Platelet function point-of-care tests in post-bypass cardiac surgery: are they relevant?

• Published in: British journal of anaesthesia : BJA Vol. 89; no. 5; pp. 715 - 721
• Main Authors: Forestier, F., Coiffic, A., Mouton, C., Ekouevi, D., Chêne, G., Janvier, G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2002
• Subjects: blood, loss; blood, platelets; monitoring, point-of-care test; surgery, cardiovascular; blood, loss; blood, platelets; surgery, cardiovascular; monitoring, point-of-care test
• ISSN: 0007-0912; 1471-6771
• DOI: 10.1093/bja/aef250

Platelet dysfunction is an important cause of excessive bleeding after cardiac surgery. We assessed two platelet function point-of-care tests: the platelet function analyser (PFA-100) and the Hemostatus™ in patients with and without excessive bleeding after cardiac surgery with cardiopulmonary bypass.
Mediastinal chest tube drainage (MCTD) was measured for the first 6 h in the intensive care unit (ICU). Haematology and coagulation tests were done on arrival in the ICU, and when excessive bleeding occurred (MCTD >1 ml kg−1 h−1) or after 3 h.
Eighteen patients bled excessively and 27 had normal MCTD. Hemostatus measurements were prolonged in those with excessive bleeding compared with the normal group. The times for PFA-100 adenosine diphosphate (ADP) and epinephrine were 91 vs 71 s (P=0.004) and 155 vs 114 s (P=0.02) in the bleeding and normal group s, respectively. None of the Hemostatus or PFA-100 values correlated with total MCTD. Depending on the agonist used, maximum aggregation was 33–81% and 52–86% in bleeding and normal groups, respectively. Only poor correlations were found between PFA-100 epinephrine and maximum aggregation in response to ADP (r=–0.52, P=0.03) or to collagen (r=–0.48, P=0.04).
Patients bleeding excessively in the ICU had abnormal measurements in point-of-care tests without a dramatic decrease in aggregation. Except for patients with increased risk of postbypass bleeding, point-of-care tests are not useful for routine use after cardiac surgery.