Am J Perinatol 2016; 33 - A015
DOI: 10.1055/s-0036-1592386

Laboratory Parameters of Blood Coagulation and Platelet Functional Activity in Premature Neonates

E. Balashova 1, E. Koltsova 2, A. Ignatova 2, D. Polokhov 2, A. Kuprash 2, A. Kirtbaya 1, M. Shakaya 1, I. V. Nikitina 1, O. Ionov 1, V. V. Zubkov 1, D. Degtyarev 1, A. Balandina 2, M. Panteleev 2, G. T. Sukhikh 1
  • 1Federal State Budget Institution, “Research Center for Obstetrics, Gynecology and Perinatology,” Ministry of Healthcare of the Russian Federation, Moscow, Russia
  • 2Federal Research and Clinical Center for Pediatric Hematology, Oncology, and Immunology named after Dmitry Rogachev, Moscow, Russia

Introduction: Premature birth is associated with significant risks of mortality and morbidity due to hemorrhage and thrombosis. However, the status of hemostatic system in premature neonates is poorly known, and almost all data in this area derive from blood samples obtained from cord blood.

Materials and Methods: We aimed at characterizing platelet-dependent hemostasis and blood coagulation in venous blood samples from four premature (33–34 weeks’ gestation) neonates on their 1st and 3rd days after birth. All patients received heparin at 50 units/kg/per day. Venous blood was collected into sodium citrate. Platelet functional activity was characterized by flow cytometry before and after activation with SFLLRN and collagen-related peptide. Levels of CD42b, CD61, CD62P, PAC1, annexin V binding, and mepacrine release were determined. Blood coagulation was characterized using thrombodynamics assay.

Results: All patients showed hypercoagulation at the 1st day despite heparin treatment, the spatial clot growth rate was 31.9 to 43.8 microns/min (normal range: 20–29), with little changes on day 3. Lag time of clot formation and clot density were normal. Platelets on the 1st day had somewhat pre-activated integrins and phosphatidylserine exposure. However, they poorly responded to stimulation: PAC1 was 9 to 23% (n.r.: 63–137%), annexin V was 1.8 to 6.7% (n.r.: 7.4–21.3%). Dense granule release was also impaired to 16 to 30% (n.r.: 52–96%) and that of α-granules was impaired to 36 to 60% (n.r.: 77–123%). Other parameters were less disturbed, and all platelet parameters showed a trend toward normality on the 3rd day sample.

Conclusion: Our results indicate that hypercoagulation and severe deficiency of platelet function occur in all premature neonates involved in our case series. These changes are sufficiently significant to be possibly associated with bleeding and thrombotic risks. Flow-cytometry-based characterization of platelets and integral assays of blood coagulation could be sensitive to the disturbances of hemostasis in neonates, and their further clinical usefulness should be evaluated in further trials addressing clinical outcomes related to early disturbances of coagulation.