Increased risk of intraventricular hemorrhage in preterm infants with thrombophilia

Incidence and clinical analysis of asymptomatic intracranial hemorrhage in neonates with cerebral hypoxic-ischaemic risk based on multisequence MR images

The incidence and clinical distribution of intracranial haemorrhage (ICH) in neonates at risk of cerebral hypoxia-ischaemia have not been reported in specific studies. Based on conventional magnetic resonance imaging (MRI) versus susceptibility weighted imaging (SWI), this study aimed to analyse the occurrence of asymptomatic ICH in newborns with or without risk of cerebral hypoxia-ischaemia and to accumulate objective data for clinical evaluations of high-risk neonates and corresponding response strategies. 317 newborns were included. MRI revealed that the overall incidence of ICH was 59.31%. The most common subtype was intracranial extracerebral haemorrhage (ICECH) which included subarachnoid haemorrhage (SAH) and subdural haemorrhage (SDH). ICECH accounted for 92.02% of ICH. The positive detection rate of ICECH by SWI was significantly higher than that by T1WI. The incidence of total ICH, ICECH and SAH was greater among children who were delivered vaginally than among those who underwent caesarean delivery. Asymptomatic neonatal ICH may be a common complication of the neonatal birth process, and SWI may improve the detection rate. Transvaginal delivery and a weight greater than 2500 g were associated with a high incidence of ICECH in neonates. The impact of neonatal cerebral hypoxia-ischaemia risk factors on the occurrence of asymptomatic ICH may be negligible.

Germinal Matrix-Intraventricular Hemorrhage: A Tale of Preterm Infants

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a common intracranial complication in preterm infants, especially those born before 32 weeks of gestation and very-low-birth-weight infants. Hemorrhage originates in the fragile capillary network of the subependymal germinal matrix of the developing brain and may disrupt the ependymal lining and progress into the lateral cerebral ventricle. GM-IVH is associated with increased mortality and abnormal neurodevelopmental outcomes such as posthemorrhagic hydrocephalus, cerebral palsy, epilepsy, severe cognitive impairment, and visual and hearing impairment. Most affected neonates are asymptomatic, and thus, diagnosis is usually made using real-time transfontanellar ultrasound. The present review provides a synopsis of the pathogenesis, grading, incidence, risk factors, and diagnosis of GM-IVH in preterm neonates. We explore brief literature related to outcomes, management interventions, and pharmacological and nonpharmacological prevention strategies for GM-IVH and posthemorrhagic hydrocephalus.

Genetic predictors of severe intraventricular hemorrhage in extremely low-birthweight infants

OBJECTIVE

To test associations between grades 3 or 4 (severe) intraventricular hemorrhage (IVH) and single nucleotide polymorphisms (SNPs) associated with coagulation, inflammation, angiogenesis, and organ development in an exploratory study.

STUDY DESIGN

Extremely low-birthweight (ELBW) infants enrolled in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network's (NRN) Cytokines Study were included if they had cranial ultrasound (CUS) and genotyping data available in the NRN Anonymized DNA Repository and Database. Associations between SNPs and IVH severity were tested with multivariable logistic regression analysis.

RESULT

One hundred thirty-nine infants with severe IVH and 687 infants with grade 1 or 0 IVH were included. One thousand two hundred seventy-nine SNPs were genotyped. Thirteen were preliminarily associated with severe IVH including five related to central nervous system (CNS) neuronal and neurovascular development.

CONCLUSION

Genetic variants for CNS neuronal and neurovascular development may be associated with severe IVH in premature infants.

Placental Pathology Findings and the Risk of Intraventricular and Cerebellar Hemorrhage in Preterm Neonates

Placental pathology as a predisposing factor to intraventricular hemorrhage remains a matter of debate, and its contribution to cerebellar hemorrhage development is still largely unexplored. Our study aimed to assess placental and perinatal risk factors for intraventricular and cerebellar hemorrhages in preterm infants. This retrospective cohort study included very low-birth weight infants born at the Gaslini Children's Hospital between January 2012 and October 2016 who underwent brain magnetic resonance with susceptibility-weighted imaging at term-equivalent age and whose placenta was analyzed according to the Amsterdam Placental Workshop Group Consensus Statement. Of the 286 neonates included, 68 (23.8%) had intraventricular hemorrhage (all grades) and 48 (16.8%) had a cerebellar hemorrhage (all grades). After correction for gestational age, chorioamnionitis involving the maternal side of the placenta was found to be an independent risk factor for developing intraventricular hemorrhage, whereas there was no association between maternal and fetal inflammatory response and cerebellar hemorrhage. Among perinatal factors, we found that intraventricular hemorrhage was significantly associated with cerebellar hemorrhage (odds ratio [OR], 8.14), mechanical ventilation within the first 72 h (OR, 2.67), and patent ductus arteriosus requiring treatment (OR, 2.6), whereas cesarean section emerged as a protective factor (OR, 0.26). Inotropic support within 72 h after birth (OR, 5.24) and intraventricular hemorrhage (OR, 6.38) were independent risk factors for cerebellar hemorrhage, whereas higher gestational age was a protective factor (OR, 0.76). Assessing placental pathology may help in understanding mechanisms leading to intraventricular hemorrhage, although its possible role in predicting cerebellar bleeding needs further evaluation.

Role of Fibronectin-1 polymorphism genes with the pathogenesis of intraventricular hemorrhage in preterm infants

BACKGROUND/INTRODUCTION

Intraventricular hemorrhage (IVH) is a dangerous complication facing a significant proportion of preterm infants. It is multifactorial in nature, and an observed fibronectin deficiency in the germinal matrix basal lamina is among the most prominent factors that influence such rupture. Better understanding of the FN1 gene polymorphisms and their role in IVH may further clarify the presence of a genetic susceptibility of certain babies to this complication. The aim of this study was to assess if 5 single nucleotide polymorphisms of the fibronectin gene may be linked to an increased incidence of IVH.

MATERIAL AND METHODS

The study included 108 infants born between 24 and 32 weeks of gestation. IVH was diagnosed using cranial ultrasound performed on the 1st,3rd, and 7th day after birth and classified according to Papile et al. IVH classification. The 5 FN1 gene polymorphisms assessed in the study were the following: rs3796123; rs1968510; rs10202709; rs6725958; and rs35343655.

RESULTS

IVH developed in 51 (47.2%) out of the 108 preterm infants. This includes, 18 (35.3%) with stage I IVH, 19 (37.3%) with stage II, 11 (21.6%) with stage III, and 3 (5.9%) with stage IV IVH. Incidence of IVH was higher in infants with lower APGAR scores, low gestational age, and low birthweight. Analysis showed that IVH stage II to IV was approximately seven times more likely to occur in infants with the genotype TT FN1 rs10202709 (OR 7237 (1046-79.59; p = 0,044)). No other significant association was found with the rest of the polymorphisms.

