Continuous Heparin Infusion to Prevent Catheter-related Thrombosis

A Randomized, Controlled Trial of Continuous Heparin Versus Placebo Infusion to Prevent Catheter-related Thrombosis in Infants After Cardiac Surgery

Catheter-related thrombosis could impair blood flow in the vein, block the central venous catheter, induce catheter-related infection or venous thromboembolism in the deep veins or pulmonary vessels, which furthermore progress into the post-thrombotic syndrome. Researches using echogenic mass as the primary outcome could miss those premature thrombi which might not be seen on traditional ultrasonography but may be detected by Duplex and Doppler ultrasound with vessel compression. Moreover, studies indicated that some thrombus developed after the catheter removal. Removal of the catheter is not the endpoint of thrombus detection. This study is designed to determine the preventive effects of continuous heparin infusion on real-world central venous catheter-related thrombosis in infants after cardiac surgery.

Catheter-related thrombosis could impair blood flow in the vein, block the central venous catheter, induce catheter-related infection or venous thromboembolism in the deep veins or pulmonary vessels, which furthermore progress into the post-thrombotic syndrome. Researches using echogenic mass as the primary outcome could miss those premature thrombi which might not be seen on traditional ultrasonography but may be detected by Duplex and Doppler ultrasound with vessel compression. Moreover, studies indicated that some thrombus developed after the catheter removal. Removal of the catheter is not the endpoint of thrombus detection. This study is designed to determine the preventive effects of continuous heparin infusion on real-world central venous catheter-related thrombosis in infants after cardiac surgery. One hundred and twenty-four infants were randomized to the intervention group or the control group. Unfractionated heparin or normal saline was infused continuously through each lumen of the central venous catheter at the speed of 0.5 ml/h/line until the catheter was removed. Catheter-related thrombosis was detected by point-of-care Duplex and Doppler ultrasound periodically until 30 days after the cardiac surgery or discharge, whichever comes first.

Infant participants were blinded naturally, while ultrasonographers for central venous catheter (CVC)-related thrombosis were blinded, especially after interventions were stopped.

For infants without thrombosis at enrollment, heparin 1 U/kg/h/line for term infants was used and 0.5 U/kg/h/line for preterm infants. The speed of infusion was 0.5ml/h. For infants with thrombosis at enrollment, heparin 10-15 U/kg/h for term infants was used with a target activated partial thromboplastin time 60-70s. Other interventions were at the clinical team's discretion under the local protocol.

CVC-related thrombosis of any catheter as imaged by echocardiogram or ultrasound at 30 days after cardiac surgery. Thrombus was defined as an echogenic mass near the tip of the catheter or slow/no flow detected by Duplex and Doppler ultrasound at the nearby vessels and the on-site vessel couldn't be clasped as narrow as the collateral vessel by compression of the probe.

Abnormal coagulation and hemostasis were defined as treatment initiation by the clinical teams at the discretion of heparin adverse events. Heparin-induced thrombocytopenia was confirmed with consistent low platelet level and positive enzyme-linked immunosorbent assay heparin-platelet factor 4 antibody assay. Catheter-related sepsis was defined as culture of the same organism from both the catheter tip and at least one percutaneous blood culture. Culture of the same organism from the catheter was also accepted as an alternative of culture of catheter tip.

The symptoms of post-thrombotic syndrome included aching, swelling, itchy and ulcer in the indwelling site and the collateral varicose veins.

Inclusion Criteria: less than 3 months of age at admission, post-cardiac surgery, with CVC indwelled Exclusion Criteria: parents' refusal, requiring postoperative anticoagulant administration (extracorporeal membrane oxygenation support, prosthetic devices), the contradiction to heparin (coagulopathy or hypercoagulable state, platelet level less than 50000/dL, clinically significant bleeding tendency, allergy to heparin)

All data published and other related data were available after publication. No private information would be published.