Antithrombotic therapy in neonates and children: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Left ventricular thrombus formation after repair of anomalous left coronary artery from the pulmonary artery

Although thrombus formation following myocardial infarction in adults is well known, intracardiac thrombosis in children is uncommon. We report the case of a large left ventricular thrombus in an infant with ischemic cardiomyopathy secondary to anomalous origin of the left coronary artery from the pulmonary artery. Given its mobility and protrusion across the aortic valve, the patient underwent urgent thrombus removal through a transaortic approach. There were no embolic or neurologic complications. This case highlights that thrombectomy may be performed safely and successfully in critically ill pediatric patients.

Low molecular weight heparin for prevention of central venous catheterization-related thrombosis in children

BACKGROUND

The prevalence of children diagnosed with deep vein thrombosis or pulmonary embolism has been increasing in the last decade. The most common thrombosis risk factor in neonates, infants and children is the placement of a central venous catheter (CVC). To date, it is unknown if the practice of anticoagulation prophylaxis with low molecular weight heparin (LMWH) decreases CVC-related thrombosis in children.

OBJECTIVES

The primary objective of this review was to determine the effect of LMWH prophylaxis on reducing the incidence of CVC-related thrombosis in children.Secondary objectives were to determine the effect of LMWH on occlusion of CVCs, number of days of CVC patency, episodes of catheter-related sepsis, side effects of LMWH (allergic reactions, major and minor bleeding complications, abnormal coagulation profile, osteoporosis) and mortality during therapy.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched June 2013), CENTRAL (2013, Issue 5) and clinical trial databases. The authors searched MEDLINE and EMBASE (July 2013). Bibliographies of identified articles were searched. There were no language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing LMWH prophylaxis to standard care given to prevent CVC-related thrombotic events in children were included. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified eligible studies, which were assessed for study quality including bias, and extracted unadjusted data where available. In the data analysis step, all outcomes were analysed as binary or dichotomous outcomes. The effects of interventions were summarised with risk ratios (RR) and their respective 95% confidence intervals (CI).

MAIN RESULTS

One of 17 studies retrieved for full-text assessment for eligibility was included in the final analysis. This study included a total of 186 participants and investigated the effect of LMWH to prevent CVC-related thrombosis compared to standard care. The risk of bias of the study was assessed to be low, except for the unclear risk of selection bias (allocation concealment not reported) and detection bias since it was an open-label study. Nonetheless, outcome adjudication was blinded. However, overall the quality of the evidence was low due to the fact that the study was underpowered. The CIs for the risk of CVC-related thrombosis (symptomatic and asymptomatic events) were compatible with benefits of either LMWH (reviparin) or the control (RR for symptomatic thrombosis 1.03, 95% CI 0.21 to 4.93; RR for asymptomatic thrombosis 1.17, 95% CI 0.45 to 3.08). Similarly, only one patient in the standard care group suffered a major bleeding event, while minor bleeding was found in 53.3% of patients in the reviparin arm and in 44.7% of patients in the standard care arm (major bleeding RR 0.34, 95% CI 0.01 to 8.26; minor bleeding RR 1.20, 95% CI 0.91 to 1.58). Lastly, there were two deaths within the study and neither were the result of a venous thrombotic event (VTE), occurring in the standard care arm. No additional adverse effects were reported. Other pre-specified outcomes for this review were not reported.

AUTHORS' CONCLUSIONS

A single study reported imprecise effects for the risk of CVC-related thrombosis in children on a CVC anticoagulant prophylaxis regimen. The quality of the evidence was low due to the fact that the included study was clearly underpowered, hampering any conclusions in regards to the efficacy of LMWH prophylaxis to prevent CVC-related thrombi in children. Further prospective randomised studies are highly encouraged.

Different unfractionated heparin doses for preventing arterial thrombosis in children undergoing cardiac catheterization

BACKGROUND

The role of cardiac catheterization in pediatrics has progressed significantly over the last two decades, evolving from a primary diagnostic tool to a primary treatment modality in children with congenital heart disease. Vascular complications, particularly arterial thrombosis, are among the most common unwanted post-cardiac catheterization events. In 1974, unfractionated heparin proved to be superior to placebo in decreasing the incidence of arterial thrombosis in pediatric patients. However, the optimal dose of unfractionated heparin to be utilized in this setting remains a matter of controversy.

OBJECTIVES

To evaluate the use of low-dose (< 100 units/kg) versus high-dose (≥ 100 units/kg) unfractionated heparin administered as an intravenous bolus at the time of initiation of cardiac catheterization (that is, immediately after arterial puncture), with or without subsequent heparin maintenance doses, for the prevention of post-procedural arterial thrombosis in children.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched November 2013) and CENTRAL (2013, Issue 10). The authors searched MEDLINE, EMBASE, and the Virtual Health Library. Clinical trials databases and sources of grey literature were searched. No language restrictions were applied.

SELECTION CRITERIA

Randomized or quasi-randomized trials that compared low dose to high dose unfractionated heparin administered prior to cardiac catheterization were included. We selected studies conducted in children aged 0 to 18 years.

DATA COLLECTION AND ANALYSIS

The first screening of potentially eligible studies was conducted by one of the authors (MLA). The second screening, quality assessment and data extraction were independently conducted by two authors (MLA, LRB). Outcomes (thrombotic events, bleeding complications, other complications) were treated as dichotomous variables. The effect measures used were risk ratio (RR), risk difference (RD) and number needed to treat (NNT), with 95% confidence intervals (CI).

