Thromboelastographic Profile in Healthy Newborns and Infants of Diabetic Mothers Using TEG6s

Thromboelastography (TEG), is a laboratory technique used to examine the process of clot formation and degradation by measuring and reporting the kinetic changes, the rate of clot formation, clot strength, and clot stability in umbilical cord blood samples. TEG provides numeric values and a graphical representation of the primary and secondary hemostatic systems and fibrinolysis. The current standard assessments of coagulation status require a combination of multiple tests with multiple blood samples. These tests, including prothrombin time (PT), partial thromboplastin time (aPTT), fibrinogen level, and platelet count, only partially reflect components of the coagulation system, whereas TEG reflects the complex interplay between coagulation factors, cellular components, enzymes, and highly organized feedback mechanisms that maintain equilibrium between clot formation and lysis. TEG has advantages over routine coagulation studies because it is able to assess coagulation function more quickly and with a single smaller blood sample.

A few studies, however, have established normative TEG results in newborns. These studies used older TEG systems/technology. There is a newer TEG6s platform which is currently available at Arkansas Children's Hospital (ACH) and only 3 other children's hospitals in the country. Normative values using TEG6s have not been established in healthy neonates. In fact, although there are investigations in adults, there are no published studies using this newer technology in newborns. The lack of normative standards for TEG6s in newborns is limiting the use of this technology in research and clinical practice.

TEG6s simplifies and standardizes the technique for performing TEG by eliminating the need for manual pipetting. This platform also enables multiple assays to be performed simultaneously from a single blood sample. The TEG6s measures clot viscoelasticity throughout the coagulation process by using resonance technology. Using light-emitting diode illumination, an infrared detector measures vertical motion of the coagulating blood meniscus. Greater clot strength causes higher resonant frequencies, which is subsequently identified by the detector and converted to a graphical image. The TEG6s can deliver the same quality test results without the complicated test preparation process required when using the older TEG platform.

There are a number of well-established perinatal risk factors for thrombosis in the newborn, including systemic infections, dehydration, congenital heart disease, birth asphyxia, polycythemia, presence of intravascular catheters, inherited thrombophilias, and transplacental passage of maternal antiphospholipid and anticardiolipin antibodies. Described since at least 1965, however, maternal diabetes is the most frequently identified risk factor. This risk of thrombosis in infants of diabetic mothers (IDM) has been found to be 15.8% compared with <1% in the non-IDM group. Despite the well-established hypercoagulable state observed in IDMs, there have been no studies evaluating TEG in these newborns.

Currently, there are few published studies on TEG as it relates to neonates. The clotting profile in neonates differs vastly from adults and even the pediatric population, explaining why prior data on TEG from these populations cannot be extrapolated to this special population of newborns. The significant difference is likely explained by the delicate balance in the neonatal hemostatic system that is composed of lower levels of plasma coagulation inhibitors, such as antithrombin, protein C, and protein S, while having procoagulant factor levels, such as factor VIII, von Willebrand factor (vWF), and factor XIII levels that are comparable to the levels in adults.

There have been prior studies establishing normative values for TEG in term newborns but none with the new TEG6s platform. Furthermore, there have been minimal studies looking into the diverse subgroups of the neonatal population on either TEG or TEG6s. With regards to my proposed project, TEG is likely to identify differences among healthy newborns and IDMs, which will help explain the propensity to clot and guide further research into prevention and treatment of this complication.

The study of coagulation currently entails multiple tests, requires multiple blood samples, and has a waiting period for laboratory results. Large volumes of repeated blood sampling in this physically small-sized population can lead to iatrogenic anemia. TEG6s, however, uses a single blood sample to deliver results quickly with both a graphical representation and numeric value. The results provided by TEG are useful in helping to determine specific deficiencies affecting a patient, for example, clotting factors, heparin, fibrinogen and platelets.