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.     

Efficacy of different low-density lipoprotein apheresis methods.

Low-density lipoprotein (LDL) apheresis is a treatment option in patients with coronary heart disease and drug resistant hypercholesterolemia. Various apheresis systems based on different elimination concepts are currently in use. We compared the efficacy of 4 different apheresis systems concerning the elimination of lipoproteins. The study included 7 patients treated by heparin extracorporeal LDL precipitation (HELP), 10 patients treated by immunoadsorption, 8 patients treated by dextran-sulfate adsorption, and 4 patients treated by cascade filtration. Ten subsequent aphereses were evaluated in patients undergoing regular apheresis for more than 6 months. Total cholesterol decreased by approximately 50% with all 4 systems. LDL cholesterol (LDL-C) (64-67%) and lipoprotein a [Lp(a)] (61-64%) were decreased more effectively by HELP, immunoadsorption, and dextran-sulfate apheresis than by the less specific cascade filtration system [LDL-C reduction 56%, Lp(a) reduction 53%]. Triglyceride concentrations were reduced by 40% (dextran-sulfate) to 49% (cascade filtration) and high-density lipoproteins (HDL) by 9% (dextran-sulfate) to 25% (cascade filtration). On the basis of plasma volume treated, HELP was the most efficient system (LDL-C reduction 25.0%/L plasma), followed by dextran-sulfate (21.0%/L plasma), cascade (19.4%/L plasma), and immunoadsorption (17.0%/L plasma). However, a maximal amount of 3 L plasma can be processed with HELP due to concomitant fibrinogen reduction while there is no such limitation with immunoadsorption. Therefore, the decision of which system should be used in a given patient must be individualized taking the pre-apheresis LDL concentration, concomitant pharmacotherapy, and fibrinogen concentration into account.     

Three low density lipoprotein apheresis techniques in treatment of patients with familial hypercholesterolemia: a long-term evaluation.

Low density lipoprotein (LDL) apheresis is a treatment option for patients with severe hypercholesterolemia not adequately responding to drug treatment who have developed coronary heart disease. We regularly treated 18 patients with immunoadsorption, 8 with heparin induced extracorporeal LDL precipitation (HELP) and 8 with dextran sulfate adsorption for a mean of 4.6 +/- 2.6 years. The effects on LDL cholesterol, high density lipoprotein (HDL) cholesterol, and lipoprotein (a) were comparable among all 3 techniques. Twelve patients were treated for longer than 5 years and 18 patients for longer than 3 years. The evaluation of coronary angiograms (23 patients) revealed a definite regression of coronary lesions in 3 patients; in all other patients, there was a halt in progression. Three patients suffered a sudden cardiac death and 1 patient a nonfatal myocardial infarction due to the occlusion of a coronary bypass. In 9 of 11 patients, no atherosclerotic lesions developed in the coronary bypasses. No severe side effect of either procedure was observed. In conclusion, aggressive lipid lowering by LDL apheresis can stabilize coronary atherosclerosis in most patients.     

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.     

Coronary risk factor management for the prevention and treatment of graft vessel disease in heart transplant patients.

There is increasing evidence that atherogenic risk factors largely contribute to the pathogenesis of graft vessel disease (GVD) after heart transplantation. Initial endothelial damage of the transplant heart derives from reperfusion ischemia during operation, repeated infections, and rejection episodes. Immunosuppressive medication considerably increases low density lipoprotein (LDL) cholesterol, lipoprotein(a), and fibrinogen blood levels, which in turn further damage the endothelium of the graft coronaries. Probably, this interplay of immunological and atherogenic factors accounts for the rapid development of GVD and its poor prognosis. The rapidity of the disease process makes it necessary to eliminate important risk factors as early and as efficiently as possible. Therefore, we studied whether heart transplant patients could benefit from a combined treatment of statins and apheresis heparin extracorporeal LDL/fibrinogen precipitation (HELP), which has already been shown to be beneficial for the treatment of advanced coronary artery disease. Such a combined treatment allows simultaneous and drastic reduction of LDL, lipoprotein(a), and fibrinogen blood levels and significantly prevented GVD. Moreover, it did not affect the prevention of rejections and infections, respectively.     

