of total cholesterol, LDL cholesterol, and Lp(a) were significantly reduced by 50–60% (p < 0.0001). The concentration of high density lipoprotein (HDL) cholesterol was slightly affected. After one treatment session, LDL cholesterol and Lp(a) were decreased on average by 65% and then increased to reach about 70–75% of the pretreatment values before the next session. Prior to the treatment with LDL apheresis, each patient had suffered one myocardial infarction and had had 2 coronary angiographies. After treatment with LDL apheresis, neither cardiac complaints nor myocardial infarction were observed. The xanthomas were much decreased during the treatment or disappeared. We conclude that LDL apheresis can be continued safely and without major technical problems for several years. Apheresis effectively lowers the serum levels of total and LDL cholesterol. Furthermore, it reduces Lp(a), which is not influenced by lipid-lowering drugs. The reduction of LDL cholesterol and Lp(a) may delay the progression of the atherosclerotic process, thereby helping to reduce the risk of new episodes of coronary heart disease and thus extending the life expectancy in these patients.     

Low–Density Lipoprotein Apheresis Versus Lipid Lowering Drugs in the Treatment of Severe Hypercholesterolemia: Four Years' Experience

Abstract: Elevated lipoprotein concentrations seem to be linked strongly in a dose dependent manner to an increased incidence of atherosclerosis. A total of 47 patients suffering from severe hyperlipidemia were matched to treatment with LDL apheresis (Baxter, Kaneka, Li–popak; 24 patients, aged 50.2 ±11.5 years), diet, and/or lipid–lowering drugs or with diet and lipid–lowering drugs only (23 patients, aged 48.8 ±11.8 years). After treatment periods of 49.8 ±13.4 months (apheresis group, 2,396 treatment sessions) and 38.6 ± 15.1 months (drug group), the ensuing results revealed significant differences (p <0.0001): –47.3% versus –12.1% for total cholesterol, –46.9% versus –21.8% for LDL, +8.4% versus +0.9% for HDL, –52.0% versus – 13.1% for the LDL/HDL ratio, –36.4% versus –16.2% for triglycerides, and –25.9% versus + 1.5% for lipoprotein (a). In the apheresis group, one patient died of myocardial infarction; in the drug group, there was one nonfatal myocardial infarction and the manifestation of coronary heart disease in 3 cases. There were no severe side effects in either group. All patients in the apheresis group responded to therapy. The present trial suggests that a continuing reduction in serum lipid concentrations may lower, in a dose dependent manner, the risk for development and progression of coronary heart disease. Regarding clinical and laboratory results, LDL apheresis seems to be safe, effective therapy for treatment of severe hyperlipidemia.     

Extracorporeal treatment of hypercholesterolaemia

Extracorporeal removal of LDL cholesterol (LDL apheresis) hasbeen carried out in patients with diet- and drug-resistant hypercholesterolaemiato prevent or to reduce coronary heart disease. Plasma separationis the first step in all five LDL-apheresis methods presentlyavailable. Plain plasma exchange and double-membrane filtrationare unselective and remove HDL cholesterol and plasma proteins.Adsorption of LDL to dextran sulphate, to LDL antibodies, orprecipitation of LDL by heparin at low pH are more selective.With all methods LDL cholesterol reduction per treatment is60–70%. In most patients one treatment per week is sufficientto reduce mean LDL to 100–150 mg/dl. Minor side-effectsoccur in 10±5% of treatments. Major side-effects arerare. Long-term LDL apheresis increased survival in patientswith homozygous familial hypercholesterolaemia. In heterozygousfamilial hypercholesterolaemia controlled studies regardingsurvival are not available. Uncontrolled trials indicate regressionof coronary artery disease in heterozygotes with drug- and diet-resistantLDL cholesterol > 200 mg/dl. Hence, LDL apheresis is indicatedin all patients with homozygous familial hypercholesterolaemia.LDL apheresis in heterozygous familial hypercholesterolaemiashould be restricted to patients with diet- and drug-resistantLDL cholesterol >200 mg/dl with coronary heart disease and/orother atherosclerotic vascular lesion.     

