Heparin-induced extracorporeal low-density lipoprotein precipitation.

Heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) is a selective and careful apheresis procedure. Through the application of heparin and lowering the pH value, lipoproteins and fibrinogen are reduced by 50-60%. In addition, adhesion molecules (ICAM-1, VCAM-1, p-selectin) which play a key role in the development and progression of atherosclerosis, are also markedly reduced. A PET scan performed 20 h after LDL apheresis shows the improvement of coronary vasodilation capacity. This is supposed to be mainly due to the marked reduction of LDL cholesterol and fibrinogen with consecutive improvement of endothelial dysfunction and rheology.