Aspects of anticoagulation in children

Adverse Drug Reactions in Children with Congenital Heart Disease: A Scoping Review

BACKGROUND

Congenital heart disease (CHD) is one of the leading causes of death. Safe and timely medical interventions, especially in children, can prolong their survival. The drugs prescribed for children with CHD are mainly based on the outcomes of drug therapy in adults with cardiovascular diseases, and their adverse drug reactions (ADRs) might be different. Therefore, the aim of this study was to investigate ADRs in children with CHD.

METHODS

This was a scoping review conducted in 2023. PubMed, Web of Science, Scopus, the Cochrane Library, Ovid, ProQuest, and Google Scholar databases were searched. All studies that reported ADRs for children with CHD and were published in English by 1 November 2023 were included in this study. Finally, the results were reported using a content analysis method.

RESULTS

A total of 87 articles were included in the study. The results showed that symptoms/signs/clinical findings, and cardiovascular disorders were the most common ADRs reported in children with CHD. The results also showed that most of the ADRs were reported for prostaglandin E1, amiodarone, prostaglandin E2, dexmedetomidine, and captopril, respectively.

CONCLUSION

The review underscores the wide array of ADRs in children with CHD, particularly in antiarrhythmics, diuretics, beta-blockers, anticoagulants, and vasodilators, which affected cardiovascular, respiratory, endocrine, metabolic, genitourinary, gastrointestinal, and musculoskeletal systems. Tailored treatment is imperative, considering individual patient characteristics, especially in the vulnerable groups. Further research is essential for optimizing dosing, pharmacogenetics, and alternative therapies to enhance patient outcomes in CHD management.

Systemic Catheter-Related Venous Thromboembolism in Children: Data From the Italian Registry of Pediatric Thrombosis

BACKGROUND

Central venous catheters (CVCs) represent one of the main risk factors for venous thrombotic events (VTEs) in children.

METHODS

We studied the Italian Registry of Pediatric Thrombosis (RITI) with regard to systemic radiologically confirmed CVC-related VTEs (CVC-VTEs) occurred during 6.5 years in children aged 29 days to 18 years.

RESULTS

A total of 78 CVC-VTEs were included, which occurred in 76 patients (40/76, 53% males). CVC-VTEs comprised 67 non-cardiac VTEs (86%) and 11 intracardiac thrombotic events (ICTEs) (14%); the median age at onset was 19 and 17 months, respectively. The most frequent reason for CVC insertion was supportive therapy. The catheters were placed percutaneously in 85% of cases (56/66) and surgically in the remaining 15% (10/66). Peripherally inserted central catheters (PICCs) were used in 47% (31/66) cases, partially implanted catheters in 42% (28/66), non-implantable catheters in 7% (5/66), and totally implanted catheters (Port) in 2% (1/66). CVC-VTEs were symptomatic in 77% of cases (60/78), while in the remaining 23%, they were incidentally detected on the imaging performed for the underlying condition. The median time between CVC insertion and the onset of symptoms was 10 days in non-cardiac VTEs and 39 days in ICTEs. Doppler ultrasound was the diagnostic technique most frequently used. The venous compartment most frequently affected was the veins of the lower extremities (52%, 43/73). Anti-thrombotic treatment was administered in 96% of CVC-VTEs (75/78). About 2.6% (2/76) of patients experienced a second thrombotic event. At discharge, post-thrombotic syndrome was reported in 13.5% (5/37) events with available data, CVC replacement in 10.8% (4/47), and ischemic necrosis with toe finger amputation in 2.7% (1/37). Three patients died due to an underlying condition; no CVC-VTE-related deaths were reported.

CONCLUSIONS

We have carried out a registry-based study on CVC-VTEs in the children in Italy, providing the data that may help improve the detection and management of this CVC-related complication.