Efficacy and safety of a new whole-blood low-density lipoprotein apheresis system (Liposorber D) in severe hypercholesterolemia

Low-density lipoprotein (LDL) apheresis is an extracorporeal modality to lower LDL cholesterol. While most of the devices eliminate LDL particles from plasma, a recently introduced whole-blood perfusion column (DALI) adsorbs lipoproteins directly from whole blood. We investigated the efficacy and safety of a new whole-blood LDL apheresis system (Liposorber D) in 10 patients with severe hypercholesterolemia in a multicenter trial. In 93 LDL aphereses, the mean reduction in LDL cholesterol and lipoprotein(a) was 62.2 +/- 11.5% and 55.6 +/- 16.9%, respectively (P < 0.01). If hemodilution during apheresis was considered, the reductions were 58.0 +/- 10.9 and 55.3 +/- 10.9%, respectively (P < 0.01), while high-density lipoprotein (HDL) cholesterol did not change significantly. Three mild episodes of hypocalcemia and two mild episodes of arterial hypotension were observed; however, LDL apheresis could be continued in each case. In conclusion, the new whole-blood LDL apheresis with Liposorber D is a safe, simple, and useful modality to reduce LDL cholesterol and lipoprotein(a) in cardiovascular high-risk patients.     

Low–Density Lipoprotein Apheresis in the Treatment of Two Patients with Coronary Heart Disease and Extremely Elevated Lipoprotein (a) Levels

Abstract: Hyperlipidemia and elevated lipoprotein (a) (Lp[a]) levels have been linked to the development and progression of premature atherosclerosis. Our study concerned 2 white male patients (aged 36 and 42 years) with heterozygous familial hypercholesterolemia and extremely elevated Lp(a) concentrations that were resistant to diet regimens and lipid–lowering drugs. The patients were treated with low–density lipoprotein (LDL) apheresis for 59 months (Liposorber system, Kaneka, Japan) and 19 months (immunoadsorption system, special Lp(a) columns; Lipopak; Pocard, Russia), respectively. The concentration of Lp(a) decreased on average by 50%, total cholesterol by 27%, LDL cholesterol by 41%, triglycerides by 43%, and fibrinogen by 16%. High–density lipoprotein (HDL) cholesterol increased by approximately 4%. Before treatment with LDL apheresis, each patient had suffered 3 myocardial infarctions, and had had 4 and 6 coronary angiographies with 2 and 4 percutaneous transluminal angioplasties (PTCAs), respectively. Since treatment with LDL apheresis, no myocardial infarctions or cardiac complaints were observed. In the course of treatment, both patients reported an increased performance. Available data suggest that LDL apheresis may be effective in the treatment of patients, the only risk factor for premature atherosclerosis being extremely elevated Lp(a) concentrations.     

Development of Selective Low-Density Lipoprotein (LDL) Apheresis System: Immobilized Polyanion as LDL-Specific Adsorption for LDL Apheresis System

Abstract: Low-density lipoprotein (LDL) is widely recognized as one of the major risk factors for developing coronary heart diseases. Despite intensive development of LDL-lowering drugs, there still exist those patients with refractory hyperlipidemia whose plasma LDL levels are not sufficiently lowered by drugs. LDL apheresis, direct removal of plasma LDL from circulating blood, is thought to be the most promising treatment for such refractory patients. Various techniques, such as the use of an im-munoadsorbent utilizing an anti-LDL antibody, have been used in an attempt to achieve the selective removal of LDL. However, none were widely used because of complications, poor selectivity, and so forth. To establish a safe and effective LDL apheresis system, we chose a synthetic affinity adsorbent as the LDL-removing device. Synthetic polyanion compounds were used as the affinity ligands for LDL adsorbent to simulate the anion-rich sequence of LDL binding sites in the human LDL receptor. Among various polyanion compounds, those polyanions with sulfate or sulfonate groups and hydrophilic backbone were found to have strong affinity for LDL. In contrast, polyanions with carboxyl groups showed poor affinity. Dextran sulfate (DS) was selected as the affinity ligand of LDL adsorbent for its high affinity and low toxicity. The influence of its charge density and molecular weight on its affinity for LDL was suitable. The affinity rapidly increased as the charge density increased, then, reached a constant value. Little affinity was found for either the DS monomer (glucose sulfate) or DS with a molecular weight higher than 10⁴ daltons whereas DS with molecular weights in the midrange showed strong affinity. DS with a midrange molecular weight was immobilized on cellulose hard gel to give LDL adsorbent clinical application. The adsorbent demonstrated an excellent selectivity for LDL and very low density lipoprotein (VLDL) in vitro. Adsorption of high-density lipoprotein and major plasma proteins was almost negligible. Additional study of the LDL-binding mechanism revealed that DS directly interacts with positively charged sites on LDL, which demonstrates that the nature of the interaction is the same as that of LDL receptor. An LDL adsorption column (Liposorber) packed with an LDL adsorbent and polysulfone hollow-fiber plasma separator (Sulflux) was developed as an efficient LDL apheresis system. Clinical investigation proved that this system is capable of intensively lowering the plasma LDL level without affecting major plasma components.     

