Umbilical venous catheterization and the risk of portal vein thrombosis

Incidence of umbilical vein catheter-associated thrombosis of the portal system: A systematic review and meta-analysis

BACKGROUND

The use of umbilical venous catheters (UVCs) in the perinatal period may be associated with severe complications, including the occurrence of portal vein thrombosis (PVT).

AIM

To assess the incidence of UVC-related PVT in infants with postnatal age up to three months.

METHODS

A systematic and comprehensive database searching (PubMed, Cochrane Library, Scopus, Web of Science) was performed for studies from 1980 to 2020 (the search was last updated on November 28, 2020). We included in the final analyses all peer-reviewed prospective cohort studies, retrospective cohort studies and case-control studies. The reference lists of included articles were hand-searched to identify additional studies of interest. Studies were considered eligible when they included infants with postnatal age up to three months with UVC-associated PVT. Incidence estimates were pooled by using random effects meta-analyses. The quality of included studies was assessed using the Newcastle-Ottawa scale. The systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines.

RESULTS

Overall, 16 studies were considered eligible and included in the final analyses. The data confirmed the relevant risk of UVC-related thrombosis. The mean pooled incidence of such condition was 12%, although it varied across studies (0%-49%). In 15/16 studies (94%), diagnosis of thrombosis was made accidentally during routine screening controls, whilst in 1/16 study (6%) targeted imaging assessments were carried out in neonates with clinical concerns for a thrombus. Tip position was investigated by abdominal ultrasound (US) alone in 1/16 (6%) studies, by a combination of radiography and abdominal US in 14/16 (88%) studies and by a combination of radiography, abdominal US and echocardiography in 1/16 (6%) studies.

CONCLUSION

To the best of our knowledge, this is the first systematic review specifically investigating the incidence of UVC-related PVT. The use of UVCs requires a high index of suspicion, because its use is significantly associated with PVT. Well-designed prospective studies are required to assess the optimal approach to prevent UVC-related thrombosis of the portal system.

Epidemiology of thrombosis in Canadian neonatal intensive care units

OBJECTIVE

To assess the rate, location, risk factors, management, and outcomes of neonatal thrombosis (NT).

DESIGN

A retrospective study investigating infants admitted to NICUs in Canadian Neonatal Network between January 2014 and December 2016 and diagnosed with NT. Each infant with NT was matched with an infant without NT.

RESULTS

Of 39,971 infants, 587 (1.5%) were diagnosed with NT: 440 (75%) venous, 112 (19%) arterial, 29 (5%) both. NT rate was 1.4% in full-term and 1.7% in preterm infants. Venous thrombi occurred most commonly in the portal vein and arterial thrombi in the cerebral artery. Conservative management and low molecular weight heparin were the most common treatment modalities. Hospital stay was longer (p < 0.001) in the NT patients, but mortality was similar.

CONCLUSIONS

NT was diagnosed in ~15/1000 NICU admissions and most commonly in the portal vein and cerebral arteries. Management varied based on the type and location of thrombi. Large multicenter trials are needed to address the best management strategies.

Outcomes following neonatal portal vein thrombosis: A descriptive, single-center study and review of anticoagulant therapy

BACKGROUND

Neonatal portal vein thrombosis (PVT) is uncommon with potentially serious complications that may manifest in infancy and childhood.

OBJECTIVE

The primary aim of our study was to describe the short-term and long-term outcomes of neonatal PVT.

METHODS

A retrospective chart review was conducted from 2008 to 2016 of neonates diagnosed with PVT. A systematic review was also performed from 2000 to 2018 to evaluate anticoagulant therapy (ACT) in neonatal PVT.

RESULTS

Forty-four premature and 30 term infants (mean gestational age 30.7 vs 39.1 weeks, respectively) had PVT. Sixty-eight involved the left portal vein, one involved only the main portal vein, and 5 involved ≥1 vein. PVT was catheter associated in 46 (62%); none of the 7 neonates tested had thrombophilia. Of 74 neonates, 19 (26%) received ACT and 55 (74%) were untreated. The mean follow-up duration was 16.6 months (SD = 17.62; range, 0-89.6); 59.5% were followed for ≥6 months. On last ultrasound examination, thrombus resolution was documented in treated (ACT; n = 19) and nontreated (n = 55) neonates: 12 (63%) versus 32 (58%) with complete resolution, 1 (5%) versus 6 (11%) partial, 0 versus 1 (2%) extension, and 6 (32%) versus 16 (29%) had nonprogressive lesions, respectively. Seventy-one (96%) had no complications. Seventy-one articles met inclusion criteria for the systematic review and 19 were retained for analysis after assessment.