Systematic review of warfarin-induced skin necrosis case reports and secondary analysis of factors associated with mortality

OBJECTIVE

Warfarin-induced skin necrosis (WSN) is a rare (0.0.1%-0.1%) and severe adverse reaction. The clinical characteristics of this reaction and its mortality rate have not been explored in a large population. Therefore, we present the case of a Peruvian patient who developed WSN and perform a systematic review of case reports of WSN.

METHODS

A systematic search was performed using the Pubmed/Medline, Scopus, Web of Science and Embase databases. Patient clinical data were collected and extracted from every case report. Furthermore, we analysed the factors associated with mortality because of WSN using the Poisson regression model with robust variations, obtaining risk ratios (RR) and their respective confidence intervals (95% CI).

RESULTS

We identified 90 case reports that included a total of 111 patients with WSN (mean age 52.5 years), 20.72% of whom died of complications because of WSN. Being male (RR: 2.87; 95% CI 1.21-6.83) and having three or more affected regions (RR: 6.81; 95% CI 2.62-17.74) were associated with an increased risk of death caused by WSN.

CONCLUSION

This systematic review identified 90 case reports of WSN with three or more affected body regions. Male sex was associated with an increased risk of death. Further studies are needed to analyse and confirm these results.

Revisiting prosthesis choice in mitral valve replacement in children: Durable alternatives to traditional bioprostheses

OBJECTIVE

To determine risk factors for re-replacement and death or transplant following mitral valve replacement (MVR) in children METHODS: This is a retrospective 26-year review of patients younger than 20 years of age undergoing MVR between 1992 and 2018 at single institution. Outcomes included freedom from re-MVR and transplant-free survival. Cox proportional hazards regression models assessed association between outcomes and potential risk factors.

RESULTS

At median age 4.2 years, 190 children underwent 290 MVR: 180 mechanical, 63 porcine, 13 pericardial, and 34 stented bovine jugular vein valves. Re-MVR occurred in 100 valves. Freedom from re-MVR at 5 and 10 years was 76% and 44%. Times to re-MVR were associated with prosthesis type (P < .001), with porcine and pericardial valves at greatest risk. Other risk factors for prosthetic failure included smaller prosthesis size and left ventricular hypoplasia. There were 9 transplants and 44 deaths. Transplant-free survival at 5 and 10 years was 81% and 76%. Prosthesis type was significantly associated with time to death/transplant in univariate analysis only (P = .021), with porcine at greater risk than mechanical. Independent risk factors for death/transplant included larger indexed geometric orifice area and longer bypass time.

CONCLUSIONS

In pediatric patients undergoing MVR, mechanical and stented bovine jugular vein valves were associated with increased durability compared with fixed-diameter bioprosthetic alternatives.

USE OF WARFARIN IN PEDIATRICS: CLINICAL AND PHARMACOLOGICAL CHARACTERISTICS

Objective:

To describe how children respond to oral anticoagulation with warfarin, verifying the influence of age, clinical condition, route of administration of warfarin and use of total parenteral nutrition (TPN), as well as to describe risk factors for the occurrence of thrombotic events (TE) in childhood.

Methods:

A retrospective descriptive study including all patients ≤18 years old for whom warfarin was prescribed in a university hospital. Patients were divided according to clinical condition, age, route of medication administration and use of TPN. Data was collected from the patients’ medical records and the analysis considered the risk factors for TE already described in the literature, the time and the dose required in order to reach the first International Normalized Ratio (INR) in the target and the adverse events in this period. After reaching the INR, the maintenance of anticoagulation was verified by the prescribed dose and INR tests.

Results:

Twenty-nine patients were included in the study. The major risk factor for TE was the use of a central venous catheter in 89.6% of the patients. Patients with short bowel syndrome and total parenteral nutrition required significantly higher doses (p≤0.05) to achieve and maintain the INR in the target. Patients ≤1 year old needed longer periods and required an increased dose of anticoagulation and maintenance than older patients. The mean number of INR examinations below the target was 48.2% in the groups studied.

Conclusions:

The observed complexity of anticoagulant therapy reinforces the need to develop protocols that guide clinical practice.

