Platelet mapping as part of modified thromboelastography (TEG^®) in patients undergoing cardiac surgery and cardiopulmonary bypass

Abstract

Summary The platelet‐mapping assay of the thromboelastograph was used to measure platelet aggregation and to examine the effect of cardiopulmonary bypass on multiple platelet receptors and the role of altered receptor activity in postoperative bleeding. The percentage platelet aggregation for collagen, adenosine diphosphate and arachidonic acid was measured in 40 patients divided post‐hoc into high‐ or low‐bleeding groups depending on postoperative 24‐h chest tube output. Platelet aggregation was lower after cardiopulmonary bypass compared to before it using collagen (mean (SD) 45 (25) vs 19 (12) %, p < 0.001), adenosine diphosphate (76 (23) vs 35 (24) %, p < 0.001), and arachidonic acid (61 (33) vs 31 (35) %, p < 0.001). Only platelet aggregation as measured using collagen pre‐ and post‐cardiopulmonary bypass was significantly less in the high‐ compared to the low‐bleeding group. This finding was significantly correlated with the 24‐h chest tube drainage, and it predicted postoperative bleeding with a sensitivity of 83% and a specificity of 68%. Therefore, platelet aggregation is reduced following cardiopulmonary bypass, and this may play a role in predicting postoperative blood loss.

Global assays of hemostasis

“…These systems have also been utilized to evaluate anticoagulant activity [82, 83] and determine what the critical threshold value is for the initiation of antifibrinolytic therapy in trauma [84]. The platelet mapping assay system, used to measure platelet aggregation, is more frequently being used in the clinical setting [85], including in patients undergoing cardiac surgery and cardiopulmonary bypass, in which their TEG findings as measured using collagen were correlated with postoperative bleeding [86]. Whereas, in a study on thromboembolic complications in Fontan patients, the use of thromboelastography profiles in whole blood did not demonstrate hypercoagulability [87].…”

Low-Dose Sevoflurane May Reduce Blood Loss and Need for Blood Products After Cardiac Surgery

“…12 For example, chest tube drainage after surgery has been associated with impaired collagen-induced platelet aggregation. 13 Risk of massive blood loss can be reduced by increasing the numbers of collagen-activated functional platelets. 6 …”

Nichtkardiochirurgische operative Eingriffe bei Patienten nach Implantation eines „ventricular assist device“

“…B. mit der sog. Thromboelastographie (TEG), sinnvoll sein um den Zeitraum des Aussetzens der Thrombozytenaggregationshemmung zu minimieren und somit vaskuläre Komplikationen zu vermeiden [32,33,34].…”