Heparin-Induced extracorporeal low-density lipoprotein precipitation apheresis: a new therapeutic concept in the treatment of sudden hearing loss.

Vascular events, immunological processes, and viral infections have to be considered as pathomechanisms for most cases of sudden hearing loss (SHL). In order to clarify predisposing conditions for vascular events. hemorheological parameters have been studied in 53 patients suffering from SHL within 5 days of onset, along with a control group. The striking result was a significantly elevated level of plasma fibrinogen leading to a significantly increased erythrocyte aggregation and plasma viscosity. No significant difference could be found in all other parameters of clinical chemistry, hematology, and hemostasis. These results encouraged us to use heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) apheresis, which acutely and drastically reduces LDL. fibrinogen, and lipoprotein (a) in the treatment of patients suffering from sudden hearing loss and hyperfibrinogenemia or hypercholesterolemia. In a pilot study including 30 patients, we found a better recovery of hearing in the patients treated with a single HELP apheresis when compared to conventional treatment for 10 days with prednisolone and dextranes. Currently, we verify these results in a larger multicenter trial in patients regardless of their fibrinogen or LDL levels. In the future, there will be different specific treatments of sudden hearing loss based on the different pathomechanisms. The clinical impression and first controlled data make it likely that HELP apheresis is useful in the therapy of sudden hearing loss with suspected vascular origin.     

Hyperlipoprotein(a)aemia in nephrotic syndrome

The nephrotic syndrome is frequently associated with hyperlipidaemia and hyperfibrinogenaemia, leading to an increased coronary and thrombotic risk, which may be enhanced by high lipoprotein (a) [Lp(a)] concentrations. We followed the quantitative and qualitative pattern of plasma lipoproteins over 18 months in a patient with nephrotic syndrome suffering from premature coronary artery disease and with elevated level of Lp(a) (470 mg dL⁻¹). Analysis of kinetic parameters after heparin-induced extracorporeal plasma apheresis revealed a reduced fractional catabolic rate for both low-density lipoprotein (LDL) and Lp(a). After improvement of the nephrotic syndrome, Lp(a) decreased to 169 mg dL⁻¹ and LDL concentrations were normalized. The decrease of Lp(a) was associated with an increase in plasma albumin concentrations. Analysis of apo(a) isoforms in the patient showed the presence of isoform S2 (alleles 10 and 19). Consequently, the authors' present strategy is to normalize the elevated Lp(a) and fibrinogen levels. For this purpose heparin-mediated extracorporeal LDL precipitation (HELP) apheresis is a promising regimen, helping to reduce the thrombotic risk and prevent coronary and graft atherosclerosis as well as the progression of glomerulosclerosis in our patient.     

Effect of heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) apheresis on hepatitis C plasma virus load.

Association of the hepatitis C virus (HCV) with apolipoprotein B containing lipoproteins has been suggested, and this led to the concept that the low-density lipoprotein (LDL) receptor may also serve as a candidate receptor for HCV uptake into the liver. We have investigated whether heparin-induced extracorporeal LDL precipitation (HELP) LDL apheresis treatment reduces HCV plasma load in 6 patients, all infected for more than 4 years with HCV and resistant against established anti-HCV therapy. HELP apheresis treatment caused an HCV-RNA decrease of 77.3% in mean. This decline was not correlated with LDL-cholesterol reduction. HCV-RNA was retained on the HELP filter as shown for 1 patient. The effect of RNA lowering was only transient due to the high turnover of HCV. However, HELP apheresis may open a window of opportunity for an immune-modulating and antiviral therapy in the interval between two apheresis procedures in patients with high virus load.     

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.     

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.     