How We Manage Pediatric Deep Venous Thrombosis

Over the past two decades, the incidence and recognition of venous thromboembolism (VTE) in children has significantly increased, likely as a result of improvements in the medical care of critically ill patients and increased awareness of thrombotic complications among medical providers. Current recommendations for the management of VTE in children are largely based on data from pediatric registries and observational studies, or extrapolated from adult data. The scarcity of high-quality evidence-based recommendations has resulted in marked variations in the management of pediatric VTE among providers. The purpose of this article is to summarize our institutional approach for the management of VTE in children based on available evidence, guidelines, and clinical practice considerations. Therapeutic strategies reviewed in this article include the use of conventional anticoagulants, parenteral targeted anticoagulants, new direct oral anticoagulants, thrombolysis, and mechanical approaches for the management of pediatric VTE.

Skin Necrosis and Purpura Fulminans in Children With and Without Thrombophilia--A Tertiary Center's Experience

Purpura fulminans (PF) is a very rare clinicopathologic skin disorder comprising dermal microvascular thrombosis associated with perivascular hemorrhage of multiple origins. It may occur as the presenting symptom of severe congenital deficiency of protein C (PC) or protein S (PS) during the newborn period, or later in life following oral anticoagulant therapy with vitamin K antagonists, or of sepsis that may be associated with disseminated intravascular coagulation. Treatment consists of anticoagulants and PC concentrates during acute episodes. We report our experience in the diagnosis and management of pediatric PF. The medical records of the 6 children aged 2-16 years (median: 5 years) who presented with PF to our tertiary care center between 1996 and 2013 were studied. The thrombophilia workup revealed either the presence of congenital homozygous PC deficiency, prothrombotic polymorphisms (factor V Leiden and FIIG20210A heterozygosity), acquired PC/PS deficiency, or no discernible thrombophilia. The skin necrosis resolved following conservative fresh-frozen plasma/anticoagulant therapy in 2 cases, whereas 3 children required interventional plastic surgery. The sixth case, a 10-year-old child with severe PC deficiency, heterozygous factor V Leiden, and FIIG20210A, received recombinant activated PC. PF in childhood is rare and has multiple etiologies. Understanding of the variable pathogenesis and risk factors will facilitate diagnosis and appropriate clinical management.

Strategies to Prevent and Manage Thrombotic Complications of Acute Lymphoblastic Leukemia in Children and Young People Vary Between Centers in the United Kingdom

There is a lack of evidence-based guidance for the prevention and management of thrombosis in children and young people treated for acute lymphoblastic leukemia. To determine current UK practice, a survey was sent to 28 centers participating in the Medical Research Council UKALL 2011 trial. Marked variation in practice was noted. In total, 43% of centers defer central venous access device insertion until end of induction for treatment of low-risk disease. Central venous access devices are removed at the end of intensive blocks in 38% and end of treatment in 42%. Duration of anticoagulation for line-associated thrombosis is 6 weeks in 43% and 3 months in 33% and for cerebral sinovenous thrombosis is 3 months in 71% and 6 months in 24%. Platelet transfusion to maintain platelet count >50×10/L, in preference to interrupting therapeutic anticoagulation, is used by 50% for line-associated thrombosis and 73% for cerebral sinovenous thrombosis. Conformity of practice was seen in some areas. In total, 70% treat thrombosis with twice-daily low-molecular weight heparin and 86% monitor antifactor Xa activity levels. In total, 91% reexpose individuals to asparaginase following a thrombotic event. Given this variation in practice, in the absence of high-quality evidence, consensus guidelines may be helpful.

Monitoring the harm associated with use of anticoagulants in pediatric populations through trigger-based automated adverse-event detection

BACKGROUND

The safety profile of anticoagulants, which are being used with increasing frequency in pediatric populations, is not well studied. Automatic triggers built into electronic health record systems (EHR) have been shown to be an effective way to monitor for and identify medication errors. Anticoagulant-associated adverse events were examined through the use of an anticoagulant trigger panel.

