Management of Pediatric Patients with HLHS and SVAD
For pediatric patients with Hypoplastic Left Heart Syndrome (HLHS) and a Systemic Ventricular Assist Device (SVAD), anticoagulation with direct oral anticoagulants (DOACs) such as rivaroxaban or dabigatran is recommended over standard-of-care anticoagulants to reduce thrombus recurrence and improve outcomes. 1
Anticoagulation Management
Primary Anticoagulation Strategy
- DOACs (rivaroxaban or dabigatran) are preferred over standard-of-care anticoagulants (LMWH, UFH, VKAs, fondaparinux) due to reduced thrombus recurrence rates and improved thrombus resolution 1
- Either rivaroxaban or dabigatran can be used, though individual factors may influence the choice between these agents 1
- When selecting between rivaroxaban and dabigatran, consider that dabigatran has more reported gastrointestinal side effects 1
Special Considerations for HLHS with SVAD
- Patients with HLHS on SVAD are at high risk for thrombotic complications and require vigilant anticoagulation monitoring 2
- For patients with hemodynamic compromise due to thrombosis, thrombolysis followed by anticoagulation should be considered rather than anticoagulation alone 1
- Antithrombin (AT) replacement therapy should be considered in addition to standard anticoagulation if the patient fails to respond clinically to standard anticoagulation and has low AT levels based on age-appropriate reference ranges 1
CVAD Management in HLHS Patients with SVAD
CVAD Retention vs. Removal
- For functioning CVADs with symptomatic CVAD-related thrombosis, maintain the CVAD if venous access is still required 1
- Remove non-functioning or unneeded CVADs in patients with symptomatic CVAD-related thrombosis 1
- For patients requiring CVAD removal, delay removal until after initiation of anticoagulation (typically a few days) to reduce risk of emboli leading to PE or paradoxical stroke 1
Management of Thrombotic Complications
- For worsening signs or symptoms of CVAD-related thrombosis despite anticoagulation, consider CVAD removal if alternative venous access is available 1
- For patients with PE and hemodynamic compromise, thrombolysis followed by anticoagulation is recommended rather than anticoagulation alone 1
- Avoid thrombectomy followed by anticoagulation in favor of anticoagulation alone unless there is cardiovascular compromise secondary to the thrombosis 1
Comprehensive Management Approach
Surgical and Interventional Considerations
- For high-risk HLHS patients with major cardiac risk factors, a hybrid approach (bilateral pulmonary bands, PDA stent placement, and atrial septectomy if needed) combined with SVAD can be considered as a bridge to transplantation 3
- The hybrid approach minimizes comorbidities of HLHS stage I palliation such as small patient size, ventricular dysfunction, and multisystem organ failure 1
- Retrograde aortic arch obstruction with fully open PDA is a contraindication to the hybrid stage I palliation due to potential acute obstruction to coronary flow 1
Monitoring and Follow-up
- Regular assessment for thrombotic complications, including daily neurological assessment for patients with severe symptoms 4
- Monitor for signs of in-stent stenosis of PDA stent or development of retrograde coarctation, which may be heralded by deterioration in right ventricular pressure or increasing tricuspid regurgitation 1
- Close observation for restenosis of the atrial septum is necessary in hybrid-palliated HLHS patients 1
Common Pitfalls and Caveats
- Failing to distinguish between superficial and deep vein thrombosis, which have different management approaches 5
- Inadequate follow-up that might miss progression to more serious thrombosis 5
- Overtreatment with anticoagulation for uncomplicated superficial thrombosis, exposing patients to unnecessary bleeding risk 5
- Immediate removal of thrombosed vascular access without prior anticoagulation, increasing the risk of embolization 6
- Underestimating the risk of thrombotic complications in HLHS patients with SVAD despite therapeutic anticoagulation 2