MAIN RESULTS

Two studies with a total of 492 participants were eligible for inclusion. Risk of bias was low for all domains in one of the studies and unclear for the other. One of the trials was stopped early. The quality of evidence for our key outcomes was moderate. The CI for the risk of arterial thrombotic events was compatible with benefits of either high or low unfractionated heparin dose regimens (RR low-dose versus high-dose 1.06, 95% CI 0.58 to 1.92). Only one of the studies reported the frequency of bleeding events for the cohort of patients and found no statistically significant difference in the incidence of major and minor bleeding events between arms (RR low-dose versus high-dose 1.38, 95% CI 0.46 to 4.13 for minor bleeding; RR low-dose versus high-dose 2.96, 95% CI 0.12 to 71.34 for major bleeding events). This study also reported on the incidence of deep vein thrombosis when comparing the high versus low dose of heparin and reported a non-significant difference (RR low-dose versus high-dose 0.34, 95% CI 0.01 to 8.28). The other study lacked information about bleeding. Side effects of heparin other than bleeding complications were not reported in either of the studies.

AUTHORS' CONCLUSIONS

Due to the limitations of the current evidence, small number of included studies, and lack of details reported in one study, we are unable to determine the effects of different dosing regimens of unfractionated heparin for the prevention of vascular thrombosis during cardiac catheterization in children. A further adequately powered, randomized clinical trial is needed.

Thrombophilia testing in children: a 7 year experience

BACKGROUND

Incidence of venous thromboembolism (VTE) in children is reported to be increasing. We examined thrombophilia testing results in children with VTE that presented in inpatient and outpatient settings to explore patterns of thrombophilia testing.

PATIENTS/METHODS

Children, ages 0-20 years with VTE seen at our institution from Jan 2005 to Apr 2012 were studied retrospectively. All patients with VTE confirmed by imaging were eligible and the presence of significant risk factors was evaluated. Thrombophilia was diagnosed if >1 tests confirmed: persistently low protein C (PC), protein S (PS), and antithrombin (AT) following VTE resolution, persistent antiphospholipid antibodies (APA) positivity >12 weeks from first test, factor V Leiden (FVL) and prothrombin mutation (PTm) hetero- or homozygosity, elevated plasminogen activator inhibitor (PAI-1) levels with 4G/5G or 4G/4G polymorphisms, methylene tetrahydrofolate reductase (MTHFR) polymorphisms with elevated fasting homocysteine levels.

RESULTS

Three hundred ninety-two patients met inclusion criteria. At least one test was ordered in 157/239 inpatients. All 153 outpatients had >1 test ordered. Thrombophilia rate differences between inpatients and outpatients did not reach statistical significance except for PC deficiency, which was significantly higher in outpatients. Of inpatients, central venous line (CVL) was significantly associated with not having tests done (P < 0.0022).

CONCLUSIONS

This study of pediatric VTE demonstrated a low thrombophilia rate in both inpatient and outpatient populations. The role of testing in other pediatric patients should be further explored.

Consensus statements on the risk, prevention, and treatment of venous thromboembolism in inflammatory bowel disease: Canadian Association of Gastroenterology

BACKGROUND & AIMS

Guidelines for the management of venous thromboembolism (VTE) from the American College of Chest Physicians do not address patients with inflammatory bowel disease (IBD), a group with a high risk of both VTE and gastrointestinal bleeding. We present recommendations for the prevention and treatment of VTE in patients with IBD.

METHODS

A systematic literature search was performed to identify studies on VTE in IBD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Statements were developed through an iterative online platform, then finalized and voted on by a working group of adult and pediatric gastroenterologists and thrombosis specialists.

RESULTS

IBD patients have an approximately 3-fold higher risk of VTE compared with individuals without IBD, and disease flares further increase this risk. Anticoagulant thromboprophylaxis is recommended for IBD patients who are hospitalized with IBD flares without active bleeding and is suggested when bleeding is nonsevere. Anticoagulant thromboprophylaxis is suggested during moderate-severe IBD flares in outpatients with a history of VTE provoked by an IBD flare or an unprovoked VTE, but not otherwise. The recommended duration of anticoagulation after a first VTE is based on the presence of provoking factors. Specific suggestions are made for the prevention and treatment of VTE in pediatric and pregnant IBD patients.

CONCLUSIONS

Using the American College of Chest Physicians' guidelines as a foundation, we have integrated evidence from IBD studies to develop specific recommendations for the management of VTE in this high-risk population.

Commentary on 'Interventions for restoring patency of central venous catheter lumens'

This is a commentary on a Cochrane review, published in this issue of EBCH, first published as: van Miert C, Hill R, Jones L. Interventions for restoring patency of occluded central venous catheter lumens. Cochrane Database of Systematic Reviews 2012, Issue 4. Art. No.: CD007119. DoI: 10.1002/14651858.CD007119.pub2. Further information for this Cochrane review is available in this issue of EBCH in the accompanying Summary article.

Hospital-associated venous thromboembolism in children: incidence and clinical characteristics

OBJECTIVE

To determine incidence and clinical characteristics of hospital-associated venous thromboembolism (VTE) in pediatric patients.

STUDY DESIGN

A retrospective analysis of patients with hospital-associated VTE at the Johns Hopkins Hospital from 1994 to 2009 was performed. Clinical characteristics of patients aged 21 years and younger who developed VTE symptoms after 2 days of hospitalization or <90 days after hospital discharge were examined. International Classification of Diseases, Ninth Revision codes were used to categorize patients with complex chronic medical conditions and trauma.

