Platelet function point-of-care tests in post-bypass cardiac surgery: are they relevant?
BACKGROUND
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(TM) in patients with and without excessive bleeding after cardiac surgery with cardiopulmonary bypass.


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Forestier
F
F
Department of Anaesthesia II and Haemobiology Laboratory, Hôpital cardiologique, CHU de Bordeaux, Avenue de Magellan, F-33604 Pessac cedex, France.
Coiffic
A
A
Mouton
C
C
Ekouevi
D
D
Chêne
G
G
Janvier
G
G
D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000502:physiology*; D002315:Cardiopulmonary Bypass; D004322:Drainage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation; D010976:Platelet Count; D019095:Point-of-Care Systems; D019106:Postoperative Hemorrhage / Q000209:etiology / Q000503:physiopathology*