Pathological and angiographic regression of coronary atherosclerosis by LDL-apheresis in a patient with familial hypercholesterolemia

Changes in Lipids and Lipoproteins after Selective LDL Apheresis (7-Year Experience)

Background. The aim of the study was to investigate the changes in plasma lipids and lipoproteins and the cardiovascular events after selective LDL apheresis. Methods and Results. Two pediatric patients with familial hypercholesterolemia aged 11 and 13 years and 19 dyslipidemic adults aged 41 ± 14 years underwent direct adsorption of lipoproteins (DALI) sessions. The mean follow-up period was 47 ± 23 months. The total cholesterol (TC) values before and after treatment were 8.2 ± 2.2 and 3.1 ± 1.6 mmol/l (318 ± 86 and 122 ± 62 mg/dL), respectively. The interval mean of TC was 6.9 ± 1.9 mmol/l (268 ± 75 mg/dL). The LDL cholesterol concentrations before and after treatment were 6.6 ± 2.1 and 1.7 ± 1.1 mmol/l, (256 ± 82 mg/dL and 65 ± 41 mg/dL), respectively. The percentage of acute LDL cholesterol reduction was 75 ± 11%. Cardiovascular events were observed in seven patients. The average annual event rate was 5.51%. Conclusion. LDL apheresis is a very important therapeutic tool in managing patients at high risk for premature CAD or with aggressive CAD, despite adequate medical treatment.

Rescue left main coronary artery stenting for acute myocardial ischemia after coronary angiography in a 7-year-old girl with homozygous familial hypercholesterolemia

Homozygous familial hypercholesterolemia (HFH), resulting from mutation of the low-density lipoprotein (LDL) receptor gene with subsequent defective catabolism of the LDL cholesterol, leads to premature atherosclerosis and coronary artery disease. We report a successful urgent stent implantation in a 7-year-old patient with HFH and a severe left main coronary artery stenosis, who presented critical acute myocardial ischemia immediately after left coronary angiography. Percutaneous transluminal coronary angiography with stent implantation allowed for rapid coronary flow reestablishment without sequelae. Aggressive lipid-lowering therapy with high doses statins and LDL-apheresis was maintained, together with lifelong antiaggregant acetylsalicylic treatment with good short-term patency of the stent at 1-year follow-up. In conclusion, coronary artery stent implantation may be considered as a valid rescue therapeutic alternative for pediatric patients with HFH and severe ostial coronary stenosis in case of emergency.

Direct Adsorption of Lipoproteins from Whole Blood by Direct Adsorption of Lipoprotein Apheresis: First Experience in Two Hypercholesterolemic Children

Low density lipoprotein (LDL) cholesterol apheresis, combined with lipid lowering drugs, provides a safe and effective means of improving the prognosis of patients with homozygote familial hypercholesterolemia, especially if started before the age of seven. The direct adsorption of lipoprotein (DALI) is the first extracorporeal low density lipoprotein removing system compatible with whole blood. The purpose of the present study was to clarify the efficacy and safety of DALI in children with homozygous familial hypercholesterolemia. Two boys, aged 9 and 15 years, with familial hypercholesterolemia, who were highly resistant to dietary regimes and to drug therapy, were treated with the low density lipoprotein adsorber DALI apheresis once every 2 weeks for 24 weeks. The treated blood volumes for each procedure were 2911 mL (493 +/- SD) and 5982 mL (1129 +/- SD), respectively. In our patients, the acute mean LDL cholesterol reductions were 44.7 +/- 8.9% and 58.8 +/- 4.5%. The corresponding reductions were 42.5 +/- 7.2% and 56 +/- 4.3% for total cholesterol, and 46.5 +/- 17.1% and 55 +/- 7.5% for very low density lipoprotein cholesterol (VLDL-C). There were insignificant losses of high density lipoprotein (12.2 +/- 5.7%, 8.3 +/- 5.5%). Treatment was well tolerated in general, and neither patient suffered from irreversible or long-lasting adverse effects. Our experience with DALI apheresis is encouraging. The present report is the first on the use of DALI in children. Based on this short-term evaluation we think that DALI might be safe and effective in children with homozygote familial hypercholesterolemia, however further evaluation of long-term effects is needed.

Contact activation in low-density lipoprotein apheresis systems

BACKGROUND

Anaphylactoid reactions due to contact activation have been observed in patients on ACE inhibitor therapy and hemodialysis with negatively charged dialysis membranes. Negatively charged surfaces are functional constituents of different LDL apheresis systems. Therefore, contact activation was investigated during LDL apheresis with three different systems: (i) heparin-induced extracorporeal LDL precipitation (HELP); (ii) dextran sulfate cellulose (DSC) columns; and (iii) modified polyacrylate gels (DALI) in a clinical setting.

METHODS

24 prevalent patients on regular LDL apheresis treatment were included in the study. Bradykinin, prekallikrein, and HMW kininogen were measured during a single LDL apheresis at different sites of the systems.

RESULTS

LDL apheresis with DSC and DALI was associated with an extreme release of bradykinin after the passage of plasma or blood through the LDL adsorbers as well as with a decrease of prekallikrein and HMW kininogen during the course of the treatment. Bradykinin release exceeded the degradation capacity of the kininase II, since markedly elevated bradykinin concentrations were observed in the arterial line of the extracorporeal circuits of both systems. This was not associated with anaphylactoid reactions. In contrast to the treatments with DSC and DALI, the HELP system did not lead to any activation of the kallikrein-kinin system.

CONCLUSION

From our data we conclude that angiotensin converting enzyme (ACE) inhibitors are contraindicated in patients on LDL apheresis with the DSC and the DALI system. Because the HELP system does not activate the kallikrein-kinin system, patients who need ACE inhibitors are predisposed for this LDL apheresis procedure.