RESULTS

There were 270 episodes of hospital-associated VTE in 90,485 admissions (rate 30 per 10,000 admissions). Young adults (18-21 years) and adolescents (14-17 years) had significantly increased rates of VTE compared with children (2-9 years) (incidence rate ratio [IRR] 7.7, 95% CI 5.1-12.0; IRR 4.3, 95% CI 2.7-6.8, respectively). A central venous catheter (CVC) was present in 50% of patients, and a surgical procedure was performed in 45% of patients before VTE diagnosis. For patients without a CVC, trauma was the most common admitting diagnosis. CVC-related VTE was diagnosed most frequently in infants (<1 year old) and in patients with malignancy. Renal and cardiac diseases were associated with the highest rates of VTE (51 and 48 per 10,000, respectively). Rates were significantly higher among those with ≥ 4 medical conditions compared with those with 1 medical condition (IRR 4.0, 95% CI 1.4-8.9).

CONCLUSION

Older age and multiple medical conditions were associated with increased rates of hospital-associated VTE. These data can contribute to the design of future clinical trials to prevent hospital-associated VTE in high-risk children.

IV enoxaparin in pediatric and cardiac ICU patients

OBJECTIVES

To report our experience with the use of IV enoxaparin in neonatal and pediatric patients in the ICU.

DESIGN

We performed a case control from January 1, 2009, to June 30, 2012, comparing patients that received IV enoxaparin to controls that received subcutaneous enoxaparin. Cases were matched to controls in a 1:2 manner. IV enoxaparin doses were infused over 30 minutes and anti-Factor Xa levels were drawn 4 hours after the start of the IV infusion or 4 hours after a subcutaneous dose.

SETTING

The pediatric and cardiac ICUs of a tertiary/quaternary, free-standing, academic children's hospital.

PATIENTS

Forty-five neonatal and pediatric patients receiving prophylactic or therapeutic enoxaparin.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fifteen cases and 30 controls were included. Of 15 patients, 13 received IV enoxaparin for treatment and two received IV enoxaparin for prophylaxis as compared with 25 of 30 controls receiving subcutaneous enoxaparin for treatment and five receiving subcutaneous enoxaparin for prophylaxis. The ages for the cases ranged from 21 days to 16 years with a median weight of 5 kg, and the ages for controls ranged from 10 days to 23 years with a median weight of 31 kg. The median duration of IV therapy was 11 days (range, 1-120 d) and the median duration for subcutaneous therapy was 15 days (range, 3-85 d). The mean initial IV dose was 1.14 ± 0.38 mg/kg/dose q12h, and the mean initial subcutaneous dose was 0.85 ± 0.2 mg/kg/dose subcutaneous q12h (p = 0.003). The mean therapeutic IV dose was 1.31 ± 0.52 mg/kg/dose q12h, and the mean therapeutic subcutaneous dose was 0.9 ± 0.3 mg/kg/dose q12h (p = 0.016). There were no adverse events reported related to bleeding, thrombosis, or hypersensitivity in any of the cases or controls evaluated.

CONCLUSION

The pharmacodynamics of a 30-minute IV enoxaparin infusion was found to produce therapeutic 4 hour anti-Factor Xa levels similar to subcutaneous doses. Although this was a small study, there were no adverse events, suggesting the safety profile of IV enoxaparin may be similar to subcutaneous dosing with the added benefit of less pain associated with IV dosing. These findings suggest that IV enoxaparin may be a viable option for anticoagulating critically ill children and its use warrants further study.

Acute ischemic stroke in a 12-year-old successfully treated with mechanical thrombectomy

We report the case of a healthy 12-year-old girl with an acute ischemic stroke successfully treated with mechanical thrombectomy. The child was referred to our hospital 6 hours after sudden onset of severe headache and left hemiparesis. Cerebral angiography findings were consistent with right distal internal carotid artery occlusion in addition to ipsilateral middle cerebral artery occlusion. Subsequent mechanical thrombectomy with Solitaire AB device resulted in complete vessel recanalization. The patient experienced progressive neurologic improvement with good clinical recovery at the 3-month follow-up. To our knowledge, only 3 cases of primary mechanical thrombectomy in children have been previously reported in the literature. Safety and efficacy data for endovascular therapies in pediatric acute ischemic stroke are lacking. We propose mechanical thrombectomy as an option in children with significant neurologic deficits and proven arterial occlusion, especially when the therapeutic window for intravenous thrombolysis has been exceeded.

Approach to acute ischemic stroke in childhood

OPINION STATEMENT

Acute ischemic stroke in childhood is a medical emergency. Prompt recognition and intervention is necessary to rescue potentially viable brain tissue, prevent complications, and minimize the risk of recurrent stroke. Conditions that could result in recurrent stroke such as cardiac thrombus or cervical artery dissection need to be identified and treated promptly. Although the care of childhood stroke is based largely on extrapolation from adults, an organized approach to the care of these children is critical to optimize outcome.

