Prevention of intraventricular haemorrhage: a role for recombinant activated factor VII?

Characterization of laboratory coagulation parameters and risk factors for intraventricular hemorrhage in extremely premature neonates

BACKGROUND

Extremely premature neonates have increased risk for bleeding, perhaps the most devastating version of which being intraventricular hemorrhage (IVH). Limited data are available for coagulation parameters in this vulnerable population.

OBJECTIVES

We conducted a prospective cohort study characterizing coagulation laboratory parameters in extremely premature neonates 23-30 weeks gestational age (GA) and determined coagulation parameters and clinical risk factors associated with IVH.

PATIENTS/METHODS

One hundred twenty neonates 23-30 weeks GA were enrolled, and umbilical cord blood samples were obtained and processed at the time of birth. Coagulation parameters including prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (APTT), and activity assays for factors II, VII, IX, X, XIII, and XIII subunit A antigen were performed by standard methods. Clinical risk factors were analyzed for association with IVH.

RESULTS

Of the enrolled neonates, 29 (24.2%) experienced IVH. Persistent pulmonary hypertension (PPHN) independently predicted IVH risk with odds ratio (OR) 5.3 (95% confidence interval [CI] 1.1-24.3), P = .0338; and chronic lung disease (CLD) approached significance with OR 2.3 (95% CI 0.9-5.5), P = .0659. Coagulation parameters were evaluated for association with IVH, and there was no significant difference among coagulation tests in neonates with or without IVH or per GA. Reduced factor XIII subunit A showed significant association with death, P = .003.

CONCLUSIONS

We present a large, prospective study of laboratory coagulation parameters in extremely premature neonates, including factor X, factor XIII, and factor XIII subunit A not previously described in this population. These findings may impact clinical practice and should encourage additional study in this vulnerable population.

Neonatal thrombocytopenia: Thrombin generation in presence of reduced platelet counts and effects of rFVIIa in cord blood

Healthy neonates exhibit a well-functioning haemostatic system despite peculiarities regarding composition of clotting factors and inhibitors as well as impaired platelet aggregation. Thrombocytopenia and severe bleeding events are feared in sick infants. Recombinant factor VIIa (rFVIIa) is a haemostatic agent used as a last resort in neonates with refractory bleedings. Aim of this study was to investigate in-vitro (i) changes in thrombin generation with different platelet counts, (ii) effects of rFVIIa under conditions of thrombocytopenia and (iii) potentially differing dose-response of rFVIIa in cord blood as a surrogate for neonatal blood compared to adult blood. Thrombin generation parameters were observed in cord blood plasma and adult plasma with various platelet counts, with or without addition of rFVIIa, respectively. Low platelet counts did not influence thrombin generation in cord blood in contrast to adult blood. RFVIIa primarily affected lag time throughout all platelet concentrations. Interestingly, peak height was reduced exclusively in cord blood plasma after addition of rFVIIa. No significant differences regarding dose-response were observed between cord blood and adult blood. In contrast to adult blood, thrombocytopenia in cord blood does not significantly influence thrombin generation. Even at very low platelet counts there is enough negatively charged surface to support rFVIIa action in plasma from cord blood and adult blood in-vitro.

Risk factors associated with intraventricular hemorrhage in extremely premature neonates