Immunoadsorption of Cholesterol on Protein A Oriented Beads

Anti-low density lipoprotein antibody (anti-LDL) molecules were attached covalently and oriented through Protein A onto poly(2-hydroxyethyl methacrylate-ethylene glycol dimethacrylate) [poly(HEMA-EGDMA)] beads in order to remove cholesterol specifically from hypercholesterolemic human plasma. Poly(HEMA-EGDMA) beads were produced by suspension polymerization. Blood compatibility tests were performed. All the clotting times were increased when compared with control plasma. Loss of platelets and leukocytes was very low. The maximum anti-LDL attachment was 11.6 mg . g(-1) in the case of random immobilization and 28.3 mg . g(-1) in the case of oriented immobilization. In the latter case, Protein A loading was 8.3 mg . g(-1) at pH 7.5 (borate buffer, 0.15 M NaCl). There was low non-specific cholesterol adsorption onto the poly(HEMA-EGDMA) beads, about 0.83 mg . g(-1). Random and oriented anti-LDL attached beads adsorbed 8.2 mg and 11.7 mg cholesterol per g of bead from hypercholesterolemic human plasma, respectively. Up to 96% of the adsorbed cholesterol was desorbed. The binding-elution cycle was repeated 6 times using the same beads. There was no significant loss of binding capacity.

Ten-year Follow-up of Familial Hypercholesterolemia Patients After Intensive Cholesterol-lowering Therapy

To prevent coronary artery disease, it is necessary for patients with familial hyper-cholesterolemia (FH) to maintain a low cholesterol level. Recently a combination therapy of low-density lipoprotein (LDL) apheresis and statins has been used for FH patients, but their long-term prognosis over 10 years is unknown. In this single center prospective report, 18 FH patients with severe coronary stenosis received LDL apheresis every 2 or 4 weeks and statin therapy for 9.8 +/- 3.0 years. Probucol was given to 17 of the 18 patients. We observed their clinical events as well as coronary stenosis findings and ejection fractions for 10.7 +/- 2.6 years. Total and LDL cholesterol levels before therapy were 345 +/- 46 and 277 +/- 48 mg/dL, respectively. Immediately following LDL-apheresis, these levels decreased to 104 +/- 7.5 and 66 +/- 16 mg/dL, respectively. There were no cardiac deaths and 4 patients were free from any coronary events. There was one noncardiac death. Nonfatal myocardial in-farction occurred in 2 patients and coronary bypass surgery was required in one patient. Twelve patients received additional coronary angioplasty. There was little change in coronary stenosis and ejection fraction following 10 years of the combination therapy. Univariate Cox regression analysis revealed that the calculated mean LDL cholesterol level was the predictive value of treatment efficacy (mean LDL cholesterol < 140 mg/dL, hazard ratio 0.23, P = 0.028). The combination therapy of LDL-apheresis and antilipid drugs delayed the progression of coronary atherosclerosis and prevented a major cardiac event, although complete inhibition was limited to a small group. Additional coronary angioplasty is likely to be required for a favorable clinical outcome in FH patients.

Practical aspects of direct adsorption of lipoproteins from whole blood by DALI LDL-apheresis

Direct adsorption of lipoproteins (DALI) from whole blood is the first LDL-hemoperfusion procedure. The present paper addresses practical questions of DALI apheresis in order to optimise DALI therapy in sometimes critically ill coronary patients. The reduction of LDL and Lp(a) by DALI can be optimised by increasing the treated blood volume and the DALI adsorber volume. Hypotension (1.2% of sessions) may be minimised by fluid intake before the session, isovolemic connection of the patient to the ECC, reduced blood flow and low ACD-A ratio. Hypocalcemia may be avoided by low citrate anticoagulation (1:40) and reduced blood flow. Bradykinin release peaks at ca. 1000 ml of treated blood volume and may cause Quincke edema (tight throat), hypotension and flush. Reduction of the blood flow rate and decrease of citrate admixture as well as administration of iv. calcium may be helpful. While ACE inhibitors are contraindicated in DALI patients, sartans may be used without problems. Some "intrinsic" PTT increase is caused by adsorption of coagulation factors; undue PTT prolongations after DALI may be avoided by reduction of the heparin dosage during priming and treatment. In patients prone to alkalosis and hypokalemia, a reduction of the ACD-A ratio is recommended. Rises of adsorber inlet pressure may be due to insufficient anticoagulation and adsorber clotting or malfunctioning of the venous access. Rinsing of the adsorber with saline, administration of a heparin bolus and increase of the citrate admixture as well as a rinse and/or repositioning of the venous access are helpful measures. If these basic rules are followed, DALI LDL-apheresis is a safe, efficient, rapid and user-friendly LDL-apheresis procedure as evidenced by more than 80,000 DALI sessions successfully performed to date.

Improvement of endothelium-dependent coronary vasodilation after a single LDL apheresis in patients with hypercholesterolemia

The purpose of this study was to determine whether a single LDL apheresis would improve impaired endothelium-dependent dilation of the coronary artery in patients with hypercholesterolemia. Hypercholesterolemia is associated with impaired endothelial function, and human studies using cholesterol-lowering drugs indicate that endothelial function in the coronary arteries improves with reduction of serum LDL cholesterol over 6 to 12 months. The internal diameter of the left coronary artery and the coronary blood flow were measured by intracoronary Doppler-wire measurement and quantitative angiography before and immediately after a single LDL apheresis in a population of 15 patients with familial hypercholesterolemia. Endothelium-dependent vasodilation was assessed by intracoronary infusion of acetylcholine (1, 10, and 50 microg/min), and endothelium-independent vasodilation was assessed by intracoronary bolus infusion of isosorbide dinitrate (2.5 mg) or papaverine (10 mg). A single 3-hour LDL apheresis reduced serum LDL cholesterol by an average of 86.6 +/- 1.7%. After the LDL apheresis, the changes in the coronary artery diameter and coronary blood flow in response to an infusion of 50 microg/min of acetylcholine increased significantly compared to the pre-apheresis values (from -19.7 +/- 4.8 to -2.9 +/- 3.0% [P < 0.01] and from 80.7 +/- 27.6 to 155.3 +/- 23.5% [P < 0.01], respectively). The LDL apheresis did not significantly change the response of either parameter to infusion with isosorbide dinitrate or papaverine. The endothelial function of the epicardial coronary artery and the coronary microvasculature improved in hypercholesterolemic patients after only a single LDL apheresis, a procedure that markedly reduces the serum level of LDL cholesterol.