Prevention and treatment of intraluminal catheter thrombosis in children hospitalised in a paediatric intensive care unit

AIM

The aim of the study was to develop and implement a protocol for the prevention and treatment of catheter related intraluminal thrombosis in a paediatric intensive care unit

METHODS

A computerised search was carried out on MEDLINE, through PubMed, using the medical subject heading 'central venous catheter', 'central venous access device', 'central venous line' associated with 'occlusion', 'obstruction', 'catheter-related thrombosis', 'critically ill patients' and 'thrombolytic therapy'. References of reviewed articles were also searched for relevant titles as well as non-randomised controlled trials and series of cases when no information of higher level of evidence was available.

RESULTS

With the information gathered, a protocol for the prevention and treatment of catheter related intraluminal thrombosis was elaborated and those recommendations that best suit our environment were included. They were agreed upon by a broad panel of professionals working in the Pediatric Intensive Care Unit and the Pharmacy Department.

CONCLUSIONS

Due to the variety of options available for the pharmacotherapeutic management of intraluminal catheter thrombosis, one measure to improve the quality of the therapy and to diminish the variability in the prescription could be the implementation of a protocol as described in this paper.

Survey results: characterization of direct thrombin inhibitor use in pediatric patients

OBJECTIVES

The objective of this multicenter survey is to characterize the use of direct thrombin inhibitors (DTIs) in the pediatric population. The results of this survey may be used to design a prospective multicenter study with the ultimate goal of developing a dosing/titration recommendation for the use of DTIs in the pediatric population.

METHODS

This is a multicenter, descriptive study to survey hospitals around the country regarding the use of DTIs (argatroban, bivalirudin, and lepirudin) in the pediatic population. Institutional review board approval was obtained. The survey consisted of 42 questions and was designed utilizing Survey Monkey. The survey was emailed to members of the Pediatric Pharmacy Advocacy Group. Listserv members who responded to the survey within 4 weeks of when the survey was emailed were included in the study. Descriptive statistics were performed utilizing Microsoft Excel 2007.

RESULTS

Responses were obtained from 56 institutions from 29 states in the United States. Multiple agents are available on formulary with argatroban being the most common (~80%). The large majority of institutions (41.1%) utilize DTIs 2 to 4 times a year with an additional 33.9% utilizing them less than twice a year. There is no consistent approach to dosing and titration amongst pediatric institutions.

CONCLUSIONS

There are a wide variety of methods used by pediatric institutions with regard to dosing and titration of DTIs. Recently published prospective studies and package insert updates should help guide practitioners toward a more consistent approach to dosing of these high-risk medications.

Coagulation and the surgical neonate

Both coagulopathy and abnormal thrombosis can complicate the anesthetic and surgical management of neonatal patients; however, the patterns of bleeding and thrombosis in neonates differ from those in adults or older children. Severe coagulopathic bleeding most commonly occurs during heart surgery and almost certainly contributes to morbidity and mortality in this population. Such severe bleeding is rare during other surgery; the exception is babies presenting to the operating room with established coagulopathy secondary to severe sepsis. Alternatively, pathological thrombosis will mainly occur in association with indwelling vascular access devices or surgically created vascular shunts. There are important differences between the coagulation system in neonates and older patients. The implication of this is that therapies established in other patient groups will not be optimal for neonates without adaptation. While evidence from high-quality clinical trials is rarely available, an understanding of how coagulation in neonates differs can help to guide practice. This review will discuss important differences between the coagulation system of neonates and older patients and how these relate to newer models of coagulation. The emphasis will be on issues likely to impact on perioperative care. In particular, the management of severe bleeding, the manipulation of coagulation during heart surgery, and the management of coagulopathy in septic neonates will be discussed in detail.

Gradenigo's syndrome: is fusobacterium different? Two cases and review of the literature

Gradenigo's syndrome is a rare but life threatening complication of acute otitis media (AOM), which includes a classic triad of otitis media, deep facial pain and ipsilateral abducens nerve paralysis. The incidence of Fusobacterium necrophorum infections has increased in recent years. We describe two cases of Gradenigo's syndrome caused by F. necrophorum. Additional four cases were identified in a review of the literature. Gradenigo's syndrome as well as other neurologic complications should be considered in cases of complicated acute otitis media. F. necrophorum should be empirically treated while awaiting culture results.

Venous thromboembolism in children with cancer - a population-based cohort study

Introduction

Cancer is a known risk factor for venous thromboembolism (VTE) in adults, but population-based data in children are scarce.

Materials and methods

We conducted a cohort study utilising linkage of the Clinical Practice Research Database (primary care), Hospital Episodes Statistics (secondary care), UK Cancer Registry data and Office for National Statistics cause of death data. From these databases, we selected 498 children with cancer diagnosed between 1997 and 2006 and 20,810 controls without cancer. We calculated VTE incidence rates in children with cancer vs. controls, and hazard ratios (HRs) using Cox regression.

Results

We identified four VTE events in children with cancer compared with four events in the larger control population corresponding to absolute risks of 1.52 and 0.06 per 1000 person-years respectively. The four children with VTE and cancer were diagnosed with hematological, bone or non-specified cancer. Childhood cancer was hence associated with a highly increased risk of VTE (HR adjusted for age and sex: 28.3; 95%CI = 7.0-114.5).

Conclusions

Children with cancer are at increased relative risk of VTE compared to those without cancer. Physicians could consider thromboprophylaxis in children with cancer to reduce their excess risk of VTE however the absolute risk is extremely small and the benefit gained therefore would need to be balanced against the risk invoked of implementing such a strategy.

