Heparin extracorporeal LDL precipitation (HELP) : an effective apheresis procedure for lowering Lp(a) levels

Abstract Heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) is based on the precipitation of apolipoprotein B (apo B) containing lipoproteins with heparin at low pH (4.85). In in vitro experiments we could show that Lp(a) is quantitatively (>99%) precipitated from plasma by heparin in the pH range 4.6–5.2. The acute changes in Lp(a) after a single HELP-LDL apheresis were investigated in twelve patients with Lp(a), concentrations > 30 mg/dl. A single treatment caused a highly significant decrease (62%) in the concentration of Lp(a), similar to the decrease (60%) observed for LDL-cholesterol. Analysis of the data from ten patients with different apo(a) phenotypes indicated that Lp(a) is eliminated with almost 100% efficiency in the extracorporeal circulation, irrespective of apo(a) phenotype and plasma concentration. The mean rate of recovery of Lp(a) following HELP-LDL apheresis was slightly slower than that of LDL-cholesterol. Plasma Lp(a) concentrations were monitored in seven patients over 2 years. Mean Lp(a) concentrations after 2 years were lower than pre-treatment levels, indicating that repeated elimination of the lipoprotein does not lead to an induction in its synthesis. HELP-LDL apheresis should be particularly suitable for treatment of patients with elevated LDL-cholesterol levels who are also at increased coronary risk because of high Lp(a) concentrations.