Immunoaffinity beads for selective removal of cholesterol from human plasma

Anti-low density lipoprotein antibody (anti-LDL antibody) attached poly(2-hydroxyethyl methacrylate-methacryloylamidophenylalanine) (poly(HEMA-MAPA)) beads were prepared for selective removal of cholesterol from hypercholesterolemic human plasma. Poly(HEMA-MAPA) beads were produced by a modified suspension polymerization and then characterized by swelling tests and SEM. Blood-compatibility tests were also investigated. The water swelling ratio of the poly(HEMA-MAPA) beads increased significantly (68%) compared with pHEMA (55%). All the clotting times increased when compared with poly(HEMA) beads. Loss of platelets and leukocytes was very low. The maximum anti-LDL antibody attachment was achieved at pH 7.0. Attachment of anti-LDL antibody was 29.6 mg/g. There was a very low non-specific cholesterol binding onto the poly(HEMA-MAPA) beads, about 0.74 mg/g. Anti-LDL antibody attached beads adsorbed in the range of 13.3-16.0 mg cholesterol/g from hypercholesterolemic human plasma. Up to 92% of the adsorbed LDL was desorbed. The binding-elution cycle was repeated 10 times using the same beads. There was no significant loss of binding capacity.

Changes in oxidative stress and microcirculation by low-density lipoprotein apheresis

Low-density lipoprotein apheresis (LDLA) leads to an improvement of microcirculation during the very early stages of treatment, and continued treatment may produce antiatherogenic effects in patients with peripheral arterial disease (PAD). Suppression of oxidative stress, improvement of endothelial functions and alteration in the action of vasoactive compounds may occur with the improvement of the rheological property of blood as a result of aggressive removal of atherogenic factors including LDL, possibly resulting in the suppression of development of atherosclerosis. As these effects of LDLA may ameliorate not only PAD but also ischemia in other organs, it is suggested that repeated LDLA prevents the progression of atherosclerotic diseases and probably improves the long-term prognosis of patients with PAD.

Effectiveness of long-term heparin-induced extracorporeal LDL precipitation (HELP) in improving coronary calcifications

There is clear clinical evidence that a drastic lowering of plasma LDL-Cholesterol (LDL) concentrations significantly reduces the rate of total and coronary mortality as well as the incidence of cardiovascular events in high risk hypercholesterolemic patients. We describe the case of a 51-year-old woman with coronary heart disease (CHD) who presented with increasing angina on exertion in 1995, at the age of 45. She suffered from a heterozygous familial hypercholesterolemia and in 1985 her total cholesterol (TCHO) was 328 +/- 62 mg/dl (mean value of ten analysis). After ten years of statins her mean values (20 analysis, 2 per year) were: TCHO 259 +/- 71, LDL 209 +/- 47, HDL 35 +/- 7 mg/dl. Coronary angiography (CA) performed in 1995 disclosed three vessel coronary heart disease with significant stenoses of the distal right coronary artery, multiple calcifications of the interventricularis artery and multiple plaques with significant stenoses in the ramus circumflexus. The woman underwent coronary by-pass surgery. Thereafter the patient was treated for six years with HELP in biweekly intervals, in combination with statins. TCHO, LDL, HDL and fibrinogen (fb) levels were measured before and after each treatment. Their mean values for an amount of 120 sessions were: TCHO pre 216 +/- 23, post 111 +/- 18 LDL pre 152 +/- 16 post 67 +/- 18, HDL pre 42 +/- 5 post 35 +/- 4 fb pre 306 +/- 48 post 125 +/- 31. In 2001 a new CA was performed. Calcifications disappeared and stenoses were identical to the previous CA or reduced. There were no further clinical manifestations of CHD. We trust that the clinical benefit of the HELP procedure will be substantial for those patients who have problems in clearing LDL from their plasma pool and who are at the same time sensitive to elevated LDL levels by the development of premature coronary sclerosis.

Blood purification therapies using dextran sulfate cellulose columns Liposorber and Selesorb

Liposorber is a column used for plasma purification that adsorbs low-density lipoproteins with high selectivity, while Selesorb is a column that selectively adsorbs anti-DNA antibodies, anticardiolipin antibodies, and immune complexes. Both columns are packed with carriers, where a dextran sulfate ligand is bound to porous cellulose beads. Liposorber is used to treat familial hypercholesterolemia (FH), peripheral arterial disease (PAD), and focal segmental glomerulosclerosis (FGS): Selesorb is used to treat systemic lupus erythematosus (SLE). Treatment utilizing both columns is being used effectively in patients with refractory disease that is resistant to pharmacotherapy.