Short–and Long–Term Effects on Serum Lipoproteins by Three Different Techniques of Apheresis

Abstract: Low–density lipoprotein (LDL) apheresis is applied in patients with coronary heart disease because of severe inherited forms of hypercholesterolemia, for which dietary and combined drug treatment cannot lower LDL cholesterol concentrations less than 130 mg/dl. The following article describes the changes in lipoprotein levels in a total of 19 patients undergoing weekly LDL apheresis. Immunoadsorption, operating with polyclonal antibodies against apolipoprotein B–100, was used in 6 patients. Five patients were put on heparin–induced extracorporeal LDL precipitation (HELP) therapy; 6 received dextran sulfate adsorption treatments. Under steady–state conditions a single treatment reduced LDL cholesterol by 149 ± 3 m/dl with immunoadsorption, 122 ± 2 mg/dl with HELP, and 124 ± 18 mg/dl with dextran sulfate adsorption. Lipoprotein (a) (Lp[a]) declined by 52 to 65%. Very low density lipoprotein (VLDL) cholesterol and VLDL triglycerides declined by 45 to 55% because of the activation of lipoprotein lipase and precipitation during the HELP procedure. In all procedures, there was a small reduction in the different high–density lipoprotein fractions, which had returned to normal after 24 h. The long–term HDL3 cholesterol levels increased significantly. During all procedures there was a decrease in the molar esterification rate of lecithin cholesterol acyltrans–ferase activity. All changes in lipid fractions were paralleled by changes in the corresponding apolipoprotein levels. It is concluded that all three techniques described are powerful tools capable of lowering LDL cholesterol in severe hereditary forms of hypercholesterolemia. In HELP and dextran sulfate adsorption, the amount of plasma is limited by the elimination of other plasma constituents. Immunoadsorption may thus be preferred in very severe forms of hypercholesterolemia.     

Activity of Free Radical Scavenging Enzymes in Red Cells and Plasma of Patients Undergoing Extracorporeal Low-Density Lipoprotein Apheresis

There is evidence that reactive oxygen species (ROSs) are generated in extracorporeal circuits. Free radical scavenging enzymes (FRSEs) such as glutathione reductase (GSSG-R), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) protect against the damaging effect of ROSs. The influence of extracorporeal treatment on FRSE activity was investigated in the plasma and red blood cells (RBCs) of 21 patients undergoing regular low-density lipoprotein (LDL) apheresis. The FRSEs GSSG-R, GSH-Px, and SOD were measured. Determinations were made before and after a single treatment. Because all apheresis patients suffered from coronary heart disease (CHD), 201 CHD patients and 90 individuals without CHD, neither group undergoing apheresis, served as controls. In apheresis patients, GSH-Px (33.9 ± 8.2 U/g Hb) and GSSG-R (7.6 ± 0.9 U/g Hb) activities were increased whereas SOD activity (5.4 ± 1.5 U/g Hb) was decreased in RBCs before a single treatment compared to controls. Plasma FRSEs of apheresis patients were not different from those of controls. There was no effect of a single treatment on FRSEs in RBCs. However, a significant decrease in plasma GSH-Px activity (209.9 ± 24.9 U/ml) due to the extracorporeal treatment was observed. These data show that long-term extracorporeal therapy with LDL apheresis modulates the activity of antioxidant enzymes in RBCs whereas a single treatment was without major effect on FRSE activity in RBCs and plasma, except for plasma GSH-Px.     

Treatment of Severe Hyperlipidemia: Six Years' Experience with Low–Density Lipoprotein Apheresis

Abstract: In total, 30 patients suffering from familial hypercholesterolemia, resistant to diet and lipid–lowering drugs, were treated for up to 6 years (3.6 ± 1.6; range, 0.2–6.8 years) with low–density lipoprotein (LDL) apheresis. Three different systems were used; the dextran sulfate adsorption system (Kaneka) for 27 of 30 patients, the immunoadsorption system from Baxter for 2 of 30 patients, and the immunoadsorption system with special li–poprotein(a) (Lp[a]) columns from Lipopak for one patient. Prior to the LDL apheresis, 23 of 30 patients suffered from coronary heart disease. Twenty of 23 patients suffered intermittently from symptoms of angina, excertional dyspnea, and claudication. With LDL apheresis, reductions of 47% for total cholesterol, 49% for LDL, 26% for Lp(a), and 40% for triglycerides were reached. Severe side effects such as shock or allergic reactions were very rare (0.55%). In the course of treatment with LDL apheresis, an improvement in general well–being and increased performance were experienced in 27 of 30 patients. A reduction of nitrate medication between 60 and 100% was observed in 17 of 23 patients. The present data clearly demonstrate that treatment with LDL apheresis in patients suffering from severe familial hyperlipidemia, resistant to maximum conservative therapy, is very effective and safe even over long periods of time.     