METHODS

In a retrospective, five-year (September 2007-September 2012) observational study, four automated triggers were used to detect anticoagulant-related adverse events: activated partial thromboplastin time (aPTT) > 100 seconds in patients on an unfractionated heparin (UFH) infusion, International Normalized Ratio (INR) > 4, anti-factor Xa (anti-FXa) >1.5U/mL for patients on enoxaparin, and the documented use of protamine.

RESULTS

For the 1,664 triggers evaluated, 12 were associated with the aPTT trigger, only 1 of which was preventable. Receiver operator characteristic curve analysis indicated that increasing the aPTT trigger > 140 seconds would optimize sensitivity and specificity. The INR trigger identified four outpatients with adverse events. No adverse events were associated with the anti-FXa trigger. The protamine trigger identified 12 adverse events and was associated with more severe events. Minimal overlap was found with protamine and aPTT triggers.

CONCLUSION

Laboratory- and medication-based triggers can be effective monitoring tools for anticoagulants. For patients receiving a UFH infusion, an aPTT cutoff value of > 140 seconds is more precise. We also found that protamine use as a trigger adds value to a trigger-based anticoagulant monitoring system. Continued improvement in the logic algorithms associated with the EHR-based trigger tool will allow expanded use of this tool in a clinical manner.

Characterizing the Risk Factors Associated With Venous Thromboembolism in Pediatric Patients After Central Venous Line Placement

OBJECTIVES

With the apparent increase in venous thromboembolism noted in the pediatric population, it is important to define which children are at risk for clots and to determine optimal preventative therapy. The purpose of this study was to determine the risk factors for venous thromboembolism in pediatric patients with central venous line placement.

METHODS

This was an observational, retrospective, case-control study. Control subjects were patients aged 0 to 18 years who had a central venous line placed. Case subjects had a central line and a radiographically confirmed diagnosis of venous thromboembolism.

RESULTS

A total of 150 patients were included in the study. Presence of multiple comorbidities, particularly the presence of a congenital heart defect (34.7% case vs. 14.7% control; p < 0.005), was found to put pediatric patients at increased risk for thrombosis. Additionally, the administration of parenteral nutrition through the central line (34.7% case vs. 18.7% control; p = 0.03) and location of the line increased the risk for clot formation.

CONCLUSIONS

With increased awareness of central venous line-related thromboembolism, measures should be taken to reduce the number and duration of central line placements, and further studies addressing the need for thromboprophylaxis should be conducted.

Pharmacogenetics of warfarin in a paediatric population: time in therapeutic range, initial and stable dosing and adverse effects

Warfarin is used in paediatric populations, but dosing algorithms incorporating pharmacogenetic data have not been developed for children. Previous studies have produced estimates of the effect of polymorphisms in Cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) on stable warfarin dosing, but data on time in therapeutic range, initial dosing and adverse effects are limited. Participants (n=97) were recruited, and routine clinical data and salivary DNA samples were collected from all participants and analysed for CYP2C9*2, *3 and VKORC1-1639 polymorphisms.VKORC1 -1639 was associated with a greater proportion of the first 6 months' treatment time spent within the target International Normalised Ratio (INR) range, accounting for an additional 9.5% of the variance in the proportion of time. CYP2C9*2 was associated with a greater likelihood of INR values exceeding the target range during the initiation of treatment (odds ratio (OR; per additional copy) 4.18, 95% confidence interval (CI) 1.42, 12.34). CYP2C9*2 and VKORC1-1639 were associated with a lower dose requirement, and accounted for almost 12% of the variance in stable dose. VKORC1-1639 was associated with an increased likelihood of mild bleeding complications (OR (heterozygotes vs homozygotes) 4.53, 95% CI 1.59, 12.93). These data show novel associations between VKORC1-1639 and CYP2C9*2 and INR values in children taking warfarin, as well as replicating previous findings with regard to stable dose requirements. The development of pharmacogenomic dosing algorithms for children using warfarin has the potential to improve clinical care in this population.