Meaning of low-density lipoprotein-apheresis for hypercholesterolemic patients at high risk for recurrence of coronary heart disease

The goal of cholesterol-lowering therapy in hypercholesterolemic patients at high risk for recurrence of coronary heart disease (CHD) is the prevention of acute coronary syndrome by stabilization of coronary atheromatous plaque. We often encounter patients in whom it is difficult to maintain the serum cholesterol level at a desirable level with dietary therapy and drug treatment, despite the development and use of statins. For secondary prevention in patients who are at high risk for the recurrence of CHD and whose cholesterol level cannot be controlled by drugs alone, low-density lipoprotein (LDL)-apheresis therapy, which involves removal of LDL through extracorporeal circulation, is now available. Many reports concerning improvement of vascular endothelial function, improvement of myocardial ischemia, regression of coronary atherosclerotic lesions, stabilization of coronary plaque, and reduction in the incidence of cardiac events as a result of LDL-apheresis treatment have been published in various countries. We believe that LDL-apheresis should be performed on hypercholesterolemic patients with existing CHD for whom diet and maximum cholesterol-lowering drug therapies have been ineffective or not tolerated and whose LDL cholesterol level is 160 mg/dL or higher.

Intravascular ultrasound evaluation of coronary plaque regression by low density lipoprotein-apheresis in familial hypercholesterolemia: the Low Density Lipoprotein-Apheresis Coronary Morphology and Reserve Trial (LACMART)

OBJECTIVES

We sought to assess the effects of low density lipoprotein (LDL)-apheresis (LDL-A) for regression of coronary plaque in familial hypercholesterolemia (FH), we set up a one-year follow-up multicenter trial using coronary angiography and intravascular ultrasound (IVUS).

BACKGROUND

It is still unclear whether aggressive lipid-lowering therapy by LDL-A leads to the regression of coronary plaque in patients with FH.

METHODS

Eighteen patients with FH were assigned to one of two groups: medication + LDL-A (LDL-A group, n = 11) and medication only (medication group, n = 7). Total cholesterol, triglycerides, high density lipoprotein cholesterol and LDL cholesterol were measured in all subjects at the outset of treatment (baseline) and every three months thereafter. Coronary angiography and IVUS were performed at the outset and after the one-year follow-up period to measure minimal lumen diameter (MLD) by coronary angiogram and plaque area (PA) by IVUS.

RESULTS

The LDL-A group showed 28.4% reduction in total cholesterol (from 275 +/- 27 mg/dl to 197 +/- 19 mg/dl) and 34.3% reduction in LDL cholesterol (from 213 +/- 25 mg/dl to 140 +/- 27 mg/dl) after one-year follow-up, while the medication group showed no changes in cholesterol levels. There were significant interactions between both treatments in total cholesterol (p = 0.0001), LDL cholesterol (p = 0.0001), MLD (p = 0.008) and PA (p = 0.017) using two-way repeated-measures analysis of variance by the SAS system (SAS Institute Inc., Cary, North Carolina). Significant differences were seen in net change in MLD (p = 0.004) and PA (p = 0.008) during the one-year follow-up period between both groups.

CONCLUSIONS

These results suggest that aggressive lipid-lowering therapy using the combination of LDL-A and lipid-lowering drugs may induce regression of coronary atherosclerotic plaque in FH patients.

Preparation of immuno-affinity membranes for cholesterol removal from human plasma

Anti-low density lipoprotein antibody (anti-LDL) immobilized polyhydroxyethylmethacrylate (pHEMA) based membrane was prepared for selective removal of cholesterol from hypercholesterolemic human plasma. In order to further increase blood-compatibility, a newly synthesized comonomer, methacryloylamidophenylalanine (MAPA) was included in the membrane formulation. p(HEMA-MAPA) membranes were produced by a photopolymerization and then characterized by swelling tests, SEM and contact angle studies. Blood-compatibility tests were also investigated. The water swelling ratio of the p(HEMA-MAPA) membrane increases significantly (133.2.9%) compared with pHEMA (58%). p(HEMA-MAPA) membranes have large pores around in the range of 5-10 microm. All the clotting times increased when compared with pHEMA membranes. Loss of platelets and leukocytes was very low. The maximum anti-LDL antibody immobilization was achieved around pH 7.0. Immobilization of anti-LDL antibody was 12.6 mg/ml. There was a very low non-specific cholesterol adsorption onto the plain p(HEMA-MAPA) membranes, about 0.36 mg/ml. Anti-LDL antibody immobilized membranes adsorbed in the range of 4.5-7.2 mg cholesterol/ml from hypercholesterolemic human plasma. Up to 95% of the adsorbed LDL antibody was desorbed. The adsorption-desorption cycle was repeated 10 times using the same membrane. There was no significant loss in the adsorption capacity.

Beneficial effect of aggressive low-density lipoprotein apheresis in a familial hypercholesterolemic patient with severe diabetic scleredema

We present a 59-year-old woman with severe diabetic scleredema (DS) associated with heterozygous familial hypercholesterolemia (FH). She had been treated with drugs to lower blood glucose, with insulin for diabetes mellitus (DM), and with low-density lipoprotein (LDL) apheresis therapy monthly or every 2 weeks in addition to drugs to lower serum lipids for FH. However, her scleredema had not improved. After we had tried weekly LDL apheresis therapy for a period of 3 years to treat her hyperlipidemia, the levels of her serum lipids were reduced to normal ranges, and scleredema in her nape improved. We also demonstrated the histopathological improvement in dermis of her cervical skin. We conclude that weekly LDL apheresis therapy is effective for diabetic scleredema that is resistant to conventional treatments.

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.