CONCLUSION

The results of our study indicate a sevenfold increased genetic susceptibility to IVH in preterm infants with the TT FN1 rs10202709 gene polymorphism. The fibronectin gene polymorphism may therefore be of crucial importance as a genetic risk factor for IVH in preterm infants. Further studies are warranted.

Predictors of severe intraventricular hemorrhage in preterm infants under 29-weeks gestation

Purpose: Preterm infants <29 weeks of gestation are at risk for severe intraventricular hemorrhage (IVH). Lower gestational age, birth weight, severe illness, as indexed by higher Score for Neonatal Acute Physiology - Perinatal Extension II (SNAPPE-II) are associated with severe IVH. The role of coagulation abnormalities on the first day after birth in severe IVH remains controversial. The present study investigated factors that predict the risk of severe IVH, including SNAPPE-II at 12 h and coagulation parameters on the first day after birth.Materials and methods: A retrospective chart review of infants < 29 weeks of gestation from January 2008 to December 2013 was performed. Prenatal and postnatal characteristics, SNAPPE-II at 12 h, coagulation parameters [prothrombin time (PT), INR, partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen] on the first day and cranial ultrasound examination records were collected. The association between clinical and laboratory variables and severe IVH was determined. A joint predictive model for the risk of severe IVH (grades 3 and 4) versus no-mild IVH (grades 0, 1, and 2) was developed using multiple regression analysis.Results: Preterm infants of gestational age < 29 weeks were included (n = 101). Fifteen (15%) infants had severe IVH. Lower gestational age (p = .006), birth weight (p = .008), African American race (p = .031) and higher SNAPPE-II at 12 h (p = .001) were associated with severe IVH. Infants with severe IVH had longer PT (p = .004), higher INR (p = .004) and lower platelet count (p = .034) than those with no-mild IVH. Stepwise logistic regression showed that only SNAPPE-II at 12 h was an independent predictor of severe IVH. For each unit increase in SNAPPE-II, the log odds of severe IVH increased by 0.045 (95% CI: [0.017, 0.073]; p = .002). A threshold of 55 on the SNAPPE-II yielded a sensitivity of 60% (9/15), a specificity of 91% (78/86), a positive predictive value (PPV) of 53% (9/17) and a negative predictive value (NPV) of 93% (78/84). All other demographic and clinical variables and coagulation abnormalities had an insignificant coefficient (p > .05) when included in a bivariate logistic model with SNAPPE-II.Conclusion: SNAPPE-II at 12 h after birth is an independent predictor of severe IVH in preterm infants with gestational age < 29 weeks.

Challenges for intraventricular hemorrhage research and emerging therapeutic targets

INTRODUCTION

Intraventricular hemorrhage (IVH) affects both premature infants and adults. In both demographics, it has high mortality and morbidity. There is no FDA approved therapy that improves neurological outcome in either population highlighting the need for additional focus on therapeutic targets and treatments emerging from preclinical studies. Areas covered: IVH induces both initial injury linked to the physical effects of the blood (mass effect) and secondary injury linked to the brain response to the hemorrhage. Preclinical studies have identified multiple secondary injury mechanisms following IVH, and particularly the role of blood components (e.g. hemoglobin, iron, thrombin). This review, with an emphasis on pre-clinical IVH research, highlights therapeutic targets and treatments that may be of use in prevention, acute care, or repair of damage. Expert opinion: An IVH is a potentially devastating event. Progress has been made in elucidating injury mechanisms, but this has still to translate to the clinic. Some pathways involved in injury also have beneficial effects (coagulation cascade/inflammation). A greater understanding of the downstream pathways involved in those pathways may allow therapeutic development. Iron chelation (deferoxamine) is in clinical trial for intracerebral hemorrhage and preclinical data suggest it may be a potential treatment for IVH.

Evolution of Factor V Leiden

Factor V Leiden is a procoagulant mutation associated with venous and arterial thrombosis and pregnancy complications. Its high prevalence of 5% in Caucasians suggests that there are evolutionary benefits as well. Carriers are indeed reported to have various advantageous phenotypes related to haemostasis, inflammation and fertility: less acute blood loss; less menstrual blood loss; decreased risk of intracranial haemorrhage; milder phenotypes of haemophilia; higher survival in and lower susceptibility to severe sepsis; higher survival in acute respiratory distress syndrome; less severe diabetic nephropathy and higher fecundity in both men and women. Not all these associations come from high quality adequately powered studies and many have not been confirmed by further research. The evolutionary influence of the alleged associations varies and is difficult to establish, partly due to a shift over time in risk factors of the diseases concerned. For most of the phenotypes possible mechanistic explanations can be provided. The procoagulant phenotype and perhaps also certain pregnancy complications follow from activated protein C (APC) resistance. Elevated APC levels possibly mediate anti-inflammatory effects. Higher sperm counts and more successful embryo implantation seem to play a role in the increased fecundity.

The role of FV 1691G>A, FII 20210G>A mutations and MTHFR 677C>T; 1298A>C and 103G>T FXIII gene polymorphisms in pathogenesis of intraventricular hemorrhage in infants born before 32 weeks of gestation

BACKGROUND

Congenital thrombophilia is associated with an increased intraventricular hemorrhage (IVH) risk among newborns, but it may also play a protective role. The role of genetic polymorphisms involved in the coagulation pathway of IVH pathogenesis is probably a consequence of an increased risk of thrombosis in the fine blood vessels in the germinal matrix region.

MATERIAL AND METHODS

The aim of this study was to evaluate the possible relationship between Factor V (FV) 1691G>A, Factor II (FII) 20210G>A mutations and methylenetetrahydrofolate reductase (MTHFR) 677C>T; 1298A>C and Factor XIII (FXIII) 103G>T gene polymorphisms and the occurrence of IVH in 100 infants born from 24 + 0 to 32 + 0 weeks of gestation, born from singleton pregnancy, before 32 + 0 weeks of gestation, exposed to antenatal steroid therapy, and without congenital abnormalities.

RESULTS

IVH developed 45 (45%) infants, including 15 (33.33%) diagnosed with IVH stage I, 20 (42.22%) with stage II, 8 (17.77%) with stage III, and 3 (6.66%) with stage IV. Analysis showed a prevalence 4.5 times higher of IVH stages II to IV in infants with the genotype CC (OR 4511 (1147-17.75); p = 0.026) of MTHFR 1298A>C gene polymorphism. Our investigation did not confirm any significant prevalence of IVH development in other studied mutations/polymorphisms.

CONCLUSIONS

This study confirmed that the MTHFR 1298A>C polymorphism is associated with the risk of IVH. IVH is a significant problem for preterm infants. In addition to little progress in preventing IVH in preterm babies, substantial research that is focused on understanding the etiology, mechanism, and risk factors for IVH is imperative. In the era of personalized medicine, identification of genetic risk factors creates opportunities to generate preventative strategies.

