Bleeding issues in neonates and infants – update 2015

The Vascular Endothelium and Coagulation: Homeostasis, Disease, and Treatment, with a Focus on the Von Willebrand Factor and Factors VIII and V

The vascular endothelium has several important functions, including hemostasis. The homeostasis of hemostasis is based on a fine balance between procoagulant and anticoagulant proteins and between fibrinolytic and antifibrinolytic ones. Coagulopathies are characterized by a mutation-induced alteration of the function of certain coagulation factors or by a disturbed balance between the mechanisms responsible for regulating coagulation. Homeostatic therapies consist in replacement and nonreplacement treatments or in the administration of antifibrinolytic agents. Rebalancing products reestablish hemostasis by inhibiting natural anticoagulant pathways. These agents include monoclonal antibodies, such as concizumab and marstacimab, which target the tissue factor pathway inhibitor; interfering RNA therapies, such as fitusiran, which targets antithrombin III; and protease inhibitors, such as serpinPC, which targets active protein C. In cases of thrombophilia (deficiency of protein C, protein S, or factor V Leiden), treatment may consist in direct oral anticoagulants, replacement therapy (plasma or recombinant ADAMTS13) in cases of a congenital deficiency of ADAMTS13, or immunomodulators (prednisone) if the thrombophilia is autoimmune. Monoclonal-antibody-based anti-vWF immunotherapy (caplacizumab) is used in the context of severe thrombophilia, regardless of the cause of the disorder. In cases of disseminated intravascular coagulation, the treatment of choice consists in administration of antifibrinolytics, all-trans-retinoic acid, and recombinant soluble human thrombomodulin.

Evaluation of primary care physicians' approaches to hemophilia and bleeding disorders: a questionnaire survey

Bleeding disorders are causes of great concern and panic for parents and primary care providers. Lack of knowledge and awareness on appropriate screening tests and factor product preparation contributed to potential diagnostic delays, increased complications, and economic costs. This study aimed to determine and compare the approach of primary care physicians (including general practitioners) and emergency physicians with a questionnaire including simulation-based cases on hemophilia. This simulation and two-stage questionnaire study was conducted with 244 participants. Before-after questionnaires, two case simulations, a brief presentation, and statistical analysis were performed. Participants mostly preferred tests, such as prothrombin time (PT) or partial thromboplastin time (PTT) to bleeding time for primary hemostasis (PT/PTT n: 192, 84.2%, bleeding time n: 94, 41.2%). Similar results were found for secondary hemostasis (bleeding time n: 144, 63.4%). There was a lack of knowledge in the management of simulation-based cases of acute hemorrhagic complications and factor product preparation (complication case: correct n: 100, 55.2%; initial doses correct n: 56, 43.4%, factor preparing correct n: 37, 49.3%, factor admission correct n: 36, 24.3%). All changed significantly, after the presentation (P = 0.000). Our study shows that there is probably a lack of knowledge of diagnostic investigations and appropriate factor product preparation with possible consequences for patients and economics.

Developmental hemostasis in the neonatal period

BACKGROUND

The hemostatic system is complex and evolves continuously since gestation and well into the adult years, in a process known as "developmental hemostasis."

DATA SOURCES

A comprehensive review was performed after an extensive literature search on PubMed/MEDLINE concerning developmental hemostasis during the neonatal period. Relevant cross references were also included.

RESULTS

Although part of a system, each component of the hemostatic system evolves differently, with many displaying both quantitative and qualitative age-related differences. This leads to drastic disparities between the coagulation system of neonates and both other children's and adults', while still maintaining a generally balanced and physiological hemostasis. The motives behind this process remain to be fully elucidated but may be, at least in part, related to non-hemostatic factors.

CONCLUSIONS

Knowledge regarding "developmental hemostasis" is essential for everyone caring for newborns or even children in general and in this review, we describe each hemostatic system component's neonatal characteristics and age-related progression as well as explore some of the possible physiological motives behind the process.

A retrospective study on clinical manifestations of neonates with FXIII-A deficiency

We assessed clinical presentations and the rate of central nervous system (CNS) bleeding in neonates with FXIIID who exhibited bleeding diathesis in the early days of their lives. A total of 27 neonates presented bleeding or abnormal clinical symptoms, diagnosed with FXIII deficiency were evaluated. Factor XIII concentrate was initiated as the first-line of treatment, and prophylactic therapy was given to all patients. Umbilical cord bleeding, delayed detachment of umbilical stunt, seizure, hematoma, and ecchymosis were concurrent complications in 27 (100%), 5 (18.5%), 5 (18.5%), 3 (11.1%), and 1 (3.7%) of the patients, respectively. History of having CNS bleeding was detected in 13 (48.1%) patients. There was no significant association between CNS bleeding and gender, familial history of FXIIID, or other clinical presentations. Also, there was no significant difference in the mean age of the patients who had CNS bleeding (3.4 ± 0.9 days) and without CNS bleeding (2.9 ± 0.7 days). However, a near significant threshold difference between the patients with and without CNS bleeding was found regarding the mean number of suspicious FXIIID death in their family (1.8 ± 0.5 and 0.7 ± 0.1, respectively, P = 0.05). Therefore, a suggested diagnostic algorithm based on prenatal diagnosis could be useful for timely detection of FXIII deficiency in neonates.

