Platelet composition and function in patients undergoing cardiopulmonary bypass for heart surgery.
BACKGROUND
Previous studies showed severe biochemical and functional damage to platelets in patients undergoing cardiopulmonary bypass for cardiac surgery, and suggested that this derived from the proteolytic action of plasmin on the platelet surface.


METHODS
A double-blind study was carried out to compare platelet function and composition in patients randomized to receive the protease inhibitor aprotinin or placebo during reoperation for valvular prosthesis replacement or coronary artery bypass grafting.


RESULTS
Flow cytometry with specific monoclonal antibodies and polyacrylamide gel electrophoresis did not show any significant proteolysis of platelet glycoprotein Ib and IIb-IIIa either in the placebo or the aprotinin group. Functional studies were consistent with these results, since ristocetin-induced platelet agglutination was unchanged and platelet aggregation and ATP release induced by collagen and ADP were only slightly reduced by cardiopulmonary bypass. These mild defects in platelet function were partially prevented by aprotinin infusion.


CONCLUSIONS
On the basis of our data and those from literature, we suggest that platelets may be affected very little or severely damaged during cardiopulmonary bypass for cardiac surgery, probably depending on some aspects of the technical procedure which remain to be identified. Aprotinin infusion significantly protects platelets in the latter condition, while its role is obviously slight in the former.
Bertolino
G
G
Department of Internal Medicine (Internal Medicine and Medical Oncology), University of Pavia, IRCCS Policlinico S. Matteo, Italy.
Locatelli
A
A
Noris
P
P
Maurelli
M
M
Ceriana
P
P
Mazzini
G
G
Spedini
P
P
Belletti
S
S
Balduini
C L
CL
D007611:Aprotinin / Q000627:therapeutic use*; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002315:Cardiopulmonary Bypass; D004311:Double-Blind Method; D006801:Humans; D015842:Serine Proteinase Inhibitors / Q000627:therapeutic use*
D015842:Serine Proteinase Inhibitors; D007611:Aprotinin