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

Retrospective Comparison of 5 different Methods for Long-Term LDL-Apheresis in 20 Patients between 1986 and 2001

Purpose

To compare long-term efficacy and biocompatibility of the 5 most commonly applied LDL-apheresis techniques using a specifically modified calculation method of the area under the curve (AUC) for laboratory parameters.

Design

Retrospective long-term analysis of 20 patients with homozygous or severe heterozygous familial hypercholesterolemia.

Procedures

The following 5 extra-corporeal LDL-apheresis methods were compared: IMAL (Immuno Adsorption of Lipoproteins), DSA (Dextran Sulphate Adsorption), HELP (Heparin Induced Extra-corporeal LDL Precipitation), DALI (Direct Adsorption of Lipoproteins), MDF (Membrane Differential Filtration).

Main outcome measures

AUC derived plasma concentrations (CAUC) of lipoproteins between two apheresis procedures and their long-term course. Comparison of biocompatibility and efficacy concerning the LDL-C target of < 2.6 mmol/L of 5 apheresis techniques. Progression of atherosclerosis in patients with severe hypercholesterolemia.

Main findings

The means of AUC derived average plasma concentrations (CAUC) of all treatment intervals were for LDL-C and the LDL/HDL ratio as follows: IMAL (5.59 mmol/L; ratio 4.1), DSA (3.03 mmol/L; ratio 2.0), HELP (4.06 mmol/L; ratio 2.2), DALI (3.83 mmol/L; ratio 3.3), MDF (3.26 mmol/L; ratio 3.2). Coronary heart disease and cardiac events (myocardial infarction, PTCA/ stent implantation, CABG) progressed in only 2 patients whereas atherosclerosis manifestations (sclerosis abdominal aorta, carotid artery stenosis, peripheral vascular disease) worsened in 13 patients. Mean ergometric capacity improved from 112 to 118 Watt.

Conclusions

All 5 apheresis methods (IMAL, DSA, HELP, DALI, MDF) proved to be safe and suitable for long-term treatment in patients with severe hypercholesterolemia. The introduction of the CAUC revealed that the target of LDL-C < 2.6 mmol/L was not achieved with regard to the time averaged concentration (CAUC).

Dextran-sulfate-adsorption of atherosclerotic lipoproteins from whole blood or separated plasma for lipid-apheresis—Comparison of performance characteristics with DALI and lipidfiltration

For many years dextran sulfate adsorption (DSA) treatment of separated plasma has been an established technology for low-density lipoprotein (LDL)-elimination. Recently a system for the treatment of whole blood based on DSA was introduced into clinical practice. To further characterize DSA treatment of whole blood, the performance characteristics of both DSA modalities were compared at two investigational sites with two alternative LDL apheresis systems being already in routine clinical use. In prospective cross-over design, DSA whole blood treatment was compared with a whole blood polyacrylate LDL adsorption system (DALI) in one study group. DSA for plasma treatment was compared with Lipidfiltration in cross-over design in a second study group. In total, 12 patients on chronic LDL apheresis received 169 treatments. Six patients were treated twice with whole blood polyacrylate adsorption and twice with whole blood DSA. LDL-cholesterol (74.9-78.0%) and lipoprotein (a) (72.1-73.3%) were reduced by both with equal efficacy. DSA achieved a significantly higher reduction rate of fibrinogen. Another six patients were treated eight times with DSA plasma adsorption followed by 16 Lipidfiltration treatments. LDL-cholesterol (67.0-70.2%) and lipoprotein (a) (69.2-73.7%) were reduced by both with equal efficacy. Fibrinogen was eliminated more efficiently by Lipidfiltration (50.2 vs. 38.5%). DSA proved to be a safe and effective in both treatment modes, for plasma as well as for whole blood. At the discretion of the apheresis specialist, depending upon the status of national approval, DSA of whole blood complements the armamentarium of powerful modalities for extracorporeal elimination of atherosclerotic lipoproteins to meet specific individual, medical, or logistic needs.

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

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