Novelty & Impact Statements

While there is a reasonable level of knowledge about the risk of VTE in adult populations, it is not well known whether this risk is reflected in paediatric patients. We found a substantial increase in risk of VTE in children with cancer compared to a child population without cancer. While this finding is important, the absolute risk of VTE is still low and must be balanced with the risks of anticoagulation.

Pediatric thrombophilia

Pediatric thrombosis and thrombophilia are increasingly recognized and studied. In this article, both the inherited and acquired factors for the development of thrombosis in neonates and children are categorized using the elements of Virchow's triad: stasis, hypercoagulable state, and vascular injury. The indications and rationale for performing thrombophilia testing are described. Also included are discussions on who, how, when, and why to test. Finally, recommendations for the use of contraceptives for adolescent females with a family history of thrombosis are outlined.

Antithrombotic therapies: anticoagulation and thrombolysis

Pediatric deep vein thrombosis is an increasingly recognized phenomenon, especially with advances in treatment and supportive care of critically ill children and with better diagnostic capabilities. High-quality evidence and uniform management guidelines for antithrombotic treatment, particularly thrombolytic therapy, remain limited. Optimal dosing, intensity and duration strategies for anticoagulation as well as thrombolytic regimens that maximize efficacy and safety need to be determined through well-designed clinical trials using use of a risk-stratified approach.

Anticoagulant treatment with rivaroxaban in severe protein S deficiency

We report a case of a 6-year-old girl with severe protein S deficiency due to a homozygous mutation and recurrent episodes of skin necrosis. She developed purpura fulminans at birth and a catheter-related venous thrombosis complicated by massive pulmonary embolism at the sixth day of life. Long-term oral anticoagulant therapy with a vitamin K-antagonist was started with a therapeutic range of the international normalized ratio of prothrombin time between 2.0 and 3.0. Unfortunately, this common range was not sufficient because recurrent episodes of warfarin-induced skin necrosis developed if the international normalized ratio was <4.0. Vitamin K antagonists decrease plasma level of vitamin K-dependent coagulation proteins, including the natural anticoagulant protein C. In our patient, the hypercoagulable state due to warfarin-induced reduction of protein C, other than severe protein S deficiency, outweighed the anticoagulant efficacy of the inhibition of procoagulant factors II, VII, IX, and X. The switch of anticoagulant therapy from warfarin to rivaroxaban, a direct inhibitor of activated factor X that does not inhibit other vitamin K-dependent proteins, resulted in the disappearance of skin necrosis at 1 year of follow-up. Rivaroxaban may be considered as a valid anticoagulant alternative in patients with severe inherited protein S deficiency and warfarin-induced skin necrosis.

Pathology consultation on anticoagulation monitoring: factor X-related assays

OBJECTIVES

To review various anticoagulation therapies and related laboratory monitoring issues, with a focus on factor X-related chromogenic assays.

METHODS

A case-based approach is used to review pertinent published literatures and product inserts of anticoagulation drugs and to look back on clinical use of factor X-related chromogenic assays.

RESULTS

The number of anticoagulants available to clinicians has increased greatly in the past decade. Whether and how these anticoagulants should be monitored are areas of uncertainty for clinicians, which can lead to misuse of laboratory assays and suboptimal patient management. Factor X-related assays are of particular concern because of the similar and often confusing test names. Based on a common clinical case scenario and literature review regarding anticoagulant monitoring, an up-to-date discussion and review of the various factor X-related assays are provided, focusing on the differences in test designs and clinical utilities between the chromogenic anti-Xa and chromogenic factor X activity assays.

CONCLUSIONS

Anticoagulation therapy and related laboratory monitoring are rapidly evolving areas of clinical practices. A good knowledge of relevant laboratory assays and their clinical applications is necessary to help optimize patient care.

Serial cranial US for detection of cerebral sinovenous thrombosis in preterm infants

PURPOSE

To report the incidence of cerebral sinovenous thrombosis (CSVT) in a prospective cohort of preterm infants with a gestational age of less than 29 weeks.

MATERIALS AND METHODS

The local medical ethics review board approved this study, and written parental consent was obtained. Preterm infants with a gestational age of less than 29 weeks who were admitted to the neonatal intensive care unit were prospectively studied with cranial ultrasonography (US). The scanning protocol included visualization with color Doppler imaging of the superior sagittal sinus and transverse sinuses through the anterior (8.5-MHz probe) and mastoid (13-MHz probe) fontanelles. When feasible, magnetic resonance imaging was performed to confirm cranial US-diagnosed CSVT. The differences between preterm infants with and those without CSVT were analyzed by using Mann-Whitney tests for continuous variables and Fisher exact tests for categorical data.

RESULTS

Cranial US was used to document CSVT in 11 of 249 preterm infants with a gestational age of less than 29 weeks. Transverse sinuses were most frequently affected (in all 11 patients with CSVT). All infants with CSVT were asymptomatic. Postnatal age at diagnosis ranged from 5 to 34 days. The mean gestational age was significantly lower in infants with CSVT (25.9 weeks vs 26.8 weeks, P = .038). Of the risk factors studied, only duration of mechanical ventilation was associated with CSVT; it was significantly longer in the CSVT group.

CONCLUSION

Systematic serial cranial US of infants with a gestational age of less than 29 weeks showed a remarkably high incidence of CSVT of 4.4%. Cranial US including color Doppler imaging with scans obtained through the mastoid fontanelle can depict CSVT at an early stage. Treatment of this possibly important condition needs attention.

