Pre- and Post-Bypass Platelet Function Testing With Multiple Electrode Aggregometry and TEG Platelet Mapping in Cardiac Surgery.

OBJECTIVES: To investigate the differences between pre- and post-cardiopulmonary bypass platelet function tests and to examine whether post-bypass tests could predict postoperative bleeding.
DESIGN: A prospective cohort study.
SETTING: A tertiary cardiothoracic center. PARTICIPANTS: Fifty-four patients presenting for cardiac surgery.
INTERVENTIONS: Pre- and post-bypass platelet function tests with TEG Platelet Mapping (PM) and Multiple Electrode Aggregometry (Multiplate - MEA) were performed.
MEASUREMENTS AND MAIN RESULTS: The results of the paired samples were compared. Outcomes including blood loss in the first 4 and 12 hours postoperatively and requirement for resternotomy also were recorded and regression analyses performed to establish predictive factors. Tests using adenosine diphosphate (ADP) and arachidonic acid as stimulators for platelet aggregation showed significant differences pre- and post-bypass, with both MEA and PM showing greater inhibition in platelet function after bypass (p<0.01). However, there was no significant change in MEA TRAP values with cardiopulmonary bypass (p = 0.79) There was no relationship between post-bypass platelet function and the reduction in measured platelet function and blood loss in the postoperative period.
CONCLUSIONS: Post-bypass platelet function testing showed reductions in ADP and arachidonic acid-triggered aggregation but not in TRAP-triggered aggregation compared with pre-bypass testing. There was no relationship between the post-bypass tests and bleeding.