Heparin for the prevention of intraventricular haemorrhage in preterm infants

BACKGROUND

Preterm birth remains the major risk factor for the development of intraventricular haemorrhage, an injury that occurs in 25% of very low birth weight infants. Intraventricular haemorrhage is thought to be venous in origin and intrinsic thromboses in the germinal matrix are likely to play a triggering role. Heparin activates antithrombin and promotes the inactivation of thrombin and other target proteinases. The administration of anticoagulants such as heparin may offset the increased risk of developing intraventricular haemorrhage and may also reduce the risk of developing parenchymal venous infarct, a condition known to complicate intraventricular haemorrhage.

OBJECTIVES

To assess whether the prophylactic administration of heparin reduces the incidence of germinal matrix-intraventricular haemorrhage in very preterm neonates when compared to placebo, no treatment, or other anticoagulants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2015), MEDLINE (1996 to 22 November 2015), EMBASE (1980 to 22 November 2015) and CINAHL (1982 to 22 November 2015), applying no language restrictions. We searched the abstracts of the major congresses in the field (Perinatal Society of Australia and New Zealand and Pediatric Academic Societies) from 2000 to 2015.

SELECTION CRITERIA

Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing the administration of early, i.e. within the first 24 hours of life, heparin in very preterm infants (gestational age < 32 weeks).

DATA COLLECTION AND ANALYSIS

For each of the included trials, two authors independently extracted data (e.g. number of participants, birth weight, gestational age, dose of heparin, mode of administration, and duration of therapy, etc.) and assessed the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow up). The primary outcomes considered in this review are intraventricular haemorrhage, severe intraventricular haemorrhage and neonatal mortality.

MAIN RESULTS

Two randomised controlled trials enrolling a total of 155 infants met the inclusion criteria of this review. Both trials compared low-dose heparin to the same solution without heparin in very preterm newborns requiring umbilical catheterisation. No trials were identified that specifically studied the use of heparin in infants at risk of germinal matrix-intraventricular haemorrhage.We found no differences in the rates of intraventricular haemorrhage (typical RR 0.93, 95% CI 0.61 to 1.41; typical RD -0.03, 95% CI -0.17 to 0.12; 2 studies, 155 infants; I² = 57% for RR and I² = 65% for RD), severe intraventricular haemorrhage (typical RR 1.01, 95% CI 0.46 to 2.23; typical RD 0.00, 95% CI -0.11 to 0.11; 2 studies, 155 infants; I² = 0% for RR and I² = 0% for RD) and neonatal mortality (typical RR 0.69, 95% CI 0.28 to 1.67; typical RD -0.04, 95% CI -0.14 to 0.06; 2 studies, 155 infants; I² = 28% for RR and I² = 50% for RD). We judged the quality of the evidence supporting these findings as very low (rates of intraventricular haemorrhage) and low (severe intraventricular haemorrhage and neonatal mortality) mainly because of limitations in the study designs and the imprecision of estimates. We found very few data on other relevant outcomes, such as bronchopulmonary dysplasia, pulmonary haemorrhage and patent ductus arteriosus; and no study assessing long-term outcomes (e.g. neurodevelopmental disability).

AUTHORS' CONCLUSIONS

There is very limited data on the effect of prophylactic administration of heparin on the incidence and severity of IVH in very preterm neonates. Both the identified trials used heparin in the context of maintaining umbilical line patency and not specifically as an agent to prevent germinal matrix-intraventricular haemorrhage. Given the imprecision of our estimates, the results of this systematic review are consistent with either a benefit or a detrimental effect of heparin and do not provide a definitive answer to the review question. Limited evidence is available on other clinically relevant outcomes.

Antithrombin for the prevention of intraventricular hemorrhage in very preterm infants

BACKGROUND

Preterm birth remains the major risk factor for the development of intraventricular hemorrhage, an injury that occurs in 25% of very low birth weight infants. Intraventricular hemorrhage is thought to be venous in origin and intrinsic thromboses in the germinal matrix are likely to play a triggering role. Antithrombin, a glycoprotein synthesized in the liver, is the major plasma inhibitor of thrombin thus modulating blood coagulation. Very low birth weight newborn infants have low levels of antithrombin and the risk of developing intraventricular hemorrhage is increased by the presence of hypercoagulability in the first hours of life. The administration of anticoagulants such as antithrombin may offset the increased risk of developing intraventricular hemorrhage. Anticoagulants may also reduce the risk of developing parenchymal venous infarct, a condition known to complicate intraventricular hemorrhage.

OBJECTIVES

To assess whether the prophylactic administration of antithrombin (started within the first 24 hours after birth) reduces the incidence of germinal matrix-intraventricular hemorrhage in very preterm neonates when compared to placebo, no treatment, or heparin.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2015), MEDLINE (1996 to 22 November 2015), EMBASE (1980 to 22 November 2015), and CINAHL (1982 to 22 November 2015). No language restrictions were applied. We searched the abstracts of the major congresses in the field (Perinatal Society of Australia and New Zealand and Pediatric Academic Societies) from 2000 to 2015.

SELECTION CRITERIA

Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing the administration of early, i.e. within the first 24 hours of life, antithrombin in very preterm infants (gestational age < 32 weeks, any birth weight).

DATA COLLECTION AND ANALYSIS

For each of the included trials, two authors independently extracted data (e.g. number of participants, birth weight, gestational age, antithrombin formulation (plasma-derived or recombinant), mode of administration, and duration of therapy, etc.) and assessed the risk of bias (e.g. adequacy of randomization, blinding, completeness of follow-up). The primary outcomes considered in this review are intraventricular hemorrhage and severe intraventricular hemorrhage.

MAIN RESULTS

Two randomized controlled trials, for a total of 182 infants, met the inclusion criteria of this review. Both trials compared antithrombin with placebo. We found no significant differences in the rates of intraventricular hemorrhage (typical RR 1.30, CI 95% 0.87 to 1.93, typical RD 0.09, 95% CI -0.05 to 0.23; 2 studies, 175 infants; I² = 18% for RR and I² = 42% for RD) and severe intraventricular hemorrhage (typical RR 1.04, CI 95% 0.55 to 1.94; typical RD 0.01, 95% CI -0.11 to 0.12; 2 studies, 175 infants; I² = 0% for RR and I² = 0% for RD). Among secondary outcomes, we found no significant differences in terms of neonatal mortality (typical RR 2.00, CI 95% 0.62 to 6.45; typical RD 0.04, 95% CI -0.03 to 0.12; 2 studies, 182 infants; I² = 46% for RR and I² = 61% for RD) and in the other specified outcomes, such as bronchopulmonary dysplasia. The quality of the evidence supporting these findings is limited due to the imprecision of the estimates.

