Interaction of fibrinolysis and prothrombotic risk factors in neonates, infants and children with and without thromboembolism and underlying cardiac disease. a prospective study

Coagulation Profile in Neonates with Congenital Heart Disease: A Pilot Study

Background and Objectives: congenital heart disease (CHD), cyanotic and, to a lesser degree, acyanotic, often are accompanied by coagulation abnormalities, impacting substantially morbidity and mortality. Until now, no consistent hemostatic patterns have been demonstrated in neonates and children with CHD because they represent a variable and heterogenous population. The aim of the present study is to investigate the hemostatic profile, as well as the role of ADAMTS-13 (a disintegrin and metalloprotease with thrombospondin type-1 motives), the cleaving protein of von Willebrand factor (VWF) in neonates with CHD and compare them to healthy age-matched controls. Materials and Methods: twenty neonates with a mean gestational age of 37.1 ± 2.5 weeks were included in the CHD group, and 18 healthy neonates with a mean gestational age of 38.2 ± 1.5 weeks were in the control group. Results: prothrombin time was significantly prolonged, and accordingly, factor VII (FVII) levels were significantly decreased in the CHD group in comparison to controls. Factor VIII (FVIII), VWF, and ristocetin cofactor activity (Rcof) levels were significantly higher in the study vs. control group. Concentrations of ADAMTS-13 were decreased in the CHD vs. control group, but the difference was not statistically significant. Our results, in combination, indicate a balanced hemostatic mechanism, although with greater variability in neonates with CHD, while developmental aspects of coagulation are evident in the specific patient population. Conclusions: the coagulation profile is moderately impaired early in the course of CHD, though increased thrombogenicity is already present and should not be ignored.

Cerebral ultrasound abnormalities in offsprings of women with C677T homozygous mutation in the MTHFR gene: a prospective study

BACKGROUND

Perinatal stroke is a common cause of neurologic disability. Being clinically under-recognized, its true incidence is not known. Maternal thrombophilia is likely to be a predisposing factor. To date, a general consensus for evaluation of babies born to mothers with genetic thrombotic predisposition is missing. This study was undertaken to assess the frequency of cerebral abnormalities in the offspring of women with homozygous C677T mutation in the MTHFR gene, and to seek for association with additional maternal or pregnancy risk factors.

METHODS

Mother-infant pairs were consecutively recruited from October 2006 through February 2013. Neonates underwent a thorough physical examination at birth, and a cerebral ultrasound examination (cUS) was performed within 24 hours of their life. In neonates with major cerebral lesions, a thrombophilia panel test was obtained. Follow-up cUS was performed in babies with major or minor cerebral abnormalities.

RESULTS

Ninety-one neonates (47 males) were enrolled. By cUS, abnormalities were detected in 18 (19.8%) neonates. Twelve neonates were diagnosed with a minor lesion; a major ischemic/hemorrhagic lesion was found in 6 neonates. There were a neat male preponderance and significant associations with a history of suspected miscarriage, maternal coagulation factors gene mutations, and reduced protein S or protein C activity.

CONCLUSIONS

Our data confirmed a high incidence of cerebral abnormalities in neonates born to women with C677T homozygous mutation in the MTHFR gene. cUS at birth proved to be an effective screening tool or a diagnostic test, that should be routinely performed in babies born to mothers with known thrombotic predisposition.

Bleeding and Thrombotic Emergencies in Pediatric Cardiac Intensive Care

Children in the cardiac intensive care unit (CICU) with congenital or acquired heart disease are at risk for hematologic complications, both hemorrhage and thrombosis. The overall incidence of hematologic complications in the CICU is unknown, but risk factors and target groups have been identified where the essential physiologic balance between bleeding and clotting has been disrupted. Although the best management of life-threatening bleeding and clotting is prevention, the cardiac intensivist is often faced with managing life-threatening hematologic events involving patients from within the unit or those who present from outside. Part I of this review deals with the propensity of children with congenital and acquired heart disease to complications of both bleeding and clotting, and includes discussions of perioperative bleeding, thromboses in single-ventricle patients, clotting of Blalock-Taussig shunts and thrombotic complications of mechanical valves. Part II deals with the subject of stroke in children with heart disease. Part III reviews monitoring the effectiveness of anticoagulation and thrombolysis in the CICU. Currently available diagnostics modalities, medications and management strategies are reviewed and future directions discussed.

Prospective study of the incidence and predictors of thrombus in children undergoing palliative surgery for single ventricle physiology

PURPOSE

To determine the incidence and clinical and biomarker predictors of perioperative thrombosis in children with single ventricle physiology undergoing staged palliation.