Distinct effects of LDL apheresis by hemoperfusion (DALI) and heparin-induced extracorporeal precipitation (HELP) on leukocyte respiratory burst activity of patients with familial hypercholesterolemia

Hypercholesterolemia and oxidative stress are major risk factors in atherogenesis. In the last years, lipid apheresis has been established as an effective clinical therapy by lowering not only elevated plasma low-density lipoprotein (LDL) levels but also by reducing the incidence of cardiovascular events. The aim of the present study was to investigate peripheral leukocyte oxidant generation in patients with familial hypercholesterolemia (FH) undergoing regular LDL apheresis. The activity state of leukocytes was estimated prior to, immediately after, and 2 days after LDL apheresis carried out by two distinct techniques: hemoperfusion with the DALI system and heparin-induced extracorporeal LDL precipitation (HELP). Oxidant generating activity was measured by chemiluminescence (CL) in whole blood and isolated polymorphonuclear leukocytes (PMNL). The results of our study show increased baseline respiratory burst activities in FH patients as compared to healthy controls. Apheresis with the HELP system was followed by increases in leukocyte count, zymosan-induced whole blood CL, and plasma PMNL elastase levels. The DALI technique caused no changes in leukocyte count and elastase levels and decreased whole blood CL activity. Two days after lipid removal the observed changes returned to pre-apheresis levels. Leukocyte activity parameters before and after apheresis did not correlate with the corresponding plasma levels of triglycerides, total cholesterol, and LDL cholesterol, suggesting that different handling in the framework of both apheresis techniques rather than lipid profile changes during therapy accounted for leukocyte activity modulation.     

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.     

LDL-Therasorb immunoadsorption for the treatment of severe hypercholesterolemia refractory to conventional therapy.

The role of severe hypercholesterolemia (SH) as a major risk factor for coronary heart disease has been well established. Not all patients with SH can be treated sufficiently with diet and drugs. In such circumstances, extracorporeal removal of low-density lipoprotein (LDL) cholesterol is required in patients with existing atherosclerosis. The chronic regular application of extracorporeal cholesterol removal demands an efficient and selective method not influencing other plasma components. Several methods have been developed for the extracorporeal reduction of LDL cholesterol using different approaches to achieve selectivity. Today the most selective approach is the use of specific antibodies directed against apolipoprotein B-100. For 17 years, this method has been used in the therapy of patients with SH. Numerous publications demonstrate the safety and efficacy of immunoadsorption (IA) with the LDL-Therasorb System. Within an IA treatment, LDL cholesterol is reduced by 60-70%. The system, however, allows for any desired reduction in the cholesterol levels because the double column system can be alternately loaded and regenerated to enable virtually unlimited treatment of plasma. The treatable plasma quantity is not limited by the nonspecific removal of other plasma components, e.g., coagulation factors, fibrinogen, plasminogen, or immunoglobulins. In long-term studies, the influence of LDL-Therasorb IA on coronary and peripheral atherosclerotic disease has been shown to have a favorable influence on the development of stenoses. In the majority of patients, a stop of progression and even a regression of stenoses could be demonstrated.     

Apheresis technology for prevention and regression of atherosclerosis: an overview.

Low density lipoprotein (LDL) apheresis is at present one method of treatment in homozygous cases of familial hypercholesterolemia (FH). It is also effective in the prevention of the development of coronary atherosclerosis in patients with heterozygous FH and other types of mild hypercholesterolemia, leading to the regression of the stenosing lesions. In this paper, an overview is presented on the development of the devices for LDL apheresis and its short- and long-term effects on FH mainly based upon experience with the Liposorber system. LDL apheresis has served to protect the lives of patients from life threatening diseases like myocardial infarction although observations for more than 10 years in some laboratories have shown that the progression of atherosclerosis has taken place in many patients, and more importantly, the involvement of the aortic valve with calcification has developed, especially in patients who had homozygous FH, making this the most obstinate complication of FH. Therefore, more aggressive treatment or the combination of LDL apheresis with other therapies is required in the future. LDL apheresis has also been approved for the treatment of glomerulosclerosis and arteriosclerosis obliterans.     

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.     

Clinical application and effectiveness of low-density lipoprotein apheresis in the treatment of coronary artery disease.

