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Systemic Sirolimus to Prevent In-Stent Stenosis in Pediatric Pulmonary Vein Stenosis
Ryan Callahan1, Jesse J Esch2, Grace Wang2
1Department of Cardiology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Ave, Boston, MA, 02115, USA. ryan.callahan@cardio.chboston.org.
Insights
Systemic sirolimus (rapamycin) effectively slowed in-stent stenosis growth in pediatric pulmonary vein stenosis patients. This treatment was safely administered, showing promise for preventing and managing this complication after stenting.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Pharmacology
Background:
- Intraluminal pulmonary vein stenosis (PVS) often leads to in-stent stenosis (ISS) after stent implantation.
- The efficacy of systemic sirolimus (rapamycin) in preventing ISS in pediatric PVS has not been previously reported.
- High incidence of ISS necessitates effective preventative and therapeutic strategies in pediatric PVS management.
Purpose of the Study:
- To evaluate the efficacy of systemic sirolimus in preventing and managing ISS in pediatric patients with PVS.
- To assess the safety and adverse events associated with systemic sirolimus therapy in this population.
- To compare the growth rate of ISS before and after sirolimus treatment.
Main Methods:
- Retrospective review of pediatric patients treated with systemic sirolimus for ISS in PVS between January 2013 and June 2018.
- Patients received an 8-week course of sirolimus, either for primary prevention at stent implantation or secondary prevention for existing ISS.
- Analysis included stent characteristics, patient demographics, ISS growth rates, and adverse events.
Main Results:
- In the primary prevention group, 85% of stents showed no significant ISS at a median of 102 days, with a growth rate of 7.5%/month.
- In the secondary prevention group, sirolimus therapy significantly slowed ISS growth rate compared to pre-treatment rates (median 3.7%/month vs. 10.4%/month, p < 0.001).
- One patient experienced pneumonia while on sirolimus and another immunosuppressant; no other serious sirolimus-related adverse events were reported.
Conclusions:
- Systemic sirolimus effectively slows the growth rate of in-stent stenosis in pediatric patients with pulmonary vein stenosis.
- Sirolimus therapy demonstrated a favorable safety profile in this cohort of young patients with complex congenital heart disease.
- These findings suggest systemic sirolimus is a viable option for managing ISS in pediatric PVS.
Abstract:
Evaluate the efficacy of systemic sirolimus (rapamycin) in preventing in-stent stenosis (ISS) in pediatric intraluminal pulmonary vein stenosis (PVS). Report the adverse events related to sirolimus therapy. There is a high incidence of ISS following stent implantation in PVS. The use of sirolimus in preventing ISS has not been reported. Retrospective review of all patients who received sirolimus (8 week course) for treatment of ISS for PVS between January 2013 and June 2018. Forty stents (37 bare metal, 3 drug-eluting) in 20 patients were treated with sirolimus; 20 at the time of implantation (primary prevention [1P]) and 20 following documented ISS requiring transcatheter reintervention (secondary prevention [2P]). Treated patients were young (median 2 y/o [0.7-5.7]) and most had PVS associated with congenital heart disease (75%, 15/20; 4/15 with TAPVC). In the 1P group, 85% (17/20) of stents were without significant (< 50%) ISS at median of 102 days (range 56-527); the growth rate of ISS in this group was 7.5 ± 7.1%/month. In the 2P group, most stents had a slower growth rate of ISS after sirolimus therapy compared to pre-treatment (median 3.7 [- 0.2 to 13.1] vs. 10.4 [1.3 to 19.5] %/month; p < 0.001). One patient developed pneumonia on drug while concurrently taking another immunosuppressive agent. No other serious adverse events were related to sirolimus therapy. Systemic sirolimus slows the growth rate of ISS following stent implantation in PVS compared to pre-treatment rates and was administered safely in a small number of pediatric patients with complex heart disease.
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