Treatment of hypercholesterolemia with heparin-induced extracorporeal low-density lipoprotein precipitation (HELP).

Abstract

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.