Direct adsorption of lipoproteins from whole blood by DALI apheresis: technique and effects

Low-density lipoprotein (LDL) apheresis can drastically reduce atherogenic lipoproteins in coronary patients in whom LDL and lipoprotein (a) (Lp[a]) cannot be sufficiently reduced by conservative therapy. LDL and Lp(a) adsorption by polyacrylate/polyacrylamide (DALI) is the simplest procedure for clinical LDL apheresis to date. DALI was first applied in patients in 1994 and introduced into clinical routine in 1996. It is the first LDL-hemoperfusion system, i.e., it adsorbs LDL and Lp(a) directly from whole blood. This markedly simplifies the extracorporeal circuit, the handling of the system, and reduces significantly staff time and, especially at higher blood flow rates, treatment time. Its features are high selectivity and capacity of lipoprotein removal (maximum about 8 g low-density lipoprotein cholesterol per session). Using citrate anticoagulation, good biocompatibility is evidenced by the lack of cell losses, hemolysis, thrombotic events, and complement activation. Some clotting factors of the intrinsic system are also adsorbed. There is significant bradykinin activation that, however, does not cause problems in most patients if angiotensin converting enzyme inhibitor medication is avoided. In a first long-term study, 93% of sessions were uneventful. Major side effects were citrate-induced paresthesias (1.3%) and hypotension (0.8%). To date, more than 25,000 DALI sessions have been performed all over the world.

The rebound of lipoproteins after LDL-apheresis. Kinetics and estimation of mean lipoprotein levels

We studied the rebound of lipoproteins in 20 hypercholesterolemic men [mean total cholesterol (TC) levels 9.6+/-1.8 mmol/l] after LDL-apheresis (LA) to determine the rate of recovery and the change in cholesterol synthesis, and to find a uniform estimation for time-averaged levels. After 10-20 months on biweekly LA using dextran sulfate cellulose columns and concomitant simvastatin administration, time-averaged levels (+/-SD) measured by integration of the area under the curve were as follows: TC 4.4+/-1.0 mmol/l, LDL cholesterol (LDL-C) 2.5+/-1.0 mmol/l, apolipoprotein B (apo B) 1. 3+/-0.3 g/l, triglycerides (TG) 1.7+/-0.7 mmol/l, HDL-C 1.1+/-0.2 mmol/l, and lipoprotein(a) [Lp(a)] 53.7+/-49.4 mg/dl. Mean acute reductions in TC, LDL-C, apo B, Lp(a), and TG were 61, 77, 75, 76, and 62%, respectively. HDL-C levels were not influenced. Median recovery half times for TC, LDL-C, apo B, and Lp(a) were 3.0, 4.0, 2. 3, and 3.5 days, respectively. The rebound of Lp(a) was identical to LDL-C, in 12 and 13 days post-treatment, respectively, whereas apo B and TC returned to pre-treatment levels in 7.5 and 10 days, respectively, due to the fast rebound of VLDL particles. Notwithstanding these differences, time-averaged levels (C(AVG)) could be estimated uniformly for the four latter parameters with the formula: C(AVG)=C(MIN)+0.73(C(MAX)-C(MIN)), where C(MAX) and C(MIN) are the immediate pre- and post-treatment levels. During long-term treatment the whole-body cholesterol synthesis was increased as measured by the ratio lathosterol to cholesterol of 3.24+/-1.49 mmol/mmol, whereas no further transient increase in the recovery period after LA was found. In conclusion, long-term LA and simvastatin therapy induced acute and chronic changes in lipids and lipoproteins showing the feasibility of biweekly treatment. It was shown that time-averaged levels, as a measure for the effective plasma levels, can be accurately estimated from pre- and post-treatment levels only.

Long-term effects of LDL apheresis on carotid arterial atherosclerosis in familial hypercholesterolaemic patients

OBJECTIVES

To assess the long-term effect of LDL apheresis on carotid arterial atherosclerosis in severe familial hypercholesterolaemic (FH) patients.

DESIGN

Changes in existing plaque, new plaque formation and annual progression rate of carotid early plaque were evaluated by B-mode ultrasonography.

SUBJECTS

LDL apheresis group: two homozygous FH and nine heterozygous FH patients received a combination of LDL apheresis and cholesterol-lowering drug therapy for a mean of 7.8 years.

CONTROL GROUP

10 heterozygous FH patients were maintained by medication only for a mean of 5.5 years.

RESULTS

As a result of LDL apheresis treatment, LDL cholesterol levels reduced from 16.0+/-3.60 to 6.43+/-0.07 mmol L(-1) in homozygous FH patients and from 11.5+/-2.46 to 4.32+/-1.2 mmol L(-1) in heterozygous FH patients. During the long-term treatment period, the existing plaque tended to progress and new plaque formation in carotid arteries was also observed in both groups. The annual progression rate of mean maximum intima-media thickness in the common carotid artery was a mean of -0.0023+/-0.0246 mm year(-1) in heterozygous FH patients in the LDL apheresis group, suggesting regression. This was significantly lower when compared with the control group, which had a mean of 0.0251+/-0.0265 mm year(-1) CONCLUSION: The results suggest that the long-term treatment with combined LDL apheresis and drugs may delay the progression of the atherosclerotic process and prompt the stabilization of atheromatous plaque in severe FH patients.

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.

Analysis of LDL receptor gene mutations in Italian patients with homozygous familial hypercholesterolemia

The aim of this study was the characterization of mutations of the LDL receptor gene in 39 Italian patients with homozygous familial hypercholesterolemia, who were examined during the period 1994 to 1996. The age of the patients ranged from 1 to 64 years; one third of them were older than 30. Plasma LDL cholesterol level ranged from 10.8 to 25.1 mmol/L. The residual LDL receptor activity, measured in cultured fibroblasts of 32 patients, varied from <2% to 30% of normal and was inversely correlated with the plasma LDL cholesterol level (r=-0.665; P<0.003). The most severe coronary atherosclerosis was observed in those patients with the lowest residual LDL receptor activity (</=5% of normal) and the highest plasma LDL cholesterol levels. Twenty-nine patients (23 of whom were unrelated) were found to be homozygotes at the LDL receptor locus. In this group we discovered 2 major rearrangements and 12 different point mutations (9 in the coding region and 3 in splice sites). Some mutations (D200G, C358R, V502M, G528D, and P664L) were found in 3 or more unrelated patients. Patients with the same mutation shared the same haplotype at the LDL receptor gene locus and came from the same geographic area. Ten patients (9 of whom were unrelated) were found to be compound heterozygotes. The mutations found in this group consisted of one large deletion and 12 point mutations (11 in the coding sequence and one in a splice site). In 3 compound heterozygotes we failed to identify the second mutant allele at the LDL receptor locus. These observations confirm the allelic heterogeneity underlying familial hypercholesterolemia in the Italian population and indicate that the variability of phenotypic expression of homozygous familial hypercholesterolemia is, to a large extent, related to the type of mutation of the LDL receptor gene.