: Intraventricular hemorrhage (IVH) is a significant cause of morbidity in extremely premature infants despite many advances in neonatal intensive care. We conducted an institutional retrospective review aimed to correlate risk factors associated with IVH. Clinical variables reported to the Vermont-Oxford Network on less than 30 weeks gestational age infants over a 5-year period were evaluated with Pearson's chi-square and multivariate logistic regression. Of 618 infants born less than 30-week gestational age, 178 (28.8%) experienced IVH. Of those less than 1000 g, 105 (36.5%) of 288 infants experienced IVH. Multivariate analysis revealed that thrombocytopenia [odds ratio (OR) 2.03, 95% confidence interval (CI) 1.30-3.19, P = 0.0020] and cardiopulmonary resuscitation (CPR) ± intubation at delivery (OR 1.84, 95% CI 1.12-3.02, P = 0.0162) were independently associated with IVH. Among infants less than 1000 g, thrombocytopenia (OR 2.09, 95% CI 1.22-3.60, P = 0.0077) and CPR ± intubation at delivery (OR 2.01, 95% CI 1.10-3.68, P = 0.0229) were also significantly associated with IVH. IVH is a complex phenomenon with many contributing risk factors. In our study, infants less than 30-week gestational age and less than 1000 g revealed thrombocytopenia and CPR ± intubation in delivery room were independently associated with IVH. These data should alert clinicians to those neonates most likely to suffer IVH.

Recombinant Activated Factor VIIa (rFVIIa) Treatment in Very-Low-Birth-Weight (VLBW) Premature Infants with Acute Pulmonary Hemorrhage: A Single-Center, Retrospective Study

AIM

We aimed to evaluate the efficacy of intravenous administration of recombinant activated factor VIIa (rFVIIa) for acute pulmonary hemorrhage treatment in very-low-birth-weight (VLBW) premature infants.

PATIENTS AND METHODS

This study was carried out retrospectively in premature infants with pulmonary hemorrhage that were ≤30 weeks gestational age or <1250 g birth weight. The data of all VLBW premature infants with pulmonary hemorrhage who were hospitalized in our neonatal intensive care unit between 01 January 2013 and 31 December 2015 were evaluated. Group 1 (n = 21) received rFVIIa support within the first 30 min of pulmonary hemorrhage plus conventional treatment, while Group 2 (n = 21) received conventional treatment only.

RESULTS

The number of patients whose pulmonary hemorrhage was stopped within the first 2 h was significantly higher in Group 1 than Group 2 (n = 14 vs n = 4; p = 0.002). After pulmonary hemorrhage, hemoglobin values of Group 1 were higher than Group 2 (11.12 ± 1.06 vs 10.14 ± 1.59 g/dL; p = 0.024). Erythrocyte suspension (1.43 ± 4.51 vs 5.71 ± 7.46 mL/kg; p = 0.030) and fresh frozen plasma use (5.71 ± 8.10 vs 19.52 ± 12.44 mL/kg; p < 0.001) in Group 1 were lower than those of Group 2. Prothrombin time, activated partial thromboplastin time, and international normalized ratio values in Group 1 were lower than those of Group 2 (p < 0.05). No statistically significant difference was identified in recurrence of pulmonary hemorrhage after 72 h, overall mortality, mortality from pulmonary hemorrhage, surfactant use, intubation time, hospitalization duration, intraventricular hemorrhage (IVH), severe IVH, patent ductus arteriosus rates, or short-term complication rates.

CONCLUSION

rFVIIa administration was observed to be effective in stopping pulmonary hemorrhage, reducing blood product requirement, and improving coagulation test parameters. Prospective studies are needed to evaluate the efficacy, reliability, and long-term results of rFVIIa in the prevention and treatment of pulmonary hemorrhage in premature infants.

The diagnosis, management, and postnatal prevention of intraventricular hemorrhage in the preterm neonate

Intraventricular hemorrhage (IVH) occurs in 20% to 25% of very low birthweight preterm neonates and may be associated with significant sequelae. Infants who have IVH are at risk for posthemorrhagic hydrocephalus and periventricular leukomalacia; as many as 75% of those who have parenchymal involvement of hemorrhage suffer significant neurodevelopmental disability. Because of the prevalence of IVH and the medical and societal impact of this disease, many postnatal pharmacologic prevention strategies have been explored. Randomized clinical prevention trials should provide long-term neurodevelopmental follow-up to assess the impact of preterm birth, injury, and pharmacologic intervention on the developing brain.