Utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist devices

Aim: To assess utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist device (VAD).

Methods: Retrospective study of pediatric patients supported with a Berlin EXCOR VAD at a single pediatric tertiary care center during a single year.

Results: We demonstrated associations between activated thromboplastin time (aPTT) and R-thromboelastography (R-TEG) values (rs = 0.65, P < 0.001) and between anti-Xa assay and R-TEG values (rs = 0.54, P < 0.001). The strongest correlation was seen between aPTT and anti-Xa assays (rs = 0.71, P < 0.001). There was also a statistically significant correlation between platelet counts and the maximum amplitude of TEG (rs = 0.71, P < 0.001). Importantly, there was no association between dose of unfractionated heparin and either measure of anticoagulation (aPTT, anti-Xa or R-TEG value).

Conclusion: This study suggests that while there is strong correlation between aPTT, anti-Xa assay and R-TEG values for patients requiring VAD support, there is a lack of relevant correlation between heparin dose and degree of effect. This raises concern as various guidelines continue to recommend using these parameters to titrate heparin therapy.