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Published on: March 21, 2025
Impact of a modified anti-thrombotic guideline on stroke in children supported with a pediatric ventricular assist
David N Rosenthal1, Chacy A Lancaster1, Doff B McElhinney2
1Department of Pediatrics, Stanford University, Palo Alto, California, USA; The Heart Center Clinical and Translational Research Program, The Lucile Packard Children's Hospital, Palo Alto, California, USA.
Insights
A modified anti-thrombotic guideline significantly reduced stroke risk in pediatric patients using the Berlin Heart EXCOR ventricular assist device (VAD). This new approach also lowered bleeding rates, offering a safer VAD therapy.
Area of Science:
- Pediatric cardiology
- Cardiovascular surgery
- Biomedical engineering
Background:
- Stroke is a major complication for pediatric patients requiring the Berlin Heart EXCOR ventricular assist device (VAD).
- Approximately one in three children experience stroke while on this VAD.
- Current anti-thrombotic strategies aim to prevent pump thrombosis but stroke remains a significant risk.
Purpose of the Study:
- To evaluate the effectiveness of a modified anti-thrombotic guideline in reducing stroke incidence in pediatric VAD patients.
- To compare a new guideline with more intense platelet inhibition against older protocols.
- To assess if this modification impacts bleeding rates.
Main Methods:
- Retrospective analysis of pediatric patients implanted with the Berlin Heart EXCOR VAD from 2009-2014.
- Comparison of two cohorts: Edmonton Guideline (EG) using dual anti-platelet therapy (DAPT) titrated to Thromboelastrography/PlateletMapping (TEG/PM), and Stanford Guideline (SG) using triple anti-platelet therapy (TAPT) with high-dose targets.
- Analysis of stroke incidence, bleeding rates, and platelet function.
Main Results:
- The Stanford Modified Guideline (SG) cohort showed an 84% lower stroke incidence rate compared to the Edmonton Guideline (EG) cohort (0.8 vs. 4.9 events per 1,000 days, p=0.031).
- Bleeding rates were also significantly lower in the SG cohort (p=0.015).
- Higher target doses of aspirin, clopidogrel, and dipyridamole were achieved with less variability in the SG cohort, alongside increased arachidonic acid inhibition.
Conclusions:
- A triple anti-platelet regimen with high-dose targets significantly reduces stroke incidence in pediatric VAD patients without increasing bleeding risk.
- This modified anti-thrombotic strategy appears safer and more effective than DAPT titrated to TEG/PM.
- Larger studies are warranted to confirm these promising findings in pediatric VAD therapy.
Background:
Stroke is the most feared complication associated with the Berlin Heart EXCOR pediatric ventricular assist device (VAD), the most commonly used VAD in children, and affects 1 in 3 children. We sought to determine whether a modified anti-thrombotic guideline, involving more intense platelet inhibition and less reliance on platelet function testing, is associated with a lower incidence of stroke.
Methods:
All children supported with the EXCOR at Stanford from 2009 to 2014 were divided into 2 cohorts based on the primary anti-thrombotic guideline used to prevent pump thrombosis: (1) the Edmonton Anti-thrombotic Guideline (EG) cohort, which included children implanted before September 2012 when dual anti-platelet therapy was used with doses titrated to Thromboelastrography/PlateletMapping (TEG/PM); and (2) the Stanford Modified Anti-thrombotic Guideline (SG) cohort, which included children implanted on or after September 2012 when triple anti-platelet therapy was used routinely and where doses were uptitrated to high, weight-based dosing targets, with low-dose steroids administered as needed for inflammation.
Results:
At baseline, the EG (N = 16) and SG (N = 11) cohorts were similar. The incidence rate of stroke in the SG cohort was 84% lower than in the EG cohort (0.8 vs 4.9 events per 1,000 days of support, p = 0.031), and 86% lower than in the previous Investigational Device Exemption trial (p = 0.006). The bleeding rate was also lower in the SG cohort (p = 0.015). Target doses of aspirin, clopidogrel and dipyridamole were higher (all p < 0.003), with less dosing variability in the SG cohort than in the EG cohort. There was no difference in adenosine diphosphate inhibition by TEG/PM, but arachidonic acid inhibition was higher in the SG cohort (median 75% vs 39%, p = 0.008).
Conclusions:
Stroke was significantly less common in pediatric patients supported with the Berlin Heart EXCOR VAD using a triple anti-platelet regimen uptitrated to high, weight-based dosing targets as compared with the dual anti-platelet regimen titrated to PM, and without a higher risk of bleeding. Larger studies are needed to confirm these findings.
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