CONCLUSIONS

PVT resolution rate was similar to previous reports. Although a low complication rate was detected, longer follow-up is necessary to determine the need for early treatment and the precise incidence of outcomes such as portal hypertension.

Sonographic features of umbilical catheter-related complications

Umbilical catheters are commonly used in the neonatal period for blood sampling or for administering medication or parenteral nutrition. The position of the catheter is usually confirmed with radiography. However, many complications associated with the use of umbilical catheters, such as liver collections from extravasation or vascular thrombosis, are not apparent on radiographs but can be easily diagnosed with ultrasound. This pictorial review illustrates the sonographic findings of complications that should be excluded in the sick neonate with an indwelling catheter.

Systematic ultrasound examinations in neonates admitted to NICU: evolution of portal vein thrombosis

OBJECTIVE

The aim of the study was to better describe incidence, risk factors, and the natural evolution of neonatal portal vein thrombosis (PVT).

STUDY DESIGN

One hundred and twenty-three premature newborns or with birth weight <1.5 kg were prospectively included in a single center during a one-year period. Three systematic abdominal ultrasound examinations at day 3, day 10, and day 45 (and 1 year in case of persistent PVT) were performed. Clinical and biological data were recorded.

RESULTS

Seventy neonates (57%) had three normal US examinations. Fifty-three neonates (43%) had a clinical and biological asymptomatic left PVT. No right or extrahepatic portal venous thrombosis was observed. Umbilical vascular catheter (UVC) was removed in case of PVT. No anticoagulation therapy was required. No risk factor was significantly associated with PVT. At 1 year of follow-up, five infants had persistent isolated left PVT (4%).

CONCLUSION

A spontaneous favorable evolution of left PVT occurred in more than of 95%.

Thrombosis of the Abdominal Veins in Childhood

Abdominal venous thrombosis is a rare form of venous thromboembolic disease in children. While mortality rates are low, a significant proportion of affected children may suffer long-term morbidity. Additionally, given the infrequency of these thrombi, there is lack of stringent research data and evidence-based treatment guidelines. Nonetheless, pediatric hematologists and other subspecialists are likely to encounter these problems in practice. This review is therefore intended to provide a useful guide on the clinical diagnosis and management of children with these rare forms of venous thromboembolic disease. Herein, we will thus appraise the current knowledge regarding major forms of abdominal venous thrombosis in children. The discussion will focus on the epidemiology, presentation, diagnosis, management, and outcomes of (1) inferior vena cava, (2) portal, (3) mesenteric, (4) hepatic, and (5) renal vein thrombosis.

[Catheter tip position and risk of mechanical complications in a neonatal unit]

INTRODUCTION

The use of central catheters (CC) is associated with mechanical complications (MC).

OBJECTIVE

Our objetive was to determine the relationship between CC positions and associated MC in neonates.

MATERIAL

A descriptive analytical study was performed over a six year period in the NICU of the University Hospital Santa Lucía de Cartagena. Details were collected on the CC used, indication, reason for withdrawal, position in the imaging, MC, and treatment arising from them, as well as epidemiological data.

RESULTS

Of the total of 604 CC studied, the majority (347) were via the umbilical vein, followed by epicutaneous (193), and femoral vein (34). There were MC in 14.2% of catheters. Incorrect position of the tip was associated with greater MC (21.1 vs 8.2%; P<.001), including withdrawal due to MC (8.4 vs 3.1%; P<.01), extravasation (4.9 vs 1.9%; P<.05), pleural and pericardial effusions (1.4 vs 0.0%; P<.05), liver haematomas (4.6 vs 0.6%; P<.01), and ascites (2.8 vs 0.0%; P<.01). The midclavicular epicutaneous position of the tip was associated with greater MC (18.5 vs 6.8%; P<.05) than the brachiocephalic (0 vs 6.8%;NS). The low and ductal position of the umbilical vein catheter was also associated with higher rates of MC (24.5 vs 6%; P<.001 and 27 vs 6%; P<.001) due to the position of the tip. The most common complication was accidentally dislodged catheter.

CONCLUSIONS

The incorrect location of the tip was associated with more MC. The midclavicular epicutaneous had more risk than centrally or brachiocephalic locations. The low and ductal positions of the umbilical vein catheter were associated with higher rates of MC.