Extent and severity of atherosclerotic involvement of the aortic valve and root in familial hypercholesterolaemia

OBJECTIVE

To compare the frequency of valvar and supravalvar aortic stenosis in homozygous and heterozygous familial hypercholesterolaemia (FH).

DESIGN

Analysis of life time cholesterol exposure and prevalence of aortic atherosclerosis in 84 consecutive cases attending a lipid clinic.

SETTING

A tertiary referral centre in London.

PATIENTS

Outpatients with FH (six homozygous, 78 heterozygous).

INTERVENTIONS

Maintenance of lipid lowering treatment.

MAIN OUTCOME MEASURES

Calculated cholesterol x years score (CYS) and echocardiographic measurement of aortic root diameter, aortic valve thickness, and transaortic gradient.

RESULTS

Four homozygotes with a mean (SD) CYS of 387 (124) mmol/1 x years had severe aortic stenosis (treatment started after seven years of age), whereas the other two had echocardiographic evidence of supravalvar thickening but no aortic valve stenosis (treatment started before three years of age). On multivariate analysis, mean transaortic gradient correlated significantly with CYS (mean = 523 (175) mmol/1 x years) in heterozygotes (p = 0.0001), but only two had severe aortic valve and root involvement.

CONCLUSIONS

In patients with familial hypercholesterolaemia, aortic stenosis is common in homozygotes, and aortic root involvement is always present despite the lower CYS than in heterozygotes. It appears to be determined by short term exposure to high cholesterol concentrations in early life. Conversely, aortic root and valve involvement are rare in heterozygotes and occur only with severe, prolonged hypercholesterolaemia, possibly accelerating age related degenerative effects.

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).

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.

Impaired radial artery compliance in normotensive subjects with familial hypercholesterolemia

Hypercholesterolemia impairs arteriolar dilatation, but whether the vascular abnormalities accompanying this condition include large artery function is unknown. We addressed this issue in 13 normotensive subjects with familial hypercholesterolemia (serum cholesterol 401.6 +/- 16.9 mg/dl, mean +/- S.E., FHC) and no evidence of atherosclerotic lesions, in whom radial artery (RA) diameter and blood pressure (BP) were measured beat to beat by an echotracking and a Finapres device, respectively. RA compliance (RAC) was derived from the diameter/BP relationship and expressed over the systo-diastolic BP range, both at baseline and after a 12-min brachial artery occlusion. RAC was expressed also as the area under the RAC/BP curve divided for pulse BP. Measurements included maximal forearm blood flow (plethysmography) and minimal forearm vascular resistance (FVR) which were obtained from the values following the 12-min brachial arterial occlusion. Data were collected before and after 6- and 24-month lipid lowering treatment (simvastatin 40 mg/day). Ten age-matched normotensive normocholesterolemic healthy subjects (N) served as controls. Compared to N, baseline RAC was strikingly reduced in FHC (-53.5%, P < 0.01). After ischemia RAC increased significantly and markedly in N (+38.7, P < 0.01), while only a modest and non-significant increase was observed in FHC. Minimal FVR was markedly higher in FHC than in N (3.5 +/- 0.9 vs 1.6 +/- 0.1 units, P < 0.01). In FHC (7 subjects) RAC remained unchanged after 6 months of lipid lowering treatment, but increased markedly (+55.2%, p < 0.05) when treatment was prolonged to 24 months. Lipid lowering treatment also reduced minimal FVR, the effect being significant both after 6 and after 24 months. No changes in RAC and minimal FVR were seen after 6 months in controls. Thus, in subjects with a marked increase in serum cholesterol due to FHC, not only arteriolar dilatation, but also RAC and distensibility are markedly impaired. This impairment can be favourably affected by an effective lipid lowering treatment of long duration.

Abnormal regulation of the LDL-R and HMG CoA reductase genes in subjects with familial hypercholesterolemia with the "French Canadian mutation"