AUTHORS' CONCLUSIONS

The administration of antithrombin seems not to reduce the incidence and severity of intraventricular hemorrhage in very preterm infants. Limited evidence is available on other clinically relevant outcomes. Given the imprecision of the estimate, the results of this systematic review are consistent with either a benefit or a detrimental effect of antithrombin and do not provide a definitive answer to the review question.

Systematic review: hereditary thrombophilia associated to pediatric strokes and cerebral palsy

OBJECTIVES

This review aimed to organize and consolidate the latest knowledge about mutations and genetic polymorphisms related to hereditary thrombophilia and their potential association with pediatric stroke and cerebral palsy (CP).

SOURCES

Scientific articles published from 1993 to 2013, written in Portuguese, English, French, and Spanish, were selected and reviewed. The publications were searched in electronic databases, and also in the collections of local libraries. The terms "hereditary thrombophilia", "polymorphisms", "mutation", "pediatric strokes", and "cerebral palsy" were used for the research.

SUMMARY OF THE FINDINGS

The search in databases and in the bibliographic references retrieved 75 articles for inclusion in this review. Studies that investigated hereditary thrombophilias and their associations to CP and arterial and venous pediatric stroke presented contradictory results. The meta-analysis and case-control studies that showed positive results for this association described only slightly increased relative risks and sometimes had questionable conclusions. The association of two or more hereditary thrombophilias, or the association between thrombophilia and other specific clinical risk factors, suggest a higher risk of CP and pediatric stroke than isolated hereditary thrombophilia.

CONCLUSIONS

Larger, multicenter studies should be developed in order to elucidate the role of mutations leading to hereditary thrombophilia and the development of CP and pediatric stroke. The complex and multifactorial etiology of CP and stroke makes this an arduous and difficult task; however, the benefits generated by these studies are immeasurable.

Genetic variants of the vitamin K dependent coagulation system and intraventricular hemorrhage in preterm infants

Background

Pathogenesis of intraventricular hemorrhage (IVH) in premature infants is multifactorial. Little is known about the impact of genetic variants in the vitamin K-dependent coagulation system on the development of IVH.

Methods

Polymorphisms in the genes encoding vitamin K epoxide reductase complex 1 (VKORC1 -1639G>A) and coagulation factor 7 (F7 -323Ins10) were examined prospectively in 90 preterm infants <32 weeks gestational age with respect to coagulation profile and IVH risk.

Results

F7-323Ins10 was associated with lower factor VII levels, but not with individual IVH risk. In VKORC1-wildtype infants, logistic regression analysis revealed a higher IVH risk compared to carriers of the -1639A allele. Levels of the vitamin K-dependent coagulation parameters assessed in the first hour after birth did not differ between VKORC1-wildtype infants and those carrying -1639A alleles.

Conclusions

Our data support the assumption that genetic variants in the vitamin K-dependent coagulation system influence the coagulation profile and the IVH risk in preterm infants. Further studies focussing on short-term changes in vitamin K-kinetics and the coagulation profile during the first days of life are required to further understand a possible link between development of IVH and genetic variants affecting the vitamin K-metabolism.

Haemophilia in extreme immature preterm infants: increased risk for intracranial haemorrhage?

Haemophiliacs and extremely premature infants are both at an increased risk for intracranial haemorrhage; both conditions might be further elevating the risk. We report a case of a very immature preterm-infant of 26 gestational weeks (birth weight 635 g) with severe haemophilia A. Furthermore, we provide an overview of the published literature on this subject matter. Until now, deficiency of factor VIII or IX as a potential risk factor for ICH in preterm infants remains controversial. However, prophylactic substitution of factor VIII or IX in preterm infants with haemophilia may minimize the risk of bleeding complications and neurologic sequelae.

Atypical timing and presentation of periventricular haemorrhagic infarction in preterm infants: the role of thrombophilia

AIM

Periventricular haemorrhagic infarction (PVHI) is a complication of preterm birth associated with cardiorespiratory instability. To date, the role of thrombophilia as a possible additional risk factor in infants with atypical timing and presentation of PVHI has not been investigated.

METHOD

This was a retrospective cohort study of preterm infants who developed PVHI with an atypical timing and presentation either of antenatal onset or late in the postnatal course in the absence of a preceding sudden deterioration of their clinical condition. In infants with atypical PVHI mutation analysis of the factor V Leiden (G1691A), prothrombin (G20210A) gene, and C677T and A1298C polymorphisms in the MTHFR gene was performed, and plasma lipoprotein(a) and homocysteine levels were measured.

RESULTS

Sixty-two preterm infants who presented with a PVHI were studied. Seventeen had an atypical presentation (seven males, 10 females; median birthweight 1170g [range 580-1990g]; median gestational age 30.6wks [range 28.7-33.7wks]). The typical PVHI group comprised 28 males and 17 females (median birthweight 1200g [range 670-2210g]; median gestational age 29.6wks [range 25.3-33.6wks]). Among the 17 infants with atypical presentation, the factor V Leiden mutation was found in seven infants (41%) as well as in the mothers of six of these seven infants; in one infant this was concomitant with a prothrombin gene mutation. A polymorphism in the MTHFR gene was also present in these infants. In two infants with an atypical presentation who were tested for this, a mutation in the COL4A1 gene was found (reported previously). All but two of the infants with an atypical presentation developed spastic unilateral cerebral palsy.

INTERPRETATION

An atypical presentation of PVHI in preterm infants tends to occur more often in the presence of thrombophilia. Testing of thrombophilia, especially factor V Leiden and prothrombin gene mutation, is recommended in these infants.

Epidemiology of Prothrombin G20210A Mutation in the Mediterranean Region

There are many genetic and acquired risk factors that are known to cause venous thromboembolic disorders (VTE). One of these is the Prothrombin G20210A mutation, which has been identified in 1996. Prothrombin G20210A mutation causes higher levels of the clotting factor prothrombin in the blood of carriers, which creates a higher tendency towards blood clotting (hypercoagulability), and therefore the carriers become at higher risk of developing VTE. High prevalence of Prothrombin G20210A mutation was reported in Caucasian populations, but the prevalence was almost absent in non-Caucasians. That was most obvious in countries of South Europe and the Mediterranean region. This review article discusses Prothrombin G20210A mutation, how it causes VTE, the origin of the mutation, and its distribution worldwide with special concentration on the Mediterranean area.

