Heparin but not citrate anticoagulation of blood preserves platelet function for prolonged periods

Abstract

To cite this article: Truss NJ, Armstrong PCJ, Liverani E, Vojnovic I, Warner TD. Heparin but not citrate anticoagulation of blood preserves platelet function for prolonged periods. J Thromb Haemost 2009; 7: 1897-905.Summary. Background: Current guidelines state that platelet aggregation studies should be conducted within 4 h of venepuncture because of the decline in sensitivity to platelet agonists. This constrains studies of platelet activity in clinical situations where samples need to be transported or there are unavoidable delays prior to assessment. Objectives: The aim of the present study was to compare systematically the responses of platelets stored in the presence of either citrate or heparin, the two most widely used anti-coagulants, using a range of standard techniques. Methods: Blood was taken from healthy volunteers and either assessed immediately or stored at ambient temperature (18-25°C) for 24 h. Platelet reactivity to a range of agonists was determined by a combination of 96-well plate techniques; light transmission aggregometry, thrombi adhesion, ATP and ADP release, and TxA 2 release; by whole blood aggregometry; and by PFA-100. Results and conclusions: Testing using 96-well plate techniques allowed for the simultaneous measurement of responses to multiple concentrations of multiple agonists. The responses of platelets from blood anticoagulated with heparin were predominantly preserved in all assays after 24 h storage, whereas, responses of platelets stored in blood anti-coagulated with citrate were greatly diminished. Consequently, anti-coagulation with heparin, but not citrate, preserves platelet responses for up to 24 h as determined by a range of techniques.

Influence of different methods and anticoagulants on platelet parameter measurement

“…There were no significant differences in aggregability between the direct thrombin inhibitor samples and heparin samples, whereas the aggregation in citrated samples after stimulation from most of the agonists was impaired [168]. This finding is in accordance with several studies and supports the recommendation to apply hirudin in preference to citrate anti-coagulated samples [53,165,169].…”

“…Nevertheless, the application of citrated blood for platelet function tests is controversial since the Ca 2+ -binding properties of citrate create a non-physiological milieu in which the platelets are suspended [163,164]. Direct comparisons of citrate and heparin anti-coagulated samples using LTA as well as impedance aggregometry revealed that, as measured with both methods, the platelet function was impaired in citrate anti-coagulated samples after 24 h, whereas platelet function in heparin anti-coagulated blood was predominantly preserved [165]. However, other authors state that heparin is unsatisfactory due to in vitro platelet clumping and platelet adherence to the sampling device, resulting in low platelet numbers in PRP [166].…”

Preparation of highly-concentrated autologous platelet-rich plasma for biomedical use

“…Possibly it is one of a reasons some authors report the use of heparin as an effective anticoagulant for PRP preparation [27,28]. Heparin was also shown to preserve platelet function for a longer time than SC [29]. Yet most studies show heparin activates platelets [30].…”

Dual antiplatelet therapy in patients with aspirin resistance following coronary artery bypass grafting: study protocol for a randomized controlled trial [NCT01159639]

“…The search for an ideal anticoagulant for blood samples used for the quantification of platelet function is still ongoing. Heparin will be the anticoagulant used in the present study [16,17]. Blood will be collected in 4 ml heparin (Lithium Heparin 68 IU)-coated BD Vacutainer plastic tubes.…”