Reduction of heparin dose is not beneficial to platelet function.
BACKGROUND
To clarify the effects of the reduction of heparin dose on platelets, we conducted a prospective trial on patients undergoing cardiopulmonary bypass.


METHODS
Twenty-three patients undergoing coronary artery bypass grafting were studied. The systemic heparin dose was 300 IU/kg in the control group (n = 11) and 200 IU/kg in the low-dose group (n = 12). Heparin-coated cardiopulmonary bypass equipment was used for both the groups. Platelet counts, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) concentrations were measured and the arterial filters in the circuits were observed by electron microscopy.


RESULTS
Platelet counts were higher in the low-dose group than in the control group (p < 0.01). No significant differences were found in the platelet release reaction (beta-TG and PF4). Electron microscopy demonstrated that cell adhesion on the arterial filters in the control group was significantly more marked than in the low-dose group (p < 0.01) and that most of the cells on the filters were neutrophils.


CONCLUSIONS
We conclude that the reduction of heparin dose with the use of heparin-coated equipment reduces platelet loss, but does not suppress the platelet release reaction. Furthermore, the reduction of heparin dose reduces adherence of leukocytes to the filter surface.
Nakajima
T
T
Third Department of Surgery, Iwate Medical University School of Medicine, Japan. t_nakajima@imu.ncvc.go.jp
Kawazoe
K
K
Ishibashi
K
K
Kubota
Y
Y
Sasaki
T
T
Izumoto
H
H
Nitatori
T
T
D000925:Anticoagulants / Q000008:administration & dosage* / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D002315:Cardiopulmonary Bypass; D006493:Heparin / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011446:Prospective Studies
D000925:Anticoagulants; D006493:Heparin