LDL Apheresis: A Novel Technique (LIPOCOLLECT 200)

Therapeutic means to lower Lp(a) are limited. The most effective method to reduce plasma Lp(a) concentration significantly is therapeutic apheresis, namely, low‐density lipoprotein (LDL) lipoprotein(a) (Lp(a)) apheresis. A novel technique based on reusable LDL adsorber called Lipocollect 200 (Medicollect, Rimbach, Germany) allows the removal of both LDL and Lp(a) from plasma. Two male patients with hyperLp(a)lipoproteinemia and angiographically established progressive coronary heart disease, without rough elevation of LDL‐cholesterol, who did not respond to diet and medication were submitted to 50 LDL Lp(a) aphereses with Lipocollect 200 LDL Lp(a)‐adsorber at weekly and biweekly intervals. Total cholesterol and LDL cholesterol plasma levels fell significantly by 48.3% (±6.7) to 61.6% (±12.7) (first patient), and 42.5% (±6.3) to 60.6% (±14.3) (second patient), respectively (all differences: P ≤ 0.001). High‐density lipoprotein (HDL)‐cholesterol concentration in plasma did not show statistically significant change. Plasma triglycerides were also significantly reduced by 43.6% (±24.4) (first patient) and 42.3% (±13) (second patient) (both differences: P ≤ 0.001). Plasma Lp(a) showed a statistically significant percent reduction in plasma as expected: 64.7 ± 9.5 (first patient), and 59.1 ± 6.7 (second patient) (both differences: P ≤ 0.001). Plasma fibrinogen concentration was decreased by 35.9% (±18.7) (P ≤ 0.05) (first patient) and 41.8% (±11.5) (second patient) (P ≤ 0.005). Considering the reduction rate between the first and the last procedures, we have compared the mean percent reduction of the first five treatments (from session #1 to #5) with the last five treatments (from session #21 to #25). We have observed an increasing reduction of all activity parameters on both patients apart from HDL‐cholesterol (first patient) and triglyceride (second patient) that showed a decreasing reduction rate. Both patients followed the prescribed schedule and completed the study. Clinically, all sessions were well tolerated and undesired reactions were not reported. The Lipocollect 200 adsorber proved to have a good biocompatibility. In this study, the adsorber reusability for several sessions was confirmed.     

Heparin–Induced Extracorporeal Low–Density Lipoprotein Precipitation and Low–Density Lipoprotein Chemoadsorption onto Dextran Sulfate: A Comparison

Abstract: Both heparin–induced extracorporeal low–density lipoprotein precipitation (HELP) and dextran sulfate (DS) apheresis are potent tools for acute and long–term risk factor reduction in the secondary prevention treatment of coronary patients suffering from recalcitrant hypercholesterolemia. They combine high efficacy and selectivity of risk factor removal. Whereas LDL cholesterol and lipoprotein (a) adsorption onto DS offers the advantage of an unlimited treatable plasma volume and somewhat easier handling, HELP reduces fibrinogen more effectively and does not interfere with angiotension converting enzyme (ACE) inhibitors. Both systems can improve blood rheology and induce regression or stabilize coronary lesions. In an uncontrolled trial, HELP reduced the incidence of myocardial infarction. To date, no controlled prospective trials have been performed comparing the two systems with respect to their long–term risk factor reduction and their effect on coronary lesions, morbidity, and mortality.     

LDL Apheresis in a Homozygous Familial Hypercholesterolemic Child Aged 4.5

Abstract: Preliminary experience with the efficacy and safety of dextran sulfate cellulose low-density lipoprotein (LDL) apheresis for the treatment of a 4.5-year-old girl with homozygous familial hypercholesterolemia and coronary artery disease is reported. The decrease of the most atherogenic apolipoprotein B-containing lipoproteins, low-density lipoprotein (LDL) and lipoprotein(a) (Lp [a]), were in the ranges of 63.1–68.7%, and 52.5–58.6%, respectively. The child tolerated LDL apheresis without any clinically significant complications. Therefore, she was submitted to a long-term program of treatment at intervals of 15 days. The experience suggests the possibility of an early beginning of extracorporeal treatment with LDL apheresis in children severely affected by homozygous or double heterozygous familial hypercholesterolemia.     

