Severe aortic thrombosis in the neonate--successful treatment with low-molecular-weight heparin: two case reports and review of the literature

Abdominal aortic thrombus formation in a neonate with an interrupted aortic arch

We note the risk of paradoxical embolism in patients with congenital heart defects with a right-to-left shunt. These patients should be managed to ensure that abdominal aortic thrombi are not overlooked when their clinical conditions change.

Spontaneous aortic thrombosis in neonates: a case report and review of literature

Neonatal aortic thrombosis is a rare occurrence but can be life-threatening. Most aortic thrombosis in neonates is related to umbilical artery catheters. A case of a neonate with a spontaneous aortic thrombosis is described here along with a comprehensive review of the literature for cases of neonatal aortic thrombosis not related to any intravascular device or procedure. The aetiologies of these spontaneous thromboses and the relevance of hypercoagulable disorders are discussed. The cases were analysed for odds of death by treatment method adjusted for era. The reference treatment method was thrombolysis and anticoagulation. No other treatment modality had significantly lower odds than the reference. Surgery alone had higher odds for death than the reference, but this may be confounded by severity of case. The management recommendations for clinicians encountering neonates with spontaneous neonatal aortic thrombosis are discussed.

Multimodality and multiterritory vascular imaging in a toddler with acquired, complex, and unusual aortic arch anatomy

A 20-month-old otherwise well child with no cardiac history presented for evaluation of a recent onset cardiac murmur. His initial examination revealed significant right carotid bruit along with a transthoracic echocardiogram (ECHO) concerning for severe transverse arch hypoplasia with unusual appearance and left ventricular hypertrophy with preserved function. This report demonstrates the utility of various modalities including echo, CT, and MRI to assess vascular structures in different vascular territories in a challenging patient who underwent a satisfactory arch repair with unexpected pathology findings.

In Utero Aortic Arch Thrombosis Masquerading as Interrupted Aortic Arch: A Case Report and Review of the Literature

Aortic arch thrombosis is an extremely rare but life-threatening diagnosis that is often misdiagnosed in the neonatal period. Strategies including surgical intervention, systemic anticoagulation, and thrombolysis have been previously described in the treatment of these neonates. We describe the case of a neonate who presented with concern for interrupted aortic arch and was diagnosed with an in utero aortic arch thrombosis. To our knowledge, this is the first reported case with evidence of aortic arch thrombosis in fetal life. The patient underwent successful treatment with systemic thrombolysis with tissue plasminogen activator. A brief review of the literature regarding the diagnosis, treatment, and management of neonatal aortic arch thrombosis is also presented.

Transient Hemi-Lower Limb Ischemia in the Newborn: Arterial Thrombosis or Persistent Sciatic Artery?

Neonatal thromboembolism occurs with various predispositions and triggers. Early diagnosis of the thrombosis is challenging and essential for the therapeutic interventions. We herein report two newborns who presented with transient hemi-lower limb ischemia due to (1) arterial thrombosis or (2) a persistent sciatic artery (PSA). The patient with arterial thrombosis showed elevations of fibrin degradation product and D-dimer and received antithrombin and heparin intravenously. The patient with PSA was immediately assessed by a contrast-enhanced computed tomography because of a transient ischemic episode with no evidence of hypercoagulability. Newborns suspected of having arterial thrombosis may need urgent surgical intervention along with thrombolytic and anticoagulant therapy to prevent organ ischemia and amputation of extremities. Conversely, some PSA cases have reportedly been treated conservatively. This vascular anomaly was previously reported as a cause of lower limb ischemia only in a newborn. PSA is a critical differential diagnosis of neonatal arterial thrombosis that needs urgent therapeutic intervention.

