Superior vena cava thrombectomy with the X-SIZER® catheter system in a child with Fontan palliation

Thrombolytics for late superior caval vein thrombus in a patient with tricuspid atresia and single-lung Glenn anastomosis

BACKGROUND

Those with cyanotic heart disease have an elevated bleeding risk but also are hypercoaguable. Treating haemodynamically significant thrombi in this unique cohort poses a monumental challenge. Case A 29-year-old women with tricuspid atresia and left pulmonary artery atresia presented with superior caval vein syndrome. She had a right modified Blalock-Taussig shunt as a neonate. A left modified Blalock-Taussig shunt performed later failed to establish flow to her left lung. At age 5, she had a Fontan procedure to the right lung but could not tolerate the physiology and had a low cardiac output syndrome. The Fontan was taken down and she was left with a Glenn anastamosis to the right pulmonary artery. She did well for years until she had dyspnea, upper extremity oedema and "facial fullness". On examination she was tachycardic, hypotensive, and more desaturated than baseline. She also had facial plethora. Decision-making Echocardiogram showed a large 9 × 3 mm nearly occlusive thrombus in the superior caval vein at the bifurcation of the left and right innominate veins. An emergent venogram confirmed the location and size of the thrombus. Given the thrombus burden and potential for distal embolisation through the Glenn to the single functional lung, we chose to treat the patient with thrombolytics. She had uncomplicated ICU course and was sent home on warfarin. Follow-up echocardiogram showed complete resolution of clot.

CONCLUSION

This case shows the importance of history and physical exam in caring for this complex cohort of adult patients with CHD.

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.

Late catheter interventions in hypoplastic left heart syndrome

Interventional cardiology plays a key role in the diagnosis and management of patients with functionally univentricular physiology after the various stages of surgical palliation. The interventions performed are widely variable in type, including angioplasty of stenotic vessels and implantation of stents in stenotic vessels; closure of defects such as collaterals, leaks in baffles, and fenestrations; creation of fenestration; and more. In the setting of venous hypertension associated with stenosis at the Fontan baffle, conduit, or pulmonary arteries, stent implantation is often preferred, as the aim is to eliminate completely the narrowing, given that relatively mild stenosis can have a significant detrimental hemodynamic effect in patients with functionally univentricular circulation. The procedure is highly successful. In patients who fail after Fontan procedure, creation of a fenestration is often performed, with variable technique depending on the underlying anatomic substrate. To increase chances of patency of the fenestration, implantation of a stent is often required, particularly in the setting of an extracardiac conduit. For those patients with cyanosis and favorable Fontan hemodynamics, closure of the fenestration is performed using atrial septal occluder devices with high success rate. Coils compatible with magnetic resonance imaging are used widely to treat collateral vessels, although on occasion other specific embolization tools are required, such as particles or vascular plugs. Postoperative arch obstruction is successfully managed with angioplasty at a younger age, while implantation of a stent in the aorta is reserved for older patients. Specifics of these interventional procedures as applied to the population of patients with functionally univentricular hearts are described in this manuscript.