Thromb Haemost 1991; 66(02): 213-217
DOI: 10.1055/s-0038-1646392
Review Article
Schattauer GmbH Stuttgart

The Effect of Lysed Platelets on Neutralization of Heparin In Vitro with Protamine as Measured by the Activated Coagulation Time (ACT)

Arthur P Bode
The Department of Clinical Pathology and Diagnostic Medicine, East Carolina University School of Medicine and Department of Pathology, Pitt County Memorial Hospital, Greenville, North Carolina, USA
,
William J Castellani
The Department of Clinical Pathology and Diagnostic Medicine, East Carolina University School of Medicine and Department of Pathology, Pitt County Memorial Hospital, Greenville, North Carolina, USA
,
Edna D Hodges
The Department of Clinical Pathology and Diagnostic Medicine, East Carolina University School of Medicine and Department of Pathology, Pitt County Memorial Hospital, Greenville, North Carolina, USA
,
Susan Yelverton
The Department of Clinical Pathology and Diagnostic Medicine, East Carolina University School of Medicine and Department of Pathology, Pitt County Memorial Hospital, Greenville, North Carolina, USA
› Author Affiliations
Further Information

Publication History

Received 18 June 1990

Accepted 14 February 1991

Publication Date:
25 July 2018 (online)

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Summary

The effect of lysed platelets on the activated coagulation time (ACT) was studied in heparinized whole blood during titration with protamine. Frozen-thawed washed platelet suspension, or a chromatography fraction thereof, or autologous frozen-thawed platelet-rich plasma was added in various dilutions to freshly drawn blood anticoagulated with 3,000 USP units/1 heparin. After a 10 min incubation, the amount of protamine needed to restore the ACT to baseline ("protamine titration dose") was determined. We found that the protamine titration dose decreased in proportion to the amount of lysed platelet material added; expressed as a percentage of the total number of platelets present, each unit increase in lysed platelets produced a 1.7% ±0.8 (SD) reduction in the protamine dose needed to normalize the ACT. A heparin activity assay showed that this effect was not due to antiheparin activity of lysed platelets such as platelet factor 4 (PF4). Our data indicate that the procoagulant activity of platelet membranes reduced the sensitivity of the ACT to heparin. These findings suggest that membranous platelet microparticles may cause an inaccurate calculation, based on the ACT, of a protamine dose to reverse heparin anticoagulation in cardiopulmonary bypass procedures.