Low-density lipoprotein apheresis: principles and indications

Low-density lipoprotein (LDL) apheresis describes a group of apheresis techniques that selectively remove apolipoprotein B-containing lipoproteins producing an acute reduction in LDL-cholesterol (LDL-C). Six devices are available for the removal of LDL-C while sparing other important plasma components. The LDL-apheresis (LDL-A) is not routinely used for the treatment of hypercholesterolemia, which usually responds to medical management, but is used to treat familial hypercholesterolemia, an inherited metabolic abnormality resulting in premature death due to progressive coronary artery disease, and to treat patients who fail medical management. The mechanism of action of the available LDL-A devices, reactions that can occur with these treatments, and the role of this specialized apheresis technique in the treatment of hypercholesterolemia are described.     

Extracorporeal Removal of Lipids by Dextran Sulfate Cellulose Adsorption

Abstract: Extracorporeal removal of low–density lipoprotein (LDL) cholesterol by dextran sulfate adsorption is indicated in patients with diet and drug resistant hypercholesterolemia to prevent or to regress coronary heart disease. Plasma separation is the first step in the process, followed by adsorption of LDL cholesterol and lipoprotein (a) (Lp[aJ) to negatively charged dextran sulfate co–valently bound to cellulose beads. The reduction per treatment in LDL cholesterol is 65–75% and in Lp(a) 40–60%. In most patients one treatment per week is sufficient to reduce mean LDL to 100–150 mg/dl. Minor side effects occur in 2–6% of treatments. Major side effects are rare. In uncontrolled studies long–term treatment was associated with inhibition of progression and induction of regression of coronary artery disease. LDL apheresis by dextran sulfate may increase blood perfusion of some tissues, and preliminary results indicate a beneficial effect on therapy resistant nephrotic syndrome with hypercholesterolemia.     

LDL Hemoperfusion-A New Procedure for LDL Apheresis: Biocompatibility Results from a First Pilot Study in Hypercholesterolemic Atherosclerosis Patients

Abstract: Current lipid apheresis techniques can remove atherogenic lipoproteins only from plasma. The initial mandatory separation of plasma and blood cells renders the extracorporeal circuit complex. We recently described the first clinical application of a new lipid adsorber that adsorbs low-density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) directly from whole blood. In continuation of our work, this paper describes the clinical biocompatibility of this new LDL hemoperfusion system. In a 2 center phase II clinical trial, 12 hypercholesterolemic patients suffering from overt coronary or peripheral artery disease were treated once with LDL hemoperfusion. The new LDL adsorber (DALI, Fresenius, St. Wendel, Germany) contained 480 ml of polyacrylate coated polyacrylamide gel. The anticoagulation protocol consisted of an initial heparin bolus followed by an acid citrate dextrose-A (ACD-A) infusion during the treatment. One patient blood volume was treated per session. All sessions were clinically un eventful. No signs of hemolysis or extracorporeal clot formation could be detected, and cell counts remained virtually constant. In a subgroup of patients (n = 4–6), further biocompatibility parameters were studied. Activation of leukocytes (elastase release), thrombocytes (β-thrombo-globulin [β-TG] extrusion), and monocytes (interleukin (IL)-1β and IL-6) were minimal. Complement activation (C3a and C5a generation) was negligible. The chosen anticoagulation protocol was both safe (constant ionized calcium levels) and effective (low thrombin-antithrombin formation). In summary, within the scope of a first pilot study. this new LDL hemoperfusion procedure combined the features of excellent clinical tolerance, good biocompatibility, and ease of handling. Phase III clinical trials will have to show whether these encouraging preliminary results can be corroborated in a larger patient population.     

Prevention of Restenosis after Coronary Angioplasty with Low-Density Lipoprotein Apheresis

Abstract: A prospective study was performed to determine whether low-density lipoprotein (LDL) apheresis, when performed only immediately before and after percutaneous transluminal coronary angioplasty (PTCA), is effective in preventing restenosis of coronary artery lesions following PTCA. Thirty-six patients with coronary heart disease (CHD) and hypercholesterolemia were divided into 2 groups. The 9 patients in the LDL group underwent LDL-apheresis 1 day before and 5 days after PTCA while the 27 patients of the control group underwent PTCA but did not undergo LDL-apheresis. Follow-up coronary angiography (CAG) was performed 4 months after PTCA. The rate of restenosis of coronary artery lesions was significantly lower in the LDL group (0%) than in the control group (30%). These findings suggest that LDL-apheresis, when performed before and after PTCA, is effective in preventing restenosis of coronary artery lesions in patients with CHD and hypercholesterolemia.