Thrombosis in the Neonatal Intensive Care Unit

Neonates have the highest risk for pathologic thrombosis among pediatric patients. A combination of genetic and acquired risk factors significantly contributes to this risk, with the most important risk factor being the use of central venous catheters. Proper imaging is critical for confirming the diagnosis. Despite a significant number of these events being life- and limb-threatening, there is limited evidence on what the appropriate management strategy should be. Evaluation and treatment of any neonate with a clinically significant thrombosis should occur at a tertiary referral center that has proper support.

Central venous catheter-related thrombosis and thromboprophylaxis in children: a systematic review and meta-analysis

OBJECTIVES

In preparation for a pediatric randomized controlled trial on thromboprophylaxis, we determined the frequency of catheter-related thrombosis in children. We also systematically reviewed the pediatric trials on thromboprophylaxis to evaluate its efficacy and to identify possible pitfalls in the conduct of these trials.

PATIENTS/METHODS

We searched MEDLINE, EMBASE, Web of Science and the Cochrane Central Register for Controlled Trials for articles published until December 2013. We included cohort studies and trials on patients aged 0-18 years with central venous catheters who underwent active surveillance for thrombosis with radiologic imaging. We estimated the pooled frequency of thrombosis and the pooled risk ratio (RR) with thromboprophylaxis by using a random effects model.

RESULTS

From 2651 articles identified, we analyzed 37 articles with 3128 patients. The pooled frequency of thrombosis was 0.20 (95% confidence interval [CI] 0.16-0.24). In 10 trials, we did not find evidence that heparin-bonded catheters (RR 0.34; 95%CI 0.01-7.68), unfractionated heparin (RR 0.93; 95% CI 0.57-1.51), low molecular weight heparin (RR 1.13; 95% CI 0.51-2.50), warfarin (RR 0.85; 95%CI 0.34-2.17), antithrombin concentrate (RR 0.76; 95% CI 0.38-1.55) or nitroglycerin (RR 1.53; 95%CI 0.57-4.10) reduced the risk of thrombosis. Most of the trials were either not powered for thrombosis or were powered to detect large, probably unachievable, reductions in thrombosis. Missing data on thrombosis also limited these trials.

CONCLUSIONS

Catheter-related thrombosis is common in children. An adequately powered multicenter trial that can detect a modest, clinically significant reduction in thrombosis is critically needed. Missing outcome data should be minimized in this trial.

ABM clinical protocol #1: guidelines for blood glucose monitoring and treatment of hypoglycemia in term and late-preterm neonates, revised 2014

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient.

Portal vein thrombosis in children and adolescents: 20 years experience of a pediatric hepatology reference center

CONTEXT

Portal vein thrombosis refers to a total or partial obstruction of the blood flow in this vein due to a thrombus formation. It is an important cause of portal hypertension in the pediatric age group with high morbidity rates due to its main complication - the upper gastrointestinal bleeding.

OBJECTIVE

To describe a group of patients with portal vein thrombosis without associated hepatic disease of the Pediatric Hepatology Clinic of the Hospital das Clínicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil with emphasis on diagnosis, presentation form and clinical complications, and the treatment of portal hypertension.

METHODS

This is a descriptive study of a series of children and adolescents cases assisted from January 1990 to December 2010. The portal vein thrombosis diagnosis was established by ultrasound.

RESULTS

Of the 55 studied patients, 30 (54.5%) were male. In 29 patients (52.7%), none of the risk factors for portal vein thrombosis was observed. The predominant form of presentation was the upper gastrointestinal bleeding (52.7%). In 20 patients (36.4%), the initial manifestation was splenomegaly. During the whole following period of the study, 39 patients (70.9%) showed at least one episode of upper gastrointestinal bleeding. The mean age of patients in the first episode was 4.6 ± 3.4 years old. The endoscopic procedure carried out in the urgency or electively for search of esophageal varices showed its presence in 84.9% of the evaluated patients. The prophylactic endoscopic treatment was performed with endoscopic band ligation of varices in 31.3% of patients. Only one died due to refractory bleeding.

CONCLUSIONS

The portal vein thrombosis is one of the most important causes of upper gastrointestinal bleeding in children. In all non febrile children with splenomegaly and/or hematemesis and without hepatomegaly and with normal hepatic function tests, it should be suspect of portal vein thrombosis. Thus, an appropriate diagnostic and treatment approach is desirable in an attempt to reduce morbidity and mortality.

