Enoxaparin Reduces Catheter-associated Venous Thrombosis After Infant Cardiac Surgery

Central venous catheter (CVC) related venous thrombosis (VT) after pediatric cardiac surgery increases morbidity and mortality. Although VT prevention using low-dose anticoagulation therapy has proven ineffective, anticoagulation therapy using high-dose enoxaparin to achieve a therapeutic anti-Xa level has not been studied. We hypothesized that high-dose enoxaparin would reduce VT after pediatric cardiac surgery.

Enoxaparin was administered to infants aged less than 150 days when postoperative CVC duration was anticipated to extend beyond 5 days. The primary outcome was the rate of VT, reexploration for bleeding, and postoperative red blood cell transfusions per 1000 CVC days.

From 2012 to 2019, 157 infants were treated with enoxaparin. Infants were divided into two groups: (1) subtherapeutic (n = 51), in which therapeutic anti-Xa level (0.5 to 1.0 IU/mL) was not achieved; and (2) therapeutic (n = 106), in which therapeutic anti-Xa level was achieved. Baseline demographics demonstrated a lower age at operation in the therapeutic group. The subtherapeutic group had a higher VT rate per 1000 CVC days (8.2) compared with the therapeutic group (2.6; P = .005). Reexploration for bleeding was similar between groups. The number of postoperative red blood cell transfusions per 1000 CVC days was significantly greater in the subtherapeutic group (109.4 vs 81.6; P = .008). Multivariate analysis demonstrated that higher median anti-Xa levels reduced the risk of VT (odds ratio 0.02; 95% confidence interval, 0.001 to 0.63; P = .02).

These data suggest that enoxaparin treatment resulting in a therapeutic anti-Xa level reduces postoperative CVC-associated VT without increasing bleeding complications.