METHODS

Nineteen patients were enrolled and 16 completed the study. Serial ultrasounds of the central venous system were performed to evaluate for thrombus. Plasma antithrombin III, thrombin-antithrombin complex, protein C, protein S, tissue factor pathway inhibitor, plasminogen activator inhibitor-1, tissue plasminogen activator antigen, D-dimer, soluble CD40 ligand, and urinary thromboxane were measured serially before and after surgery. Cardiopulmonary bypass time, aortic cross clamp time, blood product administration, inotrope score, chest tube output, cardiac function by echocardiography, intensive care unit and hospital lengths of stay, and central venous catheter days were recorded.

RESULTS

The incidence of perioperative thrombus was 31%. Patients who developed a thrombus had poorer preoperative ventricular function (p = 0.03) and longer cardiopulmonary bypass times (p = 0.03) than those who did not develop a thrombus. Preoperative plasma antithrombin III was lower (p = 0.01) and tissue plasminogen activator antigen concentrations were higher (p = 0.02) in patients with a thrombus compared with patients without a thrombus. When measured over time, antithrombin III remained lower (p = 0.002) and tissue plasminogen activator antigen higher (p = 0.005) in those who developed a thrombus compared with those who did not. There were no other statistically significant differences in biomarkers of coagulation between patients with and without thrombosis.

CONCLUSION

One-third of patients undergoing palliative surgery for single ventricle physiology develop thrombosis. Decreased ventricular function, low antithrombin III, and increased tissue plasminogen activator may predict those most suitable for randomized clinical trials of anticoagulation.

Diagnosis and management of central-line-associated thrombosis in newborns and infants

Although the use of central lines has many valuable applications in neonates and infants, they may cause serious mechanical, infectious and thrombotic complications. In fact, the use of central lines is the main cause for thrombosis in this age group. The frequency of central-line-related thrombosis in neonates and infants is reported to be as low as 1% when including only symptomatic cases, around 44% when systematically screened for thrombosis, and as high as 65% in autopsy studies. The risk factors for line-related thrombosis in neonates and infants include those associated with the underlying medical conditions, the duration of the line in situ, the placement of the umbilical artery catheter and the therapy used through the line. The contribution of inherited and acquired thrombophilia to central-line-related thrombosis is controversial, and the data are not sufficiently consistent to make a firm recommendation for thrombophilia screening for neonates and infants with central-line-related thrombosis. Most experts will recommend pursuing a thrombophilia work-up in the setting of a significant thrombosis event and will recommend avoiding thrombophilia work-up in subclinical and asymptomatic central-line-related thrombosis. The management of line-related thrombosis is based on expert opinion guidelines and is largely dependent on the type of the catheter and the further requirement of the catheter. Continuous heparin infusion through the central lines prevents catheter occlusion, but has no effect on occurrence of thrombosis. Currently no definitive recommendations exist for thromboprophylaxis in children, infants and neonates with central lines.

Thrombosis in childhood acute lymphoblastic leukaemia: epidemiology, aetiology, diagnosis, prevention and treatment

Acute lymphoblastic leukaemia (ALL) is the most common malignancy associated with venous thromboembolism (VTE) in children. The prevalence of symptomatic VTE ranges from 0% to 36%, and the variation can be explained, at least in part, by differences in chemotherapeutic protocols. The mechanism for increased risk of VTE is associated with alterations in the haemostatic system by use of L-asparaginase (ASP) alone or in combination with vincristine or prednisone, presence of central venous lines (CVLs) and/or inherited thrombophilia. The children at greatest risk are generally those receiving Escherichia coli ASP concomitant with prednisone. The majority of symptomatic VTEs occur in the central nervous system or in the upper venous system. In the majority of cases, asymptomatic VTEs are associated with CVLs. External CVLs are affected more often than internal CVLs. Evidence-based guidelines on prevention and treatment guidelines for ALL-related VTE are lacking, and carefully designed clinical trials are needed urgently.

Myocardial infarction and arterial thrombosis in identical newborn twins with homozygosity for the PAI-1 4 G/5 G polymorphism

Myocardial infarction in the perinatal period, in the absence of congenital heart disease or coronary artery lesions, is rare. The most common etiology described are the thromboembolism and perinatal asphyxia. We report a case of monozygotic twins who developed, after birth, acute vascular events and both had PAI-1 4G/4G homozygosity.

