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.
Third Department of Surgery, Iwate Medical University School of Medicine, Japan. t_nakajima@imu.ncvc.go.jp
T
T
Nakajima
K
K
Kawazoe
K
K
Ishibashi
Y
Y
Kubota
T
T
Sasaki
H
H
Izumoto
T
T
Nitatori
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