The optimal method for monitoring antiplatelet therapy in children supported with ventricular assist devices (VADs) is unknown. We conducted a retrospective study to compare Thromboelastography Platelet Mapping (TEG/PM) with multiple electrode platelet aggregometry (MEA) on a Multiplate analyzer (Roche Diagnostics, Mannheim, Germany). We analyzed data from 66 paired blood samples from 9 patients <16 years of age on VAD where platelet function was simultaneously measured with TEG/PM and MEA. Antiplatelet dose–response relationships and intraindividual variability during steady state therapy were determined. Agreement in determination of therapeutic antiplatelet therapy was poor (arachidonic acid, κ 0.23; adenosine diphosphate [ADP], κ 0.13). Rate of aspirin and clopidogrel resistance was much higher when determined using TEG/PM than MEA. In patients receiving ≥5 mg/kg/day aspirin, 72% of TEG/PM measurements showed subtherapeutic response compared with 11% of MEA measurements. There was evidence of a dose–response relationship with clopidogrel and MEA ADP-induced aggregation (R 2 = 0.56; p < 0.0001); however, there was no association between dose and TEG/PM% ADP inhibition (p = 0.15). Intraindividual variability in platelet reactivity was far greater when measured by TEG/PM during steady state therapy. Multiple electrode platelet aggregometry appears to be more reliable than TEG/PM for monitoring antiplatelet therapy in children supported with VAD.
From the *Department of Paediatric Intensive Care, Freeman Hospital, Newcastle upon Tyne, United Kingdom
†Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom
‡Department of Haematological Sciences, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
§Department of Haematology, Freeman Hospital, Newcastle upon Tyne, United Kingdom.
Submitted for consideration September 2017; accepted for publication in revised form December 2017.
Disclosure: The authors have no conflicts of interest to report.
Reagents for the Multiplate analyzer were purchased by the Children’s Heart Unit Fund. No funding or support was received from the manufacturer of Multiplate analyzer.
Correspondence: Lee P. Ferguson, PICU, Freeman Hospital, Newcastle upon Tyne NE7 7DN, United Kingdom. Email: firstname.lastname@example.org.