Haemocompatibility of endovascular coronary stents: Wiktor GX (c)

The stent to be examined (Wiktor((C))-Stent, Medtronic ESTC, Kerkrade, NL) was mounted into a closed-loop tubular-system and perfused with platelet-ri ch plasma (PRP). As controls the tubular-system without stent (as non-throm bogenic control) and secondly the tube filled with glassbeads (as thromboge nic control) were evaluated. A decrease in the number of singularly circulating thrombocytes correlated well with an increase in circulating platelet aggregates. The increasing ac tivation of thrombocytes was demonstrated by immunolabelling of surface str uctures (CD62) which become prominent on activation of thrombocytes. The in crease in case of the non-thrombogenic controls is thought to be due to the action of the roller-pump. This increase was coincident with an increase i n immunologically labelled GPIIb/IIIa receptors and well correlated with an increase in platelet activation as demonstrated by the elevated CD62 label . In spite of the use of anticoagulation principles in the perfusion model, t hrombin was generated (measured by the TAT-complex) in all three cases and the completed coagulation (measured by the occurrence of fibrin D-dimers) a lso happened. The amount of D-dimers was small, however, in the cases of no n-thrombogenic controls and of tubes equipped with stents. Only after the c ontact of PRP with tubes filled with glass-beads a significant increase in D-dimers followed. In conclusion the implantation of a stent led to an acti vation, adherence and aggregation of thrombocytes to a somewhat greater ext ent as in the control-system. It has, however, a much less thrombogenic sur face than glass-beads.