Abstract 2354: Heparin and Catheter-related Thrombosis in Infants Following Cardiac Surgery: Interim Results From A Randomized Trial
Background: Intracardiac and/or percutaneous central venous catheters (CVCs) are used routinely to manage post-operative pediatric cardiac patients. Catheter-related thrombosis has been reported to occur in 8 –35% of pediatric patients with CVCs, and is more common in smaller patients and those with CVCs in place for several days.
Methods: To determine if treatment with a continuous heparin infusion reduces catheter-related thrombosis, we performed a randomized, placebo-controlled, double-blinded trial. Entry criteria included age < 1 year and planned insertion of at least one CVC at surgery. We excluded patients with known coagulopathy, a history of bleeding, and indication for post-operative heparin therapy. Subjects received either a continuous infusion of heparin 10 units/kg/hr or placebo (D5W) until all CVCs were removed, for up to 14 days. Thrombosis was assessed by serial ultrasonography, and any catheter malfunction was recorded. From 11/05 to 3/07 we enrolled 70 subjects; 36 received heparin, 26 received placebo, and 8 were withdrawn before initiation of study drug. We performed an interim analysis of the 62 subjects who received study drug; they represent 39% (62/160) of total planned study enrollment.
Results: Pre- and post-operative variables were comparable between treatment groups. The thrombosis rate in the heparin as compared to the placebo group was 19% vs. 15% (p=0.68). Subjects in the heparin group had a higher mean partial thromboplastin time (PTT) (55 ± 28 vs. 45 ± 10 seconds, p=0.01), and this difference was greater for those aged < 30 days (65 ± 14 vs. 45 ± 4 seconds, p=0.02). Subjects with CVCs in place > 6 days had a greater risk of catheter malfunction (OR 6.1, 95% CI 1.3–28.8, p=0.02). No differences in other secondary outcome measures or in adverse events, including bleeding or need for red cell transfusion, were observed.
Conclusions: From an interim analysis, we found catheter-related thrombosis in 18% of neonates and infants who had one or more CVCs following cardiac surgery. A continuous infusion of heparin 10 units/kg/hr appears safe but does not appear to reduce the incidence of catheter-related thrombus formation. Heparin at this dose caused an increase in PTT values, which unexpectedly was more pronounced in neonates.