Neonatal haemostasis

The maturation and postnatal development of the human coagulation system results in significant and important differences in the coagulation and fibrinolysis of neonates and young children compared to older children and adults. Importantly, these differences, which mostly reflect the immaturity of the neonatal haemostasis system, are functionally balanced. Healthy neonates show no signs of easy bruising or other bleeding diathesis and no increased tendency to thrombosis for any given stimulus compared to adults.

Systemic diseases may affect haemostasis, thus predisposing ill neonates to increased risk for haemorrhagic or thrombotic complications. In hospitalized children, neonates have increased risk of developing thrombosis compared to infants and children, mostly associated with the presence of central venous catheter. For diagnosis of haemostasis disorders, diagnostic laboratories processing pediatric samples should use age, analyzer and reagent appropriate reference ranges. Age specific guidelines should be followed for the management of neonates with hemostatic disorders.

Thromboelastography in term neonates: an alternative approach to evaluating coagulopathy

OBJECTIVE

To develop normative ranges for citrate-modified and heparinase-modified thromboelastography (TEG) in term neonates.

DESIGN

Prospective observational study.

SETTING

An outborn neonatal and cardiac intensive care unit in a free-standing academic children's hospital.

PATIENTS

Thirty term neonates were enrolled as control subjects. Seventeen infants with clinically documented bleeding requiring blood transfusion were enrolled in the comparison group.

MAIN OUTCOME MEASURES

Citrate-modified and heparinase-modified TEG parameters were calculated from blood specimens drawn via peripheral arterial stick or arterial line.

RESULTS

TEG in neonates differs from older children and adults; clotting time (R) and clot kinetics (K) values are generally lower while fibrinolysis or rate of clot breakdown (LY30) and coagulation index (CI) are often higher in neonates. TEG values in term neonates calculated as median (Q1-Q3) are as follows: R 4.150 (3.200-6.200), K 1.550 (1.200-1.800), α angle (α) 70.100 (66.000-72.900), maximum amplitude (MA) 61.850 (59.400-66.000), LY30 1.050 (0.100-1.600) and CI 1.950 (0.100 to 2.900). Cut points selected for optimal predictive value for bleeding using receiver operating curve analyses were R>6.3 (sensitivity 82.4%, specificity 80%); K>2.5 (sensitivity 82.4%, specificity 96.7%); α<59 (sensitivity 82.4%, specificity 96.7%); MA<57 (sensitivity 82.4%, specificity 86.7%); CI<-0.15 (sensitivity 88.2%, specificity 83.3%).

CONCLUSIONS

The reference ranges and cut points for citrate-modified and heparinase-modified TEG can be used to diagnose and evaluate coagulopathy in term neonates.

The bleeding newborn: A review of presentation, diagnosis, and management

The neonatal hemostatic system is continuously developing with rapidly changing concentrations of many coagulation proteins. Thus, determining the etiology of bleeding in a newborn has additional challenges beyond those seen in older children or adults. Bleeding can be seen in both well and sick newborns due to congenital causes, such as hemophilia or von Willebrand disease, and acquired causes, such as liver failure or disseminated intravascular coagulation. Traditional coagulation testing should be interpreted with caution and with the help of a hematologist, if possible, due to the greatly different normal ranges between neonates as compared with older children and adults. However, despite these challenges, both clinical and laboratory clues can guide physicians appropriately to diagnose and treat the bleeding newborn.

Congenital and acquired bleeding disorders in infancy

The diagnosis of congenital and acquired bleeding disorders in infants requires an understanding of developmental haemostasis and the effect on laboratory testing. A systematic approach to bleeding in neonates will aid clinicians in the diagnosis and treatment, which may be caused by a wide variety of diseases. The clinical setting will help to direct the diagnostic pathway. This review will focus on the presentation and diagnosis of congenital and acquired bleeding disorders, including platelet disorders. Current research in this field is ongoing, including investigation into neonatal platelets and their different functionalities, platelet transfusion thresholds and how changes in coagulation factors may be linked to other homeostatic mechanisms.