Acute brachial artery thrombosis in a neonate caused by a peripheral venous catheter

This case describes the diagnostic testing and management of an acute thrombosis of the brachial artery in a female neonate. On day seven of life, clinical signs of acutely decreased peripheral perfusion indicated an occlusion of the brachial artery, which was confirmed by high-resolution Doppler ultrasound. Imaging also showed early stages of collateralization so that surgical treatment options could be avoided. Unfractionated heparin was used initially and then replaced by low-molecular-weight heparin while coagulation parameters were monitored closely. Within several days, brachial artery perfusion was completely restored. Acetylsalicylic acid was given for additional six weeks to minimize the risk of recurring thrombosis. If inadequately fixated in a high-risk location, a peripheral venous catheter can damage adjacent structures and thus ultimately cause arterial complications.

Intracardiac thrombus in children: the fine equilibrium between the risk and the benefit

The medical records of 16 patients diagnosed as intracardiac thrombus were searched. The size, location and outcome of thrombus together with demographic data of patients were assessed. The median age of the patients was 2.2 years. Six patients were newborn and two patients were infant. The median size of thrombus was 9 mm. The localization was right atrium in seven, right ventricle in five, left ventricle in one, pulmonary artery in one, and superior vena cava in two patients. There was prematurity in five, ciyanotic congenital heart disease in one, blood culture positivity in three, malignancy in four, nephrotic syndrome in one, indwelling catheters in 10, and acquired or genetic thrombophilia in six patients as risk factors. In the treatment, the first choice was tissue plasminogen activator in two patients, heparin infusion in one patient and low molecular weight heparin in remaining 12 patients. In nine patients, therapy included parenteral antimicrobials together with anticoagulants. The result was complete resolution in 15 patients and in one patient thrombus was surgically removed. The median time was 16 (2-70) days for 50% resolution and 26 (3-93) days for complete resolution. There was a statistically significant (P = .027 and r = 0.5) correlation between the size and the complete resolution time. There was no anticoagulant therapy related major complication. In patients with intracardiac thrombus, selection of anticoagulant therapy may decrease the risk of complications. Surgery is rarely required and thrombolytics are not usually necessary for resolution of thrombus.

Describing the profile of patients on concurrent rifampin and warfarin therapy in western Kenya: a case series

Background

Rifampicin’s ability to induce hepatic enzymes is responsible for causing a clinically significant drug interaction with warfarin. Little data exists to guide clinicians on managing this interaction, especially in Sub-Saharan Africa where many patients are exposed to this combination due to a higher burden of tuberculosis.

Objective

The objective of the case series is to provide insight to practicing clinicians of the unique dynamics of this drug interaction in resource-constrained settings. The case series will provide details on commonly encountered scenarios and the dosage adjustments required to maintain a therapeutic INR.

Methods

A retrospective chart review was conducted of patients attending the Moi Teaching and Referral Hospital anticoagulation clinic in Eldoret, Kenya. Patients were included if they had a history of concurrent rifampicin and warfarin therapy and a minimum follow up of 2 months. Descriptive statistics were used to explain the demographic characteristics, time to therapeutic INR and average weekly warfarin dose. The inference on proportions test was conducted to compare the time in the therapeutic range (TTR) for patients on concurrent rifampicin to the rest of the patients not receiving rifampicin in the clinic.

Results

Of the 350 patient charts evaluated, 10 met the inclusion criteria. The median percentage increase of the weekly warfarin dose from baseline was 15.7 %. For the patients in this analysis, the median TTR was 47 %.

Discussion

Patients on concurrent therapy should be rigorously monitored with regular INR checks and warfarin dosage adjustments. Empiric dosage adjustments of warfarin should be avoided but patient characteristics can aid in understanding the alterations seen in INR.