Thrombin generation determined by calibrated automated thrombography (CAT) in pediatric patients with congenital heart disease

INTRODUCTION

Thrombin generation was studied in pediatric patients with congenital heart disease (CHD) undergoing cardiac surgery using the calibrated automated thrombography (CAT) in terms of the lag time until the onset of thrombin formation, time to thrombin peak maximum (TTP), endogenous thrombin potential (ETP), and thrombin peak height. The possible suitability to determine the coagulation status of these patients was investigated.

MATERIALS AND METHODS

CAT data of 40 patients with CHD (age range from newborn to 18 years) were compared to data using standard coagulation parameters such as prothrombin (FII), antithrombin (AT), tissue factor pathway inhibitor (TFPI), prothrombin fragment 1.2 (F 1.2), thrombin-antithrombin (TAT), activated partial thromboplastin time (aPTT), and prothrombin time (PT).

RESULTS

A significant positive correlation was seen between ETP and FII (p<0.01; r=0.369), as well as between peak height and F II (p<0.01; r=0.483). A significant negative correlation was seen between ETP and TFPI values (p<0.05; r=-0.225) while no significant correlation was seen between peak height and TFPI. A significant negative correlation was seen between F 1.2 generation and ETP (p<0.05; r=-0.254) and between F 1.2 generation and peak height (p<0.05; r=-0.236). No correlation was seen between AT and ETP or peak.

CONCLUSIONS

Our data indicate that CAT is a good global test reflecting procoagulatory and inhibitory factors of the hemostatic system in pediatric patients with CHD.

Risk factors for perinatal arterial stroke: a study of 60 mother-child pairs

The objective of the present study was to examine demographic, historical, and prothrombotic risk factors in infants with perinatal arterial stroke and their mothers. Risk factors were evaluated in 60 mother-child pairs with perinatal arterial stroke. Prothrombotic factors analyzed included the DNA mutations factor V Leiden, prothrombin 20210, MTHFR C677T and A1298C; serum activity levels for protein C, protein S, and antithrombin III; serum levels of lipoprotein(a); and, in the mothers, antiphospholipid antibodies. Boys predominated, 36:24. There were four twin sets. Sixty percent were term and 22% were post-date. Ten were large for gestational age. Five mothers had abdominal trauma. Nine mothers (15%) had preeclampsia. Emergency caesarean section was performed in 17 cases (28%). Eight placental exams revealed seven with abnormalities. Seizures were the presenting sign in 70%, and 30% presented with early handedness or cerebral palsy. Prothrombotic risk factors were found in 28 of 51 mothers (55%) and 30 of 60 children (50%). Forty-one pairs (68%) had at least one abnormality in mother, child, or both. Long-term sequelae included cerebral palsy (40 of 51; 78%), cognitive impairment (35 of 51; 68%), seizures (23 of 51; 45%), and microcephaly (26 of 51; 51%). Perinatal arterial stroke is the result of multifactorial, synergistic fetal and maternal factors among which the prothrombotic factors, both fetal and maternal, appear significant.

Evaluation of the Coagulation System in Children with Two-Ventricle Congenital Heart Disease

BACKGROUND

Multiple coagulation factor abnormalities involving both procoagulant and anticoagulant proteins have been described in children with single-ventricle physiology. This study used age-matched controls to evaluate coagulation factors in children with two-ventricle congenital heart disease (CHD).

METHODS

Coagulation factors were assayed in 120 patients with CHD, divided into four age groups: group 1, 0 to 3 months; group 2, 3 to 12 months; group 3, 12 to 48 months; and group 4, older than 48 months. Healthy children without CHD were assayed as controls. Concentration of factors II, V, VII, VIII, IX, and X; protein C and S, plasminogen, and antithrombin III, were measured by standard assays. Normal ranges were determined by the empirical 95% confidence intervals.

RESULTS

Significant reductions were found in mean levels of both procoagulant and anticoagulant factors in patients in groups 1, 2, and 3 compared with controls, but no differences were found in group 4. In group 1, all variables had significantly lower concentrations except fibrinogen and protein S; in group 2, all variables had significantly lower concentrations except for fibrinogen, factors VIII and IX, and plasminogen and protein S; and in group 3, all variables had significantly lower concentrations except fibrinogen, factors VIII and IX, and antithrombin III, plasminogen, and protein S.

CONCLUSIONS

Neonates and infants with two-ventricle CHD have lower levels of procoagulant and anticoagulant factors compared with aged-matched controls approaching normal levels in children aged older than 4 years. These coagulation factor abnormalities are similar to those described in patients with single-ventricle physiology.

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.