Surgical management of portal hypertension in children

The management of children with portal hypertension has dramatically changed during the past decade, with an improvement in outcome. This has been achieved by improved efficiency of endoscopic variceal control and the success of liver transplantation. Emergency surgical shunt procedures are rarely required, with acute bleeding episodes generally controlled endoscopically or, occasionally in adults, by interventional radiological procedures. Portosystemic shunts may be considered as a bridge to transplant in adults but are rarely used in this context in children. Nontransplant surgery or radiological interventions may still be indicated for noncirrhotic portal hypertension when the primary cause can be cured and to allow normalization of portal pressure before liver parenchyma is damaged by chronic secondary changes in some specific diseases. The meso-Rex bypass shunt is used widely but is limited to those with a favorable anatomy and can even be performed preemptively. Elective portosystemic shunt surgery is reserved for failure to respond to conservative management in the absence of alternative therapies.

Neonatal portal vein thrombosis: diagnosis and management

Neonatal portal vein thrombosis (PVT) is an increasingly recognized event. Patients are generally asymptomatic in the neonatal period. The diagnosis is made with Doppler ultrasound. Umbilical catheterization, exchange transfusion and sepsis are risk factors for neonatal PVT. Thrombophilia is possibly a contributing risk factor. Although there are potential serious acute complications such as hepatic necrosis, the outcome is good in the majority of cases, followed up to 8 years of age. Thrombus resolution occurs in 30-70% in days to months. Liver lobe atrophy may occur following PVT, and does not appear to be associated with any impairment of liver function. Non-occlusive thrombosis is more likely to resolve than non-occlusive thrombosis. A subset of patients without resolution is at risk for developing portal hypertension over the next decade of life. There are no current defining features present during the neonatal period to enable identification of neonates at risk for portal hypertension. There is no evidence that anticoagulation therapy improves time to resolution or decreases the likelihood of portal hypertension. Anticoagulation therapy may be considered. A management algorithm is proposed.

Portal vein thrombosis

Portal vein thrombosis (PVT) can be a difficult clinical problem to assess and manage. A high index of suspicion is needed for a PVT diagnosis given the subtle presentation and potentially serious long-term complications. It should be considered a clue to the presence of one or several underlying disorders, including prothrombotic disorders, whether or not a local precipitating factor is identified. The accruing evidence shows that acute PVT can and probably should be treated with anticoagulation or thrombolytic agents in an effort to prevent extension of thrombus, mesenteric vessel occlusion, and portal hypertension. However, chronic PVT should be treated conservatively with measures to control major consequences related to portal hypertension. Anticoagulation therapy duration should be tailored to the identified predisposing factors.

Childhood outcomes of neonates diagnosed with portal vein thrombosis

AIM

The study aims to determine childhood outcomes of neonates diagnosed with portal vein thrombosis (PVT).

METHODS

A retrospective chart review of neonates diagnosed with PVT who had documented follow up (physical examination, laboratory tests or ultrasonographic examination) at the age of 2 years or beyond was conducted.

RESULTS

Data were available for 70 children (71% of eligible neonates) at a median age of 5 years (range 2-8 years). Physical examination was unremarkable in all who were examined (n= 68). Twenty-five children had liver functions assessed and only mild abnormalities were detected in nine children. Six of 25 patients tested for thrombophilia showed abnormalities. Thirty-seven children had ultrasonographic follow up. Left lobar atrophy (LLA) was noted in 20 children (16 had isolated LLA, two had LLA and splenomegaly, and two had LLA and portal hypertension). Five children who had normal ultrasound examinations at discharge had splenomegaly (two with additional finding of LLA) at follow up. Two children with portal hypertension diagnosed during neonatal period needed porta-caval shunting.

CONCLUSION

Our results show that among patients, who had PVT as neonates, 28% still had asymptomatic LLA in childhood, 7% had slowly progressive splenomegaly and 3% required shunting because of progression of portal hypertension. Ultrasonographic follow up was the most sensitive method in detecting progression associated with neonatal PVT. Until more data are available, periodic long-term ultrasonographic follow up should be considered for neonates diagnosed with PVT.

Umbilical vascular catheter associated portal vein thrombosis detected by ultrasound

OBJECTIVE

To determine catheter-associated thrombosis by color Doppler ultrasound and to detect duration of catheter placement as a risk factor for thrombosis.

METHODS

All newborn infants with umbilical vascular catheterization for more than 6 h duration were included in this study. Color Doppler ultrasound examination was performed within 24-48 h of catheter insertion, 48-72 h after its withdrawal and weekly until hospital discharge or clot resolution.

RESULTS

Portal vein thrombosis (PVT) was determined in five cases (3.04%) of 164 infants received umbilical vascular catheterization. The mean duration of catheter placement in patients with PVT was 3.4 ± 1.94 days, which was not significantly different from infants without thrombosis (3.5 ± 2.03). Thrombosis was completely recanalized and resolved after 3-6 weeks in three survived neonates. There was history of exchange transfusion for hyperbilirubinemia via umbilical vein in two neonates with PVT.

