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Thrombotic occlusion is frequently a complication of central venous catheters (CVCs). The original designers and producers of CVCs recommended heparin flush regimens to prevent thrombosis and maintain patency. This has become standard practice although no studies have demonstrated a relationship between heparin flushing and reduction of catheter thrombosis. Many consider the routine use of heparin flushing innocuous. However, serious complications including drug interactions and heparin induced thrombocytopenia and thrombosis syndrome (HITS) have been reported in association with heparin flushing. Numerous studies comparing heparin to saline flushing in peripheral devices suggest equal rates of thrombotic occlusions. The purpose of this study was to examine the incidence of thrombotic occlusions in CVCs using heparin compared to saline flushing. The study involved 78 cancer patients undergoing apheresis collection for peripheral blood stem cells; 29 received saline flushes and 49 received heparin (100 U/ml of saline) flushes. Study endpoints included slow apheresis flow rate (< 50 ml/min), urokinase use for thrombolysis, and radiographic evidence of catheter thrombosis. No significant differences were found for any endpoint between the two groups. These findings suggest saline may be as effective as heparin for maintaining patency of CVCs.

No previously published studies have described double-lumen hemodialysis/apheresis catheters for use with continuous-flow apheresis collection of peripheral stem cell (PSC). We prospectively evaluated experiences with these catheters during both PSC collection and transplantation. Because of previously-described successful experiences with single-lumen apheresis catheters placed in the inferior vena cava, all catheters evaluated in this study were placed in this anatomic location. Our experience demonstrated high rates of thrombotic occlusion (65%) and catheter-related infections (15%). This method of access should not be considered optimal in its present state of use. Further investigation into preferred catheter design, anatomic location, and thrombosis prophylaxis during continuous-flow apheresis is warranted.

Granulocyte-macrophage colony stimulating factor (GM-CSF) has been used to augment circulating hemopoietic stem cells in the peripheral blood and promote efficient peripheral stem cell (PSC) collection. Anecdotal reports indicate that GM-CSF may contribute to apheresis catheter dysfunction during PSC collection. We prospectively evaluated thrombotic occlusion rate of inferior vena cava (IVC) catheters following introduction of GM-CSF compared with a control group who underwent PSC collection prior to introduction of GM-CSF. Both groups were given aspirin (325 mg daily). The active treatment group was given GM-CSF (starting dose 250 micrograms/m2/day) as continuous infusion via the IVC catheter. The rate of thrombotically occluded catheters increased from 1/29 (3%) to 20/37 (54%) (p < 0.0001). Thrombi developing during GM-CSF therapy were unusual as 25/36 (69%) occlusions cleared with mechanical clot aspiration and did not require lytic agents.