Thrombolysis of venous and arterial thrombosis by catheter-directed low-dose infusion of tissue plasminogen activator in children

Role of tenecteplase (rtPA) to re-establish flow in intraprocedural stent thrombosis in infants undergoing ductal stenting for duct-dependent pulmonary circulation-a case series

Ductal stenting in patients with duct-dependent pulmonary circulation has allowed growth of pulmonary arteries prior to definitive surgical procedures. Intraprocedural stent thrombosis (IPST) of the arterial duct is a life-threatening complication as it leads to total circulatory collapse. Previous reports have described use of tissue plasminogen activators in infants for less emergent settings. We report three infants with IPST and the use of tenecteplase to overcome this. Also discussed are the predisposing mechanisms in each scenario and a possibility of direct catheter-guided tenecteplase administration. Judicious use of tenecteplase can be life-saving and rapid access to this drug may obviate the need for emergency extracorporeal life support.

Extremity Arterial Thromboses in Hospitalized Children: A National Database Analysis of Prevalence and Therapeutic Interventions

OBJECTIVES

The purpose of this study was to evaluate the prevalence, demographics, predisposing conditions, therapeutic interventions, and outcomes of extremity arterial thrombosis in hospitalized children.

DESIGN

Retrospective cohort study.

PATIENTS

National discharge database analysis.

MEASUREMENTS AND MAIN RESULTS

Cases of extremity arterial thrombosis in children and neonates were extracted from the Kids' Inpatient Database 2012. These were analyzed and compared with other discharges for prevalence, demographics, treatments, outcomes, and further analyzed by age group and select predisposing conditions. A total of 961 children with extremity arterial thrombosis (prevalence of 2.35/10,000 discharges) were included in our analysis. The median age of extremity arterial thrombosis patients was significantly lower when compared with other pediatric discharges (1 yr [interquartile range, 0-15 yr) vs 3 yr [interquartile range, 0-16 yr]; p < 0.0001). The proportion of females with extremity arterial thrombosis was lower (41.4% vs 53.3%; odds ratio, 0.62; 95% CI, 0.55-0.70) with no racial/ethnic variation in the prevalence of extremity arterial thrombosis. An upper extremity was involved in 18.1% and a lower extremity in 83.3%. Arterial cannulation and cardiac catheterization were much more common in the younger age groups. External trauma was documented in 13.2% of all patients with extremity arterial thrombosis and was more frequent in older age groups. A systemic thrombolytic medication was administered to 5.7% of the patients, thromboembolectomy was performed in 11.8% of the cases, and 3.1% of the patients required amputation. There was a significant variation in the use of thrombolysis, thrombectomy/embolectomy, or requirement for amputation limb based on age groups and underlying predisposing condition.

CONCLUSIONS

The study describes the national prevalence of extremity arterial thrombosis in hospitalized children. The management strategies of extremity arterial thrombosis vary with age and underlying predisposing factors.

Acute Limb Ischemia in an 8-Year-Old Patient: A Case Report

We report the case of an 8-year-old patient with a history of nephrotic syndrome, who presented to the emergency department with right foot pain. The patient's mother described intermittent pain that woke her son from sleep and was accompanied by the foot turning purple and becoming cold to touch. Physical examination revealed capillary refill of over 10 seconds in the right and less than 2 seconds in the left foot. Ankle-brachial indices (ABIs) were 0.0 on the right and 0.96 on the left. The patient was admitted and started on therapeutic intravenous heparin. After consultation with his parents, right lower extremity angiography and thrombolysis was performed over 2 days. He subsequently underwent fasciotomy and amputation of the tip of all 5 toes. Eighteen months later, there is no leg length discrepancy, he is walking with foot inserts and has normal ABIs bilaterally.

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

BACKGROUND

Neonates and children differ from adults in physiology, pharmacologic responses to drugs, epidemiology, and long-term consequences of thrombosis. This guideline addresses optimal strategies for the management of thrombosis in neonates and children.

METHODS

The methods of this guideline follow those described in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.