CONCLUSIONS

Catheter-associated portal venous thrombosis was uncommon in our study. The duration of catheter placement was not longer in patients with portal vein thrombosis than those without thrombosis.

Complications of vascular catheters in the neonatal intensive care unit

Insertion of an intravascular catheter is the most common invasive procedure in the neonatal ICU. With every passing decade, technological innovations in catheter materials and sizes have allowed vascular access in infants who are smaller and sicker for purposes of blood pressure monitoring, blood sampling, and infusion of intravenous fluids and medications. There is, however, growing recognition of potential risks to life and limb associated with the use of intravascular catheters. This article reviews complications of venous and arterial catheters in the neonatal ICU and discusses treatment approaches and methods to prevent such complications, based on current evidence.

Portal vein thrombosis in the neonate: risk factors, course, and outcome

OBJECTIVE

To determine the risk factors, clinical features, and outcome of infants diagnosed with portal vein thrombosis (PVT).

STUDY DESIGN

A retrospective chart review was conducted of all consecutive infants admitted to the Hospital for Sick Children, Toronto, between January 1999 and December 2003 diagnosed with PVT.

RESULTS

PVT was diagnosed in 133 infants, all but 5 of whom were neonates, with a median age at time of diagnosis of 7 days. An umbilical venous catheter (UVC) was inserted in 73% of the infants and was in an appropriate position in 46% of them. Poor outcome, defined as portal hypertension or lobar atrophy, was diagnosed in 27% of the infants and was significantly more common in those with an initial diagnosis of grade 3 PVT and in those with a low or intrahepatically placed UVC. Anticoagulation treatment did not appear to have a significant effect on outcome.

CONCLUSIONS

PVT occurs early in life; major risk factors in addition to the neonatal period are placement of UVC and severe neonatal sickness. Poor outcome is associated with an improperly placed UVC and with grade 3 thrombus.

Hypoglycemia in breastfed neonates

Healthy, full-term infants are programmed to make the transition from their intrauterine constant flow of nutrients to their extrauterine intermittent nutrient intake without the need for metabolic monitoring or interference with the natural breastfeeding process. Homeostatic mechanisms ensure adequate energy substrate is provided to the brain and other organs, even when feedings are delayed. The normal pattern of early, frequent, and exclusive breastfeeding meets the needs of healthy full-term infants. Routine screening or supplementation are not necessary and may harm the normal establishment of breastfeeding. Screening should be restricted to at-risk and symptomatic infants. Symptomatic infants need immediate assessment and intravenous glucose therapy, not forced feedings.

Recent concepts regarding extra-hepatic portal hypertension

Extra-hepatic portal hypertension (EHPH) defined as non cirrhotic, presinusoidal and prehepatic portal hypertension, with obstruction and cavernomatous transformation of the main portal vein, entails a high, early and prolonged risk of gastro-intestinal bleeding (GIB) mainly from esophageal and/or gastric varices, and less often a risk of cholangiopathy or protein-losing enteropathy. Diagnosis of EHPH may be done with non invasive imaging techniques. Assessment of bleeding risk is based on results of endoscopic examination. Occurence of a bleeding episode or onset during follow-up of endoscopic signs of high risk of GIB require radical eradication of varices. Radical cure of EHPH is achieved at best by bypass surgery restoring a physiological portal flow, and as a second choice by shunt surgery. Endoscopic therapy has a place as first line treatment of GIB episodes, and also in a few cases with poor extrahepatic portal network contra-indicating efficient vascular surgery.

Double-catheter technique for the proper insertion of umbilical venous catheters in newborns

OBJECTIVES

To document the usefulness and safety of inserting a second umbilical venous catheter in ill neonates, while a previously misplaced first catheter was still in its place.

SUBJECTS AND METHODS

The case series involved 25 newborn babies who were admitted to the Neonatal Intensive Care Unit, Maternity Hospital, Kuwait, over a 3-year period from 1999 to 2002. The umbilical venous catheter of the babies was misplaced and diverted to the liver, necessitating insertion of a second catheter while the previous one was still in place. The characteristics of the babies and possible catheter-related complications were recorded.

RESULTS

Of the 25 babies, 19 had the second catheter properly placed in the right atrium, while in the remaining 6 neonates, the catheter was still misplaced. Misplacement occurred mostly in full-term babies or the catheter was inserted at a later stage. No life-threatening complication was observed during the procedure.

