Gabriela Centers, MD
Pediatric Cardiac Intensive Care Attending
Indiana University / Riley Hospital for Children
Disclosure information not submitted.
Janelle Kummick, PharmD
Clinical Pharmacist
Riley Hospital for Children, Indiana University
Indianapolis, Indiana, United States
Disclosure information not submitted.
Vincent Faustino, MD, MHS
Pediatric Intensivist, Associate Professor of Pediatrics
Yale School of Medicine
New Haven, Connecticut, United States
Disclosure information not submitted.
Title: Prophylactic Enoxaparin Dosing and Quality of Anticoagulation in Critically Ill Children with CHD
Introduction: Enoxaparin is frequently used to prevent thromboses in critically ill children. Standard dosing regimens are associated with subtherapeutic levels. In this study, we aimed to determine if a 25% increase in enoxaparin dose, compared to standard dosing, was associated with increased effectiveness in achieving institutional goal anti-Xa levels.
Methods: We conducted a retrospective single center study of critically ill children with congenital heart disease. In January 2016, we implemented a catheter associated venous thrombosis prophylaxis protocol using standard empiric dosing of 0.75 mg/kg/dose bid for patients < 2 months and 0.5 mg/kg/dose for patients ≥2 months. Dose was adjusted to goal anti-Xa level of 0.25–0.49 IU/ml. In February 2017, the starting dose was increased by 25% for patients < 1 year old. We reviewed patients < 1 year old admitted postoperatively to the ICU between January 2016 - December 2018 who received prophylactic enoxaparin and had at least one steady state anti-Xa level. Comparisons were done with t tests. Time to goal anti-Xa was analyzed with Kaplan-Meier survival analysis and hazard of achieving goal level analyzed with Cox proportional hazard method accounting for multiple enoxaparin courses per patient.
Results: 151 patients received 161 enoxaparin courses, 54 in the standard dose group, 107 in the higher dose group. 49% of all enoxaparin courses achieved at least one goal anti-Xa level. Mean dose required to achieve goal was 1 mg/kg (SD=0.29) in patients < 2 months and 0.87 mg/kg (SD=0.31) in patients ≥2 months. These were significantly higher than the revised starting doses of 0.9 mg/kg and 0.75 mg/kg, respectively (p< 0.05 for both). Median time to achieve target was 12 days (IQR 4.1–20) in the standard group versus 9.2 days (IQR 3.6–15.7) in the higher dose group (p=0.3). Hazard of achieving goal level was not significantly different between groups (hazard ratio 0.77; 95% CI 0.48–1.24).
Conclusions: Compared with standard starting enoxaparin doses for prophylaxis, increased dosing to 0.9 and 0.75 mg/kg of enoxaparin for patients < 2 months and ≥2 months, respectively, was not associated with shorter times to achieve anti-Xa levels of 0.25–0.49 IU/ml. Future studies should assess enoxaparin doses of 1 and 0.87 mg/kg, respectively.