EPNS/SFNP guideline on the anticoagulant treatment of cerebral sinovenous thrombosis in children and neonates

Anticoagulation of cerebral sinovenous thrombosis (CSVT) is recommended in adults and has been also approved in the paediatric setting. Some controversies remain however between the existing paediatric professional consensus, notably about its use in children with intra-cranial haemorrhage and in neonates. The publication of further original studies prompted the French Society for Paediatric Neurology (SFNP) in association with a panel of EPNS experts, to update the level of evidence and the knowledge in this domain. A bibliographic analysis revealed that anticoagulants are widely used in paediatrics. Anticoagulation is well tolerated by children (Class I, level of evidence B) and also probably by neonates (Class IIa, level of evidence B). During the acute phase, anticoagulation is probably effective in reducing the risk of death and sequelae in children (Class IIa, level of evidence B). It is not yet possible to draw any conclusions regarding neonates (Class IIb). Anticoagulation is also effective in reducing the risk of recurrence (Class I, level of evidence B). This risk is dependent on several individual factors such as the age of the child, the cause of the thrombosis, the persistence or the recurrence of thrombogenic factors, and the speed of sinus recanalisation. The duration of anticoagulation needs therefore to be individually tailored (Class I, level of evidence B). These observations have led to the following recommendations: -In the absence of any contraindication, it is reasonable to initiate anticoagulation during the acute phase of CSVT in children. Prolonged treatment over 3-6 months is justified according to individual factors. -In the absence of any contraindication, anticoagulation may be considered individually during the acute phase of CSVT in neonates for a duration of 6-12 weeks.

Development of biomarkers to optimize pediatric patient management: what makes children different?

Despite the frequent utilization of biomarkers in medical practice, there is a relative paucity of information regarding validated pediatric biomarkers. Frequently, biomarkers found to be efficacious in adults are extrapolated to the pediatric clinical setting without considering that the pathogenesis of many diseases is distinctly different in children, and ontogeny directly influences disease evolution and therapeutic response in children. New and innovative approaches are necessary to provide reliable, validated biomarkers that can be used to improve and advance pediatric medical care.

Treating venous thromboembolic events in the pediatric population

In the pediatric population, the risk of venous thromboembolism (VTE) is lower and less defined than in adults, making the diagnosis easy to overlook. Signs and symptoms in children are usually vague, so nurse practitioners need to be aware of what to look for and how to manage VTE in children.

New frontiers with bemiparin: use in special populations

Special populations are rarely included in conventional clinical trials and subsequently there is a lack of guidance on the appropriate treatment regimens to use. This paper reviews data on the use of bemiparin in such populations, including the elderly, those with renal impairment, pregnant women and children. Pharmacokinetic data from elderly patients suggest that bemiparin is also safe in this patient population. There was no evidence of the accumulation of bemiparin after repeated prophylactic doses. At therapeutic doses, there was no significant difference in pharmacokinetic profile between groups. There is no need for dose adjustment of bemiparin in the elderly, either during prophylaxis or during treatment. Data from another pharmacokinetic study showed that bemiparin at prophylactic doses is safe in patients with mild to moderate renal impairment. In general, no dose adjustment was required in patients with mild to moderate renal impairment when bemiparin is used as therapy or prophylaxis. To date, bemiparin has not been tested in patients with severe renal impairment; therefore, conclusions on the safety of bemiparin in patients with severe renal failure cannot be drawn at present. Although there are no published data on the use of bemiparin in pregnant women, promising anecdotal data are beginning to emerge. Current guidelines recommend low molecular weight heparins (LMWH) for the treatment of venous thromboembolism (VTE) in pregnant women, with treatment maintained at therapeutic doses throughout pregnancy. Anticoagulation should continue for 6 weeks or more post-partum and should be maintained for 3 months or more after diagnosis of the VTE event. Monitoring of pregnant women receiving LMWH is not necessary, except in those at high risk. A case report describing the treatment of a neonate with renal vein thrombosis showed that 2 months' treatment with bemiparin followed by 10 months' prophylaxis was effective and safe. These data suggest that bemiparin may play a role in the treatment of VTE in paediatric patients.