Topical Nitroglycerine for Neonatal Arterial Associated Peripheral Ischemia following Cannulation: A Case Report and Comprehensive Literature Review

Arterial cannulation in neonates is usually performed for frequent blood pressure monitoring and blood sampling. The procedure, while easily executed by skilled neonatal staff, can be associated with serious complications such as vasospasm, thrombosis, embolism, hematoma, infection, peripheral nerve damage, ischemia, and tissue necrosis. Several treatment options are available to reverse vascular induced ischemia and tissue damage. Applied interventions depend on the extent of tissue involvement and whether the condition is progressive and deemed life threatening. Standard, noninvasive measures include immediate catheter removal, limb elevation, and warming the contralateral extremity. Topical vasodilators, anticoagulation, thrombolysis, and surgery are considered secondary therapeutic strategies. A comprehensive literature search indicates that topical nitroglycerin has been utilized for the treatment of tissue ischemia in three preterms with umbilical arterial catheters and four with peripheral arterial lines. We report the first successful use of nitroglycerine ointment in a critically ill preterm infant with ischemic hand changes after brachial artery cannulation.

The adult with a fontan: a panacea without a cure? Review of long-term complications

The univentricular heart includes a spectrum of complex cardiac defects that are managed by staged palliative surgical procedures, ultimately resulting in a Fontan procedure. Since 1971, when it was first developed, the procedure has undergone several variations. These patients require lifelong management, including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function, together with multi-organ evaluation. As these patients enter middle age, there is increasing awareness of long-term complications and mortality. This review highlights the concept behind the staged surgical palliations, the unique single ventricle physiology and the long-term complications in this complex cohort of patients.

Management of thrombotic complications in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common type of cancer diagnosed in children, and has been reported as the most common malignancy associated with thromboembolism in the pediatric age group. Treatment with Escherichia coli asparaginase, concomitant steroids, presence of central venous lines, and thrombophilic abnormalities are established risk factors for thromboembolism. The incidence varies with age, co-morbidities and chemotherapy regimens but the risk is highest during the induction and intensification phases. Treatment is necessary in majority of children to prevent serious sequelae. Mortality from thromboembolic events in any location is 2 to 4 % and the risk of recurrence is 7 to 10 %, further enhanced in the setting of malignancy. Randomized trials of venous thromboembolism (VTE) management in pediatric patients with ALL are lacking due to the low overall incidence, resulting in considerable variation in practice. The objective of this article is to review current knowledge on the treatment and prevention of thrombosis associated with pediatric ALL.

Two separated thrombi in deep veins associated with pulmonary embolism after Mycoplasma pneumoniae infection: a case in adolescent female

Mycoplasma pneumoniae is a common pathogen for respiratory infection in children, and vascular complication is one of the rarest extrapulmonary complications but with serious consequences. We report a twelve-year-old Chinese female presenting with fever, dry cough, and chest pain aggravated by respiration. She was diagnosed pneumonia due to Mycoplasma pneumoniae and treated with Azithromycin until unexpected tachypnea and swelling in the right lower limb happened. Then ultrasonic examination had revealed two separated thrombi in deep veins before pulmonary embolism was found. Finally she was cured by anticoagulation and immunosuppressive therapy. Though the mechanism of thrombosis after Mycoplasma pneumoniae infection remains unknown, the positive finding in anticardiolipin antibody as well as multi-site thromboses gives a strong hint to immune modulation. Thrombosis should be considered for those who have significantly increased C-reactive protein and positive anticardiolipin antibody after Mycoplasma pneumoniae infection. To our knowledge, this is the first report describing two unattached thrombi in deep veins associated with pulmonary embolism after Mycoplasma pneumonia infection.

Readmissions for warfarin-related bleeding in pediatric patients after hospital discharge

BACKGROUND

Warfarin therapy in pediatric patients can be difficult to manage with bleeding as a primary adverse event. Therapy initiation can be difficult as doses to achieve therapeutic outcomes are being determined. Evaluation of readmission for bleeding in pediatric patients discharged on warfarin therapy may be useful to prevent adverse events.

METHODS

The Pediatric Health Information System (PHIS) was queried to identify all patients <19 years of age who were discharged from a pediatric hospital on warfarin therapy. Patients who were readmitted with bleeding in the first 30 days after discharge were identified and patient variables, hospital stay variables, and medications at discharge were identified. Univariate and multivariate analysis was performed to identify independent risk factors for bleeding readmission.

RESULTS

A total of 4,883 patients met study criteria (56% male, mean age 10.1 + 5.9 years). The two most common indications for warfarin therapy were cardiac valve replacement (23.6%) and Fontan procedure (19.5%). Ninety-seven patients (1.99%) were readmitted with bleeding within 30 days of discharge [median time 9 days (IQR 5-16 days)]. Multivariate analysis identified Asian race (OR 4.0, P < 0.01); mitral valve replacement (OR 2.5, P < 0.01); escitalopram at discharge (OR 4.2, P = 0.02); levofloxacin at discharge (OR 8.3, P < 0.01); lansoprazole at discharge (OR 1.7, P = 0.047); and length of stay (OR 1.01, P = 0.047) as significant for bleeding readmission.

CONCLUSION

Pediatric patients discharged on warfarin may be readmitted for bleeding within 30 days if risk factors are present. Risk factors include patient genetic profile, drug interactions, and indications with higher goal INR values.