Familial hypercholesterolemia (FH) is seen with high frequency in the province of Québec, Canada. A large deletion (> 10 kb) of the 5'-end of the low density lipoprotein receptor (LDL-R) gene is the major mutation of the LDL-R in FH subjects in Québec (approximately 60% of FH subjects). No mRNA is produced from the allele bearing the mutation, and cellular cholesterol obtained by receptor-mediated endocytosis is under the control of the non-deletion allele. We have previously reported that some patients with the 10-kb deletion (approximately 9%) fail to respond to the hydroxymethylglutaryl coenzyme A reductase (HMG CoA reductase) inhibitor class of medications. We studied mRNA levels of the LDL-R and HMG CoA reductase genes in response to the HMG CoA reductase inhibitor lovastatin in a time- and dose-dependent fashion in cultured human skin fibroblasts and we devised an in vitro model to study the response to drug therapy in subjects with FH. We determined mRNA levels by RNase protection assay in skin fibroblasts obtained from controls (n = 3) and FH subjects with the > 10-kb deletion (responders, n = 3; non responders, n = 3; to drug therapy). We measured 125I-LDL binding on skin fibroblasts grown in the presence of lipoprotein-deficient serum with or without 1 microM lovastatin, using 10 micrograms/mL of 125I-LDL protein. Control subjects exhibited coordinate regulation of the LDL-R and HMG CoA reductase genes in response to lovastatin, 0.1-25 microM, for 0-24 h. Correlation coefficients between mRNA levels of both genes were > 0.9 in controls and FH subjects. However, by linear regression analysis, the corresponding slopes for the correlation between both genes were 0.98 (controls), 3.36 and 3.63 (FH responders and non-responders), indicating a pattern of dissociated but still coordinate regulation in FH subjects. The magnitude of increase of mRNA levels of the LDL-R gene was approximately five-fold over LPDS in controls, two-fold in FH responders and two-fold in non-responders. Binding studies using 125I-LDL reveal that a control subject and all responders had a 2-2.5-fold increase in binding to cell surface receptors but two out of three FH non-responders showed no increase in binding in response to 1 microM lovastatin. The LDL-R and HMG CoA reductase genes are expressed in coordinate regulation in fibroblasts from subjects with FH due to the > 10-kb deletion, but with a proportionately greater up-regulation of the HMG CoA reductase gene. Some subjects, with FH caused by the > 10-kb deletion of the LDL-R gene, who fail to respond to HMG CoA reductase inhibitors have abnormal LDL receptor binding activity at the cell surface in response to lovastatin in vitro.

LDL-Apheresis Atherosclerosis Regression Study (LAARS). Effect of aggressive versus conventional lipid lowering treatment on coronary atherosclerosis

BACKGROUND

Intensive lipid lowering may retard the progression of coronary atherosclerosis. LDL-apheresis has the potential to decrease LDL cholesterol to very low levels. To assess the effect of more aggressive lipid lowering with LDL-apheresis, we set up a randomized study in men with hypercholesterolemia and severe coronary atherosclerosis.

METHODS AND RESULTS

For 2 years, 42 men were treated with either biweekly LDL-apheresis plus medication or medication alone. In both groups a dose of simvistatin of 40 mg per day was administered. Baseline (mean+/-SD) LDL cholesterol was 7.8+/-1.9 mmol x L(-1) and 7.9+/-2.3 mmol x L(-1) in the apheresis and medication groups, respectively. The mean reduction in LDL cholesterol was 63% (to 3.0 mmol x L(-1)) and 47% (to 4.1 mmol x L(-1)), respectively. Primary quantitative coronary angiographic end points were changes in average mean segment diameter and minimal obstruction diameter. No differences between the apheresis and medication groups were found in mean segment diameter (-0.01+/-0.16 mm versus 0.03+/-0.16 mm, respectively) or in minimal obstruction diameter (0.01+/-0.13 mm versus 0.01+/-0.11 mm, respectively), expressed as means per patient. On the basis of coronary segment, mean percent stenosis of all lesions showed a tendency to decrease; only in the apheresis group more minor lesions disappeared in comparison to the medication group. On bicycle exercise tests, the time to 0.1 mV ST-segment depression increased significantly by 39% and the maximum level of ST depression decreased significantly by 0.07 mV in the apheresis group versus no changes in the medication group.

CONCLUSIONS

Two years of lipid lowering both with medication alone or LDL-apheresis with medication showed angiographic arrest of the progression of coronary artery disease. However, more aggressive treatment induced functional improvement, which may precede anatomic changes.

Extracorporeal removal of lipids by dextran sulfate cellulose adsorption

Extracorporeal removal of low-density lipoprotein (LDL) cholesterol by dextran sulfate adsorption is indicated in patients with diet and drug resistant hyper-cholesterolemia 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[a]) to negatively charged dextran sulfate covalently 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.

Removal of LDL from plasma by adsorption reduces adhesion molecules on mononuclear cells in patients with arteriosclerosis obliterans

BACKGROUND

There is increasing evidence that immune processes are important in the development of atherosclerosis. We investigated whether low density lipoprotein (LDL) adsorption therapy affected serum cytokine levels and the expression of adhesion molecules on peripheral blood mononuclear cells (lymphocytes and monocytes) in patients with arteriosclerotic obliterance (ASO).

METHODS AND RESULTS

LDL adsorption therapy was repeated ten times over a period of three months in ten ASO patients. The total serum cholesterol and LDL cholesterol levels were significantly reduced at the end of therapy. This was associated with a significant improvement in Fontaine's classification and ankle pressure index. We also measured serum levels of inflammatory cytokines (interleukin-1 beta (IL-1 beta), IL-6 and tissue necrosis factor alpha (TNF-alpha)) and expression of adhesion molecules (lymphocyte function-associated antigen 1 alpha (LFA-1 alpha), LFA-1 beta, CD2, very late antigen (VLA)-4, VLA-5 and CD44) on mononuclear cells in the same patients and a group of healthy subjects. Serum levels of all inflammatory cytokines were markedly higher in ASO patients compared with healthy subjects, but there was no significant difference in the level before and after LDL adsorption. VLA-4 expression on CD3+ cells, but not of other adhesion molecules, was markedly higher in ASO patients compared with healthy subjects. LDL adsorption caused a significant reduction in CD2, VLA4 and VLA-5 expression on CD3+ cells. Furthermore, VLA-4 and VLA-5 expression on monocytes diminished significantly after LDL adsorption.

CONCLUSIONS

Our results indicate that LDL adsorption-induced immunoregulation is mediated by an indirect stimulatory effect on the immune system. The results suggests that improved peripheral circulation produced by LDL adsorption may reflect improved immune dysfunctions of atherosclerotic lesions in ASO patients.