The black box of perinatal ischemic stroke pathogenesis

An improved understanding of perinatal stroke epidemiology, classification, neuroimaging, and outcomes has emerged in recent years. Despite this, little is known regarding the pathophysiological mechanisms responsible for most cases. A multitude of possible associations and putative risk factors have been reported, but most lack definitive empirical evidence supporting primary causation. These include obstetrical and maternal factors, perinatal conditions, infectious diseases, prothrombotic abnormalities, cardiac disorders, medications, and many others. The bulk of evidence is weak, dominated by case reports and retrospective case series. Findings from the small number of case-control and cohort studies that exist are limited by heterogeneous populations and methodologies. The single largest barrier to ultimately understanding and potentially improving outcomes from this common and disabling condition is the lack of comprehensive, fully powered risk factor studies required to definitively describe perinatal stroke pathogenesis. This review summarizes current evidence and suggests future directions for research.

Replication of genetic associations in the inflammation, complement, and coagulation pathways with intraventricular hemorrhage in LBW preterm neonates

Intraventricular hemorrhage (IVH) is a significant morbidity seen in very LBW infants. Genes related to the inflammation, infection, complement, or coagulation pathways have been implicated as risk factors for IVH. We examined 10 candidate genes for associations with IVH in 271 preterm infants (64 with IVH grades I-IV and 207 without IVH) weighing <1500 g. The heterozygous genotype OR = 8.1, CI = 2.5-26.0, p = 4 × 10(-4)) and the A allele (OR = 7.3, CI = 2.4-22.5, p = 1 × 10(-4)) of the coagulation factor V (FV) Leiden mutation (rs6025) were associated with an increased risk of developing IVH grade I or II but not grade III or IV after correction for multiple testing with Bonferroni. Lack of association in the severe grades of IVH may be a result of lack of power to detect an effect given the small sample size (n = 8). However, this result is consistent with previous research that demonstrates that the heterozygous genotype of the FV mutation is associated with increased risk for the development of IVH but a decreased risk for the progression or extension to more severe grades of IVH.

Germinal matrix hemorrhage: intraventricular hemorrhage in very-low-birth-weight infants: the independent role of inherited thrombophilia

BACKGROUND AND PURPOSE

The etiology of germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH) is multifactorial and the role of genetic polymorphisms is unclear. The aim of this prospective study was to evaluate prothrombotic genetic mutations as independent risk factors for the development of all grades of GMH-IVH in very-low-birth-weight infants.

METHODS

The presence of both factor V Leiden and prothrombin gain-of-function gene mutations were prospectively assessed in 106 very-low-birth-weight infants. Infants with GMH-IVH were compared to those without GMH-IVH according to genetic and clinical characteristics.

RESULTS

Twenty-two out of 106 infants had GMH-IVH develop (20.7%). Infants with GMH-IVH had significantly lower gestational ages and birth weights. In the multivariate Poisson regression model, the prevalence of GMH-IVH appeared to be inversely related to gestational age, with a risk ratio of 0.83 (95% CI, 0.72-0.97; P=0.02) per week. Risk ratio of GMH-IVH for carriers of either prothrombotic mutation was 2.65 (95% CI, 1.23-5.72; P=0.01), similar to the risk ratio associated with need for resuscitation at birth (2.30; 95% CI, 1.02-5.18; P=0.04).

CONCLUSIONS

Very-low-birth-weight infants who are carriers for either prothrombotic mutations are at increased risk for development of GMH-IVH. Genetic factors act as independent risk factors of the same magnitude as other known risk factors.

Plasminogen Activator Inhibitor I 4G/5G Polymorphism in Neonatal Respiratory Distress Syndrome

Fibrin monomers inhibit surfactant function. 4G/5G insertion/deletion polymorphism plays an important role in the regulation of plasminogen activator inhibitor 1 (PAI-1) gene expression. To examine the genotype distribution of PAI-1 polymorphism in 60 infants with respiratory distress syndrome (RDS) and 53 controls, an allele-specific polymerase chain reaction (PCR) was used. The proportion of 4G/4G, 4G/5G, and 5G/5G genotypes did not differ statistically between the RDS and control groups (P > .05). Having PAI-1 4G/4G genotype polymorphism appears to increase the risk of RDS (odds ratio [OR] =1.5; 95% confidence interval [CI], 0.5-4.3), although it was not statistically significant. No relation was found between the PAI-1 4G/5G polymorphisms and RDS, but there was an increased risk associated with the 4G variant of the PAI-1 gene. We believe that our findings of increased 4G allele of the PAI-1 gene in infants with RDS would also help to clarify the pathogenesis of RDS.

A novel mutation in LMBRD1 causes the cblF defect of vitamin B(12) metabolism in a Turkish patient

In the cblF defect of vitamin B(12) (cobalamin) metabolism, cobalamin is trapped in lysosomes. Consequently, cobalamin coenzyme synthesis is blocked, and cofactors for methionine synthase and methylmalonyl-coenzyme A (CoA) mutase are deficient. We recently identified LMBRD1 as the causative gene located on chromosome 6q13 and showed that 18 out of 24 alleles in unrelated patients carried the deletion c.1056delG (p.L352fsX18) (Rutsch et al. (Nat Genet 41:234-239, 2009). LMBRD1 encodes the lysosomal membrane protein LMBD1, which presumably facilitates lysosomal cobalamin export. Our patient is the second child of consanguineous Turkish parents. He presented on the second day of life with cerebral seizures due to intraventricular hemorrhage. Plasma homocysteine and urinary methylmalonic acid levels were elevated, and serum cobalamin level was decreased. Synthesis of both cobalamin coenzymes was deficient in cultured skin fibroblasts. The cblF defect was confirmed by somatic complementation analysis. Sequencing of LMBRD1 revealed the novel deletion c.1405delG (p.D469fsX38) on both alleles. Real-time polymerase chain reaction (PCR) revealed reduced messenger RNA (mRNA) levels in patient fibroblasts compared with controls. Transfection of patient fibroblasts with the LMBD1 wild-type complement DNA (cDNA) rescued coenzyme synthesis and function, confirming this new deletion as an additional cause of the cblF defect. This case adds to the spectrum of clinical presentations and mutations of this rare disorder of lysosomal transport.

Intracranial hemorrhage in the preterm infant: understanding it, preventing it

New discoveries in neonatal imaging, cerebral monitoring, and hemodynamics, and greater understanding of inflammatory and genetic mechanisms involved in intracranial hemorrhage (ICH) in the preterm infant are creating opportunities for innovative early detection and prevention approaches. This article covers the spectrum of ICH in the preterm infant, including germinal matrix intraventricular hemorrhage, its complications, and associated phenomena, such as the emerging role of cerebellar hemorrhage. The overall aim of this article is to review the current knowledge of the mechanisms, diagnosis, outcome, and management of preterm ICH; to revisit the origins from which they develop; and to discuss future expectations.

