Platelet Function Analysis After In Vitro Treatment with Hemostasis-Affecting Components

Abstract

An overall platelet function test in whole blood, which simulates conditions under arterial pressure, is useful in measuring tbe effect of polymer materials on blood hemostatic function. We per· formed biocompatibility tests with materials or plasma substitutes by interaction of blood from healthy volunteers and then subjected these blood samples to platelet function analysis (Thrombostat). We tested also the capacity of locally applied hemostatic agents for bleeding control by direct application of these agents onto the Thrombostat measuring cell. The biocompatibility tests with materials exposed to blood appeared very discriminating between compatible and noncompatible materials. The hemostatic capacity of blood exposed to noncompatible materials (assessed by binding of active thrombin) reduced markedly after one hour incubation of the material. The plasma substitutes did not affect hemostasis significantly. However, a blood dilution of 40%, as in cardiopulmonary bypass, increased the time required for closure of tbe measuring cell by a platelet plug exponentially. Local hemostatic agents could be selected according to their capacity to enhance platelet plug formation. In addition, ADP mixed with the bemostatic agent was most effective in improving capacity. We conclude tbat platelet function analysis contributes importantly to screening of materials and plasma substitutes with regard to their interaction with primary hemostasis.Platelet function is pivotal in hemostasis, specifically at increased shear stress and under arterial pressure. The mechanism of platelet function is multifactorial; moreover, the process of platelel plug formation is complex. Therefore, one single platelet function test, such as aggregation, may be inadequate to detect wilh high sensitivity the effect of (artificial) polymers on platelets. For precise measurement of biocompatibility or for monitoring of components wilh suspected effects on platelet function, a laboratory multifactorial platelet test, that simulates the in vivo primary hemostasis may be required. We used a platelet function analyser (Throm· bostat) to measure the effect of exposure of polymeric components to whole blood on plalelet function. In this way, we were able to determine I) biocompatibility of materials, and 2) the effect of plasma substitutes on hemostasis, and we were able to rapidly screen 3) the optimal composition of new hemostasis promoting agents for surface application. These hemostatic agents are being developed to reduce local bleeding. All these assays were performed with whole blood from healthy volunteers and therefore, could be performed under standardized conditions.

Description of an In Vitro Platelet Function Analyzer (PFA-100/PFA-200) 30 Years in the Making

“…I have no idea how much this "sponsorship" deal cost "Dade Diagnostics," but I can conclude that this was money well spent. Given that the Thrombostat-4000 was no longer in production at that time, the publications related to this instrument 11,[16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] did not raise many citations. However, the two papers related to the PFA-100 9,31 did, with both appearing in the top 100 most highly cited STH papers of all time.…”

“…12 13 14 15 Then, in 1995, the prior noted Supplement of STH was published, 1 containing 16 papers that mentioned work using the Thrombostat-4000. 11 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 At the end of the Supplement issue appeared two papers related to the “updated” Thrombostat-4000, namely the PFA-100. 9 31 Indeed, it was noted by the issue Guest Editors, in the Preface to the issue 32 that: “The Thrombostat 4000, which is no longer available, was modified and redesigned by scientists at Dade International, Inc.…”