Abdominal Aortic Thrombosis in a Healthy Neonate

Abdominal aortic thrombosis is a rare entity in neonates and has mostly been associated with umbilical artery or cardiac catheterization. We present a complicated case of an otherwise healthy neonate who developed thrombosis of abdominal aorta with renal failure. Therapy with intravenous heparin was unsuccessful, and thrombolysis was contraindicated because of disseminated intravascular coagulation so we decided to perform open thrombectomy using the left retroperitoneal approach. The following day, thrombosis recurred in the same extent and despite high risk of bleeding Alteplase was eventually given, which resulted in recanalization of the aorta 6 hours later. Renal function recovered, dialysis was discontinued, and further course was uneventful. The treatment of abdominal aortic thrombosis in neonates should be considered on a case-by-case basis because the available data on the condition are limited to case report and series. If open thrombectomy is performed, retroperitoneal approach should be preferred because it allows for easy institution of peritoneal dialysis should the need arise.

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.

Neonatal aortic arch thrombosis: analysis of thrombophilic risk factors and prognosis

Arterial thrombosis in neonates and children is a rare event and is often associated with external risk factors such as asphyxia or sepsis. We report our experiences with two neonates with spontaneous aortic arch thrombosis mimicking aortic coarctation. Despite single case reports until now, no data exist for the underlying thrombophilic risk factors and prognosis of this rare event. Both patients were carriers of a heterozygous factor V Leiden mutation, which has been reported once before as a risk factor for aortic arch thrombosis. One of our patients was operated upon successfully and is alive. The second patient suffered a large infarction of the right medial cerebral artery and had a thrombotic occlusion of the inferior caval vein. The patient obtained palliative care and died at the age of 6 days. In the literature, we identified 19 patients with neonatal aortic arch thrombosis. Of the 19 patients, 11 (58%) died. Including the two reported patients, the mortality rate of patients with multiple thromboses was 80% (8/10) compared with 18% (2/11) for patients with isolated aortic arch thrombosis; this difference reached statistical significance (p = 0.009). The analysis of thrombophilic disorders revealed that factor V Leiden mutation and protein C deficiency seem to be the most common risk factors for aortic arch thrombosis.

CONCLUSION

Neonatal aortic arch thrombosis is a very rare but life-threatening event, with a high rate of mortality, especially if additional thrombotic complications are present. Factor V Leiden mutation seems to be one important risk factor in the pathogenesis of this fatal disease.

Neonatal ascending aortic thrombus: successful medical treatment

Neonatal aortic thrombosis is a potentially life-threatening condition with significant morbidity and mortality if undiagnosed and untreated. The most common location of arterial thrombosis in neonates is in the abdominal aorta and is associated with umbilical artery catheterisation. There are only a few previous reports of thrombosis in the ascending aorta. We describe a case of ascending aortic thrombosis in a neonate who underwent successful thrombolytic therapy.

Aortic arch thrombosis in the neonate

Aortic arch thrombosis (AAT) of the neonate is rare but life-threatening by fatal compromise associated with thrombotic obstruction of the ascending aorta. We report a neonate with AAT who demonstrated a severe coarctation of the aorta and cerebral hypo-perfusion immediately after birth. Echocardiography confirmed the diagnosis of AAT on the findings of a large thrombus located on the transverse arch and blocking the cervical arterial branches. Low-molecular-weight heparin reduced the size of the thrombus and improved the hemodynamics of coarctation and cerebral perfusion. Echocardiography is a powerful tool to make a diagnosis and to monitor the size and regression of AAT.

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.

Management of neonatal aortic arch thrombosis with low-molecular weight heparin: a case series

Aortic arch thrombosis (AAT) is a potentially life threatening condition in neonates. We report 3 neonates with AAT and complete occlusion of a unilateral internal carotid artery with multiple cerebral infarcts. Multidisciplinary input led to deferral of thrombolytic therapy and surgical thrombectomy owing to the potential risk of hemorrhage within the infarcts. All the neonates were treated with low-molecular weight heparin treatment alone without any complications. Thrombus resolution was complete in 2 neonates, whereas it was near complete in one neonate. All the infants showed normal growth and development during follow-up. The rewarding outcome in these cases suggests that treatment with low-molecular weight heparin could be considered an option to treat AAT in selected patients.

Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about antithrombotic therapy in neonates and children is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see Guyatt et al in this supplement, pages 123S-131S). In this chapter, many recommendations are based on extrapolation of adult data, and the reader is referred to the appropriate chapters relating to guidelines for adult populations. Within this chapter, the majority of recommendations are separate for neonates and children, reflecting the significant differences in epidemiology of thrombosis and safety and efficacy of therapy in these two populations. Among the key recommendations in this chapter are the following: In children with first episode of venous thromboembolism (VTE), we recommend anticoagulant therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1B]. Dosing of IV UFH should prolong the activated partial thromboplastin time (aPTT) to a range that corresponds to an anti-factor Xa assay (anti-FXa) level of 0.35 to 0.7 U/mL, whereas LMWH should achieve an anti-FXa level of 0.5 to 1.0 U/mL 4 h after an injection for twice-daily dosing. In neonates with first VTE, we suggest either anticoagulation or supportive care with radiologic monitoring and subsequent anticoagulation if extension of the thrombosis occurs during supportive care (Grade 2C). We recommend against the use of routine systemic thromboprophylaxis for children with central venous lines (Grade 1B). For children with cerebral sinovenous thrombosis (CSVT) without significant intracranial hemorrhage (ICH), we recommend anticoagulation initially with UFH, or LMWH and subsequently with LMWH or vitamin K antagonists (VKAs) for a minimum of 3 months (Grade 1B). For children with non-sickle-cell disease-related acute arterial ischemic stroke (AIS), we recommend UFH or LMWH or aspirin (1 to 5 mg/kg/d) as initial therapy until dissection and embolic causes have been excluded (Grade 1B). For neonates with a first AIS, in the absence of a documented ongoing cardioembolic source, we recommend against anticoagulation or aspirin therapy (Grade 1B).

Genetic prothrombotic mutations are common in neonates but are not associated with umbilical catheter-associated thrombosis

OBJECTIVE

To evaluate the prevalence of hereditary prothrombotic mutations, and their effect on the incidence and severity of umbilical arterial or venous catheter (UAC or UVC)-associated thrombosis.

STUDY DESIGN

All neonates with a UAC or UVC were studied prospectively for the presence, severity and timing of thrombosis with duplex Doppler ultrasound scan. Genetic testing for factor V Leiden (FVL), prothrombin mutation (PTm) and methylene-tetrahydrofolate reductase (MTHFR) mutations was performed using PCR and restriction fragment length polymorphism assays.

RESULT

Umbilical catheter (UC)-associated thrombosis developed in 16/53 (31%) neonates; 23% of UACs and 22% of UVCs were associated with thrombosis. The prevalence of a significant prothrombotic mutation was present in 10/51 (20%) of infants: FVL (8%), MTHFR667 homozygosity (10%), MTHFR1298 homozygosity (2%) and PTm (0%). There was no increase in the risk of UC-associated thrombus in patients carrying these prothrombotic mutations; our study had the power to detect a 2.5-fold increased risk of thrombosis for any of these significant mutations. In addition, MTHFR667 heterozygosity was found in 41% of infants and MTHFR1298 heterozygosity in 52% and also were not associated with increased risk of UC-associated thrombus. The risk of MTHFR double heterozygosity (db het) was 14%, the risk of a significant or db het was 17/51 (33%) and the risk of any mutation was 90%.

CONCLUSION

Prothrombotic genetic mutations are common in our Neonatal Intensive Care Unit population but do not appear to increase the risk of UC-associated thrombosis.

Neonatal arterial thrombus mimicking congenital heart disease

Spontaneous neonatal arterial thrombosis is rare in the neonatal period. Four cases of neonatal arterial thrombosis presenting with suspected congenital heart disease are reported. The urgency for a correct diagnosis in this setting and the need for active treatment for a remediable condition are emphasised. These treatment options are discussed.

Idiopathic neonatal aortic thrombosis

We report a term neonate with severe aortic thrombosis involving the aorto-iliac segment and leading to renal failure. This patient did not have any predisposing risk factors. The authors have also reviewed the literature on neonatal aortic thrombosis and discuss the need for evolving evidence based consensus guidelines for management of this catastrophe.