Response to HMG CoA reductase inhibitors in heterozygous familial hypercholesterolemia due to the 10-kb deletion ("French Canadian mutation") of the LDL receptor gene

The 10-kb deletion ("French Canadian mutation") of the low-density lipoprotein (LDL) receptor gene is the most common mutation causing familial hypercholesterolemia among subjects of French Canadian descent. In affected subjects, it results in a null allele of the LDL receptor gene and provides a unique opportunity to examine single-allele regulation of this gene in humans. We sought to ascertain the response of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase in subjects with the French Canadian mutation of the LDL receptor gene and to correlate this response with biochemical variables and the haplotype of the nondeletion LDL receptor allele. The prevalence of non-responders to high doses of HMG CoA reductase inhibitors (defined as < 15% decrease in LDL cholesterol [LDL-C] from baseline values after dietary intervention) was ascertained in 105 patients heterozygous for the 10-kb deletion after excluding first-degree relatives and those on combined lipid-lowering therapy or other lipid-lowering agents. Lipoprotein cholesterol levels were examined after a diet period (30% calories as fat) and after receiving HMG CoA reductase inhibitors as mono-therapy for a minimum of 3 months. The mean reduction in total cholesterol was 45 +/- 23%, in LDL-C 33 +/- 15%, and in triglycerides 32 +/- 49% (all P < .005). There was a slight increase in high-density lipoprotein cholesterol of 8.5 +/- 18% (P > .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of restenosis after percutaneous transluminal coronary angioplasty by reducing lipoprotein (a) levels with low-density lipoprotein apheresis. Low-Density Lipoprotein Apheresis Angioplasty Restenosis Trial (L-ART) Group

This study was designed to test the hypothesis that high plasma lipoprotein (a) (Lp[a]) levels are associated with an increase incidence of restenosis after angioplasty. Elective transluminal coronary angioplasty was performed in 66 patients (58 men and 8 women) aged 57 +/- 9 years (mean +/- SD). Two days before and 5 days after angioplasty, all patients underwent low-density lipoprotein (LDL) apheresis with a dextran sulfate cellulose column as an Lp(a) absorbent; 39 patients also received 10 mg of pravastatin and 1,500 mg of niacin daily. Restenosis was defined as a recurrent luminal stenosis of > or = 50% in a previously dilated segment. Median Lp(a) levels were reduced from 23.3 mg/dl before apheresis to 10.9 mg/dl after apheresis (p < 0.0001). Angiography performed 2 to 9 months after angioplasty revealed restenosis in at least 1 site in 38% of the 137 control patients and in 32% of the 66 patients who underwent apheresis. Restenosis also occurred in 37% of the patients who underwent apheresis alone and in 28% of the patients who also received pravastatin and niacin in combination with LDL apheresis. The restenosis rate was 21% in the 42 patients whose Lp(a) levels were significantly reduced > or = 50%, and in 50% of the 24 patients whose Lp(a) levels were significantly reduced < 50% (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of lipoprotein(a) by LDL-apheresis using a dextran sulfate cellulose column in patients with familial hypercholesterolemia

Lipoprotein(a) (Lp(a)) was eliminated by LDL-apheresis using a dextran sulfate cellulose column in 3 homozygous and 10 heterozygous familial hypercholesterolemic patients. Immediately after LDL-apheresis by the LA-15 system (continuous LDL apheresis), there were significant reductions in Lp(a) concentrations (28.6 +/- 11.8 mg/dl (mean +/- S.E.) to 9.6 +/- 5.6 mg/dl (P < 0.01)), and in LDL-cholesterol concentrations (156 +/- 32 mg/dl to 48 +/- 18 mg/dl (P < 0.01)). Immediately following LDL-apheresis, Lp(a) and LDL-cholesterol were reduced by 67.4% +/- 11.6% and 68.3% +/- 11.8%, respectively. The removal of Lp(a) paralleled that of LDL-cholesterol. The reduced levels of Lp(a) nearly returned to baseline within 7 days. In 6 of the heterozygous FH patients the rates of recovery of LDL cholesterol and Lp(a) were calculated, according to Apstein's equation after discontinuing lipid altering drug treatment for 4 weeks. Mean constant k values of LDL cholesterol and Lp(a) were 0.354 (range: 0.136-0.752) and 0.427 (range 0.112-0.933), respectively. The average concentration during the 7 days following LDL-apheresis was calculated. Average reductions were 28% in LDL cholesterol and 18% in Lp(a). Pravastatin treatment, which continued for 4 weeks, significantly decreased LDL cholesterol (P < 0.01); however, before LDL-apheresis pravastatin treatment significantly increased Lp(a) levels (P < 0.05) in a small number (n = 6) of the FH patients, who had been regularly treated with LDL-apheresis. These results suggest that LDL-apheresis using the dextran sulfate cellulose column is an effective treatment to reduce levels of serum Lp(a) and LDL proportionally. This therapy may be of value in the prevention and regression of coronary artery disease in FH patients.

Extracorporeal circuit heparinization in selective low density lipoprotein apheresis: changes in patient hemostasis and low molecular weight heparin benefit

Treatment by low density lipoprotein (LDL) apheresis using dextran sulfate columns (DSC) leads to hemostasis alterations with prolonged activated partial thromboplastin time (APTT) of more than 120 seconds. In order to explain this hypocoagulability, we studied hemostasis parameters both in patients and in the extracorporeal circulation (ECC). Hemostasis changes are first related to unfractionated heparin (UFH)--needed to avoid circuit coagulation--which leads to high residual heparinemia in the patient (more than 3 times the recommended level for therapeutic use). Second, the hypocoagulability is induced by a coagulation factor decrease (primarily factors V, VIII, and X) mainly due to an adsorption mechanism on dextran sulfate. Studies on samples from column inflow, outflow, and eluate confirm this mechanism. Low molecular weight heparin (LMWH) can be used in LDL apheresis on DSC without major changes in lipid removal or coagulation factors compared to UFH. The benefit of using LMWH is to reduce residual heparinemia into the therapeutic range.