The Low-Density Lipoprotein Apheresis Coronary Atherosclerosis Prospective Study (L-CAPS) examined whether or not combined low-density lipoprotein (LDL) apheresis and drug therapy apheresis could induce the regression of coronary atherosclerotic lesions in patients with familial hypercholesterolemia. Twenty-eight patients treated with LDL apheresis and drugs and 11 patients treated with drugs alone underwent sequential coronary angiography 2.5 years apart. The frequency of cases with regression or no change was significantly higher for the apheresis group than for the control group (p = 0.004). The LDL apheresis Angioplasty Restenosis Trial (LART) investigated the hypothesis that high plasma lipoprotein (a) (Lp[a]) levels were associated with increased incidences of restenosis after coronary angioplasty. Two days before and 5 days after angioplasty, 66 patients underwent LDL apheresis. The restenosis rates were 21% in the 42 patients whose Lp(a) levels were reduced > or = 50% and 50% in the 24 patients whose Lp(a) levels were reduced < 50% (p < 0.05). LDL apheresis is effective in the prevention of the progression of coronary atherosclerosis. Its potential application in restenosis prevention should be further investigated.     

Effectiveness of cascade filtration plasmapheresis in two patients affected by familial hypercholesterolemia

Hypercholesterolemia has been recognised as a primary risk factor for coronary heart disease. Reduction of plasma levels of total and LDL cholesterol has been shown to decrease coronary atherosclerosis. Plasmapheresis represents an useful non-pharmacological tool to treat severe hypercholesterolemias. We have evaluated the effectiveness of a system of plasmapheresis using a cascade filtration method in two young male subjects (aged 16 and 26 years) with homozygous familial hypercholesterolemia. Both showed severe coronary atherosclerosis as determined by angiography. Procedures were performed at intervals of 7 days in each case. We observed a mean reduction of plasma levels of total cholesterol of 59.5% (range 31.0–75.5%); LDL-cholesterol, 61.6% (range 32.6–77.1%); triglycerides, 48.1%; HDL-cholesterol, 31.1%; apo A-I, 30.8%; and apo B, 57.6%. We also noted a reduction of other parameters, such as fibrinogen (49.9%) and Lp(a) (59.9%). At the end of each procedure about 8 g of cholesterol was removed from the total body pool. A decrease of total proteins (26.9%) and albumin (19.6%) was also observed, but this was completely restored before the next apheresis (1 week). These data show the effectiveness of the removal of LDL in a cascade filtration system, which obtains results not very different from other more selective methods. The lack of selectivity is not much of a problem, since it also reduces other risk factors such as Lp(a) and fibrinogen.     

Effects of direct adsorption of lipoproteins apheresis on lipoproteins, low-density lipoprotein subtypes, and hemorheology in hypercholesterolemic patients with coronary artery disease.

Direct adsorption of lipoproteins (DALI) apheresis has been shown to reduce effectively low-density lipoprotein (LDL) cholesterol and lipoprotein (a) concentrations. However, the effects on nontraditional risk indicators such as hemorheology and LDL subtypes have not been investigated so far. Five patients (2 women, 3 men, age 53 +/- 8 years) with coronary artery disease and severe LDL hypercholesterolemia regularly treated with other LDL apheresis devices entered the study and were then treated with DALI for the first time. Hemorheological and lipoprotein parameters were measured before and immediately after the initial DALI apheresis as well as before the fourth DALI apheresis. Compared to baseline (before the first DALI apheresis), the following parameters were significantly improved (p < 0.05) after the first DALI apheresis: LDL cholesterol (69 +/- 28 versus 208 +/- 82 mg/dl) and cholesterol in each LDL subfraction as well as plasma viscosity (1.23 +/- 0.04 versus 1.37 +/- 0.06 mPa), C-reactive protein, native blood viscosity, red cell aggregation, and red cell deformability. When parameters before the fourth DALI apheresis were compared to baseline, LDL cholesterol was still lower, and red cell deformability was still improved while cholesterol in each subfraction showed a statistical trend to lower concentrations (0.08 < p < 0.14). In conclusion, DALI apheresis not only reduces LDL cholesterol but also induced a significant reduction of cholesterol in all LDL subfractions and improved various hemorheological parameters.     

Current topics on low-density lipoprotein apheresis.

