Objectives: To investigate the in vitro effects of detergent sclerosants on antithrombotic pathways.
Materials and methods: Proteins C, S and antithrombin (AT) were assayed in normal plasma treated with increasing concentrations of sodium tetradecyl sulphate (STS) and polidocanol (POL). Activated protein C (APC) was investigated by mixing normal plasmas with sclerosants and testing with the activated partial thromboplastin time (APTT) and dilute Russell's viper venom time in the presence and absence of APC. The effect on factor Xa (FXa), heparin and enoxaparin was investigated using chromogenic anti-FXa and APTT methods.
Results: High concentration (>0.6%) STS significantly destroyed proteins C, S and AT whereas POL only caused a mild reduction in PC and AT and a moderate (60%) reduction in PS levels. STS potentiated the anticoagulant effect of APC while POL increased APC resistance. STS mimicked AT and demonstrated significant anti-Xa and anti-IIa activity. STS demonstrated a similar anticoagulant profile to heparin but was 1000x weaker. It also significantly potentiated the anticoagulant effect of heparin while POL had less effect.
Conclusion: STS and POL demonstrated quite distinct and sometimes opposite effects on the antithrombotic mechanisms assayed. These effects were concentration-dependent and in general, STS had the greatest effect on antithrombotic proteins.