Warfarin pharmacogenomics in children

Warfarin is the most commonly used oral anticoagulant worldwide. Warfarin has a narrow therapeutic index, requiring frequent monitoring of the INR to achieve therapeutic anticoagulation. The role of pharmacogenomics in warfarin disposition and response has been well established in adults, but remains unclear for pediatric patients. In this review, we focus on the important CYP2C9 and VKORC1 variants involved in warfarin response, our current understanding of warfarin disposition and pharmacogenomics, and recent warfarin pharmacogenetic studies in pediatric patients. Finally, we discuss the need for future pediatric studies and the clinical implications of developing pharmacogenetic-based dosing algorithms in children.

Thromboprophylaxis in a pediatric hospital

Venous thromboembolism (VTE) in children is an emerging area of focus in pediatric hospitals in recent years. Although VTE in hospitalized children occurs much less often than in adults, there are a significant number of children at risk of VTE who may benefit from thromboprophylaxis. The risk factors for VTE in children are known, and are usually multi-factorial, but the indications for pharmacologic prophylaxis are not clearly established. There are available clinical guidelines that have brought forward current initiatives around thromboprophylaxis in pediatric hospitals addressing this safety practice in children.

Common acquired causes of thrombosis in children

Compared to adults, venous thromboembolism in the pediatric population is a rare event. Cancer, cardiac disease, antiphospholipid antibodies, and indwelling catheters are established risk factors for thromboembolism in children. We examined the literature related to thrombophilia in children, childhood cancer and thrombosis, cardiac disease and thrombosis, and antiphospholipid antibody syndrome in children. Citations in identified articles yielded additional articles for review. We found that studies of acquired thrombophilia in children are limited. Current treatment for thromboembolism in children is based on adult data therefore optimal treatment in this population remains unclear.

Developing a pediatric endovascular thrombolysis program: a single-center experience

Deep venous thrombosis (DVT) is being increasingly recognized as a significant issue in children. Despite the low incidence of DVT, the risks of pulmonary embolism and death in children are significant. Post-thrombotic syndrome, a syndrome of chronic venous insufficiency, can have long-term adverse consequences in children and adolescents. Adult studies have shown that catheter-directed therapy can reduce the incidence of post-thrombotic syndrome. Safety of catheter-directed therapy in adolescents has also been demonstrated. These reasons compelled us to institute a pediatric endovascular thrombolysis program at our institute for management of pediatric DVT. We describe the process of developing a multi-disciplinary thrombolysis program involving interventional radiology (pediatric and adult), pediatric hematology, critical care, anesthesia and vascular surgery, and describe the role of each specialty in the development of the program. We also describe our experience with patient selection, endovascular therapy procedure, pre-, intra- and post-procedure monitoring, and follow-up management for endovascular therapy for DVT.

Inherited thrombophilia in children

Thrombosis in children has multiple etiologies, including inherited disorders such as factor V Leiden mutation, prothrombin 20210A mutation, and deficiencies in protein C, S, or antithrombin. Epidemiology of the disorders varies, as does the risk of thrombosis. Venous thromboembolism is the typical presentation. However, more severe anticoagulant protein deficiencies may present with purpura fulminans. Treatment of thrombosis is relatively uniform, regardless of the underlying genetic risk factor. In this article, we discuss the most well-studied inherited thrombophilias and the epidemiology, pathophysiology, and relative thrombotic risk of each. Treatment of thrombosis is also briefly reviewed.

Venous thromboembolism prophylaxis in the pediatric trauma population

BACKGROUND/PURPOSE

The aim of this study was to review evidence-based literature addressing pertinent questions about venous thromboembolism (VTE) after traumatic injury in children.

METHODS

Data were obtained from English-language articles identified through Pubmed published from 1995 until November 2012, and from bibliographies of relevant articles. Studies were included if they contributed evidence to one of the following questions. In the pediatric traumatic injury population: (1) What is the overall incidence of VTE? (2) Is age (adolescence versus pre-adolescence) associated with higher VTE incidence? (3) Which risk factors are associated with higher VTE incidence? (4) Does mechanical and/or pharmacological prophylaxis impact outcomes?

RESULTS

Eighteen articles were included in this systematic review. The evidence regarding each question was evaluated, graded by author consensus, and summarized.

CONCLUSIONS

The overall incidence of VTE is low. Older (>13years) and more severely injured patients are at higher VTE risk. Additional factors including injury type or presence of a central venous catheter also place a patient at higher VTE risk. Implementation of a risk-based clinical practice guideline for VTE prophylaxis has been associated with reduced symptomatic VTE at one institution. Randomized, prospective trials analyzing outcomes of VTE prophylaxis in pediatric trauma victims are needed.

Cerebral Sinus Venous Thrombosis due to Asparaginase Therapy

We report a 9-year-old boy with acute lymphoblastic leukemia (ALL) in high-risk group who suffered from left sided focal seizures and ipsilateral hemiparesis during his induction with Asparaginase chemotherapy. Superior sagittal sinus thrombosis and right frontal hemorrhage were demonstrated on brain magnetic resonance imaging (MRI) scans . Anticoagulation was initiated with unfractionated heparin and switched to low molecular weight heparin after 3 weeks and continued for 6 months. At one-year followup, he had complete response to chemotherapy for ALL, with residual mild left hemiparesis, and his MRI scans revealed recanalized venous sinuses. The case highlights the importance of considering cerebral venous thrombosis as a complication of Asparaginase therapy.