CONCLUSION

Insertion of a second umbilical venous catheter with the misplaced first catheter in situ is a useful and safe procedure.

Patterns of thrombocytosis and thrombocytopenia in hospitalized neonates

OBJECTIVE

We sought to identify changes in platelet (PLT) counts over time, and to evaluate the patterns of thrombocytopenia and thrombocytosis in hospitalized infants 23.8 weeks to term gestation.

STUDY DESIGN

Neonates were divided into four gestational age groups and their PLT counts were retrospectively compared for prevalence of thrombocytopenia, thrombocytosis, and associated conditions.

RESULTS

Postconceptional age, postnatal age, and sepsis (among other factors) affected PLT counts. When counts from noninfected appropriately grown infants were evaluated, the risk of thrombocytopenia and thrombocytosis were highest in the most preterm infants, and these risks changed with corrected gestational age. PLT counts increased weekly over the first 4 weeks of life for all but the most preterm infants.

CONCLUSIONS

These data characterize the incidence of thrombocytopenia and thrombocytosis across a wide range of gestational ages and show that, even in noninfected neonates, these conditions are common, and risk decreases with increasing maturity. The age-related changes in PLT patterns may reflect maturation of platelet regulation.

Thromboembolic Diseases in Neonates and Children

Acquired and inherited prothrombotic risk factors increase the risk of thrombosis in neonates, infants and children. After suffering thrombosis white paediatric patients should be screened for common gene mutations, i.e. the factor V G1691A, factor II G20210A and MTHFR C677T genotypes, rare inherited prothromboticrisk factors, i.e. deficiencies of protein C,protein S, and antithrombin, plasminogen, probably inherited risk factors, i.e. fibrinogen, factor VIIIC, factor XII, new candidates, i.e. elevation of lipoprotein (a),and fasting homocysteine concentrations (3-6 months after thrombotic onset). Data interpretation is based on age-dependent reference ranges or the identification of causative gene mutations/polymorphisms with respect to individual ethnic backgrounds.

Portal vein thrombosis during antineoplastic chemotherapy in children: Report of five cases and review of the literature

We report five paediatric cases of portal vein thrombosis (PVT) occurring during chemotherapy, observed in two institutions over an 8-year time period. These children aged 2.5-15 years were treated for Burkitt's lymphoma, Ewing's tumour, small cell bone tumour or medulloblastoma. PVT was diagnosed on colour Doppler ultrasonography (US). In four patients, thrombosis occurred 2-45 days after severe hepatic veno-occlusive disease (HVOD) secondary to intensive chemotherapy containing busulfan. In one case, PVT occurred in the absence of HVOD in a patient with pre-existing periportal lymphomatous infiltration. Four patients experienced persistent portal hypertension, which resulted in death in one. PVT during chemotherapy in children is a rare event and appears to be closely related to intensive chemotherapy containing busulfan and to be associated with HVOD.

Antithrombotic Therapy in Children*

This article about antithrombotic therapy in children is part of the 7th American College of Chest Physicians Conference on Antithrombotic and Thrombolytic Therapy: Evidence-Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh the risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this article are the following. In neonates with venous thromboembolism (VTE), we suggest treatment with either unfractionated heparin or low-molecular-weight heparin (LMWH), or radiographic monitoring and anticoagulation therapy if extension occurs (Grade 2C). We suggest that clinicians not use thrombolytic therapy for treating VTE in neonates, unless there is major vessel occlusion that is causing the critical compromise of organs or limbs (Grade 2C). For children (ie, > 2 months of age) with an initial VTE, we recommend treatment with i.v. heparin or LMWH (Grade 1C+). We suggest continuing anticoagulant therapy for idiopathic thromboembolic events (TEs) for at least 6 months using vitamin K antagonists (target international normalized ratio [INR], 2.5; INR range, 2.0 to 3.0) or alternatively LMWH (Grade 2C). We suggest that clinicians not use thrombolytic therapy routinely for VTE in children (Grade 2C). For neonates and children requiring cardiac catheterization (CC) via an artery, we recommend i.v. heparin prophylaxis (Grade 1A). We suggest the use of heparin doses of 100 to 150 U/kg as a bolus and that further doses may be required in prolonged procedures (both Grade 2 B). For prophylaxis for CC, we recommend against aspirin therapy (Grade 1B). For neonates and children with peripheral arterial catheters in situ, we recommend the administration of low-dose heparin through a catheter, preferably by continuous infusion to prolong the catheter patency (Grade 1A). For children with a peripheral arterial catheter-related TE, we suggest the immediate removal of the catheter (Grade 2C). For prevention of aortic thrombosis secondary to the use of umbilical artery catheters in neonates, we suggest low-dose heparin infusion (1 to 5 U/h) (Grade 2A). In children with Kawasaki disease, we recommend therapy with aspirin in high doses initially (80 to 100 mg/kg/d during the acute phase, for up to 14 days) and then in lower doses (3 to 5 mg/kg/d for > or = 7 weeks) [Grade 1C+], as well as therapy with i.v. gammaglobulin within 10 days of the onset of symptoms (Grade 1A).

