Evaluation of platelet hemostatic capacity using new thromboelastography-based assay
E. V. Roitman, I. M. Kolesnikova (Moscow, Russia)
Time: 17:15 - 18:15
Objective: Platelets plays key role to perform hemostasis including the formation of good quality clot. This is main condition to stop bleeding and to the success of platelet transfusion. The aim was to develop a method that allows to determine the hemostatic platelet activity and to evaluate the contribution of platelets to clot formation.
Methods: The method is based on two parallel thromboelastogramms recording. Test sample is platelets in any medias containing a minimum of blood plasma (e.g., platelet concentrate). The reagents are 1) diluted calcium solution, and 2) calcium solution with ADP in standard concentration for platelet aggregometry. For both cases, calcium concentration is the minimal required for blood clotting. Parallel tromboelastogramms are recorded followed by a calculation of the ratios for clot elastic modulus shear (G) and for clot maximum amplitude (MA). The first ratio reflects quantitatively the degree of involvement of activated platelets in hemostasis. The second ratio shows what are clot properties expected in a result of present platelet functional activity.
Results: MA’s-ratio correlates closely to ADP-induced platelet aggregation, spontaneous platelet aggregation and platelet apoptosis according to the percentage of P-selectin (CD62P) and phosphatidyl serine (annexin V) positive platelets. G-module's ratio showed high correlations to bleeding stop or to reducing of bloodloss rate within short time after platelet concentrate transfusion. According pilot data, after transfusion in patient blood samples MA’s-ratio demonstrates the capability of circulating platelets to perform hemostasis, and it also shows the degree of functional activity recovery of stored platelets after transfusion. G-module's ratio has predictive value for cases in which repeated transfusions of platelet concentrate might be required.
Conclusion: We have developed simple, available and low-cost assay for platelet hemostatic capacity. The method is based on generally accepted assessment methods: platelet aggregation and coagulation pattern. This assay has predictive value to clinical result of single units transfused platelets concentrates. Also the method allows to predict respect to total requirement for platelet concentrate transfusions. The method has been patented.