Hageman factor activation by polysaccharides: effect of molecular weight

Different effects of two methods of low-density lipoprotein apheresis on the coagulation and fibrinolytic systems

OBJECTIVE

Immunoadsorption (IMA) and dextran sulfate adsorption (DSA) are two methods for selective extracorporeal elimination of low-density lipoproteins which are known as LDL apheresis. Their influence on haemostasis until now is widely unknown.

DESIGN

The effects of both LDL apheresis procedures on the coagulation and fibrinolytic systems were compared amongst five patients treated with IMA and four patients who received a DSA therapy.

SUBJECTS

All patients with severe heterozygous familial hypercholesterolaemia were participants in a long-term LDL apheresis programme with treatments every 1-2 weeks.

INTERVENTION

Combined anticoagulation with heparin and citrate in IMA, and also heparin exclusively in DSA were used for the extracorporeal circulation.

MEASURES

Blood samples were taken immediately before and after a single LDL apheresis and five times during the weekly interval until the next therapy.

RESULTS

DSA had a significantly greater effect on standard clotting tests than IMA at the end of plasma therapy despite identical dosages of heparin. DSA caused a considerable reduction of the coagulation factors V, VIII:C, vWF:Ag, XI, XII, and prekallikrein by 48-99% at the end of apheresis treatment whereas only factor VIII:C showed a marked decrease of 72% after IMA. All abnormalities of the global coagulation tests and of most clotting factors were restored 1 day after treatment in both procedures followed by a moderate rebound phenomenon of single coagulation factors during the next few days in IMA-treated patients.

CONCLUSION

DSA exerts a more profound effect on the coagulation system than IMA by a substantial co-elimination of various clotting factors in addition to the desired removal of atherogenic lipoproteins.