An intravenous plasmapheresis catheter which excludes >99.4% of platelets from external ultrafiltration circuits is currently undergoing safety and efficacy trials for fluid removal from NYHA class II-IV congestive heart failure patients resistant to diuretic drug therapy. In animals, the SCIP catheter allowed a four fold increase in ultrafiltration efficiency without hemolysis, hemoinstability or external cartridge changes in 72 hours of treatment. Further, systemic anticoagulation was not required. These techniques might be envisioned for treatment of fluid overload in heart failure, surgery or trauma and may have applications in therapeutic apheresis, venous thrombosis, liver disease or autologous tissue engineering.