LDL-apheresis is a method of extracorporeal elimination of serum LDL-cholesterol used for treating patients with severe hyperlipidemia resistant to diet and pharmacotherapy. A practically applicable marker that may possibly be used to ascertain the efficacy of this treatment in lowering the activity of atherosclerosis are still to be found and remains an unresolved problem. Activity of primary hemostasis plays an important role in the process of developing atherosclerotic complications. This fact led us to hypothesize that the investigation of primary hemostatic activity might be a useful marker for monitoring LDL-apheresis efficacy. The aim of this work was to verify this hypothesis. METHODS AND PATIENTS: Commercial analyzer Dade Behring PFA-100, Germany (PFA, platelet function analysis) was used for all investigations. This analyzer enables quantitative measurement of platelet-mediated hemostasis in uncoagulated (citrated) blood. The method simulates platelet activation by mechanical stress (shear stress), and also simulates contact of platelets with collagen. A total of nine long-term treated patients with familial hypercholesterolemia were included in the study group (4 females and 5 males). Ages ranged from 17 to 59 years (average 46.4, median 55). Two patients had homozygous hypercholesterolemia. Eighteen sample pairs were examined using collagen/epinephrine (COL/EPI) membrane and 17 pairs were examined using collagen/ADP (COL/ADP) membrane, the total number of samples amounted to 70. RESULTS: Closure time (CT) values were prolonged after separation in all cases but CT prolongation was not statistically significant (p < 0.14). No differences between homozygous and heterozygous patients were found (p < 0.05). CONCLUSION: Investigation of primary hemostasis using PFA-100 analyzer is not a suitable marker and should not be used to determine the optimal intensity of individual LDL-apheresis procedures.

Department of Hematology University Hospital in Hradec Kralove Hradec Kralove Czech Republic