Retention of lepirudin at the tip of a silicone catheter: a better catheter flush solution?

Because central venous catheters often become blocked by clot at their tip despite heparin flushes, a more effective anticoagulant is needed. We hypothesize that lepirudin, a recently introduced protein anticoagulant, might be more effective than heparin because of its tendency to adsorb to silicone, a commonly used catheter material. We preliminarily tested this hypothesis in vitro by measuring residual lepirudin and heparin activity at the tip of a catheter that had been submerged in a flowing stream of water for various periods of time. We observed that lepirudin is less readily removed than heparin from the catheter by fluid washing over it. This "slow-release" property of lepirudin might provide prolonged protection against clot formation at the catheter tip. A clinical trial will be necessary, however, to determine whether this property translates into significant improvement in catheter function.