Prenatal diagnosis of portal vein thrombosis by ultrasound

Neonatal portal vein thrombosis (PVT) is a rare condition seen in the setting of thrombophilia or after umbilical vein catheterization. We report a case of fetal PVT with abnormal antenatal ultrasound findings at 27 weeks of gestation. This presented initially as dilation of the intrahepatic umbilical vein. To our knowledge, this is the first reported case evaluated prenatally. Color Doppler ultrasound was valuable in detecting constriction of the vessel with a high-velocity jet seen past the obstruction site. A discussion of this condition and differential diagnosis is presented.

Current practice regarding the enteral feeding of high-risk newborns with umbilical catheters in situ

OBJECTIVE

Textbooks recognize the controversy of concomitant enteral nutrition (EN) during umbilical catheter usage in high-risk newborns, but support for the practice varies. There is only one clinical trial examining these practices in a small but randomized, controlled trial of enterally fed newborns with umbilical arterial catheters (UACs) in situ, and that trial did not demonstrate any adverse consequences. We speculate that concomitant EN with umbilical catheter usage is more common than some textbooks suggest-practiced by at least 20% of all US neonatal intensive care units (NICUs). The objective of this study is to determine the prevalence of NICUs where high-risk newborns with UAC or umbilical venous catheter (UVC) placement receive concomitant EN.

METHODS

Medical Directors listed in the American Academy of Pediatrics United States Neonatologist and Perinatologist Directory were surveyed by mail. On return of surveys, responses to multiple choice questions were recorded by electronic scanning and validated by manually conducted quality control checks. NICU identities were recorded by code to maintain anonymity.

RESULTS

Following 2 requests for survey participation, 70% (549/785) of surveys were returned. Respectively, 82% and 62% of NICUs with and without training programs were represented. On average, surveyed medical directors had practiced neonatal medicine 18.1 +/- 0.3 years. Of surveyed NICUs, 99% reported placement of UVCs and UACs. Of the 92% believing that it is safe to provide trophic EN to newborns with UVCs in place, 51% practiced this some of the time, and 37% practiced it most of the time. By comparison, it was reported that newborns with UACs in place receive trophic EN most of the time (30%), some of the time (49%), or none of the time (22%). Of the 80% believing that it is safe to provide more complete EN to newborns with UVCs in place, 44% practiced this some of the time, and 24% practiced it most of the time. For newborns with UACs in place, more complete EN was provided most of the time (15%), some of the time (36%), or none of the time (49%).

CONCLUSIONS

Concurrent UVC and UAC usage with EN is more commonly practiced than suggested in textbooks or published articles. The relative risk-benefit profiles of these practices remain uncertain secondary to the limited number of controlled clinical observations and to the infrequent occurrence of adverse events. A prospective, multicenter, controlled trial would address the continued advisability of these unexpectedly common practices.

Maternal thrombophilia and neonatal thrombosis

In neonates and infants, numerous clinical and environmental conditions lead to elevated thrombin generation and subsequent thrombus formation. Genetic prothrombotic defects (protein C, protein S and antithrombin deficiency, mutations of coagulation factor V and factor II, elevated lipoprotein (a)) have been established as risk factors of thromboembolic events in neonates and infants. The interpretation of the laboratory evaluation relies on age-dependent normal reference values. Because appropriate clinical trials are missing in these age groups, treatment recommendations are adapted from small-scale studies in neonates and infants and from guidelines relating to adult patient protocols. Secondary long-term anticoagulation should be administered on an individual basis.

Diagnostic studies for thrombophilia in women on hormonal therapy and during pregnancy, and in children

OBJECTIVE

To review the role of acquired and inherited prothrombotic risk factors that increase the risk of thrombosis in oral contraceptive users, during pregnancy, and in neonates, infants, and children; and to determine by the consensus opinion of recognized experts in the field which risk factors should be determined in which individuals at which time.

DATA SOURCES

Review of the medical literature and current clinical practice by a panel of experts in the field of thrombophilia.