RESULTS

We suggest that where possible, pediatric hematologists with experience in thromboembolism manage pediatric patients with thromboembolism (Grade 2C). When this is not possible, we suggest a combination of a neonatologist/pediatrician and adult hematologist supported by consultation with an experienced pediatric hematologist (Grade 2C). We suggest that therapeutic unfractionated heparin in children is titrated to achieve a target anti-Xa range of 0.35 to 0.7 units/mL or an activated partial thromboplastin time range that correlates to this anti-Xa range or to a protamine titration range of 0.2 to 0.4 units/mL (Grade 2C). For neonates and children receiving either daily or bid therapeutic low-molecular-weight heparin, we suggest that the drug be monitored to a target range of 0.5 to 1.0 units/mL in a sample taken 4 to 6 h after subcutaneous injection or, alternatively, 0.5 to 0.8 units/mL in a sample taken 2 to 6 h after subcutaneous injection (Grade 2C).

CONCLUSIONS

The evidence supporting most recommendations for antithrombotic therapy in neonates and children remains weak. Studies addressing appropriate drug target ranges and monitoring requirements are urgently required in addition to site- and clinical situation-specific thrombosis management strategies.

[Thrombolytic therapy using a low dose of tissue plasminogen activator in children]

OBJECTIVE

To analyse the efficacy and side effects of low doses of tissue plasminogen activator for the treatment of acute arterial and/or venous thrombosis in children.

PATIENTS AND METHODS

Prospective observational clinical study. 18 children between 1 months and 11 years treated with low doses (0.01-0.06 mg/kg/h) of continuous intravenous thrombolytic therapy with t-PA were studied.

RESULTS

A total of 94% of patients improved with low doses t-PA (72% complete resolution of the thrombosis and 22% partial resolution). One patient suffered a severe haemorrhage secondary to t-Pa and had to stop the treatment. The incidence of severe side effects was low (5%)

CONCLUSIONS

Thrombolytic therapy with low doses of t-PA (0.01-0.05 mg/kg/h) is effective in a high percentage of children with acute arterial and/or venous thrombosis and produces a relatively low frequency of side effects.

Postoperative pulmonary embolism in a three year old with Klippel-Trenaunay syndrome

Massive pulmonary embolism (PE) in a small child is a rare event and unified guidelines for its treatment are missing. Timely diagnosis and management of massive pulmonary embolism is of crucial importance for a good outcome. We describe a unique management of PE causing oxygenation failure using a combination of catheter extraction technique, and regional thrombolysis on top of systemic heparin administration and inferior vena cava filter placement. Pulmonary hypertension was treated with inhaled nitric oxide. We believe that catheter extraction technique and regional thrombolysis is an option to consider provided that resources and expertise are available. Preoperative placement of an inferior vena cava filter should be contemplated in such high risk situations.

A thrombolytic regimen for high-risk deep venous thrombosis may substantially reduce the risk of postthrombotic syndrome in children

Important predictors of adverse outcomes of thrombosis in children, including postthrombotic syndrome (PTS), have recently been identified. Given this knowledge and the encouraging preliminary pediatric experience with systemic thrombolysis, we sought to retrospectively analyze our institutional experience with a thrombolytic regimen versus standard anticoagulation for acute, occlusive deep venous thrombosis (DVT) of the proximal lower extremities in children in whom plasma factor VIII activity and/or D-dimer concentration were elevated at diagnosis, from within a longitudinal pediatric cohort. Nine children who underwent the thrombolytic regimen and 13 who received standard anticoagulation alone were followed from time of diagnosis with serial clinical evaluation and standardized PTS outcome assessments conducted in uniform fashion. The thrombolytic regimen was associated with a markedly decreased odds of PTS at 18 to 24 months compared with standard anticoagulation alone, which persisted after adjustment for significant covariates of age and lag time to therapy (odds ratio [OR] = 0.018, 95% confidence interval [CI] = < 0.001-0.483; P = .02). Major bleeding developed in 1 child, clinically judged as not directly related to thrombolysis for DVT. These findings suggest that the use of a thrombolysis regimen may safely and substantially reduce the risk of PTS in children with occlusive lower-extremity acute DVT, providing the basis for a future clinical trial.