Case report of subdural hematoma in a patient with Sturge-Weber syndrome and literature review: questions and implications for therapy

Sturge-Weber syndrome is a neurocutaneous disorder associated with vascular abnormalities in the skin, eye, and brain leading to both acute and chronic cerebral hypoperfusion and, in some affected children, brain injury. Aspirin can reduce stroke-like events and seizure episodes and prevent further brain injuries in these patients. Although a few cases of intracranial hemorrhage in patients with Sturge-Weber syndrome have been reported, prior reports have not discussed this complication with regard to particular therapies. The authors present a toddler with Sturge-Weber syndrome who developed a subdural hematoma in the setting of a mechanical fall with minor head trauma. They discuss the possible role of aspirin in contributing to, or perhaps protecting against, intracranial hemorrhage in patients with Sturge-Weber syndrome. Further data are needed to establish the utility of aspirin in Sturge-Weber syndrome.

Obsessive-compulsive behavior as presenting symptom of primary antiphospholipid syndrome

OBJECTIVE

This study aimed to improve understanding and treatment of psychiatric symptoms in antiphospholipid syndrome (APS) and to present an approach to the medical management of patients presenting with obsessive-compulsive disorder (OCD) with suspected neurovascular pathology.

METHOD

A 15-year-old boy presented with severe OCD of recent onset. An infarct of the caudate nucleus was identified as the initial presentation of primary APS. This case report includes a selective literature review of the neuropsychiatric correlates of APS.

RESULTS

The patient had OCD for 3 months with increasing symptoms resulting in admission for psychiatric reasons. After referral to the emergency department 3 weeks later, an infarct of the caudate nucleus was documented using magnetic resonance images of the brain, and APS was diagnosed based on additional laboratory findings. Anticoagulant treatment (enoxaparin and phenprocoumon) in this patient was effective in reducing obsessive-compulsive symptom severity.

CONCLUSION

OCD may present as a neuropsychiatric manifestation of APS. The present observations are consistent with a thrombotic mechanism for neurologic or psychiatric symptoms in APS. In general, routine medical workup for childhood OCD is not indicated, but a comprehensive psychiatric, medical, and family history taking and physical examination are essential, particularly if OCD is of recent onset. The role of anticoagulant therapy in neuropsychiatric manifestations of APS without the presence of a cerebral infarct requires further research.

Incidental sonographic diagnosis of neonatal carotid occlusion

Cranial ultrasonography including colour Doppler can detect neonatal carotid flow problems at an early stage, even before symptoms occur. Different pathogeneses can be identified. The condition is more frequent than previously reported. If the circle of Willis is fully developed, this can prevent brain injury even in case of total carotid flow obstruction

CONCLUSION

Screening of the carotid artery in critically ill neonates may detect complications of treatment at an early stage.

Evaluation of the use of low-molecular-weight heparin in neonates: a retrospective, single-center study

Controversies exist over the currently recommended guidelines for the use of low-molecular-weight heparin (LMWH) in neonates. We retrospectively studied 30 neonates treated with LMWH and found a poor therapeutic response to recommended doses as measured by anti-Xa levels. Sixty percent of the study participants required their doses to be increased because of subtherapeutic anti-Xa levels during the initial course of their treatment. The mean starting enoxaparin dose was 1.53 ± 0.38 mg/kg. The mean enoxaparin dose, once therapeutic anti-Xa levels had been achieved, was 1.86 ± 0.50 mg/kg. Preterm and term infants required doses of 2.06 ± 0.61 mg/kg and 1.67 ± 0.26 mg/kg, respectively, to achieve therapeutic anti-Xa levels. In summary, our results suggest that higher initial doses are required to achieve therapeutic anticoagulation in neonates.

Alteplase for the treatment of catheter occlusion in pediatric patients

OBJECTIVE

To review the literature pertaining to the efficacy of alteplase for restoration of patency of occluded venous and dialysis catheters in pediatric patients.

DATA SOURCES

A MEDLINE search was conducted and cross-referenced with an EMBASE search through November 2012. Search terms included alteplase, tissue plasminogen activator, and catheter.

STUDY SELECTION AND DATA EXTRACTION

Search results were limited to humans, English language, and ages from neonates to 18 years. Pertinent studies discussing efficacy of alteplase for restoration of occluded venous or dialysis catheter function were included. Case reports, review articles, and studies that specified inclusion of hemophilia patients or more than 75% of children with malignancy were excluded.

DATA SYNTHESIS

Fibrinolytics are the drug class of choice for restoration of patency (defined as the ability to withdraw a blood sample) of thrombus-occluded catheters. The trials used to support Food and Drug Administration approval of alteplase for central venous catheter (CVC) occlusions generally had low pediatric enrollment; however, additional small studies are available that support use of alteplase for this indication in children. Alteplase doses of 0.5-2 mg instilled into the lumen of a CVC with dwell times ranging from 30 to more than 240 minutes plus the potential for repeat dosing were reported. Overall efficacy ranged from approximately 50% to 90%, with greater efficacy generally reported with larger doses and longer dwell times. Alteplase doses of 2-2.5 mg with dwell times of 60-120 minutes were observed in 2 studies of occluded peritoneal or hemodialysis catheters, in which efficacy was reported in 57-100% of cases. Limitations of current studies of alteplase for catheter occlusion in children include small study populations and relative lack of pediatric-specific prospective trials.

CONCLUSIONS

Alteplase appears to show efficacy for treatment of thrombus-related venous catheter occlusion in pediatric patients; however, data regarding its use in occluded dialysis catheters are limited.