DATA EXTRACTION AND SYNTHESIS

The experts made an extensive review of the published literature and prepared a draft manuscript, which included preliminary recommendations. The draft manuscript was circulated to participants in the College of American Pathologists Conference XXXVI: Diagnostic Issues in Thrombophilia prior to the conference. The manuscript and recommendations were then presented at the conference for discussion. Recommendations were accepted if a consensus of the 26 experts attending the conference was reached. The results of the discussion were used to revise the manuscript into its final form.

CONCLUSIONS

This report reviews the options for testing for thrombophilic states in women using oral contraceptives, during pregnancy, and in neonates and children. General guidelines for testing in these clinical situations are provided, along with citation of the appropriate supporting literature.

Does Umbilical Vein Catheterization Lead to Portal Venous Thrombosis? Prospective US Evaluation in 100 Neonates

PURPOSE

To establish, by means of serial ultrasonography (US), the incidence and natural history of neonatal portal venous thrombosis associated with catheterization of the umbilical vein and to evaluate the potential risk factors predisposing patients to thrombus formation.

MATERIALS AND METHODS

Neonates who had undergone umbilical vein catheterization were studied. US was performed at 2-7-day intervals, before and after the removal of the catheter, until clot resolution or hospital discharge. The presence of portal venous thrombosis and temporal evolution were noted, and various risk factors were analyzed.

RESULTS

US demonstrated clinically silent portal venous thrombosis in 43 (43%) of 100 neonates. Follow-up US revealed complete or partial resolution in 20 (56%) of 36 babies. A significant (P =.024) correlation was found between the initial size of the thrombi and spontaneous clot resolution. Statistically significant risk factors were catheterization for more than 6 days (P =.001) and transfusion (P =.019).

CONCLUSION

Portal venous thrombosis is frequently associated with the placement of an umbilical venous catheter, and spontaneous resolution is expected in many cases. The duration of catheter placement should be minimized, and US monitoring is recommended as a guide to catheter removal.

Abdominal venous thrombosis in neonates and infants: role of prothrombotic risk factors - a multicentre case-control study. For the Childhood Thrombophilia Study Group

The factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, the methylenetetrahydrofolate reductase (MTHFR) T677T genotype, together with fasting homocysteine (HCY) concentration, lipoprotein (Lp)(a), anti-thrombin (AT), protein C (PC), protein S (PS) and anti-cardiolipin antibodies were investigated in 65 consecutively recruited infants (neonate to < 12 months) with renal venous thrombosis (RVT; n = 31), portal vein thrombosis (PVT; n = 24) or hepatic vein thrombosis (HVT n = 10), and 100 age- and sex-matched healthy controls. FV G1691A was found in 14 babies (heterozygous: RVT n = 9, PVT n = 4; homozygous HVT n = 1) and five controls, the MTHFR TT677 genotype together with increased HCY in four infants with thrombosis (RVT n = 2; PVT n = 1; HVT n = 1) compared with one control, and the PT G20210A variant was present in one control only. PC type I deficiency was diagnosed in three patients (RVT n = 2; PVT n = 1) and AT deficiency in two patients (RVT n = 1; PVT n = 1). Three neonates with spontaneous thrombosis showed FV G1691A combined with Lp(a) and the FV G1691A was combined with the PT G20210A genotype in two infants. Additional triggering factors were reported in 27 patients (41.5%). The overall odds ratios (ORs) and 95% confidence intervals (CIs) with respect to the different thrombosis locations were: RVT (OR/CI: 10.9/3.85-31.1; P < 0.0001), PVT (5.47/1.7-17.6; P < 0.0007) and HVT (3.3/0.58-18.7; P = 0.18). The data presented here suggest that genetic prothrombotic risk factors also play an important role in abdominal venous thrombosis during infancy.

Neonatal vascular catheters and their complications

There has been an evolution in vascular access in the neonate. Newer types of materials and catheters, such as PICC lines and ECMO catheters, are now available. The frequency of line placement has increased, and radiologists now perform many of these procedures. This places the radiologist in the position of not only diagnosing complications, but actually causing them. Knowledge of these complications can help the practitioner avoid them and diagnose them as quickly as possible when they occur.

Venous thromboembolic events in pediatric patients. Diagnosis and management

Venous thromboembolism is a rapidly increasing secondary complication in children being treated for serious, life-threatening, primary diseases. Most current management guidelines and recommendations for imaging techniques have been extrapolated from the results of trials in adults. This may be less than optimal for children as there are important differences. The purpose of this article is to summarize the information on venous thromboembolism in children, and offer some guidelines for diagnosis, prophylaxis, and therapeutic intervention based on the best available evidence.