The prognosis of patients suffering from severe hyperlipidemia, sometimes combined with elevated lipoprotein (a) (Lp[a]) levels, and coronary heart disease (CHD) refractory to diet and lipid-lowering drugs is poor. For such patients, regular treatment with low-density lipoprotein (LDL) apheresis is the therapeutic option. Today, there are four different LDL-apheresis systems available: immunoadsorption, heparin-induced extracorporeal LDL/fibrinogen precipitation, dextran sulfate LDL-adsorption, and LDL-hemoperfusion. Despite substantial progress in diagnostics, drug therapy, and cardiosurgical procedures, atherosclerosis with myocardial infarction, stroke, and peripheral cellular disease still maintains its position at the top of morbidity and mortality statistics in industrialized nations. Established risk factors widely accepted are smoking, arterial hypertension, diabetes mellitus, and central obesity. Furthermore, there is a strong correlation between hyperlipidemia and atherosclerosis. Besides the elimination of other risk factors, in severe hyperlipidemia (HLP) therapeutic strategies should focus on a drastic reduction of serum lipoproteins. Despite maximum conventional therapy with a combination of different kinds of lipid-lowering drugs, however, sometimes the goal of therapy cannot be reached. Mostly, the prognosis of patients suffering from severe HLP, sometimes combined with elevated Lp(a) levels and CHD refractory to diet and lipid-lowering drugs is poor. Hence, in such patients, treatment with LDL-apheresis can be useful. Regarding the different LDL-apheresis systems used, there were no significant differences with respect to the clinical outcome or concerning total cholesterol, LDL, high-density lipoprotein, or triglyceride concentrations. With respect to elevated Lp(a) levels, however, the immunoadsorption method seems to be the most effective. The published data clearly demonstrate that treatment with LDL-apheresis in patients suffering from severe hyperlipidemia refractory to maximum conservative therapy is effective and safe in long-term application.     

Influence of atorvastatin versus simvastatin on fibrinogen and other hemorheological parameters in patients with severe hypercholesterolemia treated with regular low-density lipoprotein immunoadsorption apheresis.

Low-density lipoprotein (LDL) apheresis is a treatment option in patients with coronary artery disease and elevated LDL cholesterol concentrations if maximal drug therapy fails to achieve adequate LDL cholesterol reduction. This therapy is more effective when combined with strong lipid-lowering drugs, such as atorvastatin. However, conflicting data have been published concerning the effect of atorvastatin on fibrinogen concentration. Therefore, we investigated the effect of atorvastatin compared to simvastatin on fibrinogen concentration and other hemorheological parameters in patients treated by weekly LDL apheresis. Hemorheological parameters were, studied twice in 9 patients (4 female, 5 male, 54.0+/-8.9 years) with coronary artery disease treated by weekly LDL immunoadsorption, once during concomitant simvastatin therapy (40 mg daily) and once during atorvastatin therapy (40 mg daily). Fibrinogen concentration, plasma and blood viscosity at different shear rates, parameters of red cell aggregation at stasis and shear rate 3/s, and erythrocyte filterability were determined 7 days after the last LDL apheresis after each drug had been given for a minimum for 8 weeks. Fibrinogen concentration did not show any statistically significant difference during therapy with atorvastatin (3.09+/-0.36 g/L) compared to simvastatin (3.13+/-0.77 g/L). Plasma and blood viscosity as well as erythrocyte filterability were also unchanged. The increase in red cell aggregation at stasis during atorvastatin treatment (5.82+/-1.00 U versus 4.89+/-0.48 U during simvastatin; p < 0.05) was inversely correlated with a lower high-density liprotein (HDL) cholesterol concentration (1.17+/-0.21 mmol/L versus 1.31+/-0.30 mmol/L during simvastatin; p < 0.05). LDL cholesterol showed a strong trend to lower concentrations during atorvastatin (4.14+/-0.61 mmol/L versus 4.56+/-0.66 mmol/L during simvastatin; p = 0.07), despite a reduced plasma volume treated (3,547+/-1,239 ml during atorvastatin versus 3,888+/-1,206 mL during simvastatin; p < 0.05). In conclusion, fibrinogen concentration and other hemorheological parameters were unchanged during atorvastatin compared to simvastatin therapy with the exception of a higher red cell aggregation at stasis. Therefore, with respect to hemorheology, we conclude that atorvastatin should not be withheld from hypercholesterolemic patients regularly treated with LDL immunoadsorption.