Fetal intracerebral hemorrhage in familial thrombophilia

We describe a fetal intracerebral hemorrhage associated with familial thrombophilia. Intraventricular and intraparenchymal hemorrhage of the left cerebral hemisphere was diagnosed at 22 weeks of gestation. Neuropathologic examination demonstrated a large germinal zone hemorrhage and ischemic changes secondary to bleeding. The fetus manifested a heterozygous Leiden mutation of the factor V gene, and a heterozygous F76L mutation of the protein C gene. The literature indicates that the coexistence of genetic risk factors of thrombophilia and fetal intracerebral hemorrhage is rare, except in the context of pregnancy-related complications. The utility of laboratory screening is discussed.

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.

The hemostatic balance revisited through the lessons of mankind evolution

Under physiologic conditions, a hemostatic balance is achieved through the effects of natural procoagulant and anticoagulant factors which, in equilibrium with each other, provide hemostasis at the sites of vascular injury. Abnormalities of these hemostasis factors can result in a tendency toward hemorrhagic or thrombotic events. In this review the influence of inherited prothrombotic risk factors--especially the more frequent factor V Leiden and prothrombin gene mutations--on normal and abnormal hemostasis is analyzed from an evolutionary point of view. The effect of inherited bleeding disorders on the development of thrombotic or atherosclerotic processes is also discussed.

Homocysteine levels in preterm infants: is there an association with intraventricular hemorrhage? A prospective cohort study

Background

The purpose of this study was to characterize total homocysteine (tHcy) levels at birth in preterm and term infants and identify associations with intraventricular hemorrhage (IVH) and other neonatal outcomes such as mortality, sepsis, necrotizing enterocolitis, bronchopulmonary dysplasia, and thrombocytopenia.

Methods

123 infants < 32 weeks gestation admitted to our Level III nursery were enrolled. A group of 25 term infants were enrolled for comparison. Two blood spots collected on filter paper with admission blood drawing were analyzed by a high performance liquid chromatography (HPLC) method. Statistical analysis included ANOVA, Spearman's Rank Order Correlation and Mann-Whitney U test.

Results

The median tHcy was 2.75 μmol/L with an interquartile range of 1.34 – 4.96 μmol/L. There was no difference between preterm and term tHcy (median 2.76, IQR 1.25 – 4.8 μmol/L vs median 2.54, IQR 1.55 – 7.85 μmol/L, p = 0.07). There was no statistically significant difference in tHcy in 31 preterm infants with IVH compared to infants without IVH (median 1.96, IQR 1.09 – 4.35 μmol/L vs median 2.96, IQR 1.51 – 4.84 μmol/L, p = 0.43). There was also no statistically significant difference in tHcy in 7 infants with periventricular leukomalacia (PVL) compared to infants without PVL (median 1.55, IQR 0.25 – 3.45 μmol/L vs median 2.85, IQR 1.34 – 4.82 μmol/L, p = 0.07). Male infants had lower tHcy compared to female; prenatal steroids were associated with a higher tHcy.

Conclusion

In our population of preterm infants, there is no association between IVH and tHcy. Male gender, prenatal steroids and preeclampsia were associated with differences in tHcy levels.

Fetal and Neonatal Thrombophilia

Thrombophilia of the fetus and neonate may contribute to higher prevalence of perinatal thrombosis. Due to the potential interaction between thrombophilic risk factors of the neonate and maternal thrombophilia and placental vasculopathy, we recommend thrombophilia assessment be performed in any child and in the mother in case of perinatal thrombosis. Further attention and larger prospective studies are required to establish the role of thrombophilic risk factors in the pathogenesis of any other perinatal complications.

Genetic polymorphisms of hemostasis genes and primary outcome of very low birth weight infants

BACKGROUND

Recent investigations have reported an influence of thrombophilic mutations and antithrombotic risk factors with development of intraventricular hemorrhage. It was our objective for this study to investigate the impact of genetic polymorphisms of hemostasis genes on the primary outcome measures of sepsis, bronchopulmonary dysplasia, intraventricular hemorrhage, and periventricular leukomalacia in a large cohort of very low birth weight infants.

METHODS

There were 586 very low birth weight infants enrolled prospectively in a multicenter trial between September 2003 and July 2005, and an additional 595 very low birth weight infants, who had been recruited in a previous prospective trial, were studied. DNA samples were taken by buccal swab, and genotypes of factor V Leiden mutation, prothrombin G20210A mutation, the factor VII-323 del/ins polymorphism, and the factor XIII-Val34Leu polymorphisms were determined by polymerase chain reaction and restriction enzyme digestion.

RESULTS

In contrast to data published previously, the frequency of intraventricular hemorrhage or periventricular leukomalacia was not significantly influenced by any of the genetic variants tested. Carriers of the factor XIII-Val34Leu polymorphism, however, had a higher sepsis rate and a longer period of hospital care compared with noncarriers. The factor VII-323 del/ins polymorphism was found to be a potential protective factor against bronchopulmonary dysplasia.

CONCLUSIONS

We could not confirm previously reported associations of hemostasis gene variants and development of intraventricular hemorrhage in very low birth weight infants. To better understand gene-disease associations in very low birth weight infants, the prospective development of large-scale cohorts with well-defined phenotypes and corresponding DNA samples is essential.

Familial and genetic susceptibility to major neonatal morbidities in preterm twins

BACKGROUND

Intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia remain significant causes of morbidity and mortality in preterm newborns.

OBJECTIVES

Our goal was to assess the familial and genetic susceptibility to intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia.

METHODS

Mixed-effects logistic-regression and latent variable probit model analysis were used to assess the contribution of several covariates in a multicenter retrospective study of 450 twin pairs born at < or =32 weeks of gestation. To determine the genetic contribution, concordance rates in a subset of 252 monozygotic and dizygotic twin pairs were compared.

RESULTS

The study population had a mean gestational age of 29 weeks and birth weight of 1286 g. After controlling for effects of covariates, the twin data showed that 41.3%, 51.9%, and 65.2%, respectively, of the variances in liability for intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia could be accounted for by genetic and shared environmental factors. Among the 63 monozygotic twin pairs, the observed concordance for bronchopulmonary dysplasia was significantly higher than the expected concordance; 12 of 18 monozygotic twin pairs with > or =1 affected member had both members affected versus 3.69 expected. After controlling for covariates, genetic factors accounted for 53% of the variance in liability for bronchopulmonary dysplasia.

CONCLUSIONS

Twin analyses show that intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia are familial in origin. These data demonstrate, for the first time, the significant genetic susceptibility for bronchopulmonary dysplasia in preterm infants.

