Preoperative platelet dysfunction increases the benefit of aprotinin in cardiopulmonary bypass.
BACKGROUND
This study was designed to determine the benefit of aprotinin therapy in reducing bleeding during and after cardiopulmonary bypass in patients with preoperative platelet dysfunction. Platelet function involvement in the mechanism by which aprotinin acts was also investigated.


METHODS
In a double-blind, randomized study, patients received high-dose aprotinin (n = 54) or placebo (n = 52). Whole blood aggregation was measured preoperatively. Platelet function and activation in both groups were assessed intraoperatively and postoperatively at five times.


RESULTS
Aprotinin significantly reduced perioperative bleeding and postoperative blood transfusion. Placebo-treated patients with reduced preoperative platelet aggregation bled more postoperatively, but aprotinin reduced the bleeding in patients with normal or reduced platelet function to similar levels. Any cardiopulmonary bypass-induced changes in platelet aggregation, platelet activation as measured by P-selectin expression, and von Willebrand factor antigen and function were similar in aprotinin-treated and placebo-treated groups.


CONCLUSIONS
The mechanism by which aprotinin reduced bleeding was independent of any effect on platelet function. However, aprotinin produced a greater reduction in bleeding among patients whose condition was hemostatically compromised by preoperative platelet dysfunction.
Ray
M J
MJ
Department of Haematology, Prince Charles Hospital, Brisbane, Queensland, Australia.
Marsh
N A
NA
Just
S J
SJ
Perrin
E J
EJ
O'Brien
M F
MF
Hawson
G A
GA
D007611:Aprotinin / Q000627:therapeutic use*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D001792:Blood Platelets / Q000502:physiology*; D001803:Blood Transfusion; D002315:Cardiopulmonary Bypass; D004311:Double-Blind Method; D005260:Female; D005434:Flow Cytometry; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation / Q000502:physiology; D010974:Platelet Aggregation / Q000502:physiology; D010979:Platelet Function Tests; D015842:Serine Proteinase Inhibitors / Q000627:therapeutic use*; D014841:von Willebrand Factor / Q000378:metabolism
D015842:Serine Proteinase Inhibitors; D014841:von Willebrand Factor; D007611:Aprotinin