Catheterization of the radial or brachial artery in neonates and infants

BACKGROUND

In neonates and small children, percutaneous insertion of arterial catheters may be very difficult because of the small diameter of the arteries. Multiple attempts at cannulation are common and may be a predictor of serious adverse events following arterial cannulation. As an end artery, the brachial artery is usually not recommended for cannulation. However, limited data exist about brachial artery catheterization in neonates and young children. In this retrospective study, we report our experience with arterial indwelling catheters placed in neonates and small children prior to surgery for congenital heart defects.

METHODS

We reviewed 1473 patient medical files containing information about 1574 arterial lines for perioperative and intensive care monitoring. Patient data (age and weight), cannulation characteristics (site, type, percutaneous or cut down insertion), duration of catheterization and complications were documented using the anesthesia and/or intensive care unit files. Patients were divided into three groups according to body weight. Group I: patients with a bodyweight up to 5 kg (n = 561), group II: bodyweight 5-10 kg (n = 615), and group III: bodyweight 10-20 kg (n = 297).

RESULTS

The vast majority of our patients had radial or brachial artery catheterization. In group 1, we placed 200 brachial artery lines. Radial artery insertion was more successful with increasing body weight. Two 'cut downs' were necessary to place the arterial cannula (0.3%). The mean duration of the arterial cannula in place was 5.8 + 4.3 days in group I, which was significantly longer than in group III (2.9 + 2.2 days). Multiple attempts at catheter insertion were required for 200 patients in group I (P < 0.05 compared with groups II and III). The number of guide wires used was similar in all study groups. Generally, we preferred 24 and 22 G catheters for cannulation. Serious complications such as permanent ischemic damage were not observed. Temporary occlusion of an artery occurred in five of 1473 patients. The rate of local infection was 0.5% in group I, 0.7% in group II and 2.3% in group III. Local hematoma were observed more frequently, but with no relevant consequences. Most of our patients were cannulated on the right side. In group I, 112 brachial artery catheters were placed. The greater the weight, the more radial catheters were used compared with a brachial approach. The mean functional time of the catheters (5.8 +/- 4.3 days in group I) was significant shorter compared with patients from group III (2.9 +/- 2.2 days). In 33.3% (n = 200) multiple punctures were needed to place a catheter in group I (P < 0.05 compared with the other groups) whereas the use of a guide wire was evenly distributed throughout the study groups. Small catheters (24 and 22 G) were preferred for most patients. In total only eight 20 G sized catheters were used in the children of group III.

CONCLUSIONS

Even considering the nature of a retrospective study design, we conclude that the brachial artery could be considered for cannulation in neonates and small children.

Thrombosis of the abdominal aorta in a newborn: case report and review of literature

The case of a newborn infant who presented thrombosis in the abdominal portion of the aorta, which resulted in the complete occlusion is reported. Diagnosis was made using Doppler echocardiography. The initial therapeutic approach was clinical support, but as the thrombi started to increase in size (secondary thrombosis) and evolved to the infrarenal terminal aorta, anticoagulation with heparin was indicated. The total disappearance of both the secondary thrombosis and the embolus was evidenced by a subsequent echocardiography after the anticoagulation therapy.

Low molecular weight heparin for neonatal thrombosis

The clinical course of a term neonate (birthweight 3.14 kg) who developed thrombosis of the left common and internal iliac veins on day 21 following recovery from Streptococcus mitis septicemia, with shock diagnosed on day 13, is reported. Subcutaneous low molecular weight heparin (LMWH) was commenced (1.5 mg/kg 12 hourly for 10 days) after 13 h of standard heparin infusion, due to difficulties in securing a peripheral venous access. The inflammation of the left leg was completely resolved by day 5 of LMWH therapy. Prothrombin time, activated prothrombin time and fibrinogen levels were within normal limits during LMWH therapy. Treatment-related side effects, such as thrombocytopenia and bleeding tendency were not noted. Doppler studies 6 weeks after discharge home on day 33 revealed complete resolution of the thrombus. Apart from septicaemia and shock, the presence of an indwelling central venous catheter and a history of untreated maternal diabetes were additional risk factors for thrombosis. Because it is as effective as standard heparin, LMWH may be a therapeutic option for thrombosis in high-risk neonates, particularly given its ease of administration by the subcutaneous route, predictable pharmacokinetics and reduced incidence of adverse effects such as bleeding complications.