Platelet function of newborns as tested by cone and plate(let) analyzer correlates with gestational Age

The issue of platelet function in infants and neonates is of interest, and current data are debatable. A new method for assessing platelet function involves using the cone and plate(let) analyzer (CPA), applicable for small (0.2 ml) whole blood volumes. We used polystyrene surface-coated plates to evaluate cord blood neonatal platelet function under flow. One hundred and sixty full-term and 29 preterm infants born at the Sheba Medical Center between March 2003 and January 2004 were evaluated for platelet adhesion measured as surface coverage (SC; the percentage of total area covered by platelets) and platelet aggregation, defined as the average size (AS) of the aggregates. Platelets from preterm infants displayed less platelet adhesion than did those from full-term infants. Platelet SC correlated with gestational age in all infants (p < 0.05), and both groups exhibited similar aggregation (AS). AS values, however, were significantly lower than the normal adult range in our laboratory. Infants born to mothers with pregnancy-induced hypertension displayed significantly lower SC. No association was found between CPA and postnatal complications.

CONCLUSION

CPA provides a rapid, feasible option for testing platelet function in neonates. Its potential predictive value deserves further attention, and more extensive studies are warranted.

Thrombophilia and fetal germinal matrix-intraventricular hemorrhage: does it matter?

Germinal matrix-intraventricular hemorrhage (GMH-IVH) in the fetus is very rare and the role of thrombophilia in its pathogenesis is unclear. We report on the prenatal diagnosis by magnetic resonance imaging of GMH-IVH in a 24-week fetus. The newborn presented posthemorrhagic ventriculomegaly and was found to be heterozygous for two thrombophilic patterns, factor V Leiden and methylenetetrahydrofolate reductase mutation. The combination of this hypercoagulable state and prenatal GMH-IVH is discussed together with the opportunity of testing these infants for thrombophilia.

Prothrombin and intraventricular haemorrhage

In the study by Salonvaara et al., low prothrombin activity in preterm infants was associated with intraventricular haemorrhage (IVH). The interesting research question-do preterm infants who develop IVH have underlying coagulation disturbance?-could not be answered in this study.

CONCLUSION

The association needs further investigation. The role of prothrombin in perinatal brain damage in the development of IVH and of white matter damage has to be further elucidated.

Intraventricular haemorrhage in very-low-birthweight preterm infants: association with low prothrombin activity at birth

AIM

To determine the occurrence of intraventricular haemorrhage (IVH) and its association with coagulation factors at birth in preterm neonates born before 30 wk gestation.

METHODS

38 neonates (median gestational age 27 wk, range 24-29 wk; median birthweight (BW) 933 g, range 515-1760 g) admitted to the neonatal intensive care unit were studied. Blood samples for coagulation factors were taken within 2 h after birth. The first cranial ultrasonographic examination was performed within the first 3 d. The occurrence of IVH was tested statistically by the Mann-Whitney U-test for association with the activity of coagulation factors and clinical variables.

RESULTS

Thirteen IVHs occurred within the first 3 d of life. IVH was associated with BW <1000 g (p=0.012), low mean blood pressure within the first 2 d (p=0.026), gestational age <27 wk (p=0.054), low Apgar scores (<7) at 1 min (p=0.078) and intrauterine growth restriction (p=0.072). At birth (samples drawn with a median of first 36 min of life), infants with subsequent IVH had statistically significantly lower prothrombin (factor II) activity (p=0.024) than infants without IVH.

CONCLUSION

The measured low prothrombin may have been affected by a prior bleeding event. Nevertheless, preterm infants with low prothrombin activity may be susceptible to IVH, or to the progression of it, if left undiagnosed.

Genetic risk factors associated with thrombosis in children with congenital neurologic disorders

Thromboembolic events during the perinatal period are responsible for irreversible brain damage owing to cerebral hypoxia and neuronal necrosis. We investigated the presence of thrombophilia risk factors in children with congenital neurologic disorders. Nineteen children (9 males and 10 females), aged 1 to 14 years (median 4.5 years), who had presented with symptoms and signs of congenital neurologic disorders were studied. Thirty-five age-matched healthy children recruited from the same geographic area served as controls. Three patients of 19 (15.8%) were carrying the factor V Leiden mutation compared with 2 children among the controls (5.7%). One patient was heterozygous for the prothrombin G20210A variant (5.2%) compared with one child who was heterozygous among the controls. Three patients were homozygous (15.8%) and 11 were heterozygous (57.9%) for the C677T 5,10-methylenetetrahydrofolate reductase gene mutation compared with 4 (11.5%) and 18 (51.4%), respectively, among the controls. Three patients of 19 (15.8%) were carrying more than one mutation. We found 18 mutations in 79% (15/19) of the patients and 25 mutations in 69% (24/35) of the healthy children. Among the individuals carrying the homozygous 677TT 5,10-methylenetetrahydrofolate reductase genotype, we found 7 mutations in 32% (6/19) of the patients and 7 mutations in 20% (7/35) of the healthy children (P > .05). In one patient, lupus anticoagulant and antiphospholipid antibodies of IgG isotype were detected. Reduced activities of protein C, protein S, or antithrombin III were not observed in either the patient or the control group. Although, among our cases, we found some well-known risk factors associated with thrombosis in adults, the pathogenesis of these clinical entities remains obscure.

VWF-cleaving protease (ADAMTS13) in premature infants

BACKGROUND

Patients with thrombotic thrombocytopenic purpura (TTP) are deficient in von Willebrand factor (VWF)-cleaving protease, called ADAMTS13, and are prone to develop abnormal intravascular platelet aggregation leading to focal cerebral ischaemia. We speculated that low levels of ADAMTS13 are present in premature infants. This might result in platelet aggregation with subsequent ischaemia, vessel rupture and haemorrhage, and thus contribute to intraventricular haemorrhage and periventricular leucomalacia (IVH and PVL).

PATIENTS AND METHODS

Nine preterm infants with gestational ages 23.7 to 30.9 (median 25.7) wk, and 10 healthy term control infants with gestational ages 36.9 to 39 (median 37.9) wk were included. Blood was sampled from the umbilical cord at delivery, and levels of ADAMTS13, VWF antigen and VWF collagen binding activity were analysed.

RESULTS

The mean ADAMTS13 level in preterm infants was lower than in the term infants, but the difference between the groups was not statistically significant. However, in the preterm group there was a positive correlation between ADAMTS13 and both gestational age (r = 0.70, p = 0.035) and birthweight (r = 0.83, p = 0.005). Three preterm infants had ADAMTS13 of 18-20%. One of these developed a germinal matrix haemorrhage and PVL, and this infant had the lowest measured ADAMTS13 of all. The levels of VWF antigenand VWF collagen bindingactivity were higher in the preterm infants.

CONCLUSION

This pilot study showed that preterm infants have low levels of ADAMTS13. Enzyme substitution may be a therapeutic option if an association with IVH or PVL can be confirmed in larger patient groups.

Role of thrombophilic risk factors in children with non-stroke cerebral palsy

BACKGROUND

Thrombophilic risk factors play an important role in the pathogenesis of perinatal stroke and resultant cerebral palsy (CP). The association between thrombophilia and CP caused by etiologies other than stroke is undetermined.

METHODS

We assessed three genetic thrombophilic markers (mutation of Factor V Leiden [FV G1691A], 677T polymorphism of thermolabile methylenetetrahydrofolate reductase [MTHFR] and G20210A mutation of the prothrombin gene) in 49 pediatric patients with non-stroke CP and compared the findings with 118 apparently healthy controls. CP in the study group was due to periventricular leukomalacia (n=27), intraventricular hemorrhage (n=9), hypoxic ischemic encephalopathy (n=4), prematurity with no apparent complication (n=8) and intrauterine growth retardation (n=1). Twenty-five children had spastic diplegia, 20 had spastic quadriplegia and 4 had spastic hemiplegia. CP was graded as being severe in 26 children (53%).

RESULTS

No significant difference in the prevalence of thrombophilic risk factors was found between the study and control groups. Twelve study children (24.5%) had at least one of the three thrombophilic mutations compared with 27 controls (23%). There was no significant difference in the prevalence of each thrombophilic risk factor in the various etiologic groups and in the subgroups of mild/severe CP and the control group.

CONCLUSION

These findings support the notion that thrombophilia neither contributes to the occurrence nor affects the clinical outcome and severity of non-stroke CP.

A simple automatized audit system for following and managing practices of platelet and plasma transfusions in a neonatal intensive care unit

During neonatal intensive care, blood components are often used in clinical situations where both their efficacy and safety lack solid justification. A practical system to continuously analyse actual transfusion practices is a prerequisite for improvements of quality in transfusion therapy. We hypothesized that such a system would reveal inappropriate variations in clinical decision making and offer a means for staff education and quality improvement and assurance. The study consisted of three 120-152-day periods (P I, P II and P III) between January 2000 and October 2001 and involved 543 new patient admissions (141 patients with birth weight < 1501 g) and 6227 days of patient care at a single tertiary level NICU. P I was a control with no intervention, P II was after technically introducing the computer system and, the last period, P III was after presenting and discussing the results of P I and P II at a staff meeting. Upon an order of platelet or fresh frozen plasma (FFP) unit from the blood bank, a computer-based audit system compared the last platelet count or prothrombin time [expressed as percentage of normal clotting activity, prothrombin time (PT-%)] to predefined criteria. In the case of exceeding the preset thresholds, the system required additional information and recorded the pretransfusion laboratory values for later analysis. Thirty-two per cent of platelet transfusions were given with pretransfusion platelet count >49 x 10(9) L(-1), and 60% of these transfusions (19% of all platelet transfusions) could not be clinically justified in retrospective chart review. There was no significant change in this practice from P II to P III. FFP transfusions were given with significantly different pretransfusion PT-% values during P II and P III. The proportions of FFP transfusions with pretransfusion PT-% > 49% were 7.8% and 0.9% during P II and P III, respectively (P < 0.0001). In chart review, none of the FFP transfusions with pretransfusion PT-% > 49% could be justified by clinical grounds. Inappropriate transfusions of both platelets and plasma remain a significant challenge for quality assurance of neonatal intensive care. Automated recording of pretransfusion platelet count and prothrombin time reliably identified the poorly justified transfusions and thus offered a practical resource-saving tool for quality assurance of transfusion in the NICU. A significant shift towards more appropriate use of plasma was demonstrated after implementation of the audit system.

Magnetic resonance imaging of preterm brain injury

Magnetic resonance imaging (MRI) has proved to be a valuable tool for monitoring development and pathology in the preterm brain. This imaging modality is useful for assessing numerous pathologies including periventricular leukomalacia, intraventricular haemorrhage/germinal layer haemorrhage, and periventricular haemorrhagic infarction, and can help to predict outcome in these infants. MRI has also allowed the detection of posterior fossa lesions, which are not easily seen with ultrasound. Additionally, and perhaps most relevant, quantitative MR studies have shown differences between the normal appearing preterm brain at term equivalent age and term born infants, confirming that the brain develops differently in the ex utero environment. Further studies using quantifiable MR techniques will improve our understanding of the effects of the ex utero environment, including aspects of neonatal intensive care on the developing brain.

Prothrombotic factors in neonates with cerebral thrombosis and intraventricular hemorrhage

AIM

To investigate whether the factor V Leiden mutation (FVL), the prothrombin gene G20210A variant or the methylenetetrahydrofolate reductase (MTHFR) C677T genotype are risk factors for central nervous system (CNS) thrombosis or intraventricular hemorrhage (IVH) in neonates.

METHODS

Thirteen full-term infants with cerebral infarct documented with magnetic resonance imaging were assessed with the whole spectrum of assays for thrombophilia including the three DNA-based prothrombotic factors. The frequency of congenital defects was compared with that observed in 38 healthy full-term infants. The genetic defects were also assessed in 55 premature neonates, gestational age <32 wk, 17 of whom developed IVH, grade II-IV. The remaining 38 premature neonates without IVH were used as controls.

RESULTS

In the CNS thrombosis group: a prothrombotic factor was detected in 53% of patients and an underlying disease or a triggering event in 61.5%. The frequency of FVL in thrombosed neonates was higher (23%) than in the group of healthy full-term infants (10.5%), although it did not reach statistical significance. IVH developed in 30.9% of premature neonates. Apart from several maternal or neonatal risk factors for IVH, FII G20210A was found in a considerably higher prevalence in the cohort of neonates with IVH (12%) than in those without (2%), although the difference was not statistically significant.

CONCLUSION

The pathogenesis of cerebral thrombosis or IVH in neonates is multifactorial. Along with underlying diseases or triggering events, congenital prothrombotic factors (FVL or FII G20210A) showed a trend towards a higher frequency in full-term infants with CNS thrombosis or premature neonates with IVH than in controls. However, their contribution to neonatal cerebral thrombosis or IVH remains to be determined.

Thromboembolism in children

Acquired and inherited prothrombotic risk factors increase the risk of thrombosis in children. This review is based on "milestone" pediatric reports and new literature data (January 2001-February 2002) on the presence of acquired and inherited prothrombotic risk factors, imaging methods, and treatment modalities in pediatric thromboembolism. After confirming clinically suspected thromboembolism with suitable imaging methods, pediatric patients should be screened for common gene mutations (factor V G1691A, prothrombin G20210A and MTHFR C677T genotypes), rare genetic deficiencies (protein C, protein S, antithrombin, and plasminogen), and new candidates for genetic thrombophilia causing elevated levels of lipoprotein(a), and homocysteine, and probable genetic risk factors (elevations in fibrinogen, factor IX, and factor VIIIC, and decreases in factor XII). Data interpretation is based on age-dependent reference ranges or the identification of causative gene mutations/polymorphisms with respect to individual ethnic backgrounds. Pediatric treatment protocols for acute thromboembolism, including thrombolytic and